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Study on the Evaluation of Coating Adhesion and Strength of Metal Coated with Ceramic Thin Film

陶瓷薄膜金属镀层附着力及强度评价研究

基本信息

批准号：
03650060
负责人：
SHIOZAWA Kazuaki
金额：
$ 1.28万
依托单位：
TOYAMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03650060/
关键词：
TiN PVD CVD Thin Film Fatigue Strength Adhesion,Flaw Crack Initiation き裂発生

项目摘要

The ceramic coating for various kinds of machine components improves the wear resistance, heat resistance, cutting ability or corrosion resistance. Coating technology on metals will be utilized more widely for various kinds of machine components and structures which require high functional properties. The aim of this investigation is to clarify the coating adhesion, strength of thin film and the effect of hard thin film coated on the fatigue behavior of metals. Scratch test, static tensile test, residual stresses measurement in film by the X-ray method, and load-controlled high-cycle and strain controlled low-cycle fatigue tests were conducted, using specimen of 0.37% carbon steel coated with TiN by physical vapor diposition (PVD) and chemical vapor diposition (CVD) methods. Main conclusions obtained in this study are as follows:1. The scratch adhesion of TiN film coated by PVD is higher than that coated by CVD. Coating failure modes in the scratch test are different in each other; PVD … More film is failed by chipping as a result of the bending of film and CVD film is spalled by buckling.2. From the static tensile tests, it was found that flaws on PVD and CVD coating films occurred at the total tensile strains of 0.40% and 0.87%, respectively, and that they increased with the strain. It has been shown that scratch adhesion and fracture of coating film under tensile strain does not share any features.3. The fatigue life of specimens coated is affected by the applied stress ratio and the strain amplitude level. This is due to the crack initiation behavior in the substrate induced by the rupture of the coating film. The fatigue life of coated specimen decreased as compared with that of an uncoated one, if coating film fails during fatigue process as the results of fatigue damage of film itself or accumulation of plastic deformation of substrate metal. Many cracks were induced at the substrate by flaws in the coating film. The increase in fatigue strength of the coated specimen was observed under the region of low total strain amplitude and under the stress ratio of -1, because crack initiation was delayed by the hard coating film on the specimen surface which acted as a barrier to the egress of dislocations.4. The rotating bending fatigue tests were conducted in air and in 3.0% NaCl solution using the pre-flawed coating specimens. The fatigue life of pre-flawed coating specimen remarkably decreased as compared with that of an uncoated specimen. It was explained by the observation of fracture surface and the estimation of fatigue life based on the small fatigue crack propagation law that many cracks occured along the flaw of film are coalesced in each other and grow to large one crack at the early stage of fatigue process. Less

用于各种机器部件的陶瓷涂层可提高耐磨性、耐热性、切削能力或耐腐蚀性。金属涂层技术将更广泛地应用于各种需要高功能性能的机械部件和结构。本研究的目的是阐明涂层附着力、薄膜强度以及硬薄膜涂层对金属疲劳行为的影响。采用物理气相沉积（PVD）和化学气相沉积（CVD）方法对0.37%碳钢镀TiN试样进行了划痕试验、静态拉伸试验、X射线法测量膜层残余应力以及负载控制高周和应变控制低周疲劳试验。本研究得到的主要结论如下： 1． PVD涂层TiN薄膜的划痕附着力高于CVD涂层。划痕试验中涂层失效模式各不相同； PVD薄膜因弯曲而碎裂，CVD薄膜因屈曲而剥落。2．静态拉伸试验发现，PVD和CVD镀膜的缺陷分别在总拉伸应变为0.40%和0.87%时出现，且随着应变的增加而增加。结果表明，涂膜在拉伸应变下的划痕附着力和断裂没有任何共同特征。 3．涂层样品的疲劳寿命受施加的应力比和应变幅度水平的影响。这是由于涂膜破裂引起基材中的裂纹萌生行为。如果涂层膜在疲劳过程中由于膜层本身的疲劳损伤或基体金属塑性变形的积累而失效，则涂层试样的疲劳寿命与未涂层试样相比会降低。由于涂膜中的缺陷，在基材上引起了许多裂纹。在总应变幅较低、应力比为-1的情况下，涂层试样的疲劳强度有所增加，这是因为试样表面的硬质涂层膜阻碍了位错的逸出，延迟了裂纹的萌生。 4．使用预先缺陷的涂层样本在空气和 3.0% NaCl 溶液中进行旋转弯曲疲劳测试。与未涂覆的样品相比，有缺陷的涂层样品的疲劳寿命显着降低。通过断口观察和基于小疲劳裂纹扩展规律的疲劳寿命估算，解释了在疲劳过程的早期，沿膜层缺陷出现的多条裂纹相互融合并发展成一条大裂纹。较少的