A coating shear strength testing device

Abstract

The invention relates to the field of precision scientific instruments for optomechanical integration, and particularly designs a method and device for testing the shear strength of a coating interface. It can be used for hard coatings, sealing coatings, thermal barrier coatings and other coatings with a thickness of more than 50um. The device includes a load loading assembly, a sample clamp assembly, a sample stage assembly and a support; the load loading assembly includes a servo motor, a reducer, a screw, a guide rail and an indenter, and the servo motor, reducer, and guide rail are fixed on the support On the seat, the servo motor is connected horizontally with the reducer, the reducer is connected horizontally with the lead screw, the lead screw is placed on the guide rail through two self-contained supports, and the pressure head is fixed on the lead screw. The invention has the ability to apply a large load, can test a sample with a larger size and a higher shear strength, and can avoid the problem of size effect introduced by a small size sample and the problem that the interface is difficult to separate with a larger shear strength. The bonding area of ​​the coating interface detected by this test device is not less than 100mm 2 , The testable shear strength is not less than 100MPa.

Description

technical field [0001] The invention relates to the field of precision scientific instruments for optomechanical integration, and particularly designs a method and device for testing the shear strength of a coating interface. It can be used for hard coatings, sealing coatings, thermal barrier coatings and other coatings with a thickness of more than 50um. Background technique [0002] The interface mechanical properties between the coating and the substrate are the key evaluation objects to characterize the performance of the coating. The interface mechanical properties include interface bonding strength and section shear strength. The interface bonding strength refers to the ability to resist the normal separation between the coating and the substrate. Shear strength is the ability to resist tangential slipping of a coating from a substrate. The mechanical properties of the coating interface directly affect the bearing capacity of the coating, and are an important object o...

AI Technical Summary

Problems solved by technology

However, it is inevitable that the coating will be deformed during the coating peeling process, and the deformation of the coating will generate additional loads on the test results and affect the test results

[0014] The foreign patent publication number is SU1497515A1. The coating surface is bonded together with an adhesive through two identical coating samples, and then grooves are made up and down respectively. The bottom of the groove exceeds the bottom of the opposite sample coating respectively. When a tensile load is applied The coating produces shear failure, and the shear strength of the coating is measured, but the position between the two grooves is inevitably deformed during the stress process, so that the test result is not only the effect of shear load, but also the coating pulls off load action

[0015] Therefore, the existing coating interface shear strength test device is not suitable for testing the surface coating of thinner and larger parts, and cannot directly provide the interface shear strength, and requires complex observation, detection devices and theoretical analysis assistance and other problems; the existing coating interface shear strength test methods mainly include the indentation method, the bonded pair method, and the three-point / four-point bending method, and the indentation method is not suitable for thinner and larger parts. Coating testing, the bonded pair method is not suitable for coatings with a thickness of less than 0.15mm, and the three-point / four-point bending method requires special auxiliary devices and theoretical analysis, which are not suitable for the wide application of coating shear strength testing

Some devices that specialize in testing the shear strength of coatings still have limitations such as only being able to test flat coatings

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