PI/Ba(La,Ca)TiO_3复合吸波材料的制备及性能研究

Preparation and Properties of PI/Ba(La,Ca)TiO_3 Composite Absorbing Materials

以耐高温聚酰亚胺(PI)树脂作为基体,La^(3+)/Ca^(2+)共掺杂的钛酸钡(Ba(La,Ca)Ti O_3)粉体作为吸波剂,采用热压法制备了PI/Ba(La,Ca)Ti O_3复合吸波材料。研究了Ba(La,Ca)Ti O_3粉体的晶相结构、复合材料的断面结构、弯曲强度以及复合材料在低频波段的介电常数和吸波性能。结果表明:Ba(La,Ca)Ti O_3粉体晶相结构单一,晶粒发育良好,颗粒呈现类球形;复合材料介电常数的实部和虚部都随着Ba(La,Ca)Ti O_3用量的增加而提高,力学性能随着Ba(La,Ca)Ti O_3用量的增加先提高后降低;当Ba(La,Ca)Ti O_3用量为12%时,在350℃下PI/Ba(La,Ca)Ti O_3复合材料的吸波峰值为-14.7 dB(2.6 GHz),表明其具有优异的高温低频吸波性能。

A composite absorbing material based on high temperature resistant polyimide resin as matrix, and La^3+/Ca^2+ co-doped barium titanate(Ba(La,Ca)TiO3) powder as absorbing agent was prepared by hot pressing method. Crystal phase structure of Ba(La,Ca)TiO3 powder, microstructure, mechanical properties, dielectric and low frequency absorbing properties of the composite were studied. The results show that Ba(La,Ca)TiO3 powder has a single crystal phase structure, good grain development and spherical particle shape. Real and imaginary parts of the dielectric constant of composites increase with the increase of Ba(La,Ca)TiO3 content. The mechanical properties of composite increase first and then decrease with the increase of Ba(La,Ca)TiO3 content. Absorbing properties of polyimide/Ba(La,Ca)TiO3 composite was tested at 350℃. The best high temperature low frequency absorbing effect occurred when the filling amount of Ba(La,Ca)TiO3 is 12%, with absorption peak reaching-14.7 dB at 2.6 GHz.