Studies on thermal barrier coatings For gun barrel applications by Atmospheric plasma spray process

Abstract

Thermal Barrier Coatings (TBCs) were extensively employed in various elevated temperature applications to enhance thermal insulation capability and longevity. TBCs usually contains 6 to 8 wt. % Yttria Stabilized Zirconia (YSZ) and it has better thermal expansion coefficient, low thermal conductivity and longevity at temperatures lower than 1200 ºC. Several researchers pointed that YSZ and Alumina (Al2O3) coatings have greater potency for development of TBCs possessing lower thermal conductivities. These TBCs (100-250 and#956;m) provides insulation to the parts to withstand large and prolonged heat loads. newlineThe present study aims to investigate the performance of YSZ and Al2O3 TBCs deposited on EN steel substrates developed through Atmospheric Plasma Spray Process (APS) for rifle gun barrel applications. Large numbers of researchers focused on establishing new TBC systems with better thermal stability. These TBCs can be utilized in defense applications for better performance and enhanced lifetime of the component. From the literature study, it was clear that different coatings were tried for varied applications but not with YSZ and Al2O3 TBCs for defense related gun barrel applications. Hence in the present study, various EN grades have been selected as the substrate material since it is being used for making of gun barrels.Steels specimens of various grades EN8, EN19, EN24, and EN36C were taken with the 65 mm diameter and thickness of 5 mm for APS process. EN8 was selected, since it was commonly used for shafts, stressed pins and studs, and widely used for making of small arms weapons. Specifically, EN8 was used in AK 47 model rifle gun barrel for military purpose. This alloy possesses good tensile strength, wear resistance and toughness newline newline newline