INFLUENCE OF HEAT TREATMENT PARAMETERS,TEMPERATURE AND TIME, ON WEAR AND MICROHARDNESS OF NICRBSI FLAME SPRAYED COATINGS APPLIED ON CK۴۵ SUBSTRATES

The objectives of this research were to find an economical way of reducing porosities in the microstructure of coatings deposited by flame spraying technique on CK۴۵ steel and also trying to increase their cohesive strength to the substrate, so that the overall wear properties of this type of coating can be improved. So several specimens from this steel coated with NiCrBSi powder under specific conditions were subjected to various furnace heat treatment at ۱۰۰۰, ۱۰۲۵, ۱۰۵۰, ۱۰۷۵ and ۱۱۰۰ °C, each for periods of ۵, ۱۰ and ۱۵ minute before cooling them in air. Tribological properties of treated coatings were evaluated by pin on disc method. The results show the highest wear resistance and microhardness values observed in one of the sample was due to lower amount of porosity and higher amount of very fine Cr۲Ni۳B۶ particles precipitated homogeneously throughout its microstructure during specific heat treatment.

کلیدواژه ها:

NiCrBSi coatings ، Flame spraying ، Coating ، Heat treatment ، CK۴۵ ، Wear ، Microstructure ، Microhardness ،