本文選題：無(wú)氧銅 + 腐蝕行為　； 參考：《深圳大學(xué)》2017年碩士論文

【摘要】：本文以材質(zhì)為無(wú)氧銅的燃?xì)鉄崴鹘鼛啄陙?lái)在我國(guó)北方地區(qū)使用幾個(gè)月就漏水失效為背景,采用循環(huán)伏安法與Tafel曲線分析探究了無(wú)氧銅在含有C1~-、SO_4~(2-)和CO_3~(2-)的生活用水中的腐蝕行為,通過(guò)XRD、SEM及金相顯微鏡觀察分析經(jīng)模擬浸泡腐蝕試驗(yàn)后的銅管表面形貌與腐蝕產(chǎn)物,來(lái)研究換熱器的溫度與工況對(duì)銅腐蝕行為的影響。研究討論結(jié)果如下:1)在國(guó)家生活衛(wèi)生用水標(biāo)準(zhǔn)GB5749-2006的規(guī)定范圍內(nèi)C1~-、SO_4~(2-)和CO_3~(2-)對(duì)無(wú)氧銅都有侵蝕性,C1~-與SO_4~(2-)的侵蝕性最強(qiáng)。C1~-的濃度增加會(huì)加速銅全面腐蝕,會(huì)促進(jìn)銅的點(diǎn)蝕形核,但不利于點(diǎn)蝕的發(fā)展;SO_4~(2-)的濃度增加對(duì)銅的全面腐蝕影響并不大,易引起點(diǎn)蝕;CO_3~(2-)濃度的增加可加速銅的全面腐蝕;CO_3~(2-)在低于0.01 mol/L時(shí),濃度的增加易引發(fā)點(diǎn)蝕,而在CO_3~(2-)濃度大于0.03 mol/L時(shí),濃度的增加會(huì)抑制點(diǎn)蝕。2)在 C1~-與 SO_4~(2-)混合體系中,C1~-濃度對(duì)銅的全面腐蝕起著主導(dǎo)作用,C1~-濃度的增加會(huì)促進(jìn)銅的全面腐蝕;當(dāng)C1~-的濃度低于0.005 mol/L時(shí),SO_4~(2-)的增加會(huì)大大增強(qiáng)銅的點(diǎn)蝕傾向,引起點(diǎn)蝕的發(fā)生;當(dāng)C1~-濃度大于0.03 mol/L時(shí),C1~-濃度將對(duì)銅點(diǎn)蝕行為起主導(dǎo)作用。在C1~-與CO_3~(2-)混合體系和SO_4~(2-)與CO_3~(2-)混合體系中,當(dāng)溶液中CO_3~(2-)濃度小于0.01 mol/L時(shí),C1~-或SO_4~(2-)的增加會(huì)加速銅的全面腐蝕,促進(jìn)銅點(diǎn)蝕的發(fā)生;而當(dāng)溶液中CO_3~(2-)濃度大于0.03 mol/L時(shí),溶液中銅的腐蝕腐蝕行為主要由CO_3~(2-)濃度來(lái)控制,CO_3~(2-)濃度的增加會(huì)抑制銅點(diǎn)蝕的發(fā)生。3)在20~50℃范圍內(nèi),溫度的上升會(huì)加速銅的全面腐蝕,促進(jìn)銅表面的點(diǎn)蝕形核,但是會(huì)抑制點(diǎn)蝕的發(fā)展。北方地區(qū)的生活用水雖達(dá)到了GB5749-2006的要求,但是由于其SO_4~(2-)含量較高,所以會(huì)使無(wú)氧銅有很大的點(diǎn)蝕傾向,易引發(fā)點(diǎn)蝕。4)無(wú)氧銅在流水條件下的腐蝕要比靜水條件下的嚴(yán)重。無(wú)氧銅在溫度為30℃時(shí)腐蝕較為嚴(yán)重,易發(fā)生點(diǎn)蝕;30℃條件下無(wú)氧銅表面因均勻腐蝕所形成的腐蝕產(chǎn)物層脆弱保護(hù)性差,易于被擊穿,形成大陰極小陽(yáng)極的腐蝕電池而引發(fā)點(diǎn)蝕。5)晶粒尺寸對(duì)無(wú)氧銅的腐蝕行為的影響不大;表面裂紋的存在會(huì)加快銅的全面腐蝕與增大其點(diǎn)蝕敏感性;水質(zhì)對(duì)無(wú)氧銅腐蝕性的影響要大于表面裂紋的影響。6)熱交換器的失效原因?yàn)楸P管發(fā)生點(diǎn)蝕穿孔。熱交換器盤管上點(diǎn)蝕孔分布在溫度為30℃的區(qū)域,這與模擬腐蝕浸泡實(shí)驗(yàn)所得出無(wú)氧銅在溫度為30℃時(shí)易發(fā)生點(diǎn)蝕的結(jié)論相一致。7)影響無(wú)氧銅腐蝕行為的兩個(gè)主要因素是水質(zhì)與均勻腐蝕所形成的腐蝕產(chǎn)物層;無(wú)氧銅的均勻腐蝕與點(diǎn)蝕會(huì)同時(shí)進(jìn)行,均勻腐蝕的腐蝕產(chǎn)物層不均勻與缺陷的存在都會(huì)促進(jìn)點(diǎn)蝕的發(fā)生。同時(shí)水質(zhì)中含有較高的SO_4~(2-)時(shí);會(huì)大大提高無(wú)氧銅的點(diǎn)蝕敏感性,進(jìn)一步促進(jìn)無(wú)氧銅發(fā)生點(diǎn)蝕。
[Abstract]:In this paper, based on the leakage failure of gas water heaters made of oxygen free copper in the north of China in recent years, the corrosion behavior of oxygen free copper in domestic water containing C _ (1) -C _ (so _ 4) and CO _ (3) is investigated by cyclic voltammetry and Tafel curve analysis. The surface morphology and corrosion products of copper tube after simulated immersion corrosion test were observed and analyzed by XRDX SEM and metallographic microscope to study the effect of heat exchanger temperature and working condition on copper corrosion behavior. The results of the study are as follows: (1) within the scope of the National Standard for domestic Sanitary Water (GB5749-2006), the concentration of C _ (1) and C _ (1) (2) and COSP _ (2) are both corrosive to oxygen-free copper (and so _ (4) ~ (2) the concentration of the most corrosive copper,. C _ (1) ~ (-), will accelerate the overall corrosion of copper and will promote the pitting nucleation of copper. However, the increase in the concentration of so _ 4 / T _ 2) does not have a great effect on the overall corrosion of copper. The increase in the concentration of COT _ 3 / T _ 2-can accelerate the overall corrosion of copper. () when the concentration is lower than 0. 01 mol/L, the increase of the concentration will easily lead to pitting corrosion. When the concentration of CO _ 3O _ 2 is greater than 0.03 mol/L, the increase of concentration will inhibit the pitting corrosion. 2) in the mixed system of C _ (1) and S _ (4) O _ (2), the concentration of C _ (1) ~ (-) plays a leading role in the overall corrosion of copper. The increase of concentration of C _ (1) ~ (-) can promote the overall corrosion of copper. When the concentration of C1O- is lower than 0.005 mol/L, the increase of the concentration of so _ 4 ~ + _ 2) will greatly enhance the pitting corrosion tendency of copper and cause the occurrence of pitting corrosion, and when the concentration of C _ (1) ~ (-) is greater than 0.03 mol/L, the concentration of C _ (1) ~ (-) will play a leading role in the pitting corrosion behavior of copper. In the C _ 1 / C _ 3 / C _ T _ 2 / C _ _ _ The corrosion behavior of copper in the solution is mainly controlled by the concentration of COSP _ 3 ~ (2). The increase of the concentration of CO _ 3 / C _ (2) will inhibit the occurrence of copper pitting corrosion. 3) in the range of 20 ~ 50 鈩，

本文編號(hào)：1818059