Experimental Investigation on the Frictional Wear Behaviour of TiAlN Coated Brake Pads

Abstract

The brake pad is one of the imperative portions of the braking system of any automobile; which is mounted on a brake-disc rotor on each wheel; the brake pads were made by different types of materials. In recent research focuses on using Titanium (Ti) alloy-based brake pads for sophisticated cars (lightweight automobiles) and sports cars because of its high fracture toughness at low density. The most commonly preferred grade of Ti alloy is Grade 2 with 99.5% pure, but in the recent research, it was found that the Ti alloy grade 5 has good thermal stability; so, it can withstand a high tribo-thermal zone like the braking system. This study aims to investigate the frictional wear behaviour of the Ti alloy grade 5 and its performance and it is improved furtherly coating with Titanium Aluminium Nitride (TiAlN). The TiAlN is coated over the Ti alloy using Cathodic Arc Deposition (CAD) method; its surface properties such as surface hardness, surface morphology, surface roughness, and coating thickness are characterized. The wear test is conducted to the TiAlN coated Ti discs as per ASTM G99 (American Society for Testing and Materials) in against OHNS balls (Oil Hardened Nickel Steel). The Coefficient of Friction (COF) of the TiAlN coated Ti alloy has been reduced twice the time when compared with the uncoated Ti alloy. The surface morphology of the worn surfaces studied after the wear test to study the causes of the phenomenon. It reveals that the enhanced surface properties and better resistance to micro thermal effects are reasons for the improved wear resistance of the TiAlN coated Ti alloy.