• Journal of the Korean Ceramic Society
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• v.31 no.8
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• pp.849-860
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• 1994

The microstructural evolution and crystalline phases of this infiltration of Ti+Al liquids in TiC, SiC, TiC+C, and SiC+C preforms have been investigated. As the Ti and Al mixing ratio in Ti+Al infiltrated liquid changes, the newly formed reaction products, which were reacted from the Ti+Al liquid with preforms, consisted of three major phases as Ti3AlC, Al2Ti4C2 or Al4C3. The TiC grain shape was changed to spheroid, when Ti3AlC was formed. In case of Al2Ti4C2 formation, the platelet grain was formed from the original TiC grain. When Al4C3 was formed, nodular or intergranular fine-grained Al4C3 was formed around the TiC grain, while the original TiC grain shape was not changed.

• The Korean Journal of Ceramics
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• v.3 no.2
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• pp.124-128
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• 1997

An attempt was made to understand the dissolution and reprecipitation behavior of the constituent phases such as TiC, TiN, and Ti(CN) in TiC-TiN-Ni system. During the liquid-phase sintering the TiC phase was found to dissolve preferentially in Ni binder. The solid-solution phase, Ti(CN), formed around the TiN phase, resulting in a core/rim structure. This result was reproduced when large TiC particles were used with fine TiN particles. The path for the microstructural change in TiC-TiN-Ni system was largely controlled by the difference in the interfacial energy of each phase with the liquid binder phase. The results were discussed with thermodynamic principles.

• Journal of the Korean institute of surface engineering
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• v.35 no.6
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• pp.408-414
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• 2002

TiN and TiAlN coating layer were deposited on WC-Co steel substrates by an arc ion plating(AIP) technique. The crystallinity and morphology for the deposited coating layers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The impact behaviors of the deposited TiN and TiAlN coating layer were investigated with a ball-on-plate impact tester. Beyond $10^2$ impact cycle, TiAlN coating layer showed superior impact wear resistance compared to TiN coating layer. On the other hand, both TiN and TiAlN coating layers started to be partially failed between $10^2$ and $10^3$ impact cycle. Above $10^3$ impact cycle, TiN and TiAlN coating layers showed similar impact behavior because of the substrate effect.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.658-659
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• 2006

Magnetron sputtered TiN, (Ti, Al)N and TiN/(Ti, Al)N multilayer coatings grown on cemented carbide substrates have been characterized by using electron probe microanalysis (EPMA), X-ray diffraction (XRD), scanning electron spectroscopy (SEM), nanoindentation, scratcher and cutting tests. Results show that TiN coating is bell mouth columnar structures, (Ti, Al)N coating is straight columnar structures and the modulation structure has been formed in the TiN/(Ti, Al)N multilayer coating. TiN/(Ti, Al)N multilayer coating exhibited higher hardness, better adhesion with substrate and excellent cutting performance compared with TiN and (Ti, Al)N coating.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.8
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• pp.1102-1107
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• 1993

Microwave dielectric properties of CaTiO3 and CaTiO3-TiO2 ceramics for the composition range between 40 and 50 mol% CaO in CaO-TiO2 binary system were investigated. CaTiO3 ceramics with50 mol% CaO showed the dielectric constant (e,) of 178, the temperature coefficient of resonant frequency(c,) of+1000 ppm/'c and the qualify factor Q of 2760 (f0=2.7 GHz ). Dielectric constant and temperature coefficient of resonant frequency of ceramics with dual phases of CaTiO3 and TiO2 decreased gradually from those of CaTiO3 as the CaO content decreased. Q value and density were found to have minimum at the composition of 47 mol% CaO. The degradation of Q value and density in dual phase ceramics seems to be caused by the large pores at grain boundaries and/or within grains remained after rapid growth of CaTiO3 grains as TiO2 Phase decreased.

• Journal of the Korean Ceramic Society
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• v.35 no.11
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• pp.1130-1140
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• 1998

Thin films of $Bi_4Ti_3O_{12}\;nBaTiO_3(n=1&2)$ were prepared using sols erived Ba-Bi-Ti complex alkoxides. The sols were spin-cast onto $Pt/Ti/SiO_2/Si$ substrates and followed by pyrolysis for 1 hr at $620^{\circ}C,\;700^{\circ}C\;and\;750^{\circ}C$ In the thin films a pyrochlore phase seemed to be formed at a lower temperature and then tran-formed to the layered perovskite phase as the heating temperature increased. In the thin films pyrolyzed at formed to the layered perovskte phase as the heating temperature increased. In the films pyrolyzed at $750^{\circ}C$ the amount of $Bi_4Ti_3O_{12}{\cdot}BaTiO_3$ reached to 94% while $Bi_4Ti_3O_{12}{\cdot}BaTiO_3$ was 77% in composition. This result shows that the formation of the layered pervoskite phase becomes difficult as the amount of complexing $BaTiO_3$ increases. The microstructures and the electrical properties of the thin films were gen-erally improved with the incease of the heating temperature. However the presence of the pyrochlore phase could not be removed effectively. Our study showed that the electrical properties of $Bi_4Ti_3O_{12}{\cdot}BaTiO_3$ were pronouncedly improved with complexing with BaTiO3 when compared to those of $Bi_4Ti_3O_{12}$ while the presence of the pyrochlore phase was detrimental to the those of $Bi_4Ti_3O_{12}{\cdot}2BaTiO_3$.

• Analytical Science and Technology
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• v.5 no.1
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• pp.97-101
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• 1992

Potentiodynamic corrosion tests were conducted to know the corrosion characteristics of the NiTi intermetallic compound composed of pure Ni and Ti in artificial saline. Tafel extrapolation and linear polarization technique show similar results. Corrosion current Icorr and corrosion rate was increased in the order of NiTi

• Journal of the Korean institute of surface engineering
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• v.34 no.3
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• pp.195-205
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• 2001

The surface characteristics of Ti/TiN films coated on sintered stainless steels (SSS) by electron beam physical vapour deposition (EB-PVD) were investigated. Stainless steel compacts containing 2, 4, and 10wt%Cu were prepared by the electroless Cu-plating method, which results in increased homogenization in the alloying powder. The specimens were coated with Ti and TiN with a 1.0$\mu\textrm{m}$ thickness respectively by EB-PVD. The microstructures were investigated using scanning electron microscopy (SEM). The corrosion behaviors were investigated using a potentiosat in 0.1 M $H_2$$SO_4$, and 0.1M HCl solutions and the corrosion surface was observed using SEM and XPS. The Ti coated specimens showed rough surface compared to Ti/TiN coated specimens. Ti and Ti/TiN coated SSS revealed a higher corrosion and pitting potential from anodic polarization curves than that of Ti and Ti/TiN uncoated SSS. In addition, Ti/TiN coated SSS containing 10wt% Cu exhibited good resistance to pitting corrosion due to the formation of a dense film on the surface and the decrease in interconnected porosity by electroless coated Cu.

• Journal of Technologic Dentistry
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• v.27 no.1
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• pp.65-71
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• 2005

Experimental Ti-13%Zr and Ti-13%Zr-5%Cu alloys were made in an argon-arc melting furnace. The grade 2 CP Ti was used to control. The alloys were cast into phosphate bonded $SiO_2$ investment molds using an argon-arc casting machine, and The hardness and microstructures of the castings were investigated in order to reveal their possible use for new dental casting materials and to collect useful data for alloy design. The hardness of the Ti-13%Zr-5%Cu alloy(379Hv) became higher than that of Ti-13%Zr(317Hv) alloy, and the hardness of this alloys became higher than that of CP Ti(247Hv). Increasing in the hardness of the Ti-13%Zr-5%Cu alloy was considered to be solid solution hardening as the Ti-Zr system shows a completely solid solution for both high temperature $\beta$phase and low temperature $\alpha$ phase and also the inclusion of the eutectoid structure($\alpha Ti+Ti_{2}Cu$). No martensitic structures are observed in the specimen made of CP Ti, but Ti-13%Zr and Ti-13%Zr-5%Cu alloys show a kind of martensitic structure. Ti-13%Zr-5%Cu shows the finest microstructure. From these results, it was concluded that new alloys for dental casting materials should be designed as Ti-Zr-Cu based alloys.

• Journal of the Korean Vacuum Society
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• v.11 no.3
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• pp.159-165
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• 2002

The physical properties of the TiN films deposited by ALD using $TiCl_4$and $NH_3$have been investigated. The TiN deposition rate is ~0.6 $\AA$ under an optimum deposition condition and the resistivity of the TiN films is 200~350 $\mu\Omega$cm . According to the XRD analysis results TiN films are crystallized in the ALD process window. AES analysis results show that the Cl impurity concentration in the TiN films is lower than 1 at% and that the atomic ratio of the TiN films is 1:1. Also it is found by SEM observation that the step coverage of the TiN films on which TiN films with trenches the aspect ratio of which is 10:1 is excellent.