電漿氮化表面改質TiN超硬鍍膜佈層對鈦合金氫脆化研究：破壞力學特性

Hydrogen Embrittlemenet of Titanium Alloy with Plasma Nitriding Surface Modification of TiN Hard Coating: (II) Fracture Mechanics Characteristics

本篇在研究氫脆對不同表面改質的鈦合金其破裂韌性值之影響，將圓片形的試片鍍不同之鍍膜，然後再用電化學的方法充氫至鈦合金底材。利用DGS，SEM和X-ray分析表面性質。結果顯示隨著充氫時間的增加，破裂性質會降低。電漿離子氮化和離子植入TiN的試片經充氫後破裂韌性值下降了，而具CrN膜之試片經144小時充氫後，破裂韌性值依然維持不變。CrN鍍膜雖遭侵蝕但卻很有效的阻止了氫之滲透進入基材。

The effect of hydrogen embrittlement on the fracture toughness of titanium alloy with different surface modifications was investigated. Disk shape compact tension spectimens were first treated with different hard layers, then hydrogen charged into the substrate by electrochemical method. GDS, SEM, and X-ray diffractometry were applied to analyze the surface characteristics. The results revealed that as-received titanium alloy decreased with the increase of hydrogen charging time. Fracture toughness of the alloy after plasma nitriding or ion implantation decreased as well after cathodic charging, but alloy coated with CrN film, fracture toughness retained even after hydrogen charging for 144 hours. Obviously, hydrogen permeation was effectively retarded by the CrN film, but was at the sacrifice of the CrN film itself.