纳米BN对1060铝微孤氧化膜层性能的影响

目的探究微弧氧化电解液中纳米氮化硼(BN)浓度对铝微弧氧化陶瓷层组织和性能的影响。方法在硅酸盐体系电解液中加入1~5 g/L不同浓度的纳米BN,制备纳米BN复合微弧氧化层。利用扫描电镜、能谱仪和X射线衍射仪,分别表征纳米BN复合微弧氧化层的微观组织、元素分布及物相组成。采用涂层测厚仪、粗糙度仪、显微硬度计、摩擦磨损试验机等手段,研究纳米BN对1060纯铝微弧氧化膜层的厚度、粗糙度、显微硬度、摩擦学性能的影响。结果在微弧氧化BN复合膜的表层有弥散分布的BN颗粒,当电解液中添加3 g/L的纳米BN时,制备的微弧氧化层的性能最好,其表面的孔洞数量最少且孔径最小,膜层表面更加致密,其厚度可达到(93.8±1.9)μm,硬度达到(942±51)HV,粗糙度Ra降低为(3.66±0.14)μm,摩擦系数降低为0.55,磨损体积比未添加BN的膜层减少了1.18×10-2 mm3,并且磨痕平整光滑,裂纹较少。结论硅酸盐电解液中加入纳米BN能够改善1060纯铝微弧氧化膜层的综合性能。

Effect of Nano BN Additive on Performance of Micro-arc Oxide Film Formed on 1060 Aluminum

The work aims to explore effects of BN concentration in electrolyte system on microstructure and performance of the coating on aluminum in the method of micro-arc oxidation. Nano BN composite micro-arc oxide film was prepared by add-ing 1~5 g/L nano BN additive of different concentration in silicate system solution. Microstructure, element distribution and phase composition of the nano-BN composite micro-arc oxide film were characterized using scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. The effects of BN in electrolyte on thickness, roughness, microhardness and wear resistance of micro-arc oxide film on 1060 pure aluminum were investigated using coating thickness gauge, roughme-ter, microhardness and friction wear testing machine. BN particles were dispersed on the surface of micro-arc oxide BN compo-site film. Performance of the micro-arc oxide film prepared by adding 3 g/L nano BN particles in electrolyte was the best. Pores on the film surface were the least, pore size was the smallest, and the film surface was denser. The thickness was up to (93.8±1.9)μm, hardness (942±51)HV, roughness Ra down to (3.66±0.14) μm, friction coefficient 0.55, wear volume decreased by 1.18×10-2 mm3, and grinding cracks were smooth and cracks decreased. Addition of BN into the silicate electrolyte system can improveoverall performance of the micro-arc oxide film on pure aluminum.