電漿電解質氧化鍍膜的陰極電流製程參數對成長機制影響之研究

The study of effect of cathodic current on growth mechanism of coatings by plasma electrolytic oxidation

曾偉哲(Wei-Che Tseng)

指導教授 ： 楊木榮

大同大學/工程學院/材料工程學系所/碩士(2012年)

摘要

本實驗中藉由電漿電解質氧化法調整陰陽極的脈衝大小和時間，在5052鋁箔上沈積硬質陶瓷氧化膜。在陽極脈衝週期中，其融熔鋁會熔射出放電通道，並快速固化而沈積在放電通道上形成類似火山口形狀的陶瓷氧化膜；然而，在陰極脈衝週期中，則會減少微弧放電的現象，融熔離子在膜層內固化成氧化鋁，使其膜層結構更均勻、少缺陷。此電漿電解質氧化製程使用雙極脈衝模式。利用光學發射光譜儀在進紫外光範圍（285nm～900nm）內，研究製程參數對微弧電漿的影響。掃描式電子顯微鏡來探討膜層表面形貌、截面微結構。X光繞射則分析膜層結晶構造。研究得微弧電漿放電會影響膜層結構，其主要因素為強烈放電現象是發生在基材與膜層和膜層與電解液的介面中。本實驗目標在調整陰陽極脈衝的大小及時間，和脈衝停止時間去研究如何消除強烈放電的現象，及陰陽極脈衝對程膜機制的影響、關係。

關鍵字

陰極電流 ； 電漿電解質氧化 ； 陽極膜層

並列摘要

In this study, oxide films was deposited on 5052 Al foils to produce hard ceramic coatings using a Plasma Electrolytic Oxidation (PEO) process by adjusting the amplitude and duration of anodic-pulse cycle and cathodic-pulse cycle. During the anodic-pulse cycle, the molten aluminums are ejected to the discharge channel, solidifying outside the oxide film, causing the oxide films more defect. However, cathodic-pulse cycle reduced the arc discharge phenomenon, solidifying inside the oxide films, resulting in more homogeneous oxide film structures. The process utilized bipolar pulsed current modes. The effects of process parameters on the plasma discharge behavior during the PEO treatment were investigated using optical emission spectroscopy (OES) in the visible and near ultraviolet (NUV) band (285 nm - 900 nm). Scanning Electron Microscopy (SEM) was used to study the coating morphology and microstructure. Phase composition of the layers of the coatings was evaluated by X-ray diffraction. It was found that the plasma discharge behavior significantly influenced the microstructure and the morphology of the oxide coatings. The main effect came from the strongest discharges which were initiated at the interface between the substrate and the coating and between coatings and electrolytes. This work demonstrated that by adjusting the ration of the anodic to cathodic pulse currents as well as their stop timing in order to eliminate the strongest discharges and their relationships with the layer formation mechanisms.

並列關鍵字

cathodic current ； plasma electrolytic oxidation ； anodic film

參考文獻

[41] F. Mecuson, T. Czerwiec, T. Belmonte, L. Dujardin, A. Viola, G. Henrion, Surface and Coatings Technology, 200 (2005) 804-808.

[11] R.O. Hussein, X. Nie, D.O. Northwood, A. Yerokhin, A. Matthews, Journal of Physics D: Applied Physics, 43 (2010) 105203.

[13] L. Wang, L. Chen, Z. Yan, W. Fu, Surface and Coatings Technology, 205 (2010) 1651-1658.

[4] H. Dong, Surface Engineering of Light Alloys Aluminium, Magnesium and Titanium Alloys, Woodhead Publishing Limited, 2010.

[31] L. Snizhko, Electrochimica Acta, 49 (2004) 2085-2095.