Development of a System for Analysing Damage Mechanism of Coatings in Scratch Test

(1)研制了原位可观察显微划痕试验机。目前的机器还可以监测摩擦力和声发射信号，以估计临界载荷。利用该划痕测试系统可以对SKH57高速钢衬底上四种薄膜(CVD-TiC、PVD-TiC、CVD-TiN和PVD-TiN)的临界载荷进行评估。(3)对镀氢玻璃进行了划痕实验，并观察到了相应的损伤过程。随着压缩载荷的增加，Hf薄膜中的LING形裂纹逐渐形核。随着压痕的移动，它们彼此重叠，从而发生薄膜的局部剥落。

(1)A scratch test machine with in situ observable micrography has been developed. Frictional force and AE signal can also be monitored in the present machine to estimate the critical load. Failure processes of coatings can be continueously observed and monitored through a video recorder.(2)The critical loads for four kinds of thin films (CVD-TiC,PVD-TiC,CVD-TiN and PVD-TiN) coated on SKH57 high speed steel substrate could successfully be evaluated using the present scratch test system.(3)Scratch tests of Hf-coated glass were carried out and corresponding damage processes were observed in situ. Ling-shaped cracks were nucleated in Hf film with increase in compressive load. They were overlapped each other with movement of the indentor to occur local spalling of the film.