Wear Behaviour of Polyurethane Coated Aerospace Aluminium Alloy (7075)

Abstract

This paper envisages to predict the life of an aircraft coating using high strength precipitation hardening 7000 series aluminum alloys, such as 7075 which is used extensively in aerospace industry. Aerospace aluminum alloy 7075 has been researched upon especially for aircraft materials. The intention of protective coating is to save the aerospace aluminium alloy 7075 metal surface from weatherability and, at the same time, to obtain the required degree of cosmetic finish for the object. One was epoxy polyamide as primer layer and other was the polyurethane as top-coat layer of coating through conventional spray type on aluminum alloy 7075 substrates. Epoxy polyamide is useful binders for aircraft primers. Top-coats have also been prepared, but polyurethane is still the choice for aircraft coating. This coating system is typically comprised, of a primer layer and a topcoat layer. The ability of the polyurethane coating is to prevent corrosion, weatherability depends on its anti-corrosive pigments and its adhesion to the substrate. All these factors are widely variable with the geographic location and season such as temperature, wind, oxygen and atmospheric pollutants. The effect of structural and process variable on wear resistance of polyurethane coating was analyzed to determine the maximum wear rate using DOE software optimum samples were prepare according to best level of each factor and its morphology was examined by scanning electron microscope (SEM).