Microstructure and Microhardness Characterization of Cr 3 C 2 -SiC Coatings Produced by the Plasma Transferred Arc Method

The purpose of this work was to investigate the coatings made of Cr 3 C 2 and SiC powder manufactured on AISI 304 stainless steel applied by the plasma transferred arc (PTA) welding process. SiC content in the produced coated layer was varied between 0–100 wt.% and the effect of SiC concentration on the microstructure and hardness of the coating was measured experimentally. SEM analyses revealed that the composite coatings had a homogeneous, nonporous, and crack-free microstructure. Dendrites and interdendrite eutectics formed on the coating layer, subject to the temperature gradient and the solidification ratio. There was a significant increase in the hardness of coating layers with the effect of the γ -(Fe,Ni), Cr 7 C 3 , Cr 23 C 6 , Fe 5 C 2 , Cr 3 Si, CrSi 2 , Fe >0.64 Ni 0.36 , CFe 15.1 , C-(Fe,Cr)-Si phases formed in the microstructure. In comparison to the substrate, the microhardness of the coatings produced by PTA were 2.5–3.5 times harder.