Structure Formation during Preparation of Variable Porosity Titanium Foams by Solid State Replication
Fabrication of variable porosity titanium foams through incorporation of sacrificial sodium chloride powder has been investigated. A three-dimensional solid foam pore skeleton containing macro- (200-400m), micro- (5-10m) and sub-micropores (< 1.5m) was formed during high temperature sintering of commercial purity titanium powder containing sacrificial sodium chloride particles, faceting of the interior pore powder surface being noted throughout. The largest macro-pores had a cubical topography representative of the sodium chloride powder that had been vaporized during heating to the sintering temperature. Formation of the smaller micro-pores appeared to have occurred during the compaction process these being retained in the specimen body due to incomplete sintering of the host powder. Finally formation of the smallest sub-micropores was associated with high temperature gas evolution and entrapment during sodium chloride vaporization.
M. Ashraf Imam, F. H. Froes, Kevin F. Dring
Y. Orlova et al., "Structure Formation during Preparation of Variable Porosity Titanium Foams by Solid State Replication", Key Engineering Materials, Vol. 436, pp. 165-170, 2010