Performance evaluation of HVOF sprayed WC-10Co4Cr coatings under slurry erosion

Abstract

Slurry erosion is one of the main failure modes of the hydraulic turbine parts, mud pumps and drill pipes. The high velocity oxygen fuel (HVOF) spray process has been widely used for depositing protective coatings especially the cermet coatings that can significantly improve the slurry erosion resistance of substrate materials. In this work, conventional WC-10Co4Cr composite coatings and coatings with bimodal structures were deposited on the 35CrMo steel substrate by HVOF, respectively. Structures of the two kinds of coatings were analysed with SEM and XRD methods, and microhardness, porosity and roughness were also measured. Furthermore, the slurry erosion tests were carried out on the coatings to explore the effect of average particle size, slurry concentration and pH value on the erosion behaviours. The erosion failure mechanisms of the coatings were also explored. The results show that the bimodal coating has a denser microstructure, superior mechanical properties, lower porosity and better slurry erosion resistance than the conventional coating. The erosion-corrosion mechanism of the two kinds of coatings is spalling, caused by crack initiation and propagation under fatigue stress.

Insights to improve the tribo-performance of materials used under slurry erosion applications: A review

“…Mechanism of erosion-corrosion of both the type of coatings was the spalling due to the crack initiation followed by crack propagation because of fatigue. 97 The influence of modification of surface properties of low alloy steel namely, AISI 5117 (used in petroleum pipelines extensively) was investigated on the SE and erosion-corrosion wear behavior. Effect of nickel-phosphorus (Ni-P) electroless deposit was found very effective in improving the wear resistance.…”

“…8,9,14,27,31,36,57,58,66,[83][84][85][87][88][89][90][91][92] Some authors used the full factorial method for carrying out a suitable number of experiments. 93,94 Related to various researches, many authors 1,2,9,15,20,45,50,53,63,75,77,82,[94][95][96][97][98][99][100][101] discussed the surface morphologies of different materials posterior to SE testing, exhibiting the different mechanism of failure on the observed eroded surface. Surface roughness 'Ra' and 'Rz' are the parameters for characterizing such type of eroded surfaces.…”

“…Related to various researches, many authors 1,2,9,15,20,45,50,53,63,75,77,82,94–101 discussed the surface morphologies of different materials posterior to SE testing, exhibiting the different mechanism of failure on the observed eroded surface. Surface roughness ‘Ra’ and ‘Rz’ are the parameters for characterizing such type of eroded surfaces.…”

Corrosion and Wear Behavior of WC–10Co4Cr Coating under Saturated Salt Drilling Fluid

“…Hence, a hard coating could be applied to the surface of the drill pipe or joint to improve its anti-corrosion and anti-wear [ 8 , 13 , 14 , 15 , 16 ]. There are several major coating methods to prepare hard coatings, such as high-velocity oxygen–fuel spraying [ 1 , 17 ], cold spraying [ 15 , 18 ], plasma spraying [ 19 ], micro-arc oxidation [ 20 , 21 ], high-speed laser cladding [ 22 ], high-power impulse magnetron sputtering [ 16 ], plasma electrolytic oxidation [ 23 ], and so on [ 13 , 24 ]. WC-based cemented carbide possesses high hardness, outstanding strength, and excellent toughness, so is widely used as anti-wear material [ 1 , 8 , 17 ].…”

“…There are several major coating methods to prepare hard coatings, such as high-velocity oxygen–fuel spraying [ 1 , 17 ], cold spraying [ 15 , 18 ], plasma spraying [ 19 ], micro-arc oxidation [ 20 , 21 ], high-speed laser cladding [ 22 ], high-power impulse magnetron sputtering [ 16 ], plasma electrolytic oxidation [ 23 ], and so on [ 13 , 24 ]. WC-based cemented carbide possesses high hardness, outstanding strength, and excellent toughness, so is widely used as anti-wear material [ 1 , 8 , 17 ]. WC-based coatings are often coated on the surface of the pipe to increase its wear and corrosion resistance.…”