Improving wear and corrosion resistance of Ti-alloyed nodular cast irons by Al2O3 and SiC-reinforced Al2O3 coatings

Abstract

Nodular cast irons, known for their superior mechanical strengths, have been extensively utilized in the automotive, energy, and various other industries. However, these materials require additional surface quality enhancements in highly abrasive environments. This study uses the sol-gel method to investigate the development and application of Al2O3 and SiC+Al2O3 coatings on GGG40 nodular cast irons containing 0.5 wt% Ti. The primary objective is to explore the microstructural changes, wear resistance, and corrosion resistance imparted by these coatings. Experimental results reveal that adding Ti modifies graphite morphology, enhancing the wear resistance by approximately 45 % of the cast iron. The Al2O3 coating reduced the wear rate of the cast iron by up to 47 % and corrosion rate by 75 %, while SiC-reinforced coating reduced the wear rate by up to 69 % and corrosion rate by 38 %. The findings indicate that incorporating SiC into Al2O3 coating provides superior wear resistance, while pure Al2O3 coating offers better corrosion resistance.