CP titanium casting using phosphate-bonded investments : Improvement in mold sintering temperature

Abstract

In order to improve the reactive layers, we fabricated commercial pure (CP) titanium cast crowns using experimentally produced phosphate-bonded investment materials in which Li₂O was added to Al₂TiO₅, and obtained the following results regarding behavior of the reactive layers. The compressive strength at a 1,000℃ firing temperature was more than twice that for 900℃ Surface roughness was the lowest in the CP titanium crowns cast at a firing temperature of 1,200℃ using the experimentally produced investment materials. Observation of the metallic microstructures showed black erosive areas resulting from etching when the experimentally produced investing materials were used. However, the etched erosive areas decreased when the firing temperature increased to 1,200℃. Analysis of the elements on the surface of the CP titanium crowns indicated that the reactive layers contained components of the investment materials on the surface of all specimens for all firing temperatures. The depth of the reactive layer was shallowest in the specimens cast with the smallest addition of Li₂O to Al₂TiO₅ at a firing temperature at 1,200℃. Shika Igaku (J Osaka Odontol Soc) 2002 Mar; 65(1): 11-22.