IBAD界面反应及其对结合强度的影响

Interfacial Reaction of IBAD and Its Effect on Adhesion

研究了不同能量界面动态共混过程中的界面反应及其对沉积在GCr15和45#钢基体的IBADCrN薄膜结合强度的影响。用AFM和GDOES分析了不同能量共混界面的形貌和成分。用循环滚动接触法使薄膜在膜基最薄弱处产生剥落,用以分析界面反应产物,同时对膜基结合强度加以评价。用SEM,EDAX和XPS分析了滚动接触疲劳试验后的疲劳剥落区的形貌、成分及结构。结果表明40kV共混后的界面粗糙度高并出现了碳含量的升高,而20kV时界面碳含量和基体差不多。基体碳化物在离子轰击引起的热峰效应的作用下发生分解,而对基体和碳化物的选择溅射导致了碳含量的升高以及粗糙度的增加。分解后的碳以石墨态的形式存在。在滚动接触疲劳试验时循环载荷的作用下,界面处的石墨相当于孔洞引起应力集中。疲劳裂纹起始于界面石墨富集处表明它是引起结合强度差的主要原因。

Cyclic rolling contact is applied on the coating layer to fracture the interface at the weakest sites in order to reveal the interfacial reaction products. In the mean time the bonding strength value by contact fatigue method can be evaluated. Different energies of ion intermixing to process the interfaces of IBAD CrN films were studied on GCr15 and 45 steel substrates. The fractured interfacial regions after rolling contact loading were observed with AFM and the compositions were analyzed with GDOES, SEM and EDAX, XPS was also used to detect the carbon state. It's found that the carbon content in the interface of 40 kV ion intermixing reaches 12.6 at.% and for 20 kV it's about 7 at.%, which is close to that in the substrate of GCr15. The different sputtering rates of carbide and matrix lead to enrichment of carbon in the interface. The carbide decomposes by thermal spiking of the ion bombardment. and transforms into graphite. which is convinced by XPS: Graphite plays a role as pores in the interface and increases the stress concentration under cyclic loading. The fatigue fracture occurs at the. graphite and reveals this reaction product.