Nanosized WC and WC-Co powders were synthesised by chemical vapor condensation(CVC) process using the pyrolysis of tungsten hexacarbonyl(W(CO)) and cobalt octacarbonyl(Co(CO)). The microstructural changes and phase evolution of the CVC powders during post heat-treatment were studied using the XRD, FE-SEM, TEM, and ICP-MS. CVC powders were consisted of the loosely agglomerated sub-stoichimetric WC and the long-chain Co nanopowders. The sub-stochiometric CVC WC and WC-Co powders were carburized using the mixture gas of CH-H in the temperature range of 730-85. Carbon content of CVC powder controlled by the gas phase carburization at 85 was well matched with the theoretical carbon sioichiometry of WC, 6.13 wt％. During the gas phase carburization, the particle size of WC increased from 20 nm to 40 nm and the long chain structure of Co powders disappeared.

The microstructures and properties of TiC dispersed nickel-base alloy were studied in this work. The alloy prepared by powder metallurgical processing was solution treated, 1st-aged at for 16 hours, and then 2nd-aged at for 4 hours. Microstucture of sintered specimen showed that TiC particles are uniformly dispersed in Ni base alloy. In the specimen aged at for 8 hours, the fine (Al,Ti) precipitates with round shape are observed and the very fine (Al,Ti) particles with round shape are precipitated in the specimen aged at for 4 hours. The presence of precipitates in TiC/Ni base alloy increased the hardness and wear resistance of the specimen. The hardness and wear resistance of the Ni-base with TiC are higher than those of conventional Ni-base superalloy X-750 because of dispersion strengthening of TiC particles. The hardness, transverse rupture strength and resistance of the specimen 2nd-aged at for 4 hours are higher than those of 1st-aged specimen due to ultrafine (Al,Ti) precipitates.

The effect of tempering temperature on the three point bending fatigue behavior of a P/M high speed steel JYPS-23 (1.28% C, 4.20% Cr, 6.40% W, 5.00% Mo, 3.10% V, bal. Fe) was investigated. The number of cycles to failure of the specimen austenitized at drastically increased with increasing tempering temperature. As tempering temperature increased from 500 to , the volume fraction and average size of carbides (MC or M6C) did not significantly changed, while hardness decreased drastically. The reduced hardness is due to the softening of matrix, which increased the resistance of the fatigue crack propagation. For a practical application, powder compacting test were also conducted with the P/M high speed steel punches tempered at 500, 580, and . The number of compacting cycles to failure of the punches also increased with increasing tempering temperature.

광 변조량, 광학밀도, 응답시간, 순환전위전류특성을 조사하여 열처리 효과에 따른 MoO3박막의 일렉트로크로믹 특성을 연구하였다. XRD 분석 결과 as-deposited MoO3박막과 350˚C 이하로 열처리된 박막은 비정질로 밝혀졌으며, 450˚C에서열처리한 MoO3박막은 결정질로 나타났다. As-deposited MoO3박막을 사용한 일렉트로크로믹 소자가 열처리된 박막을 사용한 소자에비하여 광변조 특성과 전기화학적 특성에서 좋은 일렉트로크로믹 현상을 보여주었다. MoO3박막의 열처리 온도에 따른 효과는 일렉트로크로믹 특성과 가역변색에서 광변조특성과 전기화학적 특성을 감소시키며, 열화현상을 촉진하는 것으로 나타났다.