聚氨酯泡沫模板法低温制备SiC泡沫陶瓷

PREPARATION OF SILICON CARBIDE FOAM CERAMICS BY POLYURETHANE SPONGES TEMPLATE METHOD

利用聚氨酯泡沫浸渍聚碳硅烷(PCS)与SiC微粉制成的有机溶剂浆料,挂浆素坯经热氧化处理后于1000℃下惰性气体中烧结制备SiC泡沫陶瓷。运用X衍射分析、扫描电镜、线收缩率测定和三点弯折强度测试等手段,研究了PCS含量、SiC颗粒粒径对泡沫陶瓷线收缩率、微观形貌、抗弯强度的影响。结果表明:PCS经1000℃热解产物为无定形结构,无定形SiC将SiC颗粒粘结起来,形成泡沫陶瓷的骨架筋结构,泡沫陶瓷孔径介于0.3～0.6mm之间;SiC泡沫陶瓷线收缩率随SiC颗粒尺寸与PCS含量的增大而增加,抗弯强度随颗粒尺寸的增加而减小;在颗粒尺寸为0.3μm时,PCS含量为10%时,抗弯强度最大为2.8MPa,当SiC颗粒尺寸为1μm、5μm、10μm和20μm时,PCS含量为15%时,其抗弯强度最大值分别为2.2 MPa、2.1MPa、1.8 MPa和1.4MPa。

Polyurethane sponges were dipped into the organic solvent slurry prepared with polycarbosilane and silicon carbide powder in order to obtain green body. Silicon carbide foam ceramics were obtained by pyrolysis of the green body at 1000℃ in inert atmosphere. The phrase structure, linear shrinkage, microstructure and flexural strength were studied by X-ray diffraction, scanning electron microscope, linear shrinkage testing and flexural strength testing. Results showed that amorphous SiC was formed when pyrolysis of polycarbosilane at 1000℃ .SiC particles were bonded together by amorphous SiC to form the foam ceramics＇ pore frame structures. Pore size range was from 0.3mm to 0.6mm.The linear shrinkage was increased with the SiC particle size and PCS content increasing.The flexural strength was decreased with SiC particle size increasing. When the particle size was 0.3 g m and PCS content was 10%,the flexural strength was up to 2.8MPa. When the particle size was 1μm,5μm,10μm, 20μm and PCS content was 15%, the flexural strength had maximum was 2.2MPa, 2.1MPa, 1.8MPa and 1.4MPa, respectively.