Preparation of high-strength Si3N4 antenna window using selective laser sintering

Abstract In this study, a high-strength silicon nitride (Si3N4) antenna window was successfully developed via selective laser sintering (SLS) with cold isostatic pressing (CIP) after debinding before final sintering. The effects of CIP after debinding and sintering aids on the bulk density, total porosity, bending strength and microstructure of Si3N4 ceramics were examined. The results show that the bending strength of SLS Si3N4 ceramics can be greatly improved by adding sintering aids between Si3N4 granules and by CIP after debinding. Optimal performance of ceramics is obtained by CIP after debinding and the use of inter-granule sintering aids. The porosity, bulk density, and bending strength are 18.7%, 3.11 g/cm3, and 685 MPa, respectively. Eliminating the pores by the CIP after debinding and by inter-granule sintering aids promotes the growth of rod-like β-Si3N4, which lock with each other contribute to the strengthening of Si3N4 ceramics.