Studies on novel swirl thermal spray coating of carbonaceous nano particles on ic engine components

Abstract

The wear resistance and high hardness value of the HVOF Cermet coatings tends to create a benchmark in various industrial applications such as turbine blades, air craft landing gears, compressor blades and many others, because of its tribological characteristics (wear resistance, lubrication, Coefficient of Friction), toughness and thermal degradation. newlineCermet coating is a composite material composed of ceramic and metals and applied as an intermediate coating between metallic bond coat and ceramic top coat. The multiphase cermet coatings with reinforcement particles have been proposed as an alternative solution for hard chrome plating, CVD, laser cladding and PVD techniques. These conventional techniques find advantages for coating on complex geometry such as non-symmetric curvatures and corners, but they are toxic in environment and also not cost effective for components with huge dimensions. newlineRecent works have been noted that instead of powder injection, suspension flame spray which is a combination of fine solid particles and a base fluid (ethylene glycol), is injected into the jet using spray atomization or injection of continuous jet methods. It is revealed that in the case of suspension injection, the stand-off distance should be less than that in the case of dry powder injection (around 100mm). newlineEnhancing the kinetic energy and pressure is based on the spray nozzle design, feedstock material, fuel type and oxidizer used. The spray nozzle defines the flow dynamics of coating particles. The geometrical design of the torch and its flame flow characteristics determine the coating efficiency. newline