PRODUCTION TECHNOLOGY OF RADIO-TRANSPARENT CERAMIC MATERIALS

Abstract

Ceramic radiotransparent materials are non-metallic materials that ensure the transmission of electromagnetic radiation in the radio frequency range of 105–1012 Hz with minimal dielectric losses in the operating temperature range (tgδ 10-2–10-5, ε < 10) and a low value of the radio wave reflection coefficient (P < 1 %). Ceramic radiotransparent materials are used to create rocket and aircraft fairings that protect antenna systems from external factors. For the synthesis of radiotransparent ceramic materials, it is expedient and promising to use such crystalline phases as celsian (BaAl2Si2O8) and slawsonite (SrAl2Si2O8) due to their low dielectric constant and dielectric loss tangent, as well as rather high thermal stability and melting point compared to other aluminosilicate compounds (mullite, spodumene, cordierite, etc.). The development of technology for obtaining radio-transparent ceramic antenna fairings and elements of protective structures of antenna systems of aviation facilities based on the BaO (SrO) – Al2O3 – SiO2 system is relevant. For the formation of complex profile ceramic radiotransparent materials slurry casting in porous gypsum molds is used. In order to compare the developed ceramic compositions, the physico-mechanical, dielectric and electrodynamic properties were studied under normal conditions and in the millimeter frequency range (26-38 GHz). As a result of the research, the following have been developed: a technology for the production of ceramic radiotransparent materials based on slawsonite by semi-dry pressing method, based on celsian-slawsonite by slip casting method and based on celsian or slawsonite by slip casting method. It has been established that the developed materials meet the technical requirements for radio-transparent ceramic materials and can be used to produce elements of protective structures of antenna equipment, such as nose fairings for aircraft.