摘要
目的为提高ZrB_2-SiC复合等离子喷涂粉末的致密度。方法采用Zr-B_4C-Si体系,使用自蔓延高温合成(SHS)技术和感应等离子球化(IPS)技术制备了球形ZrB_2-SiC复合粉末,并对其相结构和微观形貌等进行了表征。结果采用SHS技术合成出的多孔ZrB_2-SiC复合陶瓷,其SiC质量分数为12.10%,由等轴颗粒构成,颗粒粒径均<5μm。经IPS处理后,粉末松装密度由1.62 g/cm^3提高到1.88 g/cm^3,其中直径<25μm的粉末为球形或椭球形,直径>25μm的粉末则保留了球化前的不规则形状,但粉末轮廓变得平滑。粉末中SiC质量分数降低为6.64%(体积分数为11.89%),粉末表层SiC质量分数降低为5.63%,部分SiC颗粒重新分布在ZrB_2颗粒的间隙处,并且粉末中出现ZrB_2-SiC的共晶或伪共晶组织。结论使用SHS技术能够制备出两相分布相对均匀、颗粒细小的ZrB_2-SiC复合陶瓷,虽然其含有较多孔洞,但颗粒之间相互接触部位的结合比较紧密。IPS处理后,粒径<25μm的ZrB_2-SiC复合粉末的致密度和球形度获得了显著提高,粉末中SiC在IPS过程中的部分分解导致其含量未能达到最佳范围。
The work aims to improve the density of ZrB2-SiC composite plasma spraying powder. Spherical ZrB2-SiC composite powders were prepared by self-propagating high-temperature synthesis(SHS) and induction plasma spheroidization(IPS)from Zr-B4C-Si system and the phase structures and micro-morphology were characterized. The porous ZrB2-SiC composite ceramics synthesized by SHS and with the content of SiC of 12.10% were composed of equiaxed particles with particle size less than 5 μm. After IPS, the apparent density of the powders increased from 1.62 g/cm3 to 1.88 g/cm^3. The powders with diameter less than 25 μm were spherical or ellipsoidal, while the larger ones with diameter more than 25 μm retained irregular shape before spheroidization, but the outline became smooth. The content of SiC decreased to 6.64%(percentage of capacity was11.89%), while SiC content in the surface layer of the powders decreased to 5.63%. Some SiC particles were redistributed in the interstices of Zr B2 particles, and the eutectic or pseudoeutectic structure of ZrB2-SiC appeared in the powders. Therefore,ZrB2-SiC composite ceramics with uniform distribution of ZrB2 and SiC can be prepared by SHS. Although there are many holes in them, the bonding between particles is tight. After IPS, the densification and sphericity of the powders with diameter less than 25 μm have been significantly improved. Partial decomposition of SiC in the powders during IPS results in that the content fails to reach the optimum range.
作者
张博康
张晓梅
李江涛
杨增朝
宁先进
王全胜
ZHANG Bo-kang;ZHANG Xiao-mei;LI Jiang-tao;YANG Zeng-chao;NING Xian-jin;WANG Quan-sheng(School of Material Science & Engineering, Beijing Institute of Technology, Beijing 100081, China;Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2019年第4期104-109,共6页
Surface Technology
关键词
ZrB2-SiC复合粉末
自蔓延高温合成
感应等离子球化
致密度
球形度
共晶组织
ZrB2-SiC composite powder
self-propagating high-temperature synthesis
induction plasma spheroidization
density
sphericity
eutectic structure
