本文探討添加不同比例稀土元素(氧化鑭)，對於Ti-6Al-4V合金表面氬銲被覆硼化鎢(WB)陶瓷被覆層之顯微結構與磨耗行為的影響。並找出影響耐磨耗能力之主要關鍵，以做為Ti-6Al-4V合金表面耐磨耗改質的依據。
研究結果顯示，WB系列之被覆層則屬於析出強化型機構。在WB被覆層中添加適量之氧化鑭(La2O3)可以使基地的顯微組織微細化，並促進析出物之形成。添加氧化鑭(La2O3)的WB被覆層內的析出相較粗大，具較佳之機械互鎖效應，在低滑動速度下(0.11m/s)，以添加4.5%氧化鑭之WB被覆層效果最佳，但在高滑動速度下時(0.22m/s)，反而以3.0%氧化鑭之WB被覆層有最佳的耐磨耗能力。適量之氧化鑭(La2O3)，可使其被覆層之耐磨耗能力有效地提升。

This thesis investigates the effect of rare earth (La2O3) on microstructure morphology and wears resistance of clad layer for Ti-6Al-4V alloy clad with WB powder. In addition, the major factors that influence wear performance of clad layer can be found in this study.
According to the results of this study, WB clad layers was strengthened by the precipitation of reinforcing phases. The results showed that adding suitable amount of La2O3 can promote microstructure refining and precipitates growing in WB clad layer. Thicker precipitates possess better mechanical interlocking effect and can increase significantly the wear-resistance ability in WB cladding specimens. Under the lower sliding speed, WB-3.0% La2O3 clad layer indicated the best wear resistance performance. However, WB-4.5% La2O3 appeared the excellent wear resistance ability when sliding in the higher sliding speed. With moderate amount of La2O3, therefore, the wear resistance could be improved considerably.

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