Effect of Zirconia-Modified Magnesia Investment on the Casting of Pure Titanium

氧化鎂包埋材添加氧化鋯後對純鈦鑄造的影響

10.6452/KJMS.200303.0121

洪純正(Chun-Cheng Hung)；侯桂林(Guey-Lin Hou)；蔡吉政(Chi-Cheng Tsai)；黃建青(Ching-Cheng Huang)

純鈦；鑄造；包埋材；熱膨脹 ； pure titanium；casting；investment；thermal expansion

The Kaohsiung Journal of Medical Sciences

19卷3期（2003 / 03 / 01）

121 - 126

英文

Several investigations have examined magnesia-based investments for pure titanium casting. However, the thermal expansion value was insufficient at low casting temperatures and high interfacial reactivity occurred at high casting temperatures. The purpose of this investigation was to modify a magnesia-based investment by adding a heat-resistant mold material, zirconia, in different ratios to produce a more accurate titanium casting. The thermal expansion value was measured using a new precise automatic laser recording machine and pure titanium was cast using an argon casting machine. The marginal accuracy was measured using stereomicroscope and the interfacial reactivity of the titanium was evaluated using X-ray diffraction analysis. The results indicate that adding different amounts of zirconia to a magnesia-based investment can increase its thermal expansion value and decrease the interfacial reactivity of the titanium. Maximal thermal expansion in the zirconia-modified investments significantly increased by 5-6 weight %（wt%）and peaked at 1.62% expansion. Selevest with 5 wt% zirconia had the smallest mean marginal discrepancy, 21.70μmat 750°C. Analysis of variance indicates significant differences in marginal discrepancy between zirconia-modified investments（p ＜ 0.001）. Adding zirconia can also decrease the interfacial reactivity of the titanium. The data indicated that proper amounts of zirconia（5-6 wt%） added to a magnesia-based investment can produce a more accurate and less interfacial reactive pure titanium casting.

Several investigations have examined magnesia-based investments for pure titanium casting. However, the thermal expansion value was insufficient at low casting temperatures and high interfacial reactivity occurred at high casting temperatures. The purpose of this investigation was to modify a magnesia-based investment by adding a heat-resistant mold material, zirconia, in different ratios to produce a more accurate titanium casting. The thermal expansion value was measured using a new precise automatic laser recording machine and pure titanium was cast using an argon casting machine. The marginal accuracy was measured using stereomicroscope and the interfacial reactivity of the titanium was evaluated using X-ray diffraction analysis. The results indicate that adding different amounts of zirconia to a magnesia-based investment can increase its thermal expansion value and decrease the interfacial reactivity of the titanium. Maximal thermal expansion in the zirconia-modified investments significantly increased by 5-6 weight %（wt%）and peaked at 1.62% expansion. Selevest with 5 wt% zirconia had the smallest mean marginal discrepancy, 21.70μmat 750°C. Analysis of variance indicates significant differences in marginal discrepancy between zirconia-modified investments（p ＜ 0.001）. Adding zirconia can also decrease the interfacial reactivity of the titanium. The data indicated that proper amounts of zirconia（5-6 wt%） added to a magnesia-based investment can produce a more accurate and less interfacial reactive pure titanium casting.