FIELD: measuring instruments.
SUBSTANCE: measuring technology for determining the adhesive strength of thin stressed coatings on mechanical engineering products. The method consists in the fact that the coated product, in which residual stresses are present, is subjected to microindentation to obtain an penetration diagram, which contains two indentation cycles. The first cycle provides interfacial separation of the coating in a certain area without destroying the continuity of the coating. The second loading cycle is carried out in the same indentation as in the first indentation cycle, but with loading providing elastic deformation of the coating under the indenter. Based on the results of the analysis of the repeated loading and unloading curves, a loading curve is constructed for a coated product without the presence of residual stresses in it. Analytical processing of these loading curves for a coating with residual stresses and an unstressed coating makes it possible to determine the radius of the interfacial crack and the deflection of the bulge of the coating. Construction of a theoretical diagram of a single indentation cycle for the product under study allows, from the difference in the areas of the theoretical diagram and the calculated penetration diagram without residual stresses, but with peeling of the coating after indentation, to calculate the amount of energy spent on interfacial destruction in the coating-base product system, taking into account the known data. Based on the amount of energy spent on the interphase destruction of the layered system and the radius of the interphase crack, the adhesive strength of the coating to the plastic substrate is calculated using a known dependence.
EFFECT: ability to significantly increase the accuracy and objectivity of determining adhesive strength of thin coatings.
9 cl, 5 dwg, 1 tbl
