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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

用于各种机械部件的陶瓷涂层，提高了耐磨性、耐热性、切削性或耐腐蚀性。金属涂层技术将更广泛地应用于各种对功能性能要求较高的机械零部件和结构。本研究的目的是阐明涂层的附着力、薄膜的强度以及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%碳钢表面TiN涂层进行了划痕试验、静态拉伸试验、膜内残余应力X射线测量以及载荷控制高周和应变控制低周疲劳试验。主要研究结论如下：1.PVD涂层TiN薄膜的划痕附着力高于CVD涂层。涂层在划痕试验中的失效模式各不相同；pvd…更多的薄膜是由于薄膜的弯曲而碎裂失效的，而CVD薄膜是由于屈曲而剥落的。静态拉伸试验发现，在总拉伸应变分别为0.40%和0.87%时，PVD和CVD薄膜均出现缺陷，且随应变的增加而增加。结果表明，涂层在拉伸应变下的划痕、附着力和断裂不具有任何特征。涂层试件的疲劳寿命受外加应力比和应变幅值的影响。这是由于涂层破裂在衬底中引起的裂纹萌生行为。如果涂层在疲劳过程中由于涂层本身的疲劳损伤或基材金属塑性变形的积累而失效，涂层试件的疲劳寿命比未涂层试件的疲劳寿命降低。涂层中的缺陷在基片上产生了许多裂纹。在总应变幅值较低、应力比为-1的情况下，涂层试件的疲劳强度有所提高，这是因为涂层表面的硬质涂层延迟了裂纹的萌生，起到了阻挡位错出口的作用。采用预制缺陷涂层试件，在空气和3.0%的氯化钠溶液中进行了旋转弯曲疲劳试验。有缺陷涂层试件的疲劳寿命较未涂层试件显著降低。通过断口观察和基于疲劳小裂纹扩展规律的疲劳寿命估算，解释了在疲劳过程的早期，沿薄膜缺陷产生的多个裂纹相互聚结并扩展成一个大的裂纹。较少