本文關(guān)鍵詞：涂層防護體系加速腐蝕失效機制研究　出處：《北京化工大學》2015年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 有機涂層防護體系 綜合評分體系 腐蝕 現(xiàn)代儀器分析 失效機制

【摘要】：有機涂層體系的廣泛使用不可避免的引起腐蝕失效的發(fā)生并造成極大危害。如果能夠盡可能的對復(fù)雜大氣環(huán)境腐蝕下有機涂層體系做出較為真實的模擬并對其的失效做出較為全面、準確的評價,知道其失效機制并采取有效措施將會大大減少腐蝕危害的發(fā)生與發(fā)展。基于以上問題,研究金屬涂層防護體系的腐蝕失效并為制定相關(guān)防腐蝕措施的標準提供重要依據(jù)就顯得尤為重要。本課題展開了對有機涂層防護體系加速腐蝕失效的研究。首先,利用層次分析法(AHP)建立涂層防護體系的綜合評價模型；其次,通過電化學數(shù)據(jù)對此評價模型進行了驗證,并利用其對涂層體系的失效結(jié)果進行評價；最后,通過一些現(xiàn)代儀器分析方法對有機涂層防護體系在光化學與腐蝕介質(zhì)協(xié)同作用下的腐蝕失效機制進行了研究。研究結(jié)果表明：綜合評價模型對涂層體系的失效程度能夠較好的評價,并且權(quán)重系數(shù)范圍界定使其有了更高的適應(yīng)性；電化學方法得到的涂層電阻對評分結(jié)果的檢驗證實了涂層評價模型的正確性。通過SEM觀察發(fā)現(xiàn)涂層體系經(jīng)過8個周期加速腐蝕實驗后其表面確實發(fā)生了鼓泡與裂紋,甚至截面出現(xiàn)剝離：通過EDS分析,發(fā)現(xiàn)腐蝕后涂層的Cl-增多,C/O顯著減小,腐蝕越嚴重這種趨勢更明顯；在截面上,Cl-隨著腐蝕介質(zhì)的滲入深度而逐漸減少。而填料二氧化鈦也隨著涂層中有效成分的破壞而逐漸流失。利用FITR分析可知三種有機涂層腐蝕失效過程具有相同的腐蝕機理,且樹脂鏈斷裂均表現(xiàn)為N-H鍵的斷裂和C-O鍵斷裂。因此,可以推斷,涂層中有效成分在光化學作用下遭到破壞,加速了氯離子等腐蝕介質(zhì)在涂層中滲入進而使涂層發(fā)生鼓泡,開裂和剝落等腐蝕失效現(xiàn)象。而涂層中的成膜物質(zhì)聚氨酯通過改性以及涂層中二氧化鈦的添加會大大改善涂層體系的耐蝕性能。表面只有超音速火焰噴涂處理的無涂層涂層體系在經(jīng)過四個周期加速實驗就發(fā)生嚴重腐蝕,通過XPS分析知,實驗前涂層體系的涂層表面無Fe元素存在而腐蝕后的有鐵元素且以FeO、Fe3O4、 Fe2O3、FeOOH、Fe2(SO4)3五種氧化物的形式存在：腐蝕不嚴重部位二價鐵的含量比腐蝕嚴重部位多,而Fe2(SO4)3在腐蝕嚴重部位含量多,則鐵的轉(zhuǎn)化過程可能是從穩(wěn)定的Fe單質(zhì)和二價鐵氧化物,中間經(jīng)過三價鐵的氧化物,最后形成硫酸鐵：超音速火焰噴涂層的失效也表現(xiàn)出C/O元素含量比在腐蝕發(fā)生后會變小,而其主要噴涂物質(zhì)WC可能以其氧化物的形態(tài)離開涂層,使其對基體金屬的保護作用逐漸失去,基體金屬則不斷遭受腐蝕介質(zhì)的腐蝕而破壞。
[Abstract]:Organic coatings are widely used will inevitably cause corrosion failure occurred and caused great harm. If possible corrosion of the complex atmospheric environment simulation system to make the organic coating more real and made more comprehensive on the failure of the accurate evaluation, know the failure mechanism and take effective measures will greatly reduce the occurrence and development of corrosion damage. Based on the above problems, the corrosion protection system of metal coating failure and corrosion protection measures for the formulation of relevant standards important basis is particularly important. This thesis researches on accelerating the corrosion of organic coating protection system. First, using the analytic hierarchy process (AHP) to establish comprehensive evaluation system for protective coating secondly, through the electrochemical data model; this evaluation model is verified, and the use of coating failure results For evaluation; finally, through some modern instrumental analysis methods to study the organic coating corrosion protection system of collaborative under photochemical and corrosion failure mechanism. The results show that the comprehensive evaluation model of the coating system can evaluate the degree of failure, and the weight coefficient scope makes it have higher adaptability; test of coating resistance electrochemical method on the score results confirmed the correctness of the coating evaluation model. Observed by SEM coating system after 8 cycles of accelerated corrosion test on the surface after the really happened bubble and crack, even stripping section: through EDS analysis, it is found that the corrosion coating of Cl- C/O was significantly increased. The more serious corrosion decreases, this trend is more obvious; in cross section, Cl- decreased with the depth of penetration of corrosive medium and titanium dioxide with filler. The active ingredient in the coating damage gradually lost. The corrosion mechanism of the same with using the FITR analysis of three kinds of organic coating corrosion process, and the resin chain showed fracture fracture and C-O bond cleavage of the N-H bond. Therefore, it can be inferred that the effective components in the coating was damaged in the photochemical effect, accelerated chloride the corrosive media in the coating and the coating into the bubble, the failure of cracking and spalling corrosion phenomena. While in the coating film material corrosion resistance of polyurethane by modified and added coating of titanium dioxide in the coating system will be greatly improved. No coating system for surface treatment only supersonic flame spraying after four cycles to accelerate the experiment of serious corrosion, through XPS analysis, the coating surface coating system before the experiment without Fe elements exist after corrosion of iron element and the FeO, Fe3O4, F E2O3, FeOOH, Fe2 (SO4) has 3 forms: five kinds of oxide corrosion is not serious in parts of two valent iron than serious corrosion site, and Fe2 (SO4) 3 in the content of serious corrosion of parts, iron transformation process may be from stable Fe elemental and two valent iron oxide, in between after the ferric oxide, and finally the formation of ferric sulfate layer failure also showed the content of C/O is smaller than the corrosion will occur after HVOF spraying, and its main material to form the oxide WC may leave the protection coating on the base metal with the base metal is gradually lost, continue to suffer the corrosion of corrosive medium and destruction.

【學位授予單位】：北京化工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TG174.4

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本文編號：1379453