• Title/Summary/Keyword: Co powder

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Preparation of Ce0.8Gd0.2O1.9 Powder Using CeO2 Powder and Gd Precipitation and Effect of CoO doping on Sintering

  • Sim, Soo-Man
    • Journal of the Korean Ceramic Society
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    • v.52 no.6
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    • pp.521-526
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    • 2015
  • $Ce_{0.8}Gd_{0.2}O_{1.9}$(GDC20) powder was prepared from a mixture of submicron-sized $CeO_2$ powder and Gd precipitates using ammonium carbonate $((NH_4)_2CO_3)$ as a precipitant. The mixture was calcined at $700^{\circ}C$ for 4 h followed by ball-milling that resulted in the GDC powder with an average particle size of $0.46{\mu}m$. The powder had a very uniform particle size distribution with particle sizes ranging from $0.3{\mu}m$ to $1{\mu}m$. Sintering of undoped GDC samples did not show a relative density of 99.2% until the temperature was increased to $1500^{\circ}C$, whereas GDC samples doped with 5 mol% CoO exhibited a significant densification at lower temperature reaching a relative density of 97.6% at $1100^{\circ}C$ and of 98.8% at $1200^{\circ}C$.

Analysis of Microstructure Evolution using Different Powder Metallurgy Process in Ti-X Alloy System (Ti-X계 합금의 분말야금 공정 차이에 따른 미세조직변화 분석)

  • Kwon, Hyeok-Gon;Kim, Doo-Hyeon;Gang, Min;Park, Ji-Hwan;Oh, Myung-Hoon
    • Journal of the Korean Society for Heat Treatment
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    • v.34 no.1
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    • pp.17-24
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    • 2021
  • In this study, Ti-X (X=Mn, Fe, Mo) powder alloys were designed and manufactured by both powder metallurgy (PM) and metal powder injection molding (MIM) process to improve strength and formability compared to CP-Ti powder materials. It was found that the lamellar microstructure consisted of α and β phases was formed in PM-processed alloys. However, MIM-processed alloys showed not the lamellar microstucture but the equiaxed α + β microstructure. It was also revealed that the contents of X component and feedstock were not affected to microstructure evolution. The reason why different microstructure was appeared between PM-processed and MIM-processed alloys is not clear yet, but supposed to be the effect of intersticial elements such as C, H and N derived from feedstock during debinding process of MIM.