The Fabrication And Properties Analysis Of Laser Cladding Ni-based Corrosion Resistant Alloy Coating

Due to its unique advantages in the development of abrasion-resistant and corrosion-resistant coating,laser cladding is considered as the new technology to prolong the service life of the metal component used in the Marine environment.In order to search the best ratio of Mo element and defocusing distance parameters to fabricate corrosion-resistant cladding layer,Ni-Cr-Mo alloy cladding layer with four different Mo element mass fraction(10wt.%,13wt.%,16wt.%,19wt.%)were fabricated on Q235 steel by semiconductor laser.By the same time,five different defocusing distance parameters(-6 mm,3mm,0mm,+3mm,+6 mm)were using to fabricate one-strip Ni-Cr-Mo-Cu cladding layer and three different defocusing distance parameters(-6mm,0mm,+6mm)were using to fabricate multistrip Ni-Cr-Mo-Cu cladding layer.And the microstructure,phase composition and the seawater corrosion resistance of all the samples were tested.The experimental results show that the four kinds of Ni-Cr-Mo alloy cladding layer is mainly composed of Ni-based solid solution with Cr,Mo,Fe,W and MoNi4 phase.With the increasement of Mo content,the content of Mo-rich phase which distributed around the boundary of Ni-rich phase gradually increased and the micro-Vickers hardness of the cladding layer gradxally increased too.Open circuit voltage and tafel curves show that within the scope of this study,seawater corrosion resistance of cladding layer gradually enhanced with the increasement of Mo content.And the sample with Mo element mass fraction of 19%has the best seawater corrosion resistance.The dilution rate of one-strip Ni-Cr-Mo-Cu alloy cladding layer with five different defocusing distance parameters(-6mm,3mm,0mm,+3mm,+6mm)is 36.68%,36.09,24.53%,]7.03%and 12.27%in turn,which showed the tendency of decreased gradually.Three kinds of Ni-Cr-Mo-Mo cladding layer is mainly composed of Ni-based solid solution with Cr,Mo,Fe,Cu and MoNi4 phase,etc.As defocusing distance changed from negative to positive,micro-Vickers hardness of the cladding layer increased gradually.Open circuit voltage and tafel curves show that the sample which was fabricated with positive defocusing distance parameters(+6mm)has the best seawater corrosion resistance.It is because the diffusion degree of Fe element from Q235 steel to the cladding layer reduced gradually.