- 學位論文
探討純鈦在不同電解液微弧氧化對生成氧化膜層的影響
Effect of the Oxide Film Properties on Titanium Substrate by Micro Arc Oxidation in Different Electrolyte Parameters
摘要
本研究藉由雙極脈衝電源供應器，使用硫酸鉀、鎢酸鈉以及氫氧化鈉為電解液，分別在不同的電解液參數下以鈦為基材進行微弧氧化處理，探討當電解液參數不同時所微弧氧化出的試片有何變化。 結果顯示：藉由微弧氧化所生成之氧化層在XRD分析下，均有二氧化鈦之銳鈦礦（Anatase）相及金紅石（Rutile）相的繞射峰。當使用硫酸鉀、鎢酸鈉以及氫氧化鈉為電解液時均可看出有明顯的金紅石（Rutile）相繞射峰。並由XRD分析可看出當電解液中硫酸鉀及鎢酸鈉克數增加時金紅石（Rutile）會有較明顯的峰值。並從SEM表面形貌分析可看出當電解液中硫酸鉀及鎢酸鈉克數增加時，陽離子反應劇烈造成試片表面產生較多的氣泡。當氣泡生成時，電流受限而無法通過，表面會產生部分區域之火花放電。此時開始發生輝光放電，當電壓持續升高則伴隨電弧放電。當達崩潰電壓時則膜層遭擊穿造成試片表面的氧化膜層有許多孔洞。後續使用耐磨耗試驗發現當電解液參數為5%硫酸鉀7%鎢酸鈉 、3%硫酸鉀 3%鎢酸鈉及5%硫酸鉀3%鎢酸鈉3%氫氧化鈉時耐磨性最佳，磨耗掉體積為7.3*10-3 mm3。此結果顯示電解液中所含電解質要適中，不可過量或過少，當微弧氧化後膜層即可保護基材。
並列摘要
Pulsed bipolar power was used for MAO coating on titanium substrate. An aqueous solution containing K2SO4、NaOH and Na2WO4 was used as electrolyte. Different compositions used for MAO on titanium were investigated in this work. The XRD pattern obtained from the surface of the MAO coated specimen shows that the coating consist of anatase and rutile. As we can see in the SEM image, the surface became porous when we add more K2SO4、NaOH and Na2WO4. We think that the surface become more and more porous which causing by ions react violently. It is the reason why that the surface morphology will get porous. When bubbles come out from the ceramic oxide film, it makes the film become porous. The bubbles will also make the current unstable. When current have been disrupted, we can discover the sparking on the surface. In the same time, we can observe the impact ionzation and tunneling ionization between each electrons in the electrolytes. When the andodic voltage keep rising, we can see the micro arc on the surface. According to the wear test, we obtain the optimum electrolyte parameters which are 5% K2SO4 7% Na2WO4 、3% K2SO4 3% Na2WO4 and 5% K2SO4 3% Na2WO4 3% NaOH this three parameters. Therefore, we obtain the porosity film on the pure titanium surface which can protect the substrate.