Processing of Titanium Hydride Powders into Uniform Hollow Spheres

摘要

The objective of the current work is to investigate the surface properties of TiH2 and the interaction of polymer dispersants and binders with this surface. The ultimate goal is to disperse TiH2 in acetone, forming slurries-exhibiting the viscosity, drying characteristics, and repeatability necessary to form highly uniform TiH2 hollow spheres. Slurry suitability is dictated by the solids loading and degree of dispersion, the influence of polymer additives on rheology and the evaporation of acetone, and the minimization of impurities soluble in the metal lattice that serve to embrittle the Ti. Heat treating these spheres results in dehydrogenation, leaving shells of titanium metal that can be bonded into lightweight foams. It is not yet possible to achieve ductile titanium foams because of the inability to control the purity of the heat treated Ti metal during firing. Of those tested, the only combination of polymers that resulted in favorable viscosity and evaporation rates when used in TiH2 slurries were Z-6020 polysilane and 2008 PMMA. Visual inspection and digital analysis found spheres made from slurries dispersed with polysilane and PMMA to be significantly more uniform than any alternative. The batch with the highest measured uniformity was formed from a slurry with a solids loading of 44 vol.% TiH2 treated with 1.0 wt.% Z-6020 polysilane and dispersed with 3.0 wt.% 2008 PMMA.