IMPROVING STRUCTURE, PROPERTIES, AND ABRASIVE WEAR RESISTANCE OF THE THERMALLY SPRAYED CO-BASED COATING BY MEANS OF La_2O_3 ADDITION

摘要

Co-based alloy modified with La_2O_3 is deposited by high velocity oxy-fuel (HVOF) spraying process. The microstructure, porosity, hardness, and abrasive wear of the coatings are investigated. The La_2O_3 addition refines the microstructure, forms new phases, and increases hardness and abrasive wear resistance of the modified coating. The abrasive wear behavior of these coatings is investigated under normal loads 5 and 15 N against 220 abrasive grit size. The abrasive wear is carried out using 30 and 50 m/min sliding rates. The abrasive wear is found to increase with the increase in normal load and sliding rates. Analysis of the worn surfaces by scanning electron microscope images revealed cutting and plowing as the material removal mechanisms in these coatings under abrasive wear conditions used in this research.