声发射监听划痕法评价膜层结合情况的有效性

本文介绍声发射技术在判断划痕临界载荷以推定膜层与基材结合情况的研究结果。实验的试样是玻璃基材真空蒸镀铝膜、软钢上电镀镍层以及不同硬度的钢样上离子镀超硬氮化钛膜层。在脆性硬质基材上无论镀软膜或硬膜,划痕试验中一旦监听到声发射信号即表明基材与膜层结合失效,此时的划痕载荷即为临界载荷。塑性基材镀软膜层直到划痕到基材也无声发射信号出现。超硬膜层与钢基材的划痕试验中,声发射信号出现时载荷往往低于临界载荷。两者的差值决定于超硬膜的厚度和膜层与基材的硬度差。

Validity of Acoustic Emission for Monitoring Scratch Test in Adhesion Evaluation of Films

The evaluation of adhesion between film and substrate in scratch test monitoredby acoustic emission has been described.A series of specimens used in this investiga-tion are Al (soft) films on glass (brittle) by vacuum evaporation,Ni coating on mildsteel (ductile) by electroplating as well as TiN(hard) films on different kinds of steels(substrate) by ion-plating.When the signal of acoustic emission (A.E.) appears inhard or soft films on brittle or hard substrates,the failure of adhesion is confirmed.Therefore,the critical load of scratch test can be identified by A.E.technique.Onthe other hand,there is no A.E.signal during scratch test for soft films on ductilesubstrates,until the film is removed.For super hard films on steel substrates,thesignal of A.E.depends on the thickness of coatings and difference of hardness bet-ween film and substrate.The critical load is always higher than the load at whichthe A.E.signal appears during scratch process.