• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2007.11a
• /
• pp.123-124
• /
• 2007

3성분계 Ti-Si-C 코팅은 PECVD 기술에 의해 WC-Co 기판에 합성되었다. 이 연구에서 Ti-Si-C코팅에서의 비정질 silicon carbide 상의 효과는 XRD, XPS, TEM에 의해 분석되었다. TiC 결정의 입자크기는 비정질 silicon carbide의 침투 현상 때문에 Si의 함유량이 증가됨에 따라 감소된다. Ti-Si-C 코팅은 5.2%의 Si함유량에서 나노크기의 nc-TiC결정과 비정질 a-SiC로 이루어져 있고 최고 경도 33GPa와 탄성율 330GPa를 각각 보여주고 있다. 이 수치들은 순수한 TiC(-21GPa, 260Gpa)보다 눈에 띄게 높아졌다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.406-407
• /
• 2006

This paper describes the ohmic contact formation between a TiW film as a contact material deposied by RF magnetron sputter and polycrystalline 3C-SiC films deposied on thermally grown Si wafers. The specific contact resistance (${\rho}_c$) of the TiW contact was measured by using the C-TLM. The contact phase and interfacial reaction between TiW and 3C-SiC at high-temperature were also analyzed by XRD and SEM. All of the samples didn't show cracks of the TiW film and any interfacial reaction after annealing. Especially, when the sample was annealed at $800^{\circ}$ for 30min., the lowest contact resistivity of $2.90{\times}10^{-5}{\Omega}cm^2$ was obtained due to the improved interfacial adhesion.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2001.11a
• /
• pp.69-77
• /
• 2001

Wear and Friction characteristics of plasma-sprayed Cr$_2$O$_3$ coating and Cr$_2$O$_3$ coating included SiO$_2$ and TiO$_2$ against SiC ball have been investigated under different loads. Worn surfaces were observed by SEM and worn surfaces were analyzed by EDS. The Friction coefficient and the Wear resistance of Cr$_2$O$_3$-5SiO$_2$-3TiO$_2$coating was less than that of Cr$_2$O$_3$ coating. The main mechanisms were plastic deformation and brittle fracture. The film on surface were made by plastic deformation and compacted wear debris. This film protect wear of coating

• Journal of Welding and Joining
• /
• v.18 no.5
• /
• pp.98-104
• /
• 2000

Aluminum alloys are being employed in automobile parts as strive to reduce overall vehicle weight to meet demands for improved fuel economy and reduction in vehicle emissions. Al-based composites reinforced with ceramic ($Al_2O_3,\;SiC,\;TiC\;and\;B_4C$) applications in a variety of components in automotive engines, such as liners, where the tribological properties of the material are important. In this study, Al-base composites reinforced with TiC particle powders has been developed for producing plasma spray coatings. The composite plasma spray powders were prepared Al-13Si-3Mg(wt%) alloy with TiC(40, 60 and 80wt%) particles ($0.2~5{\mu}textrm{m}$) by drum type ball milling. The composite powders ($36~76{\mu}textrm{m}$) were sprayed with plasma torch. Plasma sprayed coatings were heat-treated at $500^{\circ}C$ for 3 hours. The wear resistances of the plasma sprayed coatings were found to decrease with increasing TiC content and improved with heat treatment. AlSiMg-40% TiC heat-treated coatings were showed the best wear resistance in this study.

• Journal of the Korean institute of surface engineering
• /
• v.33 no.1
• /
• pp.3-9
• /
• 2000

Arc-melted alloys of TiAl-(o.25, 0.5, 1.0at%) Si were isothermally oxidized at 800, 900 and $1000^{\circ}C$ in air for 60hr. It was found that the oxidation resistance of the prepared TiAl-Si alloys was much better than that of pure TiAl, being progressively increasing with an increase in the Si content. This was attributed to the formation of $SiO_2$in addition to ($TiO_2$+$Al_2$$O_3$) oxides which formed in TiAl alloys with and without silicon additions. However, the silica formation within the oxide layer unfortunately accelerated the oxide scale spallations. During oxidation, all the elements in the base alloy diffused outward, whereas oxygen from the atmosphere diffused inward. The oxides were primarily composed of an outer thick $TiO_2$layer, an intermediate diffuse $Al_2$$O_3$layer and an inner $TiO_2$layer. A small amount of $SiO_2$was present all over the oxide scale and some voids were found around the intermediate layer.

• Analytical Science and Technology
• /
• v.5 no.3
• /
• pp.303-308
• /
• 1992

Initial reactions of Ti and Si have been studied to examine the surface roughness of titanium silicide. Formation mechanism has been explored with in-situ measurement tools such as AES(Auger electron spectroscopy) and LEED (low energy electron diffraction). One or two monolayers of Ti films have been deposited in ultrahigh vacuum on atomically clean Si(111) substrates. Atomically clean Si substrates which are reconstructed $7{\times}7$ Si(111) have been obtained after in-situ heat cleaning in ultrahigh vacuum. Deposition of the films were monitored by a quartz cuystal oscillator and the Ti films were analyzed with in-situ AES and LEED. The in-situ measurements show that the initial reactions of Ti and Si occur at room temperature and form a disordered layer. At low temperatures($200^{\circ}C{\sim}300^{\circ}C$) intermixing of Ti and Si is detected by AES. Substrate $1{\times}1$ LEED patterns are displayed after $400^{\circ}C$ anneal. This indicates that the disordered layer has transformed to form an ordered surface. The reappearance of the $7{\times}7$ LEED pattern in observed with further high temperature anneals and indicates three dimensional titanium silicide island formation.

• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.1588-1590
• /
• 2004

The composites were fabricated, respectively, using 61vol.% SiC - 39vol.% $TiB_2$ and using 61vol.% SiC 39vol.% WC powders with the liquid forming additives of 12wt% $Al_2O_3+Y_2O_3$ by pressureless annealing at 1800$^{\circ}C$ for 4 hours. Reactions between SiC and transition metal $TiB_2$, WC were not observed in this microstructure. The result of phase analysis of composites by XRD revealed SiC(6H), $TiB_2$ and YAG($Al_5Y_3O_{12}$) crystal phase on the SiC-$TiB_2$, and SiC(2H), WC and YAG($Al_5Y_3O_{12}$) crystal phase on the SiC-WC composites. ${\beta}{\rightarrow}{\alpha}$-SiC phase transformation was ocurred on the SiC-$TiB_2$, but ${\alpha}{\rightarrow}{\beta}$-SiC reverse transformation was not occurred on the SiC-WC composites. The relative density, the flexural strength showed respectively value of 96.2%, 310.19Mpa in SiC-WC composites. The electrical resistivity of the SiC-$TiB_2$ and the SiC-WC composites is all positive temperature cofficient resistance(PTCR) in the temperature ranges from 25$^{\circ}C$ to 500$^{\circ}C$.

• Proceedings of the KIEE Conference
• /
• 2006.07c
• /
• pp.1311-1312
• /
• 2006

This paper describes the ohmic contact formation between a TiW film as a contact material deposied by RF magnetron sputter and polycrystalline 3C-SiC films deposied on thermally grown Si wafers. The specific contact resistance (${\rho}_c$) of the TiW contact was measured by using 4he C-TLM. The contact phase and interfacial reaction between TiW and 3C-SiC at high-temperature were also analyzed by XRD and SEM. All of the samples didn't show cracks of the TiW film and any interfacial reaction after annealing. Especially, when the sample was annealed at $800^{\circ}$ for 30min., the lowest contact resistivity of $2.90{\times}10^{-5}{\Omega}{\cdot}cm^2$ of was obtained due to the improved interfacial adhesion.

• Journal of Technologic Dentistry
• /
• v.21 no.1
• /
• pp.5-14
• /
• 1999

Glass ceramics for dental crown prosthesis were prepared by crystallization of CaO-MgO-SiO2-$P_2O_5-TiO_2$ glasses. Their crystallization behaviors have been investigated as a function of heattreatment temperature, holding time and chemical composition in relation to mechinical properties. Crystallization peak temperatures were determined by differential thermal analysis(DTA). Crystalline phases and mircostructures of heat-treated sample were determined by the means of powder X-ray diffraction(XRD) and scanning electron microscopy(SEM). The final crystalline phase assemblages and the microstructures of the samples were found to be dependent on glass compositions, heattreatment temperature, and holding time. 1st crystallization peak temperature(TP), affected strongly by apatite, was found to be increased or decreased. From the experiment, the following results were obtained : 1. The crystallization peak temperature($T_P$) formed by apatite increased until adding up to 9wt% $TiO_2$ to base glass composition, then decreased above that. 2. Apatite($Ca_{10}P_6O_{25}$), whitlockite(${\beta}-3CaO-P_2O_5$), $\beta$-wollastonite($CaSiO_3$), magnesium tianate($MaTiO_3$) and diopside(CaO-MgO-$2SiO_2$) crystal phase were precipitated in MgO-CaO-$SiO_2-TiO_2-P_2O_5$ glass system containing 9wt% and 11wt% of $TiO_2$ 3. Vickers hardness of samples increased with increasing heat-treatment temperature and Vickers hardness of S415T9 samples heat-treated at 1075 was approxi-mately 813Kg $mm^{-2}$ as maximum value. 4. Vickers hardness of samples increased due to precipitation of apatite, whitlockite, $\beta$-wollastonite, magnesium titanate, and diopside crystal phases within glass matrix.

• The Korean Journal of Ceramics
• /
• v.5 no.2
• /
• pp.155-161
• /
• 1999

The tribological behaviour of monolithic SiC as well as SiC-TiC and SiC-TiC-$TiB_2$ particulate composite materials has been investigated in unlubricated oscillating sliding tests against $Al_2O_3$ at temperature in the range from room temperature up to $600^{\circ}C$. At temperatures below $600^{\circ}C$ the wear rate of the systems with the composite materials was up to 20 times lower than the wear of the $Al_2O_3$/SiC system and was dominated by the oxidation of the titanium phases. At $600^{\circ}C$ the oxidation rate of the TiC and -TEX>$TiB_2$ grains becomes predominant resulting in an enhanced wear rate of the composite rate of the TiC and TiB2 grains becomes predominant resulting in an enhanced wear rate of the composite materials. The coefficient of friction shows similar values for all materials of investigation, increasing from 0.25…0.3 at room temperature to 0.7…0.8 $600^{\circ}C$. The wear of the $Al_2O_3$/SiC system is mainly abrasive at temperatures above room temperature and is characterised by an enhanced wear of the alumina ball at $600^{\circ}C$.