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
The microstructures and corrosion behavior of AlSi5 CulMg alloy modified with different contents of La were investigated.Optical microscopy observations showed that the microstructures of AlSi5 Cu1 Mg-xLa(x = 0, 0.3, ...The microstructures and corrosion behavior of AlSi5 CulMg alloy modified with different contents of La were investigated.Optical microscopy observations showed that the microstructures of AlSi5 Cu1 Mg-xLa(x = 0, 0.3, 0.6, and 0.9 wt%) alloy transformed from coarse cellular to fine cellular as the content of La increased from 0 to 0.9 wt%. The results of electrochemical measurement and immersion test in 3.5 wt% NaCl solution showed that the corrosion resistance of AlSi5 CulMg-xLa alloy strongly depended on its microstructures. The AlSi5 Cu1 Mg-0.6 La sample exhibited the highest corrosion resistance due to its fine cellular structure and the cathode phases coated by the La element. The covering film of La hindered the corrosion electron flowing between the cathode and the anode. As a result, the corrosion current density of the AlSi5 CulMg-0.6 La alloy was only about 40% that of the matrix alloy in the electrochemical measurement.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.
基金supported financially by the National Natural Science Foundation of China (No. 51364035)the Natural Science Foundation of Jiangxi Province (No. 20171BAB206034)
文摘The microstructures and corrosion behavior of AlSi5 CulMg alloy modified with different contents of La were investigated.Optical microscopy observations showed that the microstructures of AlSi5 Cu1 Mg-xLa(x = 0, 0.3, 0.6, and 0.9 wt%) alloy transformed from coarse cellular to fine cellular as the content of La increased from 0 to 0.9 wt%. The results of electrochemical measurement and immersion test in 3.5 wt% NaCl solution showed that the corrosion resistance of AlSi5 CulMg-xLa alloy strongly depended on its microstructures. The AlSi5 Cu1 Mg-0.6 La sample exhibited the highest corrosion resistance due to its fine cellular structure and the cathode phases coated by the La element. The covering film of La hindered the corrosion electron flowing between the cathode and the anode. As a result, the corrosion current density of the AlSi5 CulMg-0.6 La alloy was only about 40% that of the matrix alloy in the electrochemical measurement.
