MECHANICAL PROPERTIES OF THERMAL ARC SPRAY ALUMINIUM COATING IN ATMOSPHERIC CONDITION

Abstract

Thermal arc spray coating was regard as most preferred method as a protective coating due to its ability to sustain in high temperature, high friction surface, and low cost process. It has been applied by most of industrialist especially in oil and gas field, where current application of the coating used in onshore. This research is a study on mechanical properties of thermal arc spray coating by using aluminium alloy with purity 99.5% as coating material. Two samples with different coating thickness at range of 200 μm – 300 μm and 300 μm – 400 μm were used for this research. Some of tests were prepared to evaluate coating mechanical properties. Surface microstructures were viewed and analysed using scanning electron microscope and energy dispersive x-ray analysis.  The hardness was inspected using Vickers Hardness testing. Corrosion rate was established by performing Salt Spray Test. Porosity value was calculated using Image Analyzer. Surface roughness was viewed using Infinitefocus G4 machine. Experimental results were found that coating porosity was raising with enhancing of coating thickness. The increment coating thickness also resulted in reduction of hardness and surface roughness. For corrosion rate purpose, two samples with coating thickness at range of 200 μm – 300 μm and two samples with coating thickness at range 300 μm – 400 μm were prepared. It recorded at Rating 5 – Rating 7 after exposed in salt spray cabinet within 144 hours. As a result, coating thickness at range of 200 μm – 300 μm performs the most efficiency in terms of mechanical properties; less corrosion rate, less porosity and contribute to high hardness and surface roughness.