Dry Powder Deposition and Compaction for Functionally Graded Ceramics

Abstract

Functionally graded ceramics, with property variations realized via local compositional changes or porosity, are fabricated by powder deposition and compaction. A removable fixture is used to control the location of dry powders to produce a macroscopic powder array with 2‐D or 3‐D compositional variations. A new method is presented that relies on traditional powder pressing techniques to create spatial variation in composition and density. The fixture is removed before conventional powder compaction. This dry powder deposition and compaction method is capable of producing large monolithic bodies with functional gradients. This method produces designs with 3 mm discrete regions or pixels that have a normalized positional tolerance of 0.6% for a 39 mm substrate size. The method is used to realize a UHF antenna substrate with spatially variable dielectric properties.