https://scholars.lib.ntu.edu.tw/handle/123456789/74811
標題: | 環保型鎂合金稀土金屬化成皮膜處理 | 作者: | 林招松 | 關鍵字: | 稀土金屬;化成處理;鎂合金;硝酸鈰;Rare earth metal;conversion coatings;magnesium alloys;cerium nitrate | 公開日期: | 2004 | 出版社: | 臺北市:國立臺灣大學材料科學與工程學研究所 | 摘要: | 本研究旨在探討AZ31 鎂合金板材在稀土鹽類硝酸鈰化成液中化成皮膜微結構、特性與生成機制。同時探討化成溫度、pH 值與過氧化氫含量對化成皮膜結構與成長的影響。硝酸鈰化成皮膜的生長首先是鎂離子的溶出,氫離子還原形成氫氣,試片界面pH 值迅速上升,溶液中金屬離子以氫氧化物沉積,形成化成皮膜。在未添加過氧化氫的化成系統中,化成皮膜共有三層,靠近底材的多孔層,接著是緻密層,外層為髮狀層。添加過氧化氫所形成的化成皮膜為雙層結構。靠近底材為氫氧化鎂,外層為二氧化鈰與氫氧化鎂之混和物。 Microstructure, properties and formation mechanism of cerium conversion coatings on AZ31 magnesium plates were investigated with emphasis on solution pH, temperature and the addition of hydrogen peroxide. Experimental results indicate that upon immersing in the solution, AZ31 plates dissolved to form magnesium ions and trace of aluminum ions. Meanwhile, the pH at the interface rose because of hydrogen liberation. This increase in interfacial pH caused the precipitation of magnesium and aluminum hydroxides. The coating formed in 0.05M cerium nitrate solution consisted of three layers with a porous layer overlaying the magnesium substrate, an intermediate compact layer followed by a fibrous layer as the major overlay. The coating formed in the solution with the addition of hydrogen peroxide comprised primarily the cerium oxide as the major overlay and a porous magnesium hydroxide layer intimately contacted with the substrate. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/12471 | 其他識別: | 922216E002017 | Rights: | 國立臺灣大學材料科學與工程學研究所 |
顯示於: | 材料科學與工程學系 |
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922216E002017.pdf | 1.6 MB | Adobe PDF | 檢視/開啟 |
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