http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Study on Oxidation Behavior of (W,Mo) Powders in Air at 400, 500 and
Peizhong Feng,Xuanhui Qu,Xiaohong Wang,Farid Akhtar 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1
The oxidation of (W,Mo) powders has been investigated at 400, 500 and for 12.0 hours in air. It was shown that the low temperature oxidation resistance of (W,Mo) was worse than that of , and they showed great changes in mass, volume and colour. Especialy at , the amount of volume expansion of (W,Mo) was as high as about times and color changed from black to yellow after 4.0h with , , (W,Mo) and amorphous as main reaction products. The mass gain and oxidation rate were relatively slower at and than that at .
Liu Pengfei,He Xinbo,Qu Xuanhui 한국탄소학회 2023 Carbon Letters Vol.33 No.2
This article reported a simple method for preparing diamond/SiC composites by polymer impregnation and pyrolysis (PIP) process, and the advantages of this method were discussed. Only diamond and SiC were contained in the diamond/SiC composite prepared by PIP process, and the diamond particles remained thermally stable up until the pyrolysis temperature was increased to 1600 °C. The pyrolysis temperature has a significant impact on the thermal conductivity and dielectric properties of composites. The thermal conductivity of the composite reaches a maximum value of 63.9 W/mK when the pyrolysis temperature is 1600 °C, and the minimum values of the real and imaginary part of the complex permittivity are 19.5 and 0.77, respectively. The PIP process is a quick and easy method to prepare diamond/SiC composites without needing expensive equipment, and it is of importance for promoting its application in the field of electric packaging substrate.
Thermal and mechanical properties of diamond/SiC substrate reinforced by bimodal diamond particles
Pengfei Liu,Xulei Wang,Xinbo He,Xuanhui Qu 한국탄소학회 2022 Carbon Letters Vol.32 No.3
Diamond reinforced silicon carbide matrix composites (diamond/SiC) with high thermal conductivity were prepared by tape casting combined with Si vapor infiltration for thermal management application. The effects of the mixing mode of bimodal diamond particles on the microstructure, thermal and mechanical properties of the composites were analyzed. The results reveal that the thermal conductivity of composites is affected significantly by mixing mode of diamond. In general, when the content of large diamond remains constant, adding a slight amount of small diamond was found to be effective in improving the thermal conductivity of the composite. However, excess small diamonds added will decrease thermal conductivity due to its high interfacial thermal resistance. The maximum thermal conductivity of obtained diamond/SiC is 469 W/(m K) when 38 vol% large diamond and 4 vol% small diamond were added. Such a result can be attributed to the formation of efficient heat transfer channels within the composite and sound interfacial bonding between diamond and SiC phase. Diamond/SiC with high thermal conductivity are expected to be the next generation of electronic packaging substrate.
Wide-Gap Repair of Mar-M247 Superalloy via Powder Metallurgy Route
Xiufang Gong,Yankang Yu,Tianjian Wang,Ye Liu,Lin Zhang,Zhenhuan Gao,Hou Ziyong,Xu Chen,Shuang He,Xuanhui Qu 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.11
Wide-gap defects repair of Mar-M247 superalloy was investigated by utilizing powder metallurgy. New interlayer alloy withrelatively high content of B and Zr was designed based on the isothermal solidification principle. The interlayer alloy ischaracterized by relative low melting temperature (1100 °C), and the contact angle of interlayer on the Mar-M247 substrateis ~ 70º. Based on the thermodynamic calculation results, the mixture powders with 80 wt% substrate powder and 20 wt%interlayer alloy powder was used as a filler to repair the wide gap with width of 2 mm. After repaired at 1230 °C for 2 h, nearfullydense gap was obtained. MC-type carbides, MB2-type boride, M3B2-type boride and Ni5(Zr,Hf)-type intermetallic wereobserved in the liquid zone. After post-weld heat treatment, the block borides, chain carbides and eutectic are successfullyremoved, and the tensile strength of the bonding zone is close to that of the Mar-M247 superalloy.
Wang Xulei,Li Yikang,Huang Yabo,Zhang Yalong,Wang Pei,Guan Li,He Xinbo,Liu Rongjun,Qu Xuanhui,Wu Xiaoge 한국탄소학회 2024 Carbon Letters Vol.34 No.6
Diamond/SiC composites were prepared by vacuum silica vapor-phase infiltration of in situ silicon–carbon reaction, and the thermophysical properties of the composites were modulated by controlling diamond graphitizing. The effects of diamond surface state and vacuum silicon infiltration temperature on diamond graphitization were investigated, and the micro-morphology, phase composition, and properties of the composites were observed and characterized. The results show that diamond pretreatment can reduce the probability of graphitizing; when the penetration temperature is greater than 1600 °C, the diamond undergoes a graphitizing phase transition and the micro-morphology presents a lamellar shape. The thermal conductivity, density, and flexural strength of the composites increased and then decreased with the increase of penetration temperature in the experimentally designed range of penetration temperature. The variation of thermal expansion coefficients of composites prepared with different penetration temperatures ranged from 0.8 to 3.0 ppm/K when the temperature was between 50 and 400 °C.