CrN涂层电化学剥离研究

Reaseach on Electrochemical Stripping of CrN Coatings

CrN涂层因其热稳定性、沉积温度、优秀的耐磨性能和良好的抗腐蚀性而在加工领域得到应用。不过,在某些情况下经常需要将此种涂层剥离下来而不伤及基体表面。本文利用电化学技术开发了一种在碱性溶液中剥离CrN涂层的工艺。在恒电流条件下,我们分别研究了CrN单一涂层和复合涂层剥离。由于在电流作用下氮化物具有较强的表面活性,从而产生更多的可溶成分。此控制过程简单易行,当电流密度突然上升时,就意味着CrN涂层完全剥离。涂层剥离后的样品表面形态良好,由于剥离后的表面上并没有发现蚀损斑,且表面均匀一致,这为CrN涂层的再沉积创造了必要的条件。

CrN coatings have emerged as alternative in machining application due to thermal stability,low deposition temperature,excellent wear resistance and good corrosion resistance.However,under some circumstances it is often necessary to remove these kinds of coatings without attack of the base metal surface.In this work,a stripping method based on electrochemical techniques has been developed to strip chromium nitride coatings in an oxidizing alkaline solution process.Under galvanostatic conditions,it has been applied to strip CrN coatings with different configurations.The greater activity of the nitride in this medium leads to the formation of more soluble species.The complete removal of the chromium nitride layer is indicated by a sudden rise in the potential in time,which allows simple control of the stripping process.The surface appearance of the samples at the end of the coating removal process is good,since pitting is not detected and surface homogeneity is preserved,which are necessary conditions for redeposition of this type of coatings.