SI3N4 AND SI2N2O FOR HIGH-PERFORMANCE RADOMES

Si//3N//4 is a suitable material for high temperature radome applications because of its good thermomechanical and dielectric properties. The process parameters employed in pressureless sintering to obtain high density material were investigated. The best results were obtained with a 90wt. %Si//3N//4-5wt. %MgO-5wt. %Al//2O//3 mixture which had been attrition milled, dry pressed and sintered at 1650 degree C in a nitrogen atmosphere. Suitable processes have been developed in this work to enable Si//3N//4 radomes to be fabricated.