本實驗利用雙極脈衝高電壓與電流控制的微弧氧化技術，在含有尿素、氫氧化鈉、六偏磷酸鈉和氫氧化鋰的電解液中，於6061-T6 鋁合金之表面生成一層耐高電壓且絕緣之陶瓷氮氧化膜層，在類似的電性模式操作下探討電解液組成對氧化膜層生長的影響，得到下列結論:
兩種尿素濃度，分別為500 g/l和20 g/l，顯示高尿素濃度增加膜之氮含量，也改變表面微結構及晶相，氧化鋁以gamma相存在，alpha相氧化鋁難生成，推測alpha相氧化鋁由gamma相在局部高能量電弧熔融再結晶所生成；添加六偏磷酸鈉1 g/l，則會影響鍍膜過程中微電弧出現的穩定度；鋁酸鈉添加的比例增加，通常降低氮氧化鋁膜層的崩潰電壓；電解液中氫氧化鋰1 g/l的出現，則有助於氧化膜中氮含量的增加，通常有助於崩潰電壓增加。因此，氮氧化鋁膜宜採用高尿素濃度，含氫氧化鋰及六偏磷酸鈉，適量的碳酸鈉，以達到充分的離子導電率及pH~12。

Employing a bipolar pulsed high voltage power supply, we overlay an oxynitride film on top of the 6061-T6 aluminum alloy substrate through micro arc technology with current control. The electrolyte generally contains urea, sodium hydroxide, sodium hexametaphosphate, lithium hydroxide. And we study the influences of electrolyte composition on the film, which is targeted for electrical insulation.
We compare surface microstructure and phase differences of two oxynitride films prepared in the electrolytes of high and low urea concentration, namely, 500 and 20 g/l. The electrolyte of high urea concentration raises the nitrogen content of the oxynitride film, but alters the morphology and phase drastically. The nitrogen-rich film contains a cubic phase of Al3O3N oxynitride and the gamma phase of aluminum oxide. However, the nitrogen-poor film contains the Al3O3N oxynitride and the alpha and gamma phases of aluminum oxide. It is speculated that the alpha aluminum phase has been formed by melting and recrystallization at expense of gamma phase through local high energy micro arc. Influences of other ingredients in the electrolyte are described as follows. Addition of sodium hexametaphosphate, 1 g/l, stabilizes the surface appearance of micro arc. Addition of lithium hydroxide, 1 g/l, enhances the nitrogen content, and the breakdown strength as well. In addition, the electrolyte requires sufficient ion conductivity, ~30 mS/cm, and high pH value ~12.

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