High Emissive Coatings on Titanium Alloys

Abstract

Titanium and its alloys are very interesting materials for space applications due to their low density and high Static and dynamic strength. They have outstanding strength to weight ratio, good fatigue strength and toughness, low elastic modulus, good bio compressibility, corrosion resistance and anti-magnetic properties. However the tribological properties such as low resistance, high suction Coefficient and difficulty to lubricate have a major restriction to their extensive applications. Micro-arc-oxidation is an advanced anodic oxidation process, with the combination of electrochemical oxidation and high voltage spark treatment. This novel coating technique is capable of disposing dense, hard ceramic composite coatings for the enhancement of tribological properties and the resistance towards corrosion, electrical and their conductivity and chemical actions.A method for obtaining high micro-hard coating has been discussed.The present work involves optimization of two important parameters: electrolyte composition and current density in order to get a ceramic like coating on Ti 6 Al 4 V alloy with required thermos-optical properties. It also involves the study of various other parameters that would affect the thermo-optical property, surface and characterization of the coating.