Carbothermal formation and microstrutural evolution of 伪鈥?Sialon-AlN-BN powders from boron-rich blast furnace slag

详细信息	查看全文 | 推荐本文 |

• 作者：Tao Jiang^a ; ^b ; ^{jiangt@smm.neu.edu.cn} ; Junbin Wu^a ; ^b ; Xiangxin Xue^a ; ^b ; Peining Duan^a ; ^b ; Mansheng Chu^a
• 关键词：伪&prime ; -Sialon&ndash ; AlN&ndash ; BN ; Powders ; Phase compositions ; Microstructures ; Boron-rich blast furnace slag
• 刊名：Advanced Powder Technology
• 出版年：2012
• 期刊代码：P121_09218831
• 类别：ms
• 出版时间：May, 2012
• 卷：23
• 期：3
• 页码：406-413
• 文件大小：1354 K

摘要

Boron-rich blast furnace slag of low activity is one of the major products created during the separation of iron and boron from ludwigite in a blast furnace process, and the high-efficiency utilisation of its is of great importance to the Chinese boron industry. This paper proposes one new application process to synthesize 伪鈥?Sialon-AlN-BN powders by a carbothermal reduction-nitridation method using boron-rich blast furnace slag as the staring material and describes a series of experimental studies that were performed to elucidate the mechanism of phase formation and microstructure evolution during CRN. The experimental results revealed that the phase compositions and microstructures of the synthesized products were greatly affected by the initial compositions ((Ca,Mg)_xSi_12-3xAl_3xO_xN_16-x), x = 0.3-1.8), temperature and holding time. With the compositions shifting from values of x of 0.3-1.8, the relative amount of 伪鈥?Sialon, AlN and BN increased gradually, and the amount of 伪鈥?Sialon reached a maximum at a value of x of 1.4. The optimal condition for powder synthesis was a temperature of 1480 掳C with a holding time of 8 h, under which the crystalline phases included 伪鈥?Sialon, AlN, BN and less SiC. More elongated 伪鈥?Sialon grains were observed at higher x values and temperatures. During the CRN process, MgAl₂O₄, Mg₂SiO₄, Ca₂Al₂SiO₇, MgSiN₂, 尾鈥?Sialon and 27R appeared sequentially as intermediate products. The volatilisation of SiO gas and magnesium vapour resulted in additional weight loss of the samples, which was aggravated with increases in the synthesis temperature and holding time.