Method for testing adhesive strength of interface crack expanding resistance characterizing coating

Abstract

The invention relates to a test method for the adhesion strength of the intrinsic coating for the expansion resistance of a boundary crack in the detection technical field. A wedge block inserted into a substrate is pushed by external force, so that a coating attached on a common surface of the wedge and the substrate deflects, hence the crack expands in the boundary between the coating and the substrate; by a microscopic observing device, the geometry of the crack is directly observed from the side or surface of the specimen, and the adhesion strength of the coating is calculated by the mechanics of fracture. The test method overcomes the shortcomings of prior test method for adhesion strength of coating such as complex preparation of specimen, pollution of the coating and substrate boundary, and impossibility for observing direct the crack at film-substrate boundary, etc., and provides a simple and rapid way for measuring the adhesion strength of coatings quantitatively.

Description

technical field [0001] The invention relates to a method for detecting the technical field, in particular to a test method for characterizing coating adhesion strength by interfacial crack propagation resistance. Background technique [0002] Material surface modification is an important research field in current materials science and engineering. By attaching a layer of coating to the surface of the base material, the wear resistance and corrosion resistance of the base material can be improved, and the service life of the material can be improved. However, low coating adhesion strength often causes the coating to detach from the substrate under various stresses, shortening the service life of the material. Therefore, the adhesion strength of the coating is an important performance parameter of the coating. In order to accurately characterize the coating adhesion strength, a lot of research on how to measure the coating adhesion strength has been carried out in the past te...

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Problems solved by technology

However, the disadvantages of this method are: processing the window cavity on the back of the substrate requires micromachining, and the sample manufacturing process is complicated; the photolithographic micromachining method is difficult to apply to the metal substrate; the pressure oil in the cavity has a negative effect on the coating and The substrate interface is polluted; the interface cracks generated after the coating is detached from the substrate cannot be directly observed, and the area of ​​the detachment area can only be measured indirectly through laser interference fringes, and the measurement error is limited by the wavelength of the light source

It can be seen that the above methods have certain defects. In order to measure the coating adhesion strength more accurately, it is necessary to further improve the quantitative measurement method of coating adhesion strength.

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