Effect of cobalt addition on wear behaviour of TiB₂ coating produced by TIG cladding process

Abstract

In this paper, the mechanical and tribological characteristics of TiB2 ceramic coating with and without cobalt (Co) addition developed using tungsten inert gas (TIG) cladding process on AISI 304 stainless steel (SS) were investigated. The effect of TIG process conditions as well as cobalt (Co) content on the microstructure, microhardness and resistance to wear were investigated systematically. The phase identification, microstructure, and elemental distribution map of the clad layer formed on the surface of an AISI 304SS substrate were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS), respectively. Vickers microhardness testing apparatus and a pin-on-disc tribometer were used to evaluate the microhardness, resistance to wear, and coefficient of friction (COF), respectively. The result demonstrates that a dense and defect-free composite coating with a strong metallurgical bond to the substrate is possible. The average microhardness of the TiB2 ceramic coating without Co addition was 1704 HV, and the average wear rate was 15.1576×10-9 g/N-m. In contrast, the TiB2 ceramic coating with Co addition exhibited an improved average microhardness of 1860 HV and a reduced average wear rate of 22.7364×10-9 g/N-m, while the AISI 304SS substrate had an average microhardness of 216 HV and an average wear rate of 200.45×10-9 g/N-m. The conclusion is that the TiB2 ceramic coating with Co addition exhibited superior mechanical and tribological characteristics, demonstrating its suitability for use in wear-resistant components. The higher microhardness of the TiB2 ceramic with Co-added coating indicates enhanced hardness and potential resistance to deformation, while the lower wear rate suggests improved durability and the ability to withstand frictional forces. Therefore, the TiB2 ceramic coating with Co addition shows promise for applications where wear resistance is crucial.