• Journal of Powder Materials
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• v.14 no.3 s.62
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• pp.208-214
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• 2007

The microstructure and hardness of (W,Ti)C cemented carbides with a different metallic binder composition of Ni and Co fabricated by powder technology were investigated. The densifications of the prepared materials were accomplished by using vacuum sintering at $1450^{\circ}C$. Nearly full dense (W,Ti)C cemented carbides were obtained with a relative density of up to 99.7% with 30 wt.% Co and 99.9% with 30 wt.% Ni as a metallic binder. The average grain size of the (W,Ti)C-Co and the (W,Ti)C-Ni was decreased by increasing the metallic binder content. The hardness of the dense (W,Ti)C-15 wt%Co and (W,Ti)C-15 wt%Ni, was greater than that of the other related cemented carbides; in addition, the cobalt-based cemented carbides had greater hardness values than the nickel-based cemented carbides.

• Journal of the Korean Ceramic Society
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• v.31 no.1
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• pp.25-30
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• 1994

W-Ti-C-N based multiphase hard materials have been prepared from WC/TiN powder mixture. By sintering at and above 190$0^{\circ}C$, the two phases of powder mixture has transformed into intermixed W, W2C and Ti(C, N) phases. For the temperature range between 180$0^{\circ}C$ and 210$0^{\circ}C$, the sintered or hot pressed samples show maximum density and hardness. The seems that metallic W grains enhance the fracture toughness of materials. The wear resistance of the material is found to increase with increasing hardness.

• Korean Journal of Materials Research
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• v.28 no.9
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• pp.511-515
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• 2018

W-10 wt% Ti alloys that have a homogeneous microstructure are prepared by thermal decomposition of $WO_3-TiH_2$ powder mixtures and spark plasma sintering. The reduction and dehydrogenation behavior of $WO_3$ and $TiH_2$ are analyzed by temperature programmed reduction and a thermogravimetric method, respectively. The X-ray diffraction analysis of the powder mixture, heat-treated in an argon atmosphere, shows W- oxides and $TiO_2$ peaks. Conversely, the powder mixtures heated in a hydrogen atmosphere are composed of W, $WO_2$ and $TiO_2$ phases at $600^{\circ}C$ and W and W-rich ${\beta}$ phases at $800^{\circ}C$. The densified specimen by spark plasma sintering at $1500^{\circ}C$ in a vacuum using hydrogen-reduced $WO_3-TiH_2$ powder mixtures shows a Vickers hardness value of 4.6 GPa and a homogeneous microstructure with pure W, ${\beta}$ and Ti phases. The phase evolution dependent on the atmosphere and temperature is explained by the thermal decomposition and reaction behavior of $WO_3$ and $TiH_2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.288-291
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• 1996

The surface properties after plasma etching of TiW solutions using the chemistries of BCl$_3$ and SF$\_$6/ gases with varying mixing ratio have been investigated using X-ray photoelectron spectroscopy. The elements of C, Cl, F, O and S are observed on the etched TiW films. After plasma etching with SF$\_$6/ gas, Ti-S bond are detected on the samples and Ti-S bond makes a role of passivation layer that surpresses Ti-O formation. After plasma etching wish BCl$_3$ gas, Ti are easily removed but W are hardly etched. As a results, W/Ti are increased on the etched sample.

• Journal of the Korean institute of surface engineering
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• v.46 no.4
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• pp.145-152
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• 2013

The growth behavior of nanocrystalline diamond (NCD) film has been studied for three different substrates, i.e. bare Si wafer, 1 ${\mu}m$ thick W and Ti films deposited on Si wafer by DC sputter. The surface roughness values of the substrates measured by AFM were Si < W < Ti. After ultrasonic seeding treatment using nanometer sized diamond powder, surface roughness remained as Si < W < Ti. The contact angles of the substrates were Si ($56^{\circ}$) > W ($31^{\circ}$) > Ti ($0^{\circ}$). During deposition in the microwave plasma CVD system, NCD particles were formed and evolved to film. For the first 0.5h, the values of NCD particle density were measured as Si < W < Ti. Since the energy barrier for heterogeneous nucleation is proportional to the contact angle of the substrate, the initial nucleus or particle densities are believed to be Si < W < Ti. Meanwhile, the NCD growth rate up to 2 h was W > Si > Ti. In the case of W substrate, NCD particles were coalesced and evolved to the film in the short time of 0.5 h, which could be attributed to the fact that the diffusion of carbon species on W substrate was fast. The slower diffusion of carbon on Si substrate is believed to be the reason for slower film growth than on W substrate. The surface of Ti substrate was observed as a vertically aligned needle shape. The NCD particle formed on the top of a Ti needle should be coalesced with the particle on the nearby needle by carbon diffusion. In this case, the diffusion length is longer than that of Si or W substrate which shows a relatively flat surface. This results in a slow growth rate of NCD on Ti substrate. As deposition time is prolonged, NCD particles grow with carbon species attached from the plasma and coalesce with nearby particles, leaving many voids in NCD/Ti interface. The low adhesion of NCD films on Ti substrate is related to the void structure of NCD/Ti interface.

• Korean Journal of Materials Research
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• v.14 no.6
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• pp.394-398
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• 2004

A Ti47Al1.7W-3.7Zr alloy was oxidized between $900^{\circ}C$ and $1050^{\circ}C$, and the oxide scales formed were studied. The oxide scales consisted primarily of an outer$TiO_2$ layer, an intermediate $Al_2$$O_3$-rich layer, and an inner mixed ($TiO _2$ + $Al_2$$O_3$) layer. Besides $TiO_2$ and $Al_2$$O_3$, oxidation led to the formation of some $Ti_2$AlN and TiN. Both W and Zr were preferentially segregated below the intermediate $Al_2$$O_3$-rich layer. Tungsten in the oxide scale was present as $WO_3$ and ${Ti}_{x}$$W_{1-x}$, whereas zirconium as monoclic-$ZrO_2$ and tetragonal-$ZrO_2$.

• Journal of the Korean Society for Heat Treatment
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• v.17 no.4
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• pp.236-240
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• 2004

Effect of plasma power on PECVD process were investigated in this study. TiN and TiCN films were deposited on nitrided STD11 steel with 600W, 1,200W and 1,600W plasma power. As the plasma power was increased, the preferred orientation was reinforced from (200) to (111) and the hardness of films was improved. The low plasma power was, however, effective for improving of adhesion force of films. Regarding above properties, TiN and TiCN films were deposited by gradient plasma power. It was possible to get high hardness as well as adhesion force through gradient plasma power.

• Journal of Sensor Science and Technology
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• v.7 no.5
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• pp.364-371
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• 1998

A novel antifuse has been developed for field programmable gate arrays (FPGA's) as a voltage programmable link with Al/$BaTiO_3/SiO_2$/TiW-silicide. The proper program voltage can be obtained by adjusting the deposition thickness of $BaTiO_3$ film. When a negative voltage was applied at bottom TiW-silicide electrode of the antifuse, based on $BaTiO_3(120{\AA})$/$SiO_2(120{\AA})$, the program voltage was about l4.4V and on-resistances were ranged between 40 and $50{\Omega}$. The current-voltage characteristics of antifuses are consistent with a Frenkel-Poole conduction model. However, there are some deviations depending on bias polarity that are probably due to the difference in the interface properties between Al/$BaTiO_3$ and TiW-silicide/$SiO_2$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.95-98
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• 2007

In this paper, we make an analysis of electromagnetic wave absorption properties of $TiO_2$ in W-band. Therefore, we fabricated some samples in different composition ratio of $TiO_2$ and CPE. And the material properties of samples are calculated from S-parameter of samples using $\ell-2\ell$ method. We analyze absorption properties and complex relative permittivitis of samples. As a result, it has verified that absorption properties of sample containing $TiO_2:CPE=70:30wt.%$ have been excelled in W-band.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.3
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• pp.19-23
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• 2015

In this study, two types of Au/TiW bump samples were fabricated by the electroplating process onto Al/Si and SiN/Si wafers for the COG (Chip On Glass) packaging. TiW was used as the UBM (Under Bump Metallurgy) material of the Au bump and it was deposited by a sputtering method under the sputtering powers ranges from 500 to 5000 Watt. We investigated the delamination phenomenas for the prepared samples as a function of the input sputtering powers. The stable interfacial adhesion condition was found to be 1500 Watt in sputtering power. In addition, the SAICAS (Surface And Interfacial Cutting Analysis System) measurement was used to find the adhesion strength of Au bumps for the prepared samples. TiW UBM films were deposited at the 1500 Watt sputtering power. As a results, there was a similar adhesion strengths between TiW/Au interfacial films on Al/Si and SiN/Si wafers. However, the adhesion strength of TiW UBM sputtering films on Al and SiN under films were 2.2 times differences, indicating 0.475 kN/m for Al/Si wafer and 0.093 kN/m for SiN/Si wafer, respectively.