INFLUENCE OF ANNEALING ON THE STRUCTURE, PHASE COMPOSITION AND WEAR RESISTANCE OF Fe-Al COMPOSITE COATING SPUTTERED BY HIGH-SPEED METALLIZATION METHOD

The structure, phase composition and tribotechnical properties of Fe-Al composite coating subjected to annealing in the temperature range of 350–550 °C for 10 hours have been investigated. It is established that during annealing of the coating, in a set of diffusion pairs (steel–aluminium) formed during sputtering under conditions of limited content of components, reaction diffusion takes place, leading to simultaneous formation of intermetallic compounds of different stoichiometric composition: Al13Fe4, Al3Fe, Al5Fe2, AlFe and AlFe3. It is shown that the mutual diffusion of iron into aluminium and aluminium into steel between the contacting particles of the composite coating is caused by the peculiarities of the formation of the structural-phase state of the composite coating during its obtaining. The porosity of the coating at annealing increases up to 37 vol.%, and its hardness increases up to ≈ 1.2 times in comparison with the initial state. It is established that annealing of composite coating in the temperature range of 350–550 °С for 10 hours leads to increase of its wear resistance up to 2.4 times in comparison with the initial state.