【作者】 朱丹； 高明霞； 潘颐； 方宁象； 刘永锋； 潘洪革；

【Author】 ZHU Dan;GAO Mingxia;PAN Yi;FANG Ningxiang;LIU Yongfeng;PAN Hongge;State Key Laboratory of Silicon Materials & Department of Materials Science and Engineering,Zhejiang University;Zhejiang Light-Tough Composite Materials Co.Ltd.;

【机构】 浙江大学材料科学与工程学院； 浙江省立泰复合材料有限公司；

【摘要】 本文以稻壳为原材料,采用碳热还原法制备SiC晶须及SiC颗粒。研究了碳热还原反应温度、碳化稻壳的颗粒尺寸以及堆积密度等因素对产物结构和形貌的影响。研究发现在对碳化稻壳进行研钵研磨粉碎的中等尺寸条件下,随碳热还原反应温度从1450℃增加至1550℃,产物中SiC晶须的含量增加,并且SiC晶须的直径均匀性、平均直径及长度都逐渐增加。在1550℃经6小时碳热还原反应,生成的SiC晶须的平均直径为200 nm左右,长数十微米。而在碳化稻壳粉末未进行任何研磨处理的较大尺寸条件下,在1550℃经6 h碳热还原反应后产物中SiC含量减少。而碳化稻壳经球磨粉碎成较小的颗粒尺寸后,产物中几乎不含SiC晶须,只生成SiC颗粒。过大或过小的碳化稻壳颗粒尺寸均不利于SiC晶须的生长。经研钵研磨的稻壳粉末压成片后再进行碳热还原反应,预制件较大孔隙处也有较多的SiC晶须生成,但其SiC晶须的长度较前面直接由碳化稻壳粉末碳热还原反应获得的SiC晶须略短,且晶须直径的分布范围较大。更多还原

【Abstract】 SiC whiskers and particles were prepared from rice husks by a carbothermic method.The rice husks were coked at 900 ℃ for 2 h first under flowing Ar.Effects of the carbothermal reduction temperature,the particle size of the coked rice husks(RHs) and the packing method on the morphology and the contents of the SiC whiskers were studied.It is found that the content of the SiC whiskers increases with the carbothermal reduction temperature from 1450 to 1550℃.In addition,the diameter of the SiC whsikers becomes even and increases,and the length increases also.SiC whiskers formed from grinding coked RHs by mortar and muller at 1550℃ for 6 h show diameters of ca.200 nm and length of several tens micron.The content of SiC whiskers reduces when large size raw coked RHs is used.While there is also no SiC whisker formed and there is only particle SiC when the coked RHs were ground to small size.Too large and too small size of the coked RHs all don’t favour the generation of SiC whiskers.SiC whiskers were also formed in the large space of the packed preform from the coked RHs ground by mortar and muller,however,the SiC whiskers show shorter length and inhomogenous diameter compared with the one without packing.更多还原