等离子喷涂纳米莫来石基复合吸波涂层性能研究

Performance of Mullite Matrix Microwave Absorber Coatings Fabricated by Plasma Spraying Technology

应用喷雾造粒技术制备了Mg_3Si_4O_(10)(OH)_2、C与莫来石复合吸波粉末,并采用等离子喷涂技术制备了复合吸波涂层.在涂层沉积过程中,吸收剂相的C发生反应,滑石相高温氧化、分解,生成原顽辉石.实验结果表明,结合强度随涂层厚度增加而降低,0.8mm时达到2MPa.并用小波分析方法得出涂层断裂源为晶界玻璃相.涂层中新生成相的成分增加了涂层的介质损耗性能,使得涂层的电磁波反射性能下降,并向高频部分偏移,随涂层厚度的增加,反射率曲线向低频移动.所制备涂层在0.8mm时在15～18GHz之间均小于-5dB.

The clusters of mullite matrix（steatite,carbon）composite absorber powders were produced by using spraying spheroid granulator,and the composite powders were used to fabricate composite microwave absorber coatings by plasma spraying technique.The results show that during the plasma spraying,the carbon is oxidized,and the steatite is decomposed to enstatite and quartz for the high temperature plasma gas.The experiments show that the mean adhesive strength of coatings decreases with the coating thickness increasing,which reaches 2MPa with thickness of 0.8mm.The crack extracted the coatings rupture surfacewith wavelet maximum module exists in the glass phase interface.For these coatings,with the coatings thickness increasing,the reflectivity coefficient transforms to low frequency; while with the complex permittivity of enstatite increasing,it decreases and transforms to high frequency. The reflectivity coefficients of the coatings with thickness of 0.8mm are all below -5dB in the frequency range from 15GHz to 18GHz.