One of the economical and fast solutions for failure against erosive wear in oil and gas industries is the deposition of cermets using HVOF thermal spray. Recently, especially with the new development of bimodal feedstock powders, the composition percentages of the mixed powders have played a key factor in the final coating performance. In the present study, a design of experiment (DOE) software was implemented to study the influence of different powder percentages on the coating performance. The coating mechanical properties and its performance were investigated via dry solid particle erosion tests, hardness measurement and SEM respectively. The results showed that both the hardness and erosion resistance of the coating increases as the composition percentage of the nanostructured WC-12Co increased due to the strong adhesion of WC nano size grains at the substrate/coating interface as a result of improved mechanical interlocking.

HVOF coating finds wide applications in power generation industry to protect the hot path components from high temperatures gases. The mechanical properties influence the life span of such components. In the present study, mechanical properties of HVOF spray of Inconel-625 alloy onto stainless steel surface was examined. The three point bending tests are carried out to determine the load and the flexural displacements characteristics of the coated workpieces. The workpieces were subjected to aqueous static corrosion environment before and after the three point bending tests. The surface morphology and elemental composition of the coating after the bending tests are examined using SEM and EDS. It is found that the local corrosion site in the coating result in high stiffness of the coating and the cracks extending along the surface of the coating are resulted due to the shear on the surface of the coating.