论文部分内容阅读
以硅酸盐体系为电解液,利用扫描式微弧氧化(SMAO)方法在铝合金 2024 的表面成功制备出“蛇形”和“HIT”图案的陶瓷膜层。对扫描式和传统微弧氧化工艺进行了对比,采用扫描电镜和 X 射线衍射研究了 SMAO 陶瓷膜的结构和相组成。结果表明,与传统微弧氧化放电过程不同,扫描式微弧氧化在沿阴极前进的方向上依次分布着钝化区、阳极氧化区和微弧氧化区,没有观察到弧光放电。经过一次扫描生成的陶瓷膜厚度约为17 μm,膜层只有疏松层,且其中的α-Al_2O_3含量高于γ-Al_2O_3。对扫描式微弧氧化放电机理的分析表明,电场在阳极表面的梯度变化可能是同一时间内存在不同放电区域的原因,高达2 400 A/dm~2的电流密度使扫描式微弧氧化具有高的成膜效率,同时也导致了疏松层内含有大量的α-Al_2O_3。
With the silicate system as electrolyte, the “Snake” and “HIT” patterns of ceramic coatings were successfully prepared on the surface of aluminum alloy 2024 by scanning micro-arc oxidation (SMAO) method. The comparison between scanning and conventional MAO process was carried out. The structure and phase composition of SMAO ceramic membrane were investigated by scanning electron microscopy and X-ray diffraction. The results show that, unlike the traditional micro-arc oxidation discharge process, the scanning micro-arc oxidation sequentially distributes the passivation zone, the anodic oxidation zone and the micro-arc oxidation zone in the direction along the cathode, and no arc discharge is observed. After one scan, the thickness of the ceramic film is about 17 μm, the film has only loose layer, and the content of α-Al_2O_3 is higher than that of γ-Al_2O_3. The analysis of the mechanism of the micro-arc oxidation by scanning shows that the gradient of the electric field on the surface of the anode may be the reason that different discharge regions exist at the same time. The current density up to 2400 A / dm ~ 2 makes the scanning micro- Membrane efficiency also led to a large amount of α-Al_2O_3 in the bulk layer.