Effect of nano-CeO₂ on structure and properties of high velocity flame spraying coating

Different amount of nano-CeO₂ powder was added into NiCrFe/WC for spray. The coating was produced on Q235 substrate by CP-3000 high velocity flame spraying equipment. The microstructure and surface morphology of the coating were analyzed by optical microscopy and scanning electron microscopy. The phase composition of the coating was determined by X-ray diffraction. The wear properties of the coating were investigated by an M-200-wear-tester. The adhesive strength of the coating were investigated on an SHT4605 universal testing machine. The micro-hardness of the coating was evaluated by HXD- 1000TM micro-hardness instrument. The results showed that nano-CeO₂ powder could refine the microstructure of the coating and improve the compactness of the coating,which also promoted the chemical metallurgical reaction among components in the process of solidification and crystallization of the coating. In the process of formation of the coating,some new phases were formed,such as NiCrFe、γ(Fe,Ni) solid solution and CeNi3. These new phases improved the mechanical properties of the coating through solid solution strengthening. The micro-hardness, adhesive strength and wear resistance of the coating were greatly improved. The optimal addition of nano-CeO₂ powder was 1%.