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Language：Japanese   Publisher：The Japan Society for Precision Engineering  

Although vacuum arc deposition can deposit amorphous carbon (a-C) film at high growth rates, the problem is that it leads numerous droplets than other PVD. Proposed methods for decreasing droplets, such as shield plate and magnetic filter, can actually decrease droplets, however they reduce growth rate. This study focuses on deposition of a-C films by vacuum arc deposition to achieve both higher growth rates and homogeneity of a-C films by decreasing droplets. It is necessary to control the vaporizing process of solid carbon target by improving discharge conditions for both higher growth rates and fewer droplets. Deposition of a-C film with low density of droplets at high growth rates was attempted by optimizing discharge voltage, electric charge and the structure of arc discharge unit. The optimized conditions, such as higher discharge voltages, larger electric charges and shorter distances between cathode spot and anode edge, decreased the number density of droplets per film thickness. The a-C film deposited under the optimized condition had the number density of droplets of 4.2/mm^2・nm at the growth rate of 3.5 nm/count. XPS analysis showed that deposited a-C films had sp^3 ratio of about 80%, therefore its density was estimated to be approximately 3.0g/cm^3.

DOI： 10.2493/jjspe.73.470

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DOI： 10.2493/jjspe.73.573

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Publisher：The Japan Society for Precision Engineering  

A carbon onion layer compounded with gold was formed by dispersing carbon onions on a silicon wafer coated with gold. Its solid lubricant properties were measured in vacuum ball-on-disk type friction test. The carbon onion layer compounded with gold has kept lower-friction coefficient of 0.03 for a longer time than gold layer in a certain range of gold film thicknesses and normal forces. For achieving longer lifetime of the low-friction property, coating a self-assembled monolayer (SAM) on gold thin film were attempted. SAM coating contributed to longer lifetime of the low-friction property, in addition, carbon onion layer on a SAM exhibited the low-friction property under a wide range of normal forces.

DOI： 10.2493/jspe.72.106

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Language：English   Publisher：MYU K K  

This study focuses on the preparation of amorphous carbon films by vacuum arc deposition to achieve both high growth rates and higher homogeneity of amorphous carbon films by decreasing the number of droplets. The deposition of amorphous carbon films having a low density of droplets at high growth rates was attempted by optimizing discharge voltage, electric charge and the structure of the arc discharge unit. The optimized conditions, such as high discharge voltages, large electric charges and short distances between the cathode spot and the anode edge, decreased the number density of droplets per film thickness. Amorphous carbon films deposited under the optimized conditions had a number density of droplets of 4.2/mm(2)/nm at a growth rate of 3.5 nm/count. XPS analysis showed that the deposited amorphous carbon films had an sp(3) ratio of about 80%; therefore, the density of the amorphous carbon film was estimated to be approximately 3.0 g/cm(3).

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This study focuses on the deposition of high-density amorphous carbon films by sputtering enhanced by electron-beam-excited plasma. The energies and densities of argon ions and electrons in plasma were controlled by changing deposition conditions such as target-substrate distance, target bias voltage, operating pressure and discharge voltage to produce an electron beam. As a result, amorphous carbon films with different densities ranging from 1.7 to 3.1 g/cm(3) were synthesized. X-ray photoelectron spectroscopic analysis indicated that the amount of sp(3) carbon bonding was higher in the amorphous carbon film with a density of 3.1 g/cm(3) than in that with a density of 1.7 g/cm(3). Differences in surface profiles were not observed among amorphous carbon films with various densities; however, a friction test revealed that the frictional properties of amorphous carbon films depend on their densities.

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This study focuses on the deposition of higher density a-C films by sputtering enhanced by electron beam excited plasma. Energies and densities of Ar ions and electrons in plasma were controlled by changing the deposition conditions such as target-substrate distance, the target bias voltage, pressure in the chamber and discharge voltage between the cathode and the anode. As a result, a-C films with different densities ranging from 1.7 to 3.1g/cm^3 were synthesized. XPS analysis indicated that the ratio of sp_3 bonding was higher in the a-C film with the density of 3.1g/cm^3 than that of 1.7g/cm^3. The difference of surface profiles was not observed from the a-C films with various densities, however, the friction test revealed that the frictional property of a-C films depends on the density of a-C films.

DOI： 10.2493/jspe.71.1021

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Language：English   Publisher：ELSEVIER SCI LTD  

Tribological properties of carbon onions prepared by heat treatment of diamond clusters or particles are presented. Diamond clusters used as the source material are heated with an infrared radiation furnace to 1730 degreesC in argon at atmospheric pressure. As a result of heating at 1730 degreesC for 1 min, diamond clusters are transformed into carbon onions. High resolution TEM observation is employed to confirm the formation of carbon onions that have near-spherical and multi-layered concentric structure. The particle size of these carbon onions ranges from 5 to 10 nm that corresponds to the original size of the diamond clusters. This preparation technique is also applied to diamond particles less than 0.5 mum in diameter to produce larger carbon onions. Tribological properties of the carbon onions are examined by ball-on-disc type friction testing using a silicon wafer and a steel ball. Carbon onions, which are spread on the silicon wafer without adhesive, exhibit stable friction coefficients lower than 0.1 both in air and in vacuum at room temperature. The wear rates of steel balls sliding on the silicon wafer on which carbon onions are distributed are much lower than wear rates for sliding on a wafer over which graphite powder is spread. Moreover, it is found that the larger carbon onions prepared from diamond particles show low friction property on the rough surface of silicon discs. (C) 2004 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.triboint.2004.07.006

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Sliding friction properties of carbon nanotube coatings catalytically deposited by microwave plasma CVD from a gaseous mixture of methane and hydrogen have been investigated by means of ball-on-disk type friction testing. Carbon nanotubes with different crystallinity were deposited by changing microwave power and bias voltage applied to a silicon substrate. Nickel was used as a catalyst and coated on the substrate by DC sputtering before deposition. SEM and Raman spectroscopy were employed to examine carbon nanotubes. In friction testing, a steel ball slid on the substrate coated with carbon nanotubes or covered with vapor grown carbon fibers used as a reference carbon material. Friction force was measured in air containing water vapor and a vacuum. Consequently, friction was reduced when carbon nanotube coatings are less defective and, in particular, in a water-free atmosphere such as a vacuum. Furthermore, the improvement of adhesion of carbon nanotube coatings on cemented carbide and silicon nitride substrates has led to lower friction coefficients, below 0.1, depending on the density of the carbon nanotubes that remain on the sliding surfaces. (C) 2004 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.triboint.2004.07.005

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Language：English   Publisher：ELSEVIER SCIENCE SA  

Electron field emission from chemically vapor deposited polycrystalline diamond, nanocrystalline diamond, and glassy carbon coatings are reported. Effects of hydrogen-rich or oxygen-containing CVD precursors on electron field emission from CVD carbon coatings are presented. Surface conductivity and negative electron affinity resulting from hydrogen termination of crystalline diamond were found to promote electron field emission for discrete diamond particles and non-continuous diamond films but not for high quality and continuous diamond films as well as nanocrystalline diamond and glassy carbon coatings containing conductive graphitic carbon. Graphitic carbon in nanocrystalline diamond coatings and glassy carbon coatings provided additional conduction paths for electrons and allowed more effective injection of electrons into electron emitters. Nanocrystalline diamond coatings deposited by methanol/ethanol plasmas contained more graphitic carbon than that deposited by hydrogen/methane plasmas resulting in lower turn-on electric field and higher electron field emission current. Glassy carbon coatings deposited by both processes exhibited excellent electron emission characteristics. Low turn-on electric field, i.e., 1 V/mum, for electron field emission was achieved for diamond and glassy carbon coatings deposited under optimized conditions. Among these three classes of carbon coatings, glassy carbon deposited at elevated substrate temperatures were found to exhibit the best electron field emission properties. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0925-9635(02)00356-4

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DOI： 10.11522/pscjspe.2003S.0.153.0

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Language：Japanese   Publisher：The Japan Society for Precision Engineering  

Carbon onions were synthesized by heat treatment of diamond clusters or sub-micron particles that are less than 0.5μm in diameter. X-ray diffraction and transmission electron microscopy were employed to evaluate microstructure of the carbon onions. Solid lubricant properties of the carbon onions were measured by ball-on-disk type friction testing using silicon wafers and steel balls in air and vacuum. The heat treatment up to 1730℃ in argon ambient at atmospheric pressure results in synthesis of carbon onions in various particle sizes which correspond to original diamond particles. The carbon onions with fewer defects. which have been obtained from smaller diamond particles, have shown lower friction and wear-resistant properties both air vacuum. These superior tribological properties have been exhibited in humid ambient on smooth surface of which roughness is less than the particle size of carbon onions.

DOI： 10.2493/jjspe.69.683

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DOI： 10.11522/pscjspe.2003S.0.142.0

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Milligrams of onion-1ike fullerenes, so-called carbon onions, have been synthesized by heating diamond clusters in inert ambient at atmospheric pressure. Diamond clusters, of which average grain size is 5 nm, were heated up to 1730℃ and maintained at the temperature for 1 minute in argon using an infrared image furnace. Transformation of diamond clusters into onion-like fullerenes was confirmed by high-resolution electron microscopy, which showed onion-like fullerenes have a well-controlled size ranging from 5 to 10 nm. Ball-on-disk type friction testing was conducted to characterize the tribological properties of onion-like fullerenes as a solid lubricant. As a result onion-1ike fullerenes have exhibited lower friction, compared with graphite powders, in both air and vacuum. This low friction property of onion-like fullerenes has been displayed on a sliding disk with lower surface roughness and higher hardness.

DOI： 10.2493/jjspe.67.1175

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High quality diamond films have been synthesized on substrates of high-temperature high-pressure synthesized diamond by means of arc discharge plasma jet chemical vapor deposition. Diamond films have been deposited on diamond substrate at high growth rates up to approximately 130μm/h when methane concentration was 3%. Properties of the diamond films were determined by optical microscopy. SEM, Raman spectroscopy, X-ray diffraction analysis and FT-IR. Diamond films synthesized at methane concentration of 3% have homoepitaxially grown on diamond substrates and have shown superior crystallinity similar to type IIa natural diamond Nitrogen contaminant in the diamond films was less than in diamond substrates. Moreover, quality of diamond films has been improved by pre-treatment of the surface of diamond substrates. As a result hydrogen plasma treatment of substrate surface has led to fewer defects in diamond films as compared with ion beam irradiation and thermochemical polishing using a hot iron plate.

DOI： 10.2493/jjspe.67.2032

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A new type of deposition process, ion beam sputtering enhanced by electron beam excited plasma, was proposed in order to deposit hydrogen-free and sp^3 bonding rich diamond-like carbon (DLC) films. In the process, single carbon ions and atoms are generated by ion beam sputtering, and the single atoms are ionized by collision with an electron beam. The results of enhancement by electron beam excited plasma are as follows. Firstly, growth rates of DLC film increase. Secondly, continuous and smooth DLC films are deposited without droplets. Thirdly, Raman spectroscopy of DLC films infers the change of film structure to higher sp^3 bonding content. Fourthly, DLC films are infrared transparent at the wavelength of 2.5-25 μm, and finally, the friction coefficient between a steel ball and a doped silicon wafer decreases by coating DLC film.

DOI： 10.2493/jjspe.66.1621

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Electron field emission properties of single crystal diamond particles have been investigated in order to lead higher emission current and to discuss the mechanism of electron emission. Emission current was measured by applying voltage between diamond particles and a glass plate anode coated with ITO thin film. Diamond particles were treated in plasma and by heat before measurement and placed in various arrangement manner on a metal substrate with conductive glue. As a result, higher emission current has been occurred from diamond particles treated with hydrogen plasma, that is supposed to form conductive layer on diamond surface. Moreover, direction of a tip of diamond particles towards the anode has led higher emission current. The emission current has increased with the number of diamond particles arranged and varied with the distance between diamond particles and the anode.

DOI： 10.2493/jjspe.66.709

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This paper describes the cutting performance of diamond coated cutting tool prepared with cobaltless tungsten carbide (WC) sintered by spark sintering. The mechanical strength of cobaltless WC cutting tools has been confirmed by turning gray cast iron (FC250). In order to prepare diamond coated cutting tool, diamond film was deposited on the cobaltless WC by microwave plasma CVD and hot filament CVD. The performance of the diamond coated tool has been evaluated by turning Al-18% Si alloy. As the result, it is found that the diamond coated tool which leads strong adhesion to diamond film can be produced by using cobaltless WC of which sintering density ratio is 70-90% and thickness of coated diamond film is approximately 20 μm.

DOI： 10.2493/jjspe.65.1507

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This paper describes the cutting performance of diamond coated cutting tool prepared with cobaltless tungsten carbide (WC) sintered by spark sintering. The mechanical strength of cobaltless WC cutting tools has been confirmed by turning gray cast iron (FC250). In order to prepare diamond coated cutting tool, diamond film was deposited on the cobaltless WC by microwave plasma CVD and hot filament CVD. The performance of the diamond coated tool has been evaluated by turning Al-18% Si alloy. As the result, it is found that the diamond coated tool which leads strong adhesion to diamond film can be produced by using cobaltless WC of which sintering density ratio is 70-90% and thickness of coated diamond film is approximately 20 μm.

DOI： 10.2493/jjspe.65.1507

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A magnetic field has a variety of influence on plasma and so can be applied to plasma chemical vapor deposition (CVD) to control the state of the plasma. However, the magnetic fields utilized for conventional plasma CVD are limited to less than approximately 0.2 T. In this study, superconducting magnet assisted hollow cathode plasma CVD apparatus has been developed to investigate the influence of stronger magnetic fields of up to 1.0 T on the film preparation using plasma. The characteristics of DC discharge were examined under magnetic fields of up to 1.0 T, and synthesis of carbon films was carried out with methane and hydrogen gases. The results obtained are as follows: the substrate temperature rises with increasing magnetic flux density applied to the plasma; diamond has been synthesized at a methane concentration of 1.5% when the magnetic field of 1.0 T is applied to a plasma at a substrate temperature of 650 degrees C and pressure of 2.67 kPa, while no deposits have been obtained without a magnetic field. (C) 1998 Elsevier Science S.A.

DOI： 10.1016/S0925-9635(97)00217-3

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WC with different sintering density ratio has been sintered without binder by spark sintering process High-quality diamond film, which has higher nucleation density and smaller crystals compared to that on WC-Co, has been deposited on this WC substrate by micro-wave enhanced plasma CVD method The result of a comparison study convinces that the adhesion strength of diamond films on this cobaltless sintered WC is remarkably superior to that on WC-Co, which is believed to be improved as a result of the increasing diamond nucleation densitv. the enhanced bond between the substrate and the diamond film, and the improved match of thermal expansion coefficients caused by the absence of the fatal obstacle of cobalt. Moreover. the indentation test has been proved that lower sintering density of this sintered WC may result in an increased adhesion strength.

DOI： 10.2493/jjspe.64.147

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DOI： 10.1016/S0925-9635(98)00242-8

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Language：Japanese   Publisher：The Japan Society for Precision Engineering  

The master-slave manipulator for surgical operation has been developed as an application of teleoperation. In this research, the master manipulator's positioning ability with PID controller has been estimated same as the slave one, the controller for bilateral manipulation has been designed for the intention of teleoperation system, and another controller instead of PID has been designed to improve the positioning ability. The bilateral controller is based on impedance control, and the controller for the improvement is based on type 1 digital optical control. As a result, it proved that the follow ability between master and slave with combination of impedance and optical controller is better than with that of impedance and PID. Moreover, force sensor is effective for manipulability in cutting motion. However, the vibration is generated in touching rigid body.

DOI： 10.2493/jjspe.64.685

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This paper describes the mechanical strength of the cobaltless sintered WC which is suitable for the substrate of diamondcoated tool. Cobaltless WC is sintered under different sintering conditions by Spark Sintering. Then, its mechanical characters are evaluated by Rockwell hardness on the A scale and the bending strength. As a result, by selecting the proper sintering condition, the particle size is 1.O - 1.4 μ m, sintering temperature is 1800 - 1900℃, sintering pressure is 50 MPa and sintering time is 600 s, the hardness of the cobaltless sintered WC is improved to 98 (HRA), and the bending strength is improved to 1.3 GPa.

DOI： 10.2493/jjspe.64.1811

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Language：Japanese   Publisher：The Japan Society for Precision Engineering  

This paper describes the mechanical strength of the cobaltless sintered WC which is suitable for the substrate of diamondcoated tool. Cobaltless WC is sintered under different sintering conditions by Spark Sintering. Then, its mechanical characters are evaluated by Rockwell hardness on the A scale and the bending strength. As a result, by selecting the proper sintering condition, the particle size is 1.O - 1.4 μ m, sintering temperature is 1800 - 1900℃, sintering pressure is 50 MPa and sintering time is 600 s, the hardness of the cobaltless sintered WC is improved to 98 (HRA), and the bending strength is improved to 1.3 GPa.

DOI： 10.2493/jjspe.64.1811

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DOI： 10.1016/S0925-9635(98)00242-8

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Language：Japanese   Publisher：The Japan Society for Precision Engineering  

The master-slave manipulator for surgical operation has been developed as an application of teleoperation. In this research, the master manipulator's positioning ability with PID controller has been estimated same as the slave one, the controller for bilateral manipulation has been designed for the intention of teleoperation system, and another controller instead of PID has been designed to improve the positioning ability. The bilateral controller is based on impedance control, and the controller for the improvement is based on type 1 digital optical control. As a result, it proved that the follow ability between master and slave with combination of impedance and optical controller is better than with that of impedance and PID. Moreover, force sensor is effective for manipulability in cutting motion. However, the vibration is generated in touching rigid body.

DOI： 10.2493/jjspe.64.685

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Other Link： https://jlc.jst.go.jp/DN/JALC/00053007537?from=CiNii

Language：Japanese   Publisher：The Japan Society for Precision Engineering  

WC with different sintering density ratio has been sintered without binder by spark sintering process High-quality diamond film, which has higher nucleation density and smaller crystals compared to that on WC-Co, has been deposited on this WC substrate by micro-wave enhanced plasma CVD method The result of a comparison study convinces that the adhesion strength of diamond films on this cobaltless sintered WC is remarkably superior to that on WC-Co, which is believed to be improved as a result of the increasing diamond nucleation densitv. the enhanced bond between the substrate and the diamond film, and the improved match of thermal expansion coefficients caused by the absence of the fatal obstacle of cobalt. Moreover. the indentation test has been proved that lower sintering density of this sintered WC may result in an increased adhesion strength.

DOI： 10.2493/jjspe.64.147

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DOI： 10.2493/jjspe.63.101

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In this paper, the mechanical strengths of free-standing CVD diamond thin plates have been investigated. The strengths of CVD diamond thin plates synthesized by arc discharge plasma jet CVD, RF plasma CVD and DC plasma CVD have been measured by three-point bending testing. Test pieces have been formed at dimensions of 10×3× (0.2-0.6) mm by cutting with YAG laser irradiation after polishing using a diamond wheel.The load was applied over the span of 8 mm. The bending strengths of CVD diamonds prepared by arc discharge plasma jet CVD, RF plasma CVD and DC plasma CVD are 0.5-0.8, 0.3-0.8 and 0.8-1.5 GPa, respectively. It is found that higher bending strengths occur to CVD diamond thin plates consist of smaller grains. The CVD diamond thin plates formed with grains of approximately 50 μm showed the bending strengths comparable to commercial sintered diamond at the average grain size of 25 μm.

DOI： 10.2493/jjspe.63.1054

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In this paper, the application of grinding to process ceramic micro parts has been discussed. A compact size NC grinding machine was developed using a spindle electrically driven up to 40000 rpm and stages move every 1 rim pitch. Electroplated grinding wheels of 1.5 and 10 mm in diameter are prepared with diamond abrasives of #120, #325 and #800. The specifications of a grinding wheel and the grinding conditions to minimize grinding force and surface roughness of workpieces have been examined. As a result. when the #800 grinding wheel of 5 mm in diameter has been used. 2 mm long micro poles of alumina, silicon nitride and zirconia. of which diameters are 60 μm. 150 μm and 25 μm respectively. and 2 mm long micro shoulder pole and quadrilateral pole of zirconia have been obtained.

DOI： 10.2493/jjspe.63.884

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In this paper, the mechanical strengths of free-standing CVD diamond thin plates have been investigated. The strengths of CVD diamond thin plates synthesized by arc discharge plasma jet CVD, RF plasma CVD and DC plasma CVD have been measured by three-point bending testing. Test pieces have been formed at dimensions of 10×3× (0.2-0.6) mm by cutting with YAG laser irradiation after polishing using a diamond wheel.The load was applied over the span of 8 mm. The bending strengths of CVD diamonds prepared by arc discharge plasma jet CVD, RF plasma CVD and DC plasma CVD are 0.5-0.8, 0.3-0.8 and 0.8-1.5 GPa, respectively. It is found that higher bending strengths occur to CVD diamond thin plates consist of smaller grains. The CVD diamond thin plates formed with grains of approximately 50 μm showed the bending strengths comparable to commercial sintered diamond at the average grain size of 25 μm.

DOI： 10.2493/jjspe.63.1054

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In this paper, the application of grinding to process ceramic micro parts has been discussed. A compact size NC grinding machine was developed using a spindle electrically driven up to 40000 rpm and stages move every 1 rim pitch. Electroplated grinding wheels of 1.5 and 10 mm in diameter are prepared with diamond abrasives of #120, #325 and #800. The specifications of a grinding wheel and the grinding conditions to minimize grinding force and surface roughness of workpieces have been examined. As a result. when the #800 grinding wheel of 5 mm in diameter has been used. 2 mm long micro poles of alumina, silicon nitride and zirconia. of which diameters are 60 μm. 150 μm and 25 μm respectively. and 2 mm long micro shoulder pole and quadrilateral pole of zirconia have been obtained.

DOI： 10.2493/jjspe.63.884

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Diamond films have been synthesized on substrates rotated up to 2000 rpm by arc discharge plasma jet chemical vapor deposition to determine the effects of plasma flow on the growth of diamond Flow field of a plasma jet has been numerically simulated and variations of the flow speeds of plasma above a substrate has been predicted when a substrate is rotated about the axis of a plasma jet Axial and radial components of the velocity of plasma increase and the temperature of plasma that reaches to a substrate becomes higher by rotating a substrate. Growth rate and grain size of diamond tend to increase at higher rotational speeds of a substrate without morphology change, and quality and thickness variations are improved Moreover, the area where homogeneous diamond films in quality, thickness and surface roughness are deposited has been enlarged by shifting the rotational axis of a substrate from the axis of a plasma jet.

DOI： 10.2493/jjspe.62.671

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The deposition of diamond films by conventional arc discharge plasma jet CVD is limited to control in terms of dimensions and quality. An arc discharge plasma jet CVD apparatus that utilizes a plasma jet regulated its properties by a magnetic field has been designed and developed in order to synthesize homogeneous diamond films in thickness and quality. As a result of the assistance of a magnetic field, the diameter of a plasma jet increases and the distribution of substrate temperature is improved, and uniformity of thickness, grain size and orientation of crystal faces of diamond films occurs when the magnetic flux density of above 1.6 × 10 ^-2 T is applied.

DOI： 10.2493/jjspe.62.544

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The deposition of diamond films by conventional arc discharge plasma jet CVD is limited to control in terms of dimensions and quality. An arc discharge plasma jet CVD apparatus that utilizes a plasma jet regulated its properties by a magnetic field has been designed and developed in order to synthesize homogeneous diamond films in thickness and quality. As a result of the assistance of a magnetic field, the diameter of a plasma jet increases and the distribution of substrate temperature is improved, and uniformity of thickness, grain size and orientation of crystal faces of diamond films occurs when the magnetic flux density of above 1.6 × 10 ^-2 T is applied.

DOI： 10.2493/jjspe.62.544

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A magnetic field has a variety of influence on plasma so that it is applied to plasma CVD to control the state of plasma. However, the magnetic fields that have been utilized by conventional plasma CVD are limited to that of smaller than approximately 0.2T. In this study, the superconducting magnet assisted hollow cathode plasma CVD apparatus has been developed to discuss the influence of a high magnetic field of 1T on the plasma for film preparation. The characteristics of discharge were examined under magnetic fields of up to 1T, and synthesis of carbon films was carried out with methane and hydrogen gases. The results obtained are as follows : The substrate temperature rises with increasing a magnetic field that is applied to plasma; Diamond is synthesized at methane concentration of 1.5% when high magnetic field of 1T is applied to plasma.

DOI： 10.2493/jjspe.62.1757

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Deposition conditions and growth of CVD diamond thin plate that has high optical transparency have been studied. Transparent CVD diamond thin plates have been deposited at lower methane concentration of 0.6% independent of the difference of nucleation using arc discharge plasma jet CVD. The relation between the structural properties and optical performance of CVD diamond has been discussed by observation of its cross sectional structure. The cross sectional structure of CVD diamond thin plates was exposed by the techniques of the polishing and etching using a hot iron plate and hydrogen plasma, respectively. As a result, transparent CVD diamond plates grow in well-arranged way with less defects and impurities.

DOI： 10.2493/jjspe.62.1479

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This paper describes the affected layer of a polished diamond. Hydrogen plasma etching, expected mild etching reaction, is proposed to estimate the layer. This method was applied to a single crystal diamond whose (001) surface was polished in the direction of (100) by vitrified bonded diamond grinding wheels of #400 or #1500. By both of these grinding wheels, polished surfaces were observed smooth. Once the surfaces were etched, V-shape cracks appeared in a line and the average crack length are 14pim and 61.tm, respectively. Further, (001) surface was polished to (110) direction, different from V-shape cracks, and bar-shape cracks perpendicular in the polishing direction appeared. The results obtained are as follows; (1) Hydrogen plasma etching is available to estimate the affected layer of diamond. (2) Affected layer exists under the mechanically polished diamond surface. (3) Shape and dimension of affected layer depend on both polishing direction and grain size.

DOI： 10.2493/jjspe.62.1167

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Language：Japanese   Publisher：The Japan Society for Precision Engineering  

A magnetic field has a variety of influence on plasma so that it is applied to plasma CVD to control the state of plasma. However, the magnetic fields that have been utilized by conventional plasma CVD are limited to that of smaller than approximately 0.2T. In this study, the superconducting magnet assisted hollow cathode plasma CVD apparatus has been developed to discuss the influence of a high magnetic field of 1T on the plasma for film preparation. The characteristics of discharge were examined under magnetic fields of up to 1T, and synthesis of carbon films was carried out with methane and hydrogen gases. The results obtained are as follows : The substrate temperature rises with increasing a magnetic field that is applied to plasma; Diamond is synthesized at methane concentration of 1.5% when high magnetic field of 1T is applied to plasma.

DOI： 10.2493/jjspe.62.1757

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Other Link： https://jlc.jst.go.jp/DN/JALC/00043442669?from=CiNii

Language：Japanese   Publisher：The Japan Society for Precision Engineering  

Deposition conditions and growth of CVD diamond thin plate that has high optical transparency have been studied. Transparent CVD diamond thin plates have been deposited at lower methane concentration of 0.6% independent of the difference of nucleation using arc discharge plasma jet CVD. The relation between the structural properties and optical performance of CVD diamond has been discussed by observation of its cross sectional structure. The cross sectional structure of CVD diamond thin plates was exposed by the techniques of the polishing and etching using a hot iron plate and hydrogen plasma, respectively. As a result, transparent CVD diamond plates grow in well-arranged way with less defects and impurities.

DOI： 10.2493/jjspe.62.1479

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Other Link： https://jlc.jst.go.jp/DN/JALC/00042272915?from=CiNii

Language：Japanese   Publisher：The Japan Society for Precision Engineering  

This paper describes the affected layer of a polished diamond. Hydrogen plasma etching, expected mild etching reaction, is proposed to estimate the layer. This method was applied to a single crystal diamond whose (001) surface was polished in the direction of (100) by vitrified bonded diamond grinding wheels of #400 or #1500. By both of these grinding wheels, polished surfaces were observed smooth. Once the surfaces were etched, V-shape cracks appeared in a line and the average crack length are 14pim and 61.tm, respectively. Further, (001) surface was polished to (110) direction, different from V-shape cracks, and bar-shape cracks perpendicular in the polishing direction appeared. The results obtained are as follows; (1) Hydrogen plasma etching is available to estimate the affected layer of diamond. (2) Affected layer exists under the mechanically polished diamond surface. (3) Shape and dimension of affected layer depend on both polishing direction and grain size.

DOI： 10.2493/jjspe.62.1167

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Other Link： https://jlc.jst.go.jp/DN/JALC/00041479926?from=CiNii

Language：Japanese   Publisher：The Japan Society for Precision Engineering  

Diamond films have been synthesized on substrates rotated up to 2000 rpm by arc discharge plasma jet chemical vapor deposition to determine the effects of plasma flow on the growth of diamond Flow field of a plasma jet has been numerically simulated and variations of the flow speeds of plasma above a substrate has been predicted when a substrate is rotated about the axis of a plasma jet Axial and radial components of the velocity of plasma increase and the temperature of plasma that reaches to a substrate becomes higher by rotating a substrate. Growth rate and grain size of diamond tend to increase at higher rotational speeds of a substrate without morphology change, and quality and thickness variations are improved Moreover, the area where homogeneous diamond films in quality, thickness and surface roughness are deposited has been enlarged by shifting the rotational axis of a substrate from the axis of a plasma jet.

DOI： 10.2493/jjspe.62.671

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Other Link： https://jlc.jst.go.jp/DN/JALC/00039544056?from=CiNii

Language：Japanese   Publisher：The Japan Society for Precision Engineering  

DOI： 10.2493/jjspe.62.1788

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Language：English   Publisher：ELSEVIER SCIENCE SA  

The setup and deposition conditions of electrode arrangement and pressure have been studied to synthesize diamond films at high growth rate on wide area efficiently by are discharge plasma jet chemical vapor deposition. An apparatus has been used in which four plasma torches, one is used for cathode and the others for divided anodes, are arranged and the positions of these torches are changeable. Growth rate, deposition area and thickness of diamond films have increased with changing the electrode arrangements without improvement of thickness variation. Maximum growth rate of our apparatus has occurred at the pressure of 6.7 kPa and diamond films that have less variations of quality and surface roughness have been synthesized at lower pressure during deposition. Moreover, a high conversion rate, which is the ratio of carbon atoms that form diamond in supplied methane gas, of 16% has been obtained at the pressure of 6.7 kPa and methane concentration of 2%.

DOI： 10.1016/0925-9635(95)00324-X

Web of Science

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Language：Japanese   Publisher：The Japan Society for Precision Engineering  

In order to smooth the surface roughness of CVD diamond films, ArF excimer laser at the wavelength of 193 nm was directed onto the diamond films varying energy density, pulse repetition, atmosphere and irradiation angle The difference between processing of CVD diamond by excimer laser and that of YAG laser has been discussed by investigating the minimum smoothed surface roughness and processing mechanism. As the result of smoothing by excimer laser irradiation at 80° from the normal, the surface roughness of diamond films synthesized by arc discharge plasma jet CVD and microwave plasma CVD are reduced at 2OμmRmax and 0.3μmRmax, respectively; that are smaller than the surface roughness obtained by YAG laser irradiation. Moreover, it is found that excimer laser processing of diamond films partly proceeds with breaking the bonds among carbon atoms because the temperature rising of the diamond films in excimer laser processing is much less than in YAG laser processing

DOI： 10.2493/jjspe.61.406

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Other Link： https://jlc.jst.go.jp/DN/JALC/00031909242?from=CiNii

Language：Japanese   Publisher：The Japan Society for Precision Engineering  

In order to synthesize films at low substrate temperature, an apparatus using Penning ion source has been developed and the performance of this apparatus has been discussed. A superconducting magnet has been used to produce magnetic field of up to 7 T, that is impressed on glow discharge. As a result, this newly type of a CVD apparatus can generate stable glow discharge at the pressure of 1 Pa when magnetic field of 1 T affects. Moreover, diamond-like carbon (DLC) films have been synthesized using methane and hydrogen gases, it is found that the apparatus has the possibilities of low temperature synthesis of films.

DOI： 10.2493/jjspe.61.687

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Other Link： https://jlc.jst.go.jp/DN/JALC/00033029979?from=CiNii

Language：Japanese   Publisher：The Japan Society for Precision Engineering  

In order to smooth the surface roughness of CVD diamond films, ArF excimer laser at the wavelength of 193 nm was directed onto the diamond films varying energy density, pulse repetition, atmosphere and irradiation angle The difference between processing of CVD diamond by excimer laser and that of YAG laser has been discussed by investigating the minimum smoothed surface roughness and processing mechanism. As the result of smoothing by excimer laser irradiation at 80° from the normal, the surface roughness of diamond films synthesized by arc discharge plasma jet CVD and microwave plasma CVD are reduced at 2OμmRmax and 0.3μmRmax, respectively; that are smaller than the surface roughness obtained by YAG laser irradiation. Moreover, it is found that excimer laser processing of diamond films partly proceeds with breaking the bonds among carbon atoms because the temperature rising of the diamond films in excimer laser processing is much less than in YAG laser processing

DOI： 10.2493/jjspe.61.406

CiNii Books

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Other Link： https://jlc.jst.go.jp/DN/JALC/00031909242?from=CiNii

Language：Japanese   Publisher：The Japan Society for Precision Engineering  

In order to synthesize films at low substrate temperature, an apparatus using Penning ion source has been developed and the performance of this apparatus has been discussed. A superconducting magnet has been used to produce magnetic field of up to 7 T, that is impressed on glow discharge. As a result, this newly type of a CVD apparatus can generate stable glow discharge at the pressure of 1 Pa when magnetic field of 1 T affects. Moreover, diamond-like carbon (DLC) films have been synthesized using methane and hydrogen gases, it is found that the apparatus has the possibilities of low temperature synthesis of films.

DOI： 10.2493/jjspe.61.687

CiNii Books

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Other Link： https://jlc.jst.go.jp/DN/JALC/00033029979?from=CiNii

Language：Japanese   Publisher：The Japan Society for Precision Engineering  

The effects of electrodes arrangement of the arc discharge plasma jet CVD apparatus on the growth rate and the shape of diamond films have been investigated. Moreover, the state of plasma has been estimated by emission spectrochemical analysis. An arc discharge plasma jet CVD apparatus which has a cathode and three anodes has been used to generate a plasma consists of methane, hydrogen and argon gases. As a result, the growth rate, the deposition area and the thickness of diamond films have increased with increasing the discharge distance in the radial direction of the plasma jet. However, diamond films have been thicker at the center independent of the electrodes arrangement.

DOI： 10.2493/jjspe.60.591

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Other Link： https://jlc.jst.go.jp/DN/JALC/00025941067?from=CiNii

Language：Japanese   Publisher：The Japan Society for Precision Engineering  

This paper experimentally discusses the effects of process pressure on diamond preparation by arc discharge plasma jet chemical vapor deposition (CVD) such as growth rate, deposition area, thickness and quality variations, and conversion rate. The growth rate of diamond depends on the process pressure and the maximum growth rate occurs at about 6.7 kPa when diamond has deposited by one-cathode three-anode arc discharge plasma jet CVD apparatus. Deposition at lower process pressure is effective for synthesizing of diamond films that have less variations of thickness and quality on larger area, however, the growth rate of diamond tends to decrease. Moreover, extremely high conversion rate (Diamond / Carbon in methane gas) of 16% has been obtained at methane concentration of 2% when diamond has been synthesized at process pressure of 6.7 kPa.

DOI： 10.2493/jjspe.60.1480

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Other Link： https://jlc.jst.go.jp/DN/JALC/00028896562?from=CiNii

Language：Japanese   Publisher：The Japan Society for Precision Engineering  

The effects of electrodes arrangement of the arc discharge plasma jet CVD apparatus on the growth rate and the shape of diamond films have been investigated. Moreover, the state of plasma has been estimated by emission spectrochemical analysis. An arc discharge plasma jet CVD apparatus which has a cathode and three anodes has been used to generate a plasma consists of methane, hydrogen and argon gases. As a result, the growth rate, the deposition area and the thickness of diamond films have increased with increasing the discharge distance in the radial direction of the plasma jet. However, diamond films have been thicker at the center independent of the electrodes arrangement.

DOI： 10.2493/jjspe.60.591

CiNii Books

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Other Link： https://jlc.jst.go.jp/DN/JALC/00025941067?from=CiNii

Language：Japanese   Publisher：The Japan Society for Precision Engineering  

This paper experimentally discusses the effects of process pressure on diamond preparation by arc discharge plasma jet chemical vapor deposition (CVD) such as growth rate, deposition area, thickness and quality variations, and conversion rate. The growth rate of diamond depends on the process pressure and the maximum growth rate occurs at about 6.7 kPa when diamond has deposited by one-cathode three-anode arc discharge plasma jet CVD apparatus. Deposition at lower process pressure is effective for synthesizing of diamond films that have less variations of thickness and quality on larger area, however, the growth rate of diamond tends to decrease. Moreover, extremely high conversion rate (Diamond / Carbon in methane gas) of 16% has been obtained at methane concentration of 2% when diamond has been synthesized at process pressure of 6.7 kPa.

DOI： 10.2493/jjspe.60.1480

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DOI： 10.1016/0925-9635(93)90148-U

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Language：Japanese   Publisher：The Japan Society for Precision Engineering  

In order to enlarge the diamond deposition area by arc discharge plasma CVD method, a new type of arc discharge plasma jet CVD apparatus has been developed. This apparatus has one cathode torch and three anode torches. The cathode torch is arranged perpendicularly to each of three anode torches that are arranged in axial symmetry. These torches can be moved along their own axes, so that the discharge area where the plasma jet generates can be changed. As a result, the diameter of the plasma jet has been increased by changing of the arrangement of the plasma torches and the diamond deposition area has been enlarged to 42mm diameter with the expansion of the area that the plasma jet sprays on.

DOI： 10.2493/jjspe.59.838

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Other Link： https://jlc.jst.go.jp/DN/JALC/00020752033?from=CiNii

DOI： 10.1016/0925-9635(93)90148-U

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Language：Japanese   Publisher：The Japan Society for Precision Engineering  

In order to enlarge the diamond deposition area by arc discharge plasma CVD method, a new type of arc discharge plasma jet CVD apparatus has been developed. This apparatus has one cathode torch and three anode torches. The cathode torch is arranged perpendicularly to each of three anode torches that are arranged in axial symmetry. These torches can be moved along their own axes, so that the discharge area where the plasma jet generates can be changed. As a result, the diameter of the plasma jet has been increased by changing of the arrangement of the plasma torches and the diamond deposition area has been enlarged to 42mm diameter with the expansion of the area that the plasma jet sprays on.

DOI： 10.2493/jjspe.59.838

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Language：English   Publisher：ELSEVIER SCIENCE SA LAUSANNE  

In this paper, smoothing of chemically vapour deposited diamond films by ion beam irradiation is described. Diamond films were synthesized by arc discharge plasma jet chemical vapour deposition (CVD) and microwave plasma CVD. Argon and oxygen gases are used as an ionized gas. As a result, by setting the incident angle at 0-degrees and 80-degrees , smooth surfaces of microwave plasma CVD diamond films were obtained. The peak-to-valley (p-v) surface roughness is reduced from 3-mu-m to 0.5-mu-m at 80-degrees. In addition, we discuss the smoothing mechanism of diamond films and describe it using a simple model.

DOI： 10.1016/0040-6090(92)90498-Z

Web of Science

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Language：Japanese   Publisher：The Japan Society for Precision Engineering  

In this paper, smoothing of CVD diamond films by ion beam irradiation has been described. Diamond films are synthesized by arc discharge plasma jet CVD and microwave plasma CVD. Argon and oxygen gases are used as an ionized gas. As a result, by setting up an incident angle at 0° and 80°, smooth surfaces of diamond films have been obtained. When an ion beam is irradiated to microwave plasma CVD diamond films at 80°, the surface roughness is reduced from 3 μmRmax to 0.5 μmRmax. Moreover, the mechanism of smoothing process of diamond films has been considered and described as a simple model.

DOI： 10.2493/jjspe.58.289

CiNii Books

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Other Link： https://jlc.jst.go.jp/DN/JALC/00013489038?from=CiNii

Language：Japanese   Publisher：The Japan Society for Precision Engineering  

In this paper, smoothing of CVD diamond films by ion beam irradiation has been described. Diamond films are synthesized by arc discharge plasma jet CVD and microwave plasma CVD. Argon and oxygen gases are used as an ionized gas. As a result, by setting up an incident angle at 0° and 80°, smooth surfaces of diamond films have been obtained. When an ion beam is irradiated to microwave plasma CVD diamond films at 80°, the surface roughness is reduced from 3 μmRmax to 0.5 μmRmax. Moreover, the mechanism of smoothing process of diamond films has been considered and described as a simple model.

DOI： 10.2493/jjspe.58.289

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