The microstructure,microhardness,and corrosion resistance of laser cladding Ni−WC coating on the surface of AlSi5Cu1Mg alloy were investigated by scanning electron microscopy,X-ray diffraction,microhardness testing,im...The microstructure,microhardness,and corrosion resistance of laser cladding Ni−WC coating on the surface of AlSi5Cu1Mg alloy were investigated by scanning electron microscopy,X-ray diffraction,microhardness testing,immersion corrosion testing,and electrochemical measurement.The results show that a smooth coating containing NiAl,Ni_(3)Al,M_(7)C_(3),M_(23)C_(6)phases(M=Ni,Al,Cr,W,Fe)and WC particles is prepared by laser cladding.Under a laser scanning speed of 120 mm/min,the microhardness of the cladding coating is 9−11 times that of AlSi5Cu1Mg,due to the synergistic effect of excellent metallurgical bond and newly formed carbides.The Ni−WC coating shows higher corrosion potential(−318.09 mV)and lower corrosion current density(12.33μA/cm^(2))compared with the matrix.The crack-free,dense cladding coating obviously inhibits the penetration of Cl^(−)and H^(+),leading to the remarkedly improved corrosion resistance of cladding coating.展开更多
文摘The microstructure,microhardness,and corrosion resistance of laser cladding Ni−WC coating on the surface of AlSi5Cu1Mg alloy were investigated by scanning electron microscopy,X-ray diffraction,microhardness testing,immersion corrosion testing,and electrochemical measurement.The results show that a smooth coating containing NiAl,Ni_(3)Al,M_(7)C_(3),M_(23)C_(6)phases(M=Ni,Al,Cr,W,Fe)and WC particles is prepared by laser cladding.Under a laser scanning speed of 120 mm/min,the microhardness of the cladding coating is 9−11 times that of AlSi5Cu1Mg,due to the synergistic effect of excellent metallurgical bond and newly formed carbides.The Ni−WC coating shows higher corrosion potential(−318.09 mV)and lower corrosion current density(12.33μA/cm^(2))compared with the matrix.The crack-free,dense cladding coating obviously inhibits the penetration of Cl^(−)and H^(+),leading to the remarkedly improved corrosion resistance of cladding coating.
