HVOF-sprayed CoNiCrAlYSi coatings were tested at 900 °C in a hot corrosion environment containing sodium-potassium sulphates. The HVOF spraying caused the typical splat-on-splat structure. The results after the hot corrosion testing showed that the corrosion preferentially occurred at the coating surface and the splat boundaries. The oxidation along the splat boundaries can isolate the splat fr...

The item deals with the possibilities of utilization HVOF coatings in thermal cyclic loading conditions. There were evaluated three types of coatings based on WC-Co, WC-Co-Cr and Cr3C2-25NiCr. The quality of coatings was evaluated in terms of their adhesion as sprayed and also during the cyclic thermal loading, EDX analysis and evaluation of microhardness. Construction and structure of coatings...

Abstract 30MnB5 boron alloyed steel surface is coated using different coating techniques, namely 60(Ni-15Cr-4.4Si-3.5Fe-3.2B 0.7C)-40(WC 12Co) metallic powder plasma spray, Fe-28Cr-5C-1Mn alloy wire arc WC-10Co-4Cr (thick) high velocity oxy-fuel (HVOF), and (fine) diamond jet HVOF. The microstructure of the crude sample consists ferrite pearlite matrices iron carbide structures. intermediate bi...

Hydroxyapatite (HA)ynano-zirconia composite coatings were successfully produced through high velocity oxy-fuel (HVOF) spraying of radio frequency (RF) plasma synthesized powders. Microstructure characterization and morphology analysis on the nano-structured coatings were conducted using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD), and d...

High-velocity air fuel (HVAF) coating processes have advantages over conventional high-velocity oxygen (HVOF) processes, resulting in coatings with superior properties. The present review first provides a concise overview of HVAF coatings, highlighting their HVOF coatings. Then, the fundamentals solid particle, slurry, and cavitation erosion are briefly introduced. Finally, performance for eros...

High-entropy alloys (HEAs) have great potential to be used as high-temperature materials and in coating material applications due their combination of strength, ductility, thermal stability, wear, oxidation resistance. In this work, a new HEA alloy based on NiCoCrAlSi composition was designed deposited into metallic coatings by high-velocity oxy-fuel (HVOF) air plasma spray (APS) processes, wit...

Several kinds of WC-reinforced coatings were prepared by high-velocity oxygen-fuel spray (HVOF) and electric contact strengthening (ECS), respectively, their corrosion behaviors in 3.5% NaCl solution investigated. The microstructure, element distribution, phase resistance these compared. results showed that, compared with HVOF-sprayed coatings, the ECS-prepared denser lower porosity. Simultaneo...

The major physicochemical processes involved in an industrial HVOF thermal spray process (Diamond Jet hybrid gun, Sulzer Metco, Westbury, NY) are studied by a comprehensive multiscale model. The model includes continuum type differential equations that describe the dynamics of gas phase and particles of different sizes, and a rule-based stochastic simulator that predicts the evolution of coatin...

The microstructure and local mechanical characteristics of thermal spray ferrous coatings have been determined. The emphasis has been on coatings made by the high velocity oxyfuel (HVOF) process, especially the role of Al alloy additives. The oxide phase present in the material and preferred pathways for local cracking and separation have been determined. Thin intersplat oxide layers emerge as ...