Wave-transparent silicon nitride radome material and preparation method thereof

Abstract

The invention discloses a wave-transparent silicon nitride radome material and a preparation method thereof. The wave-transparent Si3N4 radome material uses low-density porous silicon nitride as a core layer, uses silicon nitride or boron nitride chopped fibers or crystal whiskers as a core layer reinforcement phase, and uses condense silicon nitride as a surface coating layer. Firstly, after being mixed with the silicon nitride or boron nitride chopped fibers for pelletizing, silicon powder is evenly mixed with pore forming agent by a certain ratio, and is molded to a blank with a certain shape; the pore forming agent is totally decomposed at the temperature of 200-300 DEG C to obtain a porous blank. Then, the nitriding treatment is implemented to obtain a chopped fiber-reinforced porous silicon nitride ceramic body; the drying is implemented after the ultrasonic cleaning. Finally, the chemical vapor deposition (CVD) is implemented for the porous silicon nitride ceramic body to prepare a condense silicon nitride coating layer. The wave-transparent silicon nitride radome material and the preparation method thereof have the following advantages: (1) the chopped fibers or crystal whiskers are inlaid in the porous silicon nitride core layer to act the reinforcement effect; (2) the condense silicon nitride is on the outer layer of the porous silicon nitride core layer to act the water and steam permeation preventing effect; (3) the preparation process has short period and low cost.

Description

technical field [0001] The invention relates to a radome material and a preparation method thereof, in particular to a wave-transparent silicon nitride radome material and a preparation method thereof. Background technique [0002] Si 3 N 4 Ceramic materials have the advantages of high strength, good thermal stability and chemical stability, and can obtain good dielectric properties after being combined with quartz BN, etc., and are suitable for high-performance wave-transmitting materials. Since the 1980s, Si 3 N 4 The basic composition of ceramic radome materials has become one of the focuses of research in Western countries, especially in the United States. [0003] In 1982, the Boeing Company of the United States used reaction sintered Si 3 N 4 Density controllability, developed a multi-octave broadband radome. The cover wall structure is two layers, and the substrate is low-density Si 3 N 4 Core layer, surface layer is thinner high-density Si 3 N 4 Material. ...

AI Technical Summary

Problems solved by technology

For example, silicon nitride ceramics and their composite materials have high hardness, and it is difficult to form complex components by general sintering methods, and it is difficult to machine

Precursor immersion cracking method to prepare silicon nitride-based composite materials has great advantages, but the activity of silicon nitride precursor is very high, the synthesis is difficult, the cost is high, and its separation and purification are also a key issue