【摘要】 采用非对称方波输出模式的恒流交流电源,利用微弧氧化方法在铝合金表面沉积Al2O3陶瓷膜,考察了微弧氧化工艺参数(电流密度、处理时间)对膜层微观结构和耐蚀性的影响.结果表明:工艺参数对膜层组织结构和性能的影响存在较佳的范围,即氧化时间为15-20min,电流密度在20A/dm2左右;氧化时间过短时,试样表面存在陶瓷膜未完全覆盖的区域,而当电流密度过大时,膜层表面将会出现大量的显微裂纹,导致膜层性能大幅度降低;在恒流非对称方波输出模式下,工艺参数对膜层的相组成影响不大,微弧氧化膜层由晶态Al2O3和非晶态Al2O3组成.更多还原

【Abstract】 In this paper,a constant-current AC power supply with an asymmetric square-wave output mode was employed to form Al2O3 ceramic coatings on aluminium alloy by micro-arc oxidation.The effects of processing parameters,such as the current density and the oxidizing time,on the microstructure and corrosion resistance of the prepared coatings were then investigated.The results show that the ceramic coatings are of excellent microstructure and property when the current density and the oxidizing time are respectively about 20A/dm2 and 15～20min,and that a fairly short oxidizing time leads to uncoated areas on the specimen,while a fairly high current density results in many micro-cracks on the coatings,which all make the corrosion resistance of the coatings decrease.Moreover,it is found that the ceramic coatings are composed of both crystalline and amorphous Al2O3,and that there is no striking effect of the processing parameters on the phase composition in the asymmetric constant-current square-wave output mode.更多还原