鈦金屬是一個較新的金屬且已被應用於牙冠及牙橋、金屬燒附陶瓷的固定補綴物及活動牙架等牙科裝置。鈦在高溫中極易氧化及發生反應，而造成鑄造困難，且鑄造時鈦表面易與包埋材產生燒結，常導致鑄造物的表面及機械性質變差。本研究主要使用氧化鋯應用披覆技術，探討鈦鑄造物的表面反應層及表面元素擴散的情形。
使用氧化鋯粉末與100% 及50% 兩種濃度的專用磷酸液體配成泥狀，分別披覆於蠟片表面，再以市售磷酸鹽系包埋材進行包埋，並以純鈦金屬鑄造。使用市售鈦用氧化鎂系包埋材進行鈦鑄造作為對照。利用OM、SEM 及EDS針對鈦鑄造物表面進行觀察及元素分析，以維氏硬度測試鈦鑄造物表面硬度，再以雙向ANOVA針對結果進行統計分析。
結果顯示：實驗組所得之鈦鑄造物無明顯的缺陷且形態完整，表面之披覆材料及包埋材可輕易去除，硬度測試結果顯示其表面反應層厚度約為150μm，與對照組並無顯著性差異。OM觀察鑄造物的結構可見表層的燒結層，內層的α-case及最裡層結晶較長的針狀結構。經Line scanning及Mapping分析結果顯示實驗組鑄造物表面無元素擴散進入的情形，而對照組鑄造物表面則有明顯鋁元素擴散進入金屬表面的情形。
結論：本實驗所用氧化鋯披覆技術可應用於鈦金屬鑄造，透過氧化鋯的披覆可以隔絕或減少包埋材成份擴散至鈦表面，對於減少鈦金屬表面反應是有效果的。
Titanium is a relatively new metal for cast dental prostheses and has been used for crown and bridge, metal—ceramic restorations, and partial framework. Titanium is high reactive and oxidize easily at high temperature, resulting in the technological difficulties in casting it. During casting, the greater adhesive phenomenon was obtained between titanium surface and the investment; and the surface and mechanical properties of the casting became poor. In this study, the zirconium oxide was applied with coating technique. To analyze the element diffusion and surface reaction layer of titanium castings.
The mixed slurry of zirconium oxide powder and commercial Begosol® (100% and 50%) liquid was coated on the wax pattern respectively, and the commercial phosphate-bonded investment was invested. The commercial pure titanium was used for casting. The commercial magnesium oxide investment was as control. The surface of castings were observed and analyzed by OM, SEM, EDS. The Vicker’s hardness test was performed and the results were evaluated by Two-way ANOVA.
The results show the obtained castings from experimental groups were non-defect and intact. The coating material and mold was removed easily. The results of HVN shown: the thickness of surface reactive layer was about 150μm, there was no significant difference with the control group. The layer structures of casting (the outer sintering layer, α-case layer, and inner acicular structure) were observed by OM. There was not element of the coating material and mold detected on the surface of castings by line scanning and mapping, and aluminum was detected obviously on the surface of castings obtained from the control group.
In this study, the used coating material applied to titanium casting can obtain good results of reduce surface reaction and avoid elements of mold diffusing into the surface of titanium casting.
