林招松臺灣大學：材料科學與工程學研究所蔡孟熹Tsai, Meng-HsiMeng-HsiTsai2007-11-262018-06-282007-11-262018-06-282007http://ntur.lib.ntu.edu.tw//handle/246246/55314鎂與其合金的標準還原電位低於大部分的結構材料，容易造成腐蝕。潛力與現今應用產生落差，因此各種防蝕的方法因應而生。化成處理的方法之中以鉻酸鹽的防蝕具有最好效果，但六價鉻對於人體具有毒性。磷酸鹽/錳酸鹽的化成處理是具有潛力能夠替代六價鉻化成處理的方法之一。不同鋁含量的鎂鋁合金具有不同的微結構，不同的製程也會造成微結構以及性質的差異。 本研究針對AZ31、AZ80與AZ91鎂鋁合金中Mg17Al12(β相)，對短時間（30、60與120秒）磷酸鹽/錳酸鹽化成皮膜的表面形貌、微結構及性質的差異。以光學顯微鏡、掃瞄式電子顯微鏡、橫截面穿透式電子顯微鏡以及低掠角X-ray晶體繞射，分析皮膜的表面型態和結構，配合極化曲線以及交流阻抗分析皮膜的抗蝕性質，以及百格試驗分析化成皮膜的附著性。結果顯示鎂合金的製程、組成都會影響Mg17Al12(β相)的體積分率、形貌以及分佈，這些因素對化成皮膜的表面形貌、結構、附著性以及抗蝕性質有很大的影響。The standard reduction potential of magnesium and its alloys are lower than the other structural materials. Therefore, magnesium alloys are highly susceptible to corrosion, giving rise to the limitation on their practical application. Many surface modification methods have, thus, been developed to protect magnesium alloys from corrosion. Among the conversion coating methods, chromate conversion caoting exhibits the best corrosion protective properties. Howerver, Cr(VI) is toxic to human body. Phosphate-permanganate conversion treatment is one of the methods that are potentially alternative to the chromate treatments. The microstructures and the properties of magnesium alloy can be controlled by its aluminium contents and the corresponding fabrication processes. This research focuses on how the Mg17Al12 (β) phase in AZ31,AZ80 and AZ91 magnesium- aluminum alloys influences the surface morphology, microstructures and properties of the phosphate-permanganate coating formed in a short time (30, 60 and 120sec) of immersion. This research utilizes optical microscopy, SEM, TEM and low glancing-angle XRD to analyze the surface morphology and crystal structure of the coating, measures the electrochemical polarization curve and electrochemical impendence spectroscopy to analyze the corrosion properties of the coating, and uses ASTM D3359-97 method to study the adhesion of conversion coating. The results shows that the fabrication process and composition of the alloys markedly influence the shape, volume fraction and distribution of Mg17Al12 (β) phase which in turn, affects the surface morphology, microstructures, adhesion properties and corrosion properties of the coating.摘要.....................................................i Abstract................................................ii 總目錄..................................................iv 圖目錄................................................viii 表目錄................................................xiii 第一章 緒論........................................1 1.1 前言.............................................1 1.2研究動機..........................................1 第二章 文獻回顧....................................4 2.1 鎂合金簡介....................................4 2.1.1 鎂與鎂合金的特性..........................4 2.1.2 鎂合金的種類與表示方法....................4 2.2 鎂合金的防蝕處理..............................5 2.2.1 鎂合金的陽極處理..........................5 2.2.2電鍍/無電鍍處理............................5 2.2.3 物理氣相沈積法............................5 2.2.4 鎂合金的化成處理..........................6 2.2.4.1 鉻酸鹽化成處理.........................6 2.2.4.2 磷酸鹽/錳酸鹽化成處理..................8 2.2.4.3 錫酸鹽化成處理.........................9 2.2.4.4 稀土元素化成處理......................10 2.3 鎂合金微結構的效應...........................10 2.3.1 微結構對於腐蝕行為的影響.................10 2.3.2 微結構對於陽極處理的影響.................11 2.3.3 微結構對於化成處理的影響.................12 第三章 實驗方法.....................................19 3.1 實驗流程.....................................19 3.1.1材料準備與前處理..........................19 3.1.2 化成處理.................................21 3.2 巨觀性質觀察.................................21 3.2.1 表面顏色觀察.............................21 3.2.2 重量測量.................................21 3.3 微觀性質觀察.................................21 3.3.1 光學顯微鏡觀察...........................21 3.3.2 掃描式電子顯微鏡觀察.....................23 3.3.3 能量散佈光譜儀...........................23 3.3.4 低掠角X光繞射儀分析......................24 3.3.5穿透式電子顯微鏡橫截面觀察................24 3.4 化成皮膜性質分析.............................25 3.4.1 極化曲線.................................25 3.4.2 附著性測試...............................25 3.4.3 交流阻抗分析.............................26 第四章 結果與討論...................................31 4.1 鎂合金底材的分析.............................31 4.2 巨觀性質觀察.................................31 4.2.1 皮膜重量變化.............................31 4.2.2 皮膜顏色分析.............................32 4.3 微觀性質觀察.................................32 4.3.1 光學顯微鏡觀察...........................32 4.3.2 掃瞄式電子顯微鏡觀察.....................36 4.3.2.1 表面觀察..............................36 4.3.2.2 橫截面SEM觀察.........................37 4.3.3 低掠角X光繞射分析........................38 4.3.4穿透式電子顯微鏡橫截面觀察................59 4.4 皮膜性質分析.................................64 4.1.1 開路電位.................................64 4.4.2 極化曲線.................................64 4.4.3 交流阻抗分析.............................65 4.4.4 百格試驗（附著性）.......................65 4.5綜合討論......................................74 第五章 結論........................................77 第六章 參考文獻....................................792155376 bytesapplication/pdfen-USMg17Al12鎂鋁合金微結構磷酸鹽/錳酸鹽化成處理無鉻化成處理Magnesium-Aluminum alloyMicrostructure Phosphate/Permanganate Conversion CoatingChromium-free Conversion Coatingthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/55314/1/ntu-96-R92527059-1.pdf