Fabrication of broadband wave-transparent porous Si3N4 ceramics by powder hybrid mechanism combined with binder jetting 3D technology

Abstract

Binder jetting 3D printing is a novel methodology for fabricating broadband wave-transparent porous Si3N4 ceramics, but it faces challenges in low bending strength post-sintering, which impedes its broader application. This study proposed a hybrid mechanism by mixing Si and Si3N4 powders to surmount this challenge, and systematically scrutinized the mechanical and dielectric performance evolution of sintered samples at 1700–1800 °C after investigating nitride rules. Adding Si powder notably improved the bending strength, while retaining superior wave-transparent performance. When Si: Si3N4 was 50:50, at 1750 °C and 1800 °C, the bending strength was enhanced by 2.9 and 2.5 times compared to no Si powder addition. The real permittivity was consistently below 3.3. This work presented an effective methodology for modulating the overall performance of porous Si3N4 ceramics.