Three-body wear performance of co-electrodeposited cermet coatings

In this paper, the three-body abrasive wear performance of co-electrodeposited nanostructured cermet coatings composed of two types of dispersed nanosized ceramic particles (Al2O3 and TiO2) in nickel matrix is investigated using procedures and guidelines provided by ASTM G65-04 (Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus). The main objective of this research was to evaluate three-body abrasive wear performance of co-electrodeposited cermet coatings that are designed to protect the surfaces of carbon steel pipes against moving sand grains in the transported bitumen production from some new unconventional oil production techniques such as steam assisted gravity drainage and also in-situ combustion. For this purpose, the effects of particle contents in the nickel matrix, applied current density and time of electrodeposition on the hardness and wear performance of coatings were studied. The microhardness values for coatings were measured using a microhardness Vickers tester equipped with a diamond pyramid indenter. For the three-body abrasive wear tests, the mass loss, surface roughness and depth profile of wear tracks were recorded and the surfaces of wear tracks were investigated using FE-SEM. The increase in microhardness of cermet coatings compared to the pure form of nickel was explained by the rule of mixture for composites and was correlated to grain refining and dispersion strengthening mechanisms which can take place during the co-electrodeposition of coatings. The results showed that the coatings with a greater quantity of Al2O3 in the nickel matrix provide greater microhardness and therefore, an improved wear performance can be expected. Additionally, the wear surface analysis showed that rougher surfaces can be expected for coatings with lower microhardness compared to coatings with greater microhardness and this effect was explained using Archard׳s equation.