- Preparation of Nano-sized Indium Tin Oxide (ITO) Powders and Their Sintering Behavior
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In-Gyu Lee, Seung-Moo Heo
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J Korean Powder Metall Inst. 2004;11(6):467-471.
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DOI: https://doi.org/10.4150/KPMI.2004.11.6.467
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 Abstract
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- In order to fabricate a high density sintered body of ITO, nano-sized ITO powders were synthesized by coprecipitation methods. Aqueous solutions of indium and tin salts were mixed and coprecipitated by changing their pH. Coprecipitated ITO powders possessed 20-30 nm crystallite size and a relatively high BET value (35m2/g), however, aggregation of particles were occurred. Therefore, a novel recrystallization technique was applied in order to eliminate the aggregates. The recrystallized ITO material consists of a little bit larger needlelike crystals, 20nmtimes80nm, and it possesses a higher BET value (57m2/g) compared to the plain coprecipitated material (35m2/g). Metastable phase formation and higher content of aggregated particles were observed in the coprecipitated materials. Densification was 95% to 98% complete after 5 hour sintering at 1500°C for the recrystallized powders while densities of the coprecipitated powders were below 75%.
- Preparation of Bi-materials by Powder Metallurgy Method
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In-Gyu Lee, Kwang-Sik Lee, Si-Young Chang
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J Korean Powder Metall Inst. 2004;11(6):462-466.
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DOI: https://doi.org/10.4150/KPMI.2004.11.6.462
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Abstract
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- The bi-materials composed of Al-5wt%Mg and its composite reinforced with SiC particles were prepared by ball-milling and subsequent sintering process. The size of powder in Al-Mg/SiCp mixture decreased with increasing ball-milling time, it was saturated above 30 h when the ball and powder was in the ratio of 30 to 1. Both Al-5wt%Mg powders mixture and Al-5wt%Mg/SiCp mixture were compacted under a pressure of 350MPa and were bonded by sintering at temperatures ranging from 873K to 1173K for 1-5h. At 873k, the sound bi-mate-rials could not be obtained. In contrast, the bi-materials with the macroscopically well-bonded interface were obtained at higher temperatures than 873K. The length of well-bonded interface became longer with increasing temperature and time, indicating the improved contact in the interface between unreinforced Al-Mg part and Al-Mg/SiCp composite part. The relative density in the bi-materials increased as the sintering temperature and time increased, and the bi-materials sintered at 1173K for 5h showed the highest density.
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