Research And Analysis Of Ni-based Coating By High Frequency Induction Cladding

It is an effective method to improve properties of metal surface layer when metalwas coated. The coating can resist wear and corrosion of the surface, it also can increasethe strength of the metal. Therefore, it is important that coating and coating propertieswere studied. With experimental method, microstructure, phase, microhardness andCorrosion resistance in different depth of coating coated by high frequency inductioncladding (HFID) with Ni-base alloy were investigated. Sodium silicate and rosinturpentine mixture were respectively used as binder in coating.The microstructure of the coating in different depth was observed by electronscanning microscope(SEM).The chemical composition of the coating and defects wasmeasured by energy-dispersive X-ray diffraction machine(EDS).The experimentalresults showed that there is a diffusive layer between coating and substrate, No matterthe binder is Sodium silicate or rosin turpentine mixture and it appears to be a “whitebright band. Both of binders all did not produce spalling phenomena and have densecoating and fewer defects. The influence of HFID on substrate was not obvious, forMicrostructure of substrate is not changed.The volume of the element Fe in the coating and the volume of the element Ni inthe substrate near the coating were increased after sintering, which means there was adispersive process during the sintering process, which resulted in a firmly metallurgybond between the coating and substrate. the coating was consisted of Ni-Base solidsolution and CrB、Ni4B3、Cr7C5、Cr3C2、Fe3Ni2hard phases. Each phase evenlydistributed in the coatingThe HRC hardness of the surface and microhardness in different depth of thecoating were measured. It showed that the HRC hardness of the coating was muchhigher than substrate. In comparison of the microhardness in different depth of thecoating, it can be found that diffused layer was the lowest, substrate near to diffusedlayer was a little higher than diffused layer and the coating was much higher thandiffused layer. The microhardness in the coating was evenly distributed.The corrosion tests of Ni-base alloy composite coating sample were carried out in acid liquid. And compared with45steel, corrosion resistance of tow kind of binders issimilar, the corrosion lose of coatings was less. Diffused layer have strong corrosionresistance.