电解液中Y(NO3)3含量对7075铝合金微弧氧化涂层性能的影响

为了提高7075铝合金的耐磨性,对其进行微弧氧化处理,探讨电解液中Y(NO 3)3含量对涂层性能的影响。利用XRD、SEM、共聚焦显微镜和摩擦试验机表征涂层的相组成、表面形貌、摩擦因数等。研究结果表明:7075铝合金微弧氧化涂层主要由α-Al 2O 3和γ-Al 2O 3两相构成。电解液中添加Y(NO 3)3后,微弧氧化涂层覆盖均匀,涂层中更容易形成γ-Al 2O 3相。随着Y(NO 3)3含量增加,涂层中α-Al 2O 3相衍射峰加强,α-Al 2O 3含量有所增加,涂层显微硬度呈现出先增加后降低的趋势,最大值出现在添加的Y(NO 3)3质量分数为3.5‰时,约为1852 HV。当添加的Y(NO 3)3质量分数低于2.5‰,获得涂层较为平滑。但当Y(NO 3)3质量分数超过3‰后,微弧氧化涂层的腐蚀程度有所加强。在Y(NO 3)3质量分数低于2.5‰时,表面粗糙度在5.8~6.5μm间变化。当Y(NO 3)3质量分数高于2.5‰时,表面粗糙度在7.1~7.7μm区间变化。随着Y(NO 3)3含量增加,获得涂层摩擦因数有所降低,Y(NO 3)3质量分数分别达到3.5‰和4‰时,摩擦因数分别为0.8和0.6。

Influence of Y(NO 3)3 doping in the electrolyte on the properties of 7075 alloy micro-arc oxidation coating

In order to improve the wear resistance of 7075 aluminum alloy,it was treated with micro-arc oxidation to investigate the influence of Y(NO 3)3 content in electrolyte on the coating properties.XRD,SEM,confocal microscope and friction testing machine were utilized to characterize the phase composition,surface morphology and friction factor of the coating.The results showed that the micro-arc oxidation coating of 7075 aluminum alloy was mainly composed of two phases:α-Al 2O 3 andγ-Al 2O 3.After Y(NO 3)3 was added to the electrolyte,the micro-arc oxidation coating was evenly covered and the coating was more likely to form theγ-Al 2O 3 phase.With the increase of Y(NO 3)3 content,the diffraction peak ofα-Al 2O 3 phase in the coating was strengthened and the content ofα-Al 2O 3 increased.The microhardness of the coating increased first and then decreased.The maximum value appeared as the mass fraction of added Y(NO 3)3 was 3.5‰,which was about 1852 HV.As the mass fraction of Y(NO 3)3 was lower than 2.5‰,the coating was smooth.However,when the mass fraction of Y(NO 3)3 exceeded 3‰,the corrosion degree of micro-arc oxidation coating enhanced.As the mass fraction of Y(NO 3)3 was less than 2.5‰,the surface roughness varied from 5.8μm to 6.5μm.When the mass fraction of Y(NO 3)3 was higher than 2.5‰,the surface roughness varied from 7.1μm to 7.7μm.As the content of Y(NO 3)3 increased,the friction factor of the coating decreased.When the mass fraction of Y(NO 3)3 reached 3.5‰and 4‰separately,the friction factor was 0.8 and 0.6,respectively.