CAJ | 학술논문

为提高铝合金的摩擦磨损和耐蚀性能，在A390铝合金基体上通过激光熔覆制备NiCrAl/TiC复合涂层。采用XRD和EDS分析了涂层的物相组成，结合SEM观察了涂层的微观组织，运用摩擦磨损试验机和电化学工作站测试了涂层的摩擦磨损和耐腐蚀性能。结果表明：复合涂层主要物相为AlNi、Al 3 Ni 2、TiC ，同时含有少量的Cr 13 Ni 5 Si 2、Cu 9 Al 4和α(Al)。涂层自下至上分别为短棒状树枝晶、胞状晶、柱状树枝晶和等轴晶。相同磨损条件下，A390基体发生了严重的磨粒磨损和剥层磨损，而激光熔覆涂层只产生了轻微的磨粒磨损，熔覆层的相对耐磨性为3.16。在3.5%NaCl溶液中的极化曲线和电化学阻抗谱(EIS)显示：熔覆层自腐蚀电位较A390基体的正移，腐蚀电流密度减小；熔覆层呈单容抗特性，而A390基体在高频区表现为容抗特性，在中低频区则为感抗特性。在Bote图中，低频区熔覆层对应的相位角和中低频段熔覆层的阻抗模值均大于A390基体的，表明熔覆层的耐蚀性远高于A390基体的。熔覆层的腐蚀形貌为局部点蚀，A390基体的腐蚀形貌为晶间腐蚀和剥蚀。
위제고려합금적마찰마손화내식성능，재A390려합금기체상통과격광용복제비NiCrAl/TiC복합도층。채용XRD화EDS분석료도층적물상조성，결합SEM관찰료도층적미관조직，운용마찰마손시험궤화전화학공작참측시료도층적마찰마손화내부식성능。결과표명：복합도층주요물상위AlNi、Al 3 Ni 2、TiC ，동시함유소량적Cr 13 Ni 5 Si 2、Cu 9 Al 4화α(Al)。도층자하지상분별위단봉상수지정、포상정、주상수지정화등축정。상동마손조건하，A390기체발생료엄중적마립마손화박층마손，이격광용복도층지산생료경미적마립마손，용복층적상대내마성위3.16。재3.5%NaCl용액중적겁화곡선화전화학조항보(EIS)현시：용복층자부식전위교A390기체적정이，부식전류밀도감소；용복층정단용항특성，이A390기체재고빈구표현위용항특성，재중저빈구칙위감항특성。재Bote도중，저빈구용복층대응적상위각화중저빈단용복층적조항모치균대우A390기체적，표명용복층적내식성원고우A390기체적。용복층적부식형모위국부점식，A390기체적부식형모위정간부식화박식。
In order to improve the frictional wear behavior and corrosion resistance of aluminum alloy, NiCrAl/TiC composite coating was fabricated on A390 aluminum alloy by laser cladding. The phase constitution, microstructure, frictional wear behavior and corrosion resistance of the composite coating were analyzed using X-ray diffraction (XRD), energy dispersive spectrum (EDS), scanning electron microscope (SEM), friction and wear testing machine and electrochemical workstation. The results show that the coating is mainly composed of AlNi, Al 3 Ni 2 and TiC phases, and a small amount of Cr13Ni5Si2, Cu9Al4 and α(Al) phases. The microstructures of the coating from the bottom to top are dendrite crystal, cellular crystal, columnar dendrite crystal and equiaxed crystal, respectively. Under the same wear condition, A390 substrate exhibits serious abrasive wear and peeling characteristics, while the cladding coating exhibits slight abrasive wear behavior. The relative wear resistance of cladding coating is 3.16. The polarization curves and electrochemical impedance spectroscopy (EIS) in 3.5%NaCl solution indicate that the corrosion potential of the coating is more positive than that of the matrix, and the corrosion current density decreases significantly. The coating exhibits capacitive reactance behavior, but A390 substrate exhibits capacitive reactance in high frequency area and impedance in medium low frequency area. In Bote diagram, the phase angle of composite coating in low frequency area and the impedance modulus value of coating in low-middle frequency are larger than those in the matrix. This proves that the composite coating has better corrosion resistance compared to that of A390 aluminum alloy. The corrosion morphology of the cladding coating is localized pitting, but the corrosion morphology of A390 matrix is intergranular corrosion and erosion.