Experimental investigation and parameter optimization of Cr2O3 atmospheric plasma spray nanocoatings

In this research, Cr2O3 ceramic nano-sized powder particles were prepared using ball milling and then were granulated to reach the proper size for spraying. Afterward, Cr2O3 nano-coatings were deposited by atmospheric plasma spraying (APS) process onto stainless steel substrates. To optimize APS parameters, spraying was carried out under six conditions with different parameters. Microstructures of the elemental/milled powder and coatings were characterized via a field emission scanning electron microscope (FESEM) equipped with energy-dispersive spectroscopy (EDS). In this research, Cr2O3 coatings were deposited under different spraying conditions to understand the effect of APS parameters on the splat formation, deposition efficiency, and porosities of the coatings. After parameter optimization, spraying was performed under a high deposition efficiency of 46.0±1.3%. The optimized Cr2O3 coatings showed porosity content, Knoop microhardness, and adhesive strengths of 8.7±2.2%, 823±27 HK0.2, and 49±4 MPa, respectively; making them a good candidate for industrial use.