摘要
借助发泡法将气孔引入Si多孔坯体,使坯体的体积分别增加0、1、2、3倍,通过原位氮化工艺制备了氮化硅纤维材料,重点研究了发泡体积倍数对氮化硅纤维材料显微结构和性能的影响。结果表明:(1)发泡法引入气孔后,坯体中存在发泡孔、孔壁窗口、孔壁微孔三种孔结构。提高发泡倍数,试样中气孔率升高,孔壁窗口数量增多,N 2易流通,有利于氮化反应的进行。(2)氮化硅纤维只能生长在材料的孔缝部位,引入的气孔为氮化硅纤维提供了足够大的生长空间,反应后试样孔中长满了絮状的氮化硅纤维。随发泡体积倍数增加,试样孔壁中生成的氮化硅由粒状转变为纤维状,形成了氮化硅纤维交织孔壁结构。(3)发泡法引入气孔后,材料的强度由孔壁提供。随发泡倍数增加,试样的气孔率升高,单位面积内孔壁的有效截面减小,导致材料的强度降低。
By means of foaming method,the pores were introduced into Si porous billets to increase the volume of the billets by 0,1,2 and 3 times,respectively.Silicon nitride fiber materials were prepared by in-situ nitriding process,and the effect of foaming volume multiple on their microstructure and properties was studied.The results show that:(1)after introducing the pores by the foaming method,there are three pore structures in the billets:foaming pore,pore wall window and pore wall micropore.By increasing the foaming multiple,the porosity of the sample increases,the number of pore wall windows increases,which is beneficial to the nitridation since N2 is easy to circulate;(2)the silicon nitride fibers can only grow in the pore joints of the material,the introduced pores provide enough growth space for the silicon nitride fibers,after the reaction,the sample pores are filled with flocculent silicon nitride fibers;with the increase of foaming volume multiple,the silicon nitride formed in the pore wall of the sample changes from granular to fibrous,forming interwoven pore wall structure of silicon nitride fibers;(3)the strength of the material is provided by the pore wall after the introduction of the pores by the foaming method;with the increase of the foaming multiple,the porosity of the sample increases and the effective section of the inner pore wall in unit area decreases,which decreases the strength of the material.
作者
杜鹏辉
王刚
韩建燊
孙红刚
梁鹏鹏
张琪
李红霞
Du Penghui;Wang Gang;Han Jianshen;Liang Pengpeng;Zhang Qi;Yuan Bo;Li Hongxia(State Key Laboratory of Advanced Refractories,Sinosteel Luoyang Institute of Refractories Research Co.,Ltd.,Luoyang 471003,Henan,China)
出处
《耐火材料》
CAS
北大核心
2020年第6期508-512,共5页
Refractories
基金
国家自然科学基金面上项目(51672256)
河南省科技创新杰出人才基金项目(184200510024)。
关键词
氮化硅纤维
发泡倍数
发泡法
强度
silicon nitride fiber
foaming multiple
foaming method
strength
