Cr-Si-N奈米複合薄膜之抗腐蝕性質研究

The Study of Corrosion Resistance in Cr-Si-N Nanocomposite Thin Films

氮化鉻薄膜具有優秀的機械性質與抗腐蝕能力，常被鍍製於模具表面上，以增加使用壽命；而在氮化鉻薄膜中添加適量的矽元素，又可以有效提高薄膜之機械性質，然而其抗腐蝕性質則尚未有深入探討。因此本研究將採用反應式雙極非對稱脈衝直流磁控濺鍍法沉積不同含矽量之Cr-Si-N奈米複合薄膜，並分別於3.5 wt%氯化鈉水溶液中進行抗腐蝕性質的研究，再利用SEM觀察薄膜經過腐蝕之後的表面與截面形貌變化，並使用EDS分析試樣表面之成分變化，以探討矽含量對於Cr-Si-N薄膜抗腐蝕性能的影響。本研究發現。Cr-Si-N薄膜可有效提昇SKD61模具鋼之抗蝕性，而Cr-Si-N薄膜在氯化鈉水溶液的抗腐蝕能力也隨著矽含量增加而提昇，此一性質與高矽含量薄膜截面呈現無特徵的微結構相關，本研究並根據薄膜腐蝕產生之剝落現象提出可能之腐蝕損壞機制。

Chromium nitride thin films have been widely applied in the molding industries to prolong the service life of coated components due to their excellent corrosion resistance and mechanical properties. The addition of silicon element into a Cr-N thin film could render a Cr-Si-N nanocomposite thin film with adequate mechanical properties. However, the corrosion resistance of Cr-Si-N thin films has not yet been studied thoroughly. In this work, the asymmetric bipolar pulsed DC reactive magnetron sputtering technique was adopted to deposit Cr-Si-N nanocomposite thin films with different silicon contents on SKD61 tool steel substrates. The corrosion resistance of each thin film was evaluated by a potentiostat in a 3.5 wt.% NaCl aqueous solution. Scanning electron microscopy and energy dispersive spectroscopy were employed to analyze the surface morphologies and chemical compositions of the corroded substrate surfaces. The influence of silicon content on the corrosion resistance of the thin films was investigated. It was observed that the corrosion resistance of the SKD61 tool steel substrate in the 3.5 wt.% NaCl aqueous solution was improved effectively due to the Cr-Si-N nanocomposite thin film. It is also noticed that the corrosion resistance of the Cr-Si-N nanocomposite thin film increased with increasing silicon content, which was attributed to the featureless microstructure of the high silicon containing thin film. A failure mechanism for the corroded thin film was also proposed in this study.