低温合成PSN微球及其裂解制备Si-C-N空心陶瓷微球

Low-temperature Synthesis of PSN Microspheres and Preparation of Si-C-N Hollow Ceramic Microspheres via Pyrolysis Process

以含乙烯基聚硅氮烷（PSN）为先驱体聚合物,二乙烯基苯（DVB）为交联剂,采用乳液工艺,在低温条件下交联固化合成聚硅氮烷（PSN）微球,并在高温下裂解制得Si-C-N空心陶瓷微球。研究了原料比例、固化时间和裂解条件对PSN微球及Si-C-N空心陶瓷微球形貌、尺寸和形成过程的影响。结果表明,当PSN与DVB的比例为2∶1、固化时间为6 h时,可在80℃下得到表面光滑、尺寸较均匀、直径为600~800 nm的PSN微球;Si-C-N陶瓷微球随着PSN与DVB比例的增加,逐渐显现出空心结构;1000~1200℃裂解后,空心球形成,XRD表明此时产物呈非晶态;裂解温度1400℃时,空心微球表面变得粗糙,生成Si3N4和Si C晶粒。

The polysilazane（ PSN） microspheres were prepared via emulsion technique at low temperature using vinyl-containing polysilazane as precursor polymer,divinylbenzene（ DVB） as cross-linking agent,followed by pyrolysis process to obtain Si-C-N hollow ceramic microspheres. Effects of raw materials ratio,curing time and pyrolysis parameters on the morphology,size and the formation of Si-C-N hollow ceramic microspheres were studied. The results show that smooth surface and uniform PSN microspheres with diameter of 600-800 nm are formed with the mass ratio of PSN and DVB of 2∶ 1 after a 6 h reaction at 80 ℃. With the mass ratio of PSN and DVB increasing,hollow structure of the Si-C-N ceramic microspheres is gradually formed. Hollow microspheres are obtained at the pyrolysis temperature of 1000-1200 ℃,which are proved of amorphous phase by XRD data. The surface of the hollow microspheres becomes rough,and crystalline phase of Si3N4 and Si C are formed at the pyrolysis temperature of 1400℃.