(哈爾濱工業(yè)大學(xué) 先進焊接與連接國家重點實驗室，哈爾濱 150001)
摘 要: 采用恒壓模式于硅酸鹽體系中在V型內(nèi)腔試件表面制備微弧氧化膜，研究V型角度對微弧氧化膜不均勻性的影響。采用數(shù)字式測厚儀、掃描電子顯微鏡和X射線衍射儀研究其微觀結(jié)構(gòu)，利用電化學(xué)分析儀進行耐蝕性的評定。結(jié)果表明：V型試件內(nèi)表面的相組成無明顯差別，均為γ-Al2O3，但其內(nèi)表面的膜層厚度分布不同，且隨著V型試件張角的增大，其內(nèi)表面膜層厚度差值逐漸減小，由3.1 μm減小到0.4~0.9 μm，不均勻程度減小。此外，V型試件內(nèi)表面邊緣氧化膜層的耐蝕性較優(yōu)，而靠近折彎處氧化膜層的耐蝕性較差，這是由于試件內(nèi)表面受不同程度電力線屏蔽造成的。增大脈沖寬度對膜層不均勻性影響很小，但增加氧化處理時間后，試件內(nèi)表面不均勻程度增大。
關(guān)鍵字: 純鋁；V型槽；微弧氧化；不均勻性
（State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China）
Abstract:The micro-arc oxidation (MAO) coatings were formed on the V-shaped aluminum cavity in the silicate electrolyte with constant voltage mode. The effect of the V-shaped angle on the inhomogeneity of MAO coatings was investigated. The microstructure and surface morphology were investigated using the digital coating thickness gauge, SEM and XRD, and the corrosion resistance was assessed by the electrochemistry analyzer. The results show that the phase compositions are almost γ-Al2O3, which does not demonstrate obvious difference for the inner surface of V-shaped specimen. In contrast, the thickness of the coatings on the inner surface varies substantially at different sites. With the increase of the angle of the V-shaped specimen, the thickness difference becomes slight, decreasing from 3.1 μm to 0.4−0.9 μm. A better corrosion resistance is observed near the edge of the samples and a worse corrosion resistance appears near the bent position of the samples. It may be attributed to different shielding effects of the electric field in the V-shaped cavity. The effect on the inhomogeneity by increased pulse duration is small, but with the increase of oxidation time, the inhomogeneity degree enlarges.
Key words: pure aluminum; V-shaped cavity; micro-arc oxidation; inhomogeneity
