磁场强度对磁场-电沉积Ni-Al2O3纳米复合镀层性能的影响

Effect of Magnetic Field Intensity on Properties of Magnetic Field-Electrodeposited Ni-Al2O3 Nano-Coatings

目前,有关磁场对纳米复合镀层制备过程的作用机理研究较少。采用磁场-电沉积方法制备Ni-Al2O3纳米复合镀层,利用扫描电镜、EDS能谱仪、X射线衍射仪、摩擦磨损试验机、电化学工作站以及马弗炉等仪器对Ni-Al2O3纳米镀层的表面形貌、元素组成、晶格取向、耐磨性能、耐蚀性能以及抗高温氧化性能进行了分析。结果表明:当磁场强度为0.9 T时,Ni-Al2O3纳米镀层经磨损以后犁沟较少,未出现断层现象,磨损量达到最小值18.2mg,耐蚀性较好,腐蚀电位为-0.38 V、腐蚀电流密度为1.005×10^-9A/cm^2,镀层表面较为平整、空隙较少,具有较强的抗高温氧化性能,在氧化时间120 min时,氧化增重量仅为3.75 mg/cm^2。经EDS分析,证实了Ni-Al2O3纳米镀层中存在Ni、Al2O3两相,经XRD分析,Ni-Al2O3纳米镀层择优取向晶面为(1 1 1)晶面,且当磁场强度为0.9 T时,Ni衍射峰变矮、变宽,说明Ni晶粒细化,镀层性能显著提高。

Ni-Al2O3 nano-coatings were prepared by magnetic field-electrodeposition method. The surface morphology,element composition,lattice orientation,wear resistance,corrosion resistance and high temperature oxidation resistance of Ni-Al2O3 nano-coatings were analyzed by scanning electron microscopy,EDS spectrometer,X-ray diffractometer,friction abrasion testing machine,electrochemical workstation and muffle furnace. Results showed that when the magnetic filed intensity was 0.9 T,the Ni-Al2O3 nano-coatings had fewer furrows and no fault phenomenon after wearing,and the wear loss weight reached the minimum value of 18.2 mg,showing better corrosion resistance with a corrosion potential of -0.38 V and a corrosion current density of 1.005×10^-9 A/cm^2. The surface of the coating was smooth,and the voids were small.The nano-coatings had higher temperature oxidation resistance. At 120 min,the oxidation weight gain was only 3.75 mg/cm^2. EDS analysis confirmed that there were two phases of Ni and Al2O3 in Ni-Al2O3 nano-coatings. XRD analysis showed that the preferred orientation crystal plane of Ni-Al2O3 nano-coatings were( 111) crystal plane,and when the magnetic field intensity was 0.9 T,the diffraction peak of Ni became shorter and wider,meaning the grain of Ni was refined,and the performance of the coating was improved significantly.