摘要
为避免Co颗粒高温氧化及团聚等问题,用Stober方法在微米Co颗粒表面包覆SiO_2壳层、制备了Co/SiO_2复合颗粒。用扫描电子显微镜、能谱仪对复合颗粒的组分结构进行表征,并用热重量分析法和矢量网络分析法评价了其高温氧化行为和电磁性能。分析表明:所制备的SiO_2壳层均匀致密,厚度随包覆次数的增加而变大;SiO_2壳层的存在抑制了Co颗粒的氧化,经7次包覆制备的复合颗粒其初始氧化温度达800℃。SiO_2壳层达到一定厚度时可有效抑制团聚造成的涡流效应。用Co/SiO_2颗粒、厚度2.89 mm的涂层在14 GHz可实现-15dB的吸收。研究为高温电磁吸波材料的研制提出了新的思路和方法。
Co/SiO 2 composite particles are prepared by Stober method for cladding SiO 2 on the surface of Co particles to avoid the high temperature oxidation and aggregation.The microstructure is characterized via scanning electron microscope(SEM)observation and energy disperse spectroscopy(EDS)analysis.The oxidation resistance and electromagnetic properties are evaluated via thermogravimetric analysis(TGA)and vector network analyzer(VNA)measurement.It is showed that the prepared SiO 2 shell is uniform and dense and the thickness increases as the cladding times increase.The presence of SiO 2 shell isolates the oxygen and thus enhances the oxidation resistance.Co/SiO 2 with 7 layered SiO 2 does not oxidize even exposed in air at 800℃.The eddy current effect is effectively suppressed after SiO 2 is introduced,which helps to improve the electromagnetic wave absorbing performances.A maximum reflection loss of-15 dB is observed at 14 GHz in a coating of 2.89 mm.The study presents a new method to fabricate electromagnetic wave absorption(EMA)filler that can be applied at high temperature.
作者
袁勇
刘超
姜建堂
甄良
YUAN Yong;LIU Chao;JIANG Jiantang;ZHEN Liang(Shanghai Spaceflight Precision Mechanism Institute,Shanghai 201600,China;School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,Heilongjiang,China)
出处
《上海航天》
CSCD
2018年第1期75-80,共6页
Aerospace Shanghai
