KOH溶液中等离子体电解氧化涂层的制备及放电特性

Preparation and Discharge Characteristics of Plasma Electrolytic Oxidation Coatings in KOH Electrolyte

在KOH溶液中采用等离子体电解氧化技术在AZ31镁合金表面制备了陶瓷涂层。对等离子体电解氧化过程放电特性、陶瓷涂层表面形貌、晶相组成及耐腐蚀性能进行了研究,采用光发射光谱对等离子体电解氧化放电阶段等离子体活性物种进行了监测。结果表明,陶瓷涂层主要由Mg O和Mg(OH)2组成,表面具有层次感,耐腐蚀电流密度相对于基体材料提高了4个数量级。在75 V时,等离子体活性物种主要由O2+383.1 nm,Na 589.0 nm,Mg 519.4 nm,K 769.9 nm组成。这些活性物种对等离子体场能量的稳定起到了关键的作用。

The ceramic coatings on the surface of AZ31 magnesium alloys were prepared via plasma electrolytic oxidation （PEO） in KOH electrolyte. The discharge characteristics of the PEO process, the surface morphology, the composition of the coatings and the corrosion resistance were studied. The plasma active species at the discharge stage were investigated by optical emission spectroscopy （OES）. The ceramic coatings showed a sense of hierarchy with composition of MgO and Mg（OH） 2. Compared to the substrate, the corrosion resistance current density was increased by 4 orders of magnitude. At 75 V, the plasma active species were composed of 02 ＋ 383.1 nm, Na 589.0 nm, Mg 519.4 nm and K 769.9 nm. The active species played an important role on the stability of the plasma field energy.