• 한국세라믹학회지
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• 제36권8호
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• pp.835-842
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• 1999

본 연구에서는 Ag-Cu-Ti 와 Ag-Cu-In-Ti 를 사용하여 브레이징법으로 질화규소 간 접합체를 제작하고 $400^{\circ}C$와 $650^{\circ}C$에서 장시간(2000 h) 열처리 후 파괴 강도의 변화를 살펴보았다. 접합후 강도는 Ag-Cu-Ti 가 높게 나왔지만, 열처리 시간이 증가할수록 Ag-Cu-In-Ti 의 경우가 강도의 감소 정도가 작은 것으로 나타났다. 또한 고온 응용을 위해 개발된 새로운 접학 합금인 Au-Ni-Cr-Mo-Fe 계를 이용하여 질화 규소 간의 접합체를 제작하여 $650^{\circ}C$에서 100시간까지 장시간 열처리 하였다 접합 당시의 강도는 상용 접합 합금보다는 낮은 값을 보였지만, 열처리를 함에 따라 강도의 증가를 보였다 SUS316과의 접합시에는 중간재로 몰리브데늄 또는 구리를 사용하였으며 $400^{\circ}C$에서 1000시간 동안 열처리하였다. 강도는 몰리브데늄을 사용한 경우가 높게 나왔지만, 접합체의 형성이 어렵다는 단점이 있었다. 산화 실험에서는 Ti가 첨가된 접합 합금인 Ag-Cu-Ti 의 경우가 첨가되지 않은 Ag-Cu의 경우보다 산화가 잘 일어나며, 인듐을 첨가한 Ag-Cu-In-Ti 의 경우는 산화 억제의 효과가 나타났다. 전반적으로 In을 포함한 접합 합금이 고온 신뢰도 면에서 우수한 것으로 나타났다.

• 한국분말재료학회지
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• 제24권1호
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• pp.29-33
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• 2017

Titanium carbide (TiC) powders are successfully synthesized by carburization of titanium hydride ($TiH_2$) powders. The $TiH_2$ powders with size lower than $45{\mu}m$ (-325 Mesh) are optimally produced by the hydrogenation process, and are mixed with graphite powder by ball milling. The mixtures are then heat-treated in an Ar atmosphere at $800-1200^{\circ}C$ for carburization to occur. It has been experimentally and thermodynamically determined that the de-hydrogenation, "$TiH_2=Ti+H_2$", and carburization, "Ti + C = TiC", occur simultaneously over the reaction temperature range. The unreacted graphite content (free carbon) in each product is precisely measured by acid dissolution and by the filtering method, and it is possible to conclude that the maximal carbon stoichiometry of $TiC_{0.94}$ is accomplished at $1200^{\circ}C$.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.355-356
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• 2006

WC-TiC-TaC binderless cemented carbide was oxidized under low partial pressure of oxygen (50ppm) at 873K for 1 to 20 h. Surface roughness was measured using atomic force microscope, and effect of TiC amount on oxidation behavior of the carbide was investigated. WC phase was oxidized more easily than WC-TiC-TaC solid solution phase. With an increase in TiC amount, WC-TiC-TaC phase increased and the oxidation resistance of the carbide increased.

• 대한치과기공학회지
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• 제15권1호
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• pp.5-25
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• 1993

Effects of hydrogenation on microstructure and mechanical properties of pure Ti and Ti-0.15Pd alloy have been studied by means of optical microscopy, differential scanning calorimeter(DSC), Xray diffraction and micro vicker's hardness test. Grain size of pure Ti and Ti-0.15Pd alloy decresed largely by hydrogenation finer than that of pure Ti and the grain size refinement was evedent in Ti-0.15Pd alloy than that in pure Ti. Ti-.015Pd alloy carried out solution treatment at 950$^{\circ}C$, the transformation of $\alpha$' martensite was occured. The amount of Hydrogen absorption in Ti-.015Pd alloy was higher than that in pure Ti. Decomposition of hydride in pure titanium and Ti-0.15Pd alloy increased largely by hydrogenation, and micro vicker's hardness of Ti-.015Pd alloy was largely than that of pure Ti by 30% after hydrogenation. The micro vicker's hardness of Ti-0.15Pd alloy after solution treatment and dehydrogenation were higher at $\beta$ phase ranger(950$^{\circ}C$) than that phase range(750$^{\circ}C$).

• 한국세라믹학회지
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• 제24권4호
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• pp.397-403
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• 1987

Pb(Zr0.52Ti0.48)O3 powders were prepared by hydrothermal synthesis. Using soluble salts such as Pb(NO3)2, TiCl4 and ZrOCl2$.$8H2O and oxide such as PbO and TiO2 as starting materials, PZT powder was hydrothermally synthesized at the temperature range between 150$^{\circ}C$ and 200$^{\circ}C$. The result showed that reactivity by alkali was decreased in the sequence of Pb(NO3)2, TiCl4, ZrOCl2, PbO, TiO2 and ZrO2. Using the first three soluble salts, PZT powder was synthesiged at 150$^{\circ}C$ for 1hr. In PbO-TiCl4-ZrOCl2 system, PZT powder was synthesized at 150$^{\circ}C$ for 8rs. In Pb(NO3)2-TiO2-ZrOCl2 system, PZT powder was synthesized at 150$^{\circ}C$ for 16hrs, in PbO-TiO2-ZrOCl2 system, the powder was synthesized at 200$^{\circ}C$ for 8hrs.

• 한국분말재료학회지
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• 제6권2호
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• pp.139-144
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• 1999

The pure Ti, Ni and carbon powders were reaction milled to synthesize the TiC-Ni based cermet powders with ultrafine microstructures. After milling, the ultrafine TiC or amorphous Ti-Ni phase was obtained, respectively, according to the milling condition. The effects of milling variables on the synthesizing behavior of the powders were investigated in detail. The sintered TiC-Ni based cermet of the reaction milled powders consisted of very fine TiC of 0.2~1.5$\mu$m, as compared with that of a commercial cermet of 3~5$\mu$m. This demonstrates the potenial of reaction milling as an effective processing route for the preparation of cermet materials.

• Journal of Welding and Joining
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• 제14권2호
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• pp.46-56
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• 1996

HAZ impact toughness of Ti-oxide steel was investigated and compared to that of a conventional Ti-nitride steel. Toughness variations of each steel with weld peak temperatures and cooling rates were interpreted with microstructural transformation characteristics. In contrast to Ti-nitride steel showing continuous decrease in HAZ toughness with peak temperature, Ti-oxide steel showed increase in HAZ toughness above $1400^{\circ}C$ peak temperature. The HAZ microstructure of the Ti-oxide steel is characterized by the formation of intragranular ferrite plate, which was found to start from Ti-oxide particles dispersed in the matrix of the steel. Large austenite grain size above $1400^{\circ}C$ promoted intragranular ferrite plate formation in Ti-oxide steel while little intragranular ferrite plate was formed in Ti-nitride steel because of dissolution of Ti-nitrides. Ti-oxides in the Ti-oxide steel usually contain MnS and have crystal structures of TiO and/or $Ti_2O_3$.

• 한국표면공학회지
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• 제35권6호
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• pp.391-400
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• 2002

Corrosion characteristics of Ti, Ti/Cr coated and plasma-nitrided surface for stainless steel containing Ti have been studied. Stainless steels containing 0.09-0.92wt% Ti were fabricated by using vacuum furnace and solutionized for 1hr at 105$0^{\circ}C$. Ti and Cr coatings were done on solutionized stainless steel surface by EB-PVD. The Ti coated specimen were coated by Cr and were nitrided by plasma at $450^{\circ}C$ for 5hr. Microstructure and phase analysis were performed using SEM, OM and EDX. Corrosion behavior of the coated specimen was investigated by electrochemical test. The coated surface was of fine columnar structure. The Ti/Cr coated surface was denser than the Ti coated and the Ti coated-nitrided surfaces. The corrosion and pitting potential increased in proportion to the Ti content, coating temperature, coating thickness and formation of stable oxide film. The current density in active and passive region decreased in the case of Ti/Cr coated sample and Ti coated-nitrided samples. Especially the plasma nitrided specimen after Ti coating have a good corrosion resistance compared with the Ti coated specimen. The number and size of pits decreased as Ti content of matrix increased.

• 한국표면공학회지
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• 제36권1호
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• pp.89-98
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• 2003

Corrosion characteristics of Ti, Ti/Cr coated and plasma-nitrided surface for stainless steel containing Ti have been studied. Stainless steels containing 0.09-0.92wt% Ti were fabricated by using vacuum furnace and solutionized for 1hr at $1050^{\circ}C$. Ti and Cr coatings were done on solutionized stainless steel surface by EB-PVD. The Ti coated specimen were coated by Cr and were nitrided by plasma at $450^{\circ}C$ for 5hr Microstructure and phase analysis were performed using SEM, OM and EDX. Corrosion behavior of the coated specimen was investigated by electrochemical test. The coated surface was of fine columnar structure. The Ti/Cr coated surface was denser than the Ti coated and the Ti coated-nitrided surfaces. The corrosion and pitting potential increased in proportion to the Ti content, coating temperature, coating thickness and formation of stable oxide film. The current density in active and passive region decreased in the case of Ti/Cr coated sample and Ti coated-nitrided samples. Especially the plasma nitrided specimen after Ti coating have a good corrosion resistance compared with the Ti coated specimen. The number and size of pits decreased as Ti content of matrix increased.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1997년도 한국재료학회 춘계학술발표회
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• pp.21-21
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• 1997