Microstructure and properties of TiB ₂ –Ni coatings with different binder phase contents deposited by HVOF spray process

Abstract

Abstract TiB 2 –Ni coatings with different binder phase contents were sprayed on Q235 substrate by a high‐velocity oxygen‐fuel (HVOF) method using ball‐milled powders. The microstructure, phase compositions, as well as thermal shock behavior, abrasive wear, and corrosion resistance to molten Al‐12.07 wt%Si alloy performances of as‐sprayed coatings were investigated. The results show that the three TiB 2 –Ni coatings structure is dense with low porosity, and the main phase compositions of the coatings are TiB 2 and Ni similar to those of original powder. The coatings that have superior performance of thermal shock resistance have good bond to the substrate with no change in thickness and microstructure of coatings. Meanwhile, the coatings also have good durability in the molten Al‐12.07 wt%Si after 60‐h immersion test. And the mass loss of Q235 steel is five times as much as that of TiB 2 –50Ni coatings after abrasive wear test.