Browsing by Author "LIN, TS"

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AN EFFICIENT SEMI-EMPIRICAL MODEL OF THE IV CHARACTERISTICS FOR LDD MOSFETS
(1989-09-01)
CHUNG, SSS
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LIN, TS
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CHEN, YG
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
DIAMOND FILM GROWTH ON CEMENTED TUNGSTEN CARBIDES STUDIED BY SEM, AES AND XPS
(1992-11-23)
CHEN, JL
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HUANG, TH
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PAN, FM
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KUO, CT
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CHANG, CS
Diamond films were deposited on cemented WC substrates using a hot filament chemical vapor deposition (CVD) system with a mixture of CH4 and H-2 as the source gases. The effect of the surface pretreatments of scratching the surface and etching to remove the surface Co from the substrate on diamond nucleation and growth was studied. The effect of CH4 Concentration on diamond growth was also examined. Scanning electron microscopy, Auger electron, X-ray photoelectron and energy dispersive spectroscopies were used to examine the film morphology, quality and compositions. The results show that a good diamond-crystal quality can be obtained by reducing the surface Co content in the substrate to below 1%. Co in the surface layer of the substrate inhibits both diamond nucleation and growth. Polishing and etching treatments to scratch the surface and to remove the surface Co of the substrates are essential to maintain the surface roughness in an appropriate range to obtain diamond films with a good quality and adhesion. A change in CH4 Concentration in the source gases from 0.5 to 0.15% can change the preferred orientation of the diamond films fro m the {100} to the {111} plane.
THE ROLE OF CEMENTED WC SUBSTRATE MORPHOLOGY ON THE DIAMOND FILM GROWTH AND CRACKING RESISTANCE
(1992-05-01)
HUANG, TH
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KUO, CT
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LIN, TS
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機械工程學系
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Department of Mechanical Engineering
TRIBOLOGICAL BEHAVIOR OF CHEMICAL VAPOR-DEPOSITION DIAMOND FILMS ON VARIOUS CUTTING TOOLS
(1993-01-09)
HUANG, TH
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KUO, CT
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LIN, TS
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機械工程學系
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Department of Mechanical Engineering
Diamond films were deposited using a hot-filament-assisted chemical vapour deposition system on various cutting tool materials (i.e. cemented WC, sintered SiC, Si-Al-O-N, etc.). The friction coefficients of the films, the adhesion strengths of the films on the substrates, and the surface roughnesses of the substrates and the films were measured and their correlations analysed. The results indicate that the cutting performance of the diamond-coated inserts is strongly related to the adhesion strength and the friction coefficient of the film. Furthermore, the adhesion strength is also dependent upon the surface Co content and the surface roughness of the pretreated substrate, and the friction coefficient of the film is a function of the surface roughness and the quality and size of the diamond microcrystals. There exists an appropriate range of the substrate roughness values for an optimum adhesion strength. For the cemented WC substrates, the pretreatments of the substrate to remove the surface Co and to microscratch the surface to obtain an optimum surface roughness are essential to the growth of films with a lower friction coefficient and a better cutting performance. The cutting performance of the films on the cemented WC substrates is better than that of those on the sintered SiC or the Si-Al-O-N substrates. This is because there is a lower friction coefficient and a much higher adhesion strength of the film on the cemented WC substrates.
WEAR BEHAVIOR OF VARIOUS DIAMOND-COATED CUTTING TOOLS UNDER DIFFERENT DEPOSITION CONDITIONS
(1993-04-13)
HUANG, TH
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KUO, CT
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LIN, TS
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CHANG, CS
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材料科學與工程學系
A hot-filament-assisted chemical vapour deposition system was used to deposit diamond films on cemented carbide cutting tools with Co contents ranging from 6% to 22%. The surface roughness and friction coefficient of the films were measured under different deposition conditions. A block-on-ring tribotester and scanning electron microscopy were adopted to characterize the tribological behaviour and the film morphology. The results indicate that the cutting performance of the diamond-coated tools is closely related to the friction coefficient and surface roughness of the film and that the friction coefficient is a function of the surface roughness and film quality. For the 6% Co substrate the film deposited under 0.5% CH4 Concentration shows the best film quality and the lowest friction coefficient and its surface roughness is within the optimum range 0.06-0.25 mum; therefore it shows better cracking resistance and wear resistance.