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
为提高等离子喷涂Ni/WC涂层耐磨性,采用高温超声深滚(High temperature ultrasonic deep rolling,HT+UDR)对其进行强化处理。采用附带能谱仪的扫描电镜、X射线衍射仪、维式硬度计和摩擦磨损试验机检测和分析强化处理后Ni/WC涂层的耐磨...为提高等离子喷涂Ni/WC涂层耐磨性,采用高温超声深滚(High temperature ultrasonic deep rolling,HT+UDR)对其进行强化处理。采用附带能谱仪的扫描电镜、X射线衍射仪、维式硬度计和摩擦磨损试验机检测和分析强化处理后Ni/WC涂层的耐磨性。结果表明,经HT+UDR强化后,Ni/WC涂层的层状结构消除,内部孔隙和裂纹减少,涂层更加致密。HT+UDR处理后涂层表层生成Cr_(7)C_(3)、Cr_(2)B_(3)和CrB等新硬质相,X射线衍射峰半高宽展宽,涂层表层产生晶粒细化,涂层表面硬度提高了185.9 HV0.2。Ni/WC涂层的磨损机理以磨粒磨损为主,伴有疲劳磨损,HT+UDR能有效改善Ni/WC涂层的耐磨性,经HT+UDR处理后,磨损表面的剥落现象和裂纹减少,其磨损量为7.1 mg,相比于未滚压涂层降低51.3%。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.
文摘为提高等离子喷涂Ni/WC涂层耐磨性,采用高温超声深滚(High temperature ultrasonic deep rolling,HT+UDR)对其进行强化处理。采用附带能谱仪的扫描电镜、X射线衍射仪、维式硬度计和摩擦磨损试验机检测和分析强化处理后Ni/WC涂层的耐磨性。结果表明,经HT+UDR强化后,Ni/WC涂层的层状结构消除,内部孔隙和裂纹减少,涂层更加致密。HT+UDR处理后涂层表层生成Cr_(7)C_(3)、Cr_(2)B_(3)和CrB等新硬质相,X射线衍射峰半高宽展宽,涂层表层产生晶粒细化,涂层表面硬度提高了185.9 HV0.2。Ni/WC涂层的磨损机理以磨粒磨损为主,伴有疲劳磨损,HT+UDR能有效改善Ni/WC涂层的耐磨性,经HT+UDR处理后,磨损表面的剥落现象和裂纹减少,其磨损量为7.1 mg,相比于未滚压涂层降低51.3%。
