2019 Volume 59 Issue 1 Pages 104-112
The nitriding behavior of titanium sponges with nitrogen gas and the dissolution behavior of titanium nitride titanium sponges in titanium alloy melt were examined.
A titanium nitride sponge was produced using nitrogen gas. A high nitriding temperature corresponded to a longer nitriding time, and thus to a higher nitrogen concentration in the sponge. Both the titanium sponge and titanium nitride sponge featured a porous structure. Porous structures at both the surface layer and inside were formed at intervals of about 5.0 × 10−5 m. When the titanium nitride sponge was immersed into a titanium alloy melt, the melt permeated into the pores. The nominal dissolution rate of the titanium nitride sponge in the titanium alloy melt depends on the temperature of the melt. Higher melt temperatures corresponded to higher nominal dissolution rates. However, the concentration of nitrogen in the titanium nitride sponge had no influence on the nominal dissolution rate. Nitriding models of the titanium sponge with nitrogen gas, and the dissolution model of the titanium nitride sponge into the titanium alloy melt were proposed. These models considered the structure of the sponge; thus, the behavior of both the nitriding and dissolution sponges was predicted and confirmed.