以SiCl4-NH3-H2为反应体系,采用化学气相渗透(CVI)法制备Si3N4p/Si3N4透波材料.XRF测试表明试样主要含Si、N、O三种元素.XRD测试表明复合材料主要成分为α-Si3N4和非晶沉积物和非晶SiO2,并有微量的β-Si3N4和晶体Si,高温热处理可使非晶沉积物转变为α-Si3N4和β-Si3N4.SEM照片显示颗粒团间结合不够致密,残留气孔偏大.试样的弯曲强度最高为94MPa,介电常数为4.1-4.8.
Si3N4p/Si3N4 radome material was prepared by chemical vapor infiltration (CVI) with SiCl4- NH3-H2 systems. XRF analysis shows the specimen mainly contains Si, N, O three kinds of elements. XRD patterns indicate the sample consists of α-Si3N4, amorphous deposit, noncrystalline SiO2, small amount of β-Si3N4 and Si. Amorphous deposit can be converted into α-Si3N4 and β-Si3N4 by high temperature heat treatment. SEM photographs show weak bonding and large pores exist among granulae. Maximum fiexural strength of the samples is 94MPa, and dielectric constants are between 4.1 and 4.8.