Synergistic effect of the addition of TiO2 feedstock on solid particle erosion of Ni/Al2O3 and Ni/Cr2O3 coatings

Abstract

Pipelines are widely used for transportation of solids in many chemical and mining industries. Erosion wear is considered as one of the important parameters which play a significant role in slurry transportation system by affecting both initial cost and life of slurry pipelines. Erosion wear of pipeline is not only important from the design aspect but also from the equipment performance, reliability and operational durability. In the present work, erosion wear due to solid-liquid mixture has been investigated using a slurry erosion pot tester. The erosion tests have been conducted on pipeline material Mild steel (M.S.) to establish the influence of rotational speed, particle size, solid concentration and time duration. Sand was taken as the erodent material with solid concentrations ranging from 10 to 40% (by weight). The experiments were performed at four different speeds such as 750, 1000, 1250 and 1500 rpm with time duration of 30, 60, 90 and 120 min. In the present study, 5% TiO2 feedstock powder was blended with 80Ni-15Cr2O3 and 80Ni-15Al2O3 coating powders to increase their erosion wear resistance. Coating powders are deposited on pipeline material by thermal spray HVOF coating. Experimental results indicate that erosion wear has a high dependence on rotational speed, time duration and nature of erodent solid particles. Significant improvement in erosion wear resistance was also observed with the addition of 5% Titanium dioxide (TiO2) feedstock powder. 80Ni-15Cr2O3–5TiO2 coating shows better performance against solid particle erosion as compared to 80Ni-15Al2O3–5TiO2. The results are compared with uncoated mild steel pipeline material.