熱膨張抑制埋没材を用いたチタン鋳造 第３報 大粒子コロイダルシリカを練和液として用いた場合

Abstract

We studied the effects of the size of colloidal silica in a mixing liquid for phosphatebonded thermal expansion inhibited investment on the surface properties and the reaction layers of pure titanium crowns.1. Cast crowns were easiest to separate from their molds when 40% large colloidal silica particles were used.2. The surface roughness of a crown when using large colloidal silica particles was observed half as much as that when using small colloidal silica particles.3. The surface hardness of crowns showed lower values when large colloidal silica particles were used than when small colloidal silica particles were used.4. The surface roughness of investment mold showed lower values when large colloidal silica particles were used than when small colloidal silica particles were used.5. Elemental analysis revealed that there was a Ti-poor reaction layers which contained O, P and Si in the surface of the crown.Additionally, this analysis showed that the lowest concentration of Si and P was in the surface of crown when 40% large colloidal silica particles were used. These results indicate that the surface properties and the reaction layer of pure titanium crowns made by the titanium casting procedure using phosphate-bonded investment when large colloidal silica particles were used were better than those of small particles.