E. F. Grechishkin

Effect of magnetic treatment on the microstructure and abrasive resistance of WC–Co detonation-sprayed coatings

The effect of magnetic field on the phase composition and mechanical properties of VK-9 and VK-15 hardmetal detonation-sprayed coatings is studied. It is established that the magnetic field induces phase and structural transformations in sprayed coatings, such as reinforcement of the Co matrix due to the dissolution of WC in Co and the formation of WxCoyCz binary carbides. Magnetic treatment reduces residual internal stresses in the coating, decreases the amorphicity of its structure, and increases abrasive wear resistance.

Microstructure and properties of detonation-sprayed thermal barrier ZrO2 coatings

The formation of detonation-sprayed thermal barrier ZrO2 coatings is studied. The influence of spraying modes on the structure and mechanical properties of the coatings is determined. It is established that the microstructure of the coatings and thus their mechanical properties can be improved by controlling the weight of ZrO2–7%Y2O3 powder sprayed per shot. A quantitative evaluation of the mechanical properties of thermal barrier coatings by indentation method has shown good results.

Effect of magnetic treatment on the microstructure and strength of WC–Co detonation-sprayed coatings

The influence of magnetic treatment on fracture of the WC–Co detonation-sprayed coating–St3 steel substrate system is studied in bending tests. It is established that magnetic treatment leads to the redistribution of elements at the coating–substrate interface. It is shown that magnetic treatment improves the mechanical properties of the coating–substrate system: plastic strain of the system increases from 0.15% to 0.35% when coating starts cracking and stresses developed at fracture increase from 700 to 1300 MPa. The improvement of properties is due to better adhesion at the coating–substrate interface resulting from diffusion-controlled redistribution of elements during magnetic treatment.

Effect of magnetic field on residual stresses in NiAl–Re detonation coatings

The influence of a magnetic field on the internal stresses in NiAl–Re detonation coatings is experimentally confirmed. It is shown that the magnetic field has a substantial effect on the behavior and type of internal stresses. The changes are attributed to the residual stresses in the “substrate– coating” system, which are induced at all stages of preparation and subsequent treatment of the material in the magnetic field.