• Title/Summary/Keyword: nitride

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Near-Net-Shape Forming and Green Properties of Silicon Nitride by Direct Coagulation Casting Technique (직응집성형법을 이용한 질화규소의 실형상 성형공정 및 성형특성)

  • Jung, Yun-Sung;Pagnoux, Cecile;Jung, Yeon-Gil;Paik, Un-Gyu
    • Journal of the Korean Ceramic Society
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    • v.39 no.3
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    • pp.299-307
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    • 2002

  • In this proposed study, a new emerging shape forming technique Direct Coagulation Casting(DCC) which enables to fabricate complex-shaped ceramic parts has been investigated using colloid surface chemistry. Various process variables affected by dispersant, coagulation agent and sintering additives, have been evaluated in order to achieve highly concentrated stabilized silicon nitride suspensions. A high solid loading of 51 vol% in the dispersed silicon nitride suspension was prepared with 1.0wt% Tetraethylammonium Hydroxide (TEAH), which obtained a stable silicon nitride suspension with sintering additives $(Al_2O_3\;and\;Y_2O_3)$ in alkaline regions. The addition of hydroxyaluminium diacetate into the suspension, which decomposed at elevated temperatures, led to coagulate of a silicon nitride suspension. In a basic medium, aluminum ions precipitated to aluminum hydroxide $(Al(OH)_3)$, leading to decreased $OH^-$ concentration and, thus, coagulated suspension.

  • https://doi.org/10.4191/KCERS.2002.39.3.299 인용 PDF KSCI