Improved Consolidation of Nanopowders

Preparation of ceramics and composites from nanosized powders holds the promise of improved mechanical, electrical and optical properties. However, the extreme difficulty of processing these ultrafine powders often obviates the value of the small powder size. In particular, consolidation of powders to create preforms for later thermal processing is significantly hampered by the low bulk density, tendency towards agglomeration and poor flow characteristics of these powders. Poor quality preforms require higher thermal processing conditions, which in turn result in unwanted and destructive grain growth. Surmet has identified several processing opportunities that combat the low bulk density and poor consolidation problems for nanopowders. By improving the bulk density of nanopowders, better preforms can be produced with less volumetric change. Enhanced consolidating processes will further improve the quality of the preform. Our prior development has proven that reduced thermal processing requirements are required for performs with improved structure. The Phase I program will focus on further development of an existing nanopowder bulk density improvement process, and couple it with new developments in powder pressing technology to yield performs of improved density and structural uniformity. Our effort will utilize commercial nanosized spinel powders, with the intended product being a transparent optical ceramic material.