Niobium alloy electron beam surface cladding silicide coating crack control

Electron beam surface cladding silicide coating on niobium alloy experiment has been investigated in this paper.Optical microscope and scanning electron microscope were applied to characterize the surface morphologies of silicide coatings.Through the analysis of cracking rate and maximum width of cracks on the surface cladding layer,the quality of cladding coating is characterized.The results of single variable tests reveal that different processing parameters have different influence on the cracks.By means of orthogonal tests,optimized electron beam cladding process parameters were developed.The optimized parameters were as follows:electron beam current=17 mA,beam focus current=1 885 mA,beam scanning speed=540 mm/min-1.The silicide coating which was treated by electron beam surface cladding treatment with optimized processing parameters,performed good quality.There is no cracks on silicide coating surface,and the grains of coating were homogeneous and compacted.