Carbothermal reduction nitridation of slag, glass and minerals: Formation process of SiAlON powders with different morphology

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• 作者：Yun Tang ; ^{tangyunfly@126.com" class="auth_mail" title="E-mail the corresponding author} ; Hongfeng Yin ; Hudie Yuan ; Hang Shuai ; Yalou Xin
• 关键词：D. SiAlON ; Carbothermal reduction nitridation ; Phase composition ; Morphology
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：1 May 2016
• 年：2016
• 卷：42
• 期：6
• 页码：7499-7505
• 全文大小：1903 K

文摘

The phase and morphological evolutions during carbothermal reduction nitridation (CRN) process were comparatively investigated using three kinds of raw material (slag, glass and minerals) providing different Si and Al sources. The results showed that the CRN processes using different raw materials presented the same phase transformation steps. In SiAlON family, O-SiAlON was firstly formed then transformed to nitrogen-rich SiAlONs, including β-, α-SiAlON and 15R polytypoid with the increase of temperature or holding time. At the end of CRN, β and 15R were converted to α-SiAlON. In addition, gehlenite phase was also formed at the initial stage of CRN, which could be further converted to SiAlON in the presence of reductant C. The morphology of nitridation specimens was highly dependent on the liquid or gas phases formed via CRN reactions, which contributed to the formation of prismatic, hollow spherical and needle-like SiAlON powders via three CRN processes.