METHOD OF EVALUATION OF ADHESION STRENGTH OF MULTILAYER COATING Russian patent published in 2020 - IPC G01N19/04 

FIELD: physics.

SUBSTANCE: invention relates to investigation of mechanical properties of coatings, namely to methods of determining adhesion strength of coating with base, and can be used for assessment of adhesion strength of layers in multilayer coating. Method of evaluation of adhesion strength of multilayer coating consists in application of layers of tested coating on sample in the form of metal plate, in coating of transverse notch to substrate and bending of plate with tested coating at location of notch in area of extension at bending of plate and evaluation of adhesion strength by results of coating destruction, incision is made in zone of maximum deformation of metal plate at bending, at that before or after deformation microsection is prepared in plane perpendicular to notch line, and on microsection or its photographic image is determined: point O is the point of intersection of the bisector of the bending angle of the sample α passing through the centre of the notch O', with a line perpendicular to the surface of the coating at point 1 and passing through point 1, from the point O a line is drawn through point A₂ and an angle γ₁ is determined between this line OA₂ and OO' bisector, then the line is drawn from the point O through point 3 and the angle γ_max is determined between this line OA₃ and the bisector OD', then the line is drawn from the point O through point 4 and the angle γ_min between this line OA₄ and the bisector OO', where: α-angle bending sample; A₁ is point of beginning of plate deformation zone; A₂ is the end point of the coating delamination section from the base; γ₁ is angle of coating separation from base; A₃ is the end point of the section of the maximum delamination of the coating layer from the underlying coating layer; γ_max is angle of maximum delamination of coating layers; A₄ is the end point of the minimum delamination section of the coating layer from the underlying coating layer; γ_min is angle of delamination of coating layers; and by values of angles γ₁, γ_max, γ_min, adhesion strength between layers and between coating and base is determined, wherein value of angles γ₁, γ_max, γ_min, lower adhesion strength.

EFFECT: technical result is providing quantitative and qualitative evaluation of adhesion strength between coating and substrate and between layers of multilayer coating.

4 cl, 2 dwg, 1 tbl