地下水環(huán)境中典型金屬材料腐蝕行為的研究
發(fā)布時(shí)間：2018-11-05 07:52
【摘要】：采用地下深埋是處置高放廢物最安全、可行和實(shí)用的方法。金屬包裝容器作為防止高放廢物泄漏的第一道人工屏障,在長(zhǎng)期地質(zhì)處置過(guò)程中,可能會(huì)受到地下水的侵蝕而發(fā)生失效。甘肅省北山地區(qū)是我國(guó)地質(zhì)處置庫(kù)候選場(chǎng)址之一,在此環(huán)境中選用何種金屬作為包裝容器材料是我國(guó)高放廢物地質(zhì)處置工程急需解決的問(wèn)題之一。本文利用長(zhǎng)期浸泡和電化學(xué)方法,同時(shí)借助掃描電子顯微鏡(SEM)、X射線能譜(EDS)、X射線衍射(XRD)、拉曼光譜和表面輪廓儀等分析手段,研究了環(huán)境因素和合金元素對(duì)典型金屬材料在模擬北山地下水溶液中縫隙腐蝕的影響。首先,研究了碳鋼(Q235)、低合金鋼(16Mn、SPHC、Corten A和CortenB)、鑄鐵、鋁合金(2024、7B04)、純銅、純鈦、鎳基合金(C22)和不銹鋼(SUS 304、SUS430、316L)等多種材料在不同腐蝕時(shí)間、不同溫度、不同氧條件下地下水模擬溶液中的縫隙腐蝕行為。經(jīng)過(guò)1年浸泡,碳鋼、低合金鋼和鑄鐵在常溫有氧時(shí)均未觀察到縫隙腐蝕,這可能與其孕育期較長(zhǎng)有關(guān)；常溫?zé)o氧時(shí),Corten鋼出現(xiàn)了縫隙腐蝕：高溫時(shí),碳鋼和低合金鋼均表現(xiàn)出較嚴(yán)重的縫隙腐蝕。鋁合金在常溫時(shí)就發(fā)生了較嚴(yán)重的點(diǎn)蝕和縫隙腐蝕。純銅在常溫時(shí)的縫隙腐蝕較輕微,高溫時(shí)較嚴(yán)重,表現(xiàn)出“反縫隙腐蝕”現(xiàn)象。純鈦、鎳基合金和不銹鋼均沒(méi)有表現(xiàn)出縫隙腐蝕。其次,重點(diǎn)研究了地下水溶液中Cl-、SO42和CO32-對(duì)碳鋼和銅的均勻腐蝕速率和縫隙腐蝕深度的影響。在單一陰離子溶液中,碳鋼和銅的縫隙腐蝕均對(duì)SO42-最為敏感,而在復(fù)雜的地下水模擬溶液中,Cl-對(duì)碳鋼和銅的縫隙腐蝕過(guò)程起控制作用。再次,研究了低合金鋼在地下水溶液中朝上面比朝下面腐蝕嚴(yán)重的機(jī)理。電化學(xué)的測(cè)試結(jié)果表明,由于試樣上下表面氧濃度的差異,朝上面的電位比朝下面更負(fù)。在浸泡過(guò)程中,朝上面為陽(yáng)極,陽(yáng)極反應(yīng)生成的FeOOH會(huì)抑制CaCO3的沉積,因此朝上面腐蝕產(chǎn)物膜主要由疏松的FeOOH和Fe304組成;朝下面為陰極,陰極有利于CaCO3的沉積,所以朝下面的腐蝕產(chǎn)物膜主要是由致密的CaCO3和Fe3O4組成。腐蝕產(chǎn)物膜成分結(jié)構(gòu)的差異導(dǎo)致了浸泡過(guò)程中試樣上表面的腐蝕程度高于下表面。最后,研究了合金元素Cr和Cu對(duì)低合金鋼縫隙腐蝕的影響,證明了合金元素Cr和Cu在縫隙腐蝕過(guò)程中具有協(xié)同作用。當(dāng)鋼中含Cr時(shí),縫隙內(nèi)部會(huì)出現(xiàn)點(diǎn)蝕狀腐蝕坑,而Cu的添加會(huì)加速點(diǎn)蝕坑的發(fā)展。金相分析表明,Cu促進(jìn)Cr在珠光體組織富集,從而導(dǎo)致縫內(nèi)點(diǎn)蝕在珠光體組織處發(fā)生。本文通過(guò)對(duì)典型金屬材料在地下水模擬溶液中腐蝕行為的研究,初步弄清了不同類型材料在我國(guó)甘肅北山地區(qū)地質(zhì)處置環(huán)境中縫隙腐蝕的行為和機(jī)制,為金屬包裝容器材料的選擇提供了理論和實(shí)驗(yàn)依據(jù)。
[Abstract]:It is the safest, feasible and practical method to dispose high-level radioactive waste by deep underground burying. As the first artificial barrier to prevent the leakage of high-level radioactive waste, the metal packaging container may be damaged by groundwater erosion during the long term geological disposal. Beishan area of Gansu Province is one of the candidate sites for geological disposal repository in China. It is one of the urgent problems for geological disposal engineering of high-level radioactive waste in China to choose what metal as packaging container material in this environment. In this paper, long term immersion and electrochemical methods were used, and scanning electron microscope (SEM), (SEM), X ray spectrum, (EDS), X ray diffraction, (XRD), Raman spectroscopy and surface profilometer were used to analyze the results. The effects of environmental factors and alloying elements on gap corrosion of typical metal materials in simulated underground aqueous solution of Beishan were studied. First of all, the corrosion time of carbon steel (Q235), low alloy steel (16MnSSPHC-Corten A and CortenB), cast iron), aluminum alloy (20247B04), pure copper, pure titanium, nickel-base alloy (C22) and stainless steel (SUS 304SUS430316L) were studied. The crevice corrosion behavior of groundwater is simulated under different temperature and oxygen conditions. After one year immersion, no crevice corrosion was observed in carbon steel, low alloy steel and cast iron at room temperature, which may be related to the longer incubation period. Crack corrosion occurs in Corten steel at room temperature and oxygen free, and serious crevice corrosion occurs in carbon steel and low alloy steel at high temperature. Serious pitting and crevice corrosion occurred in aluminum alloy at room temperature. The crevice corrosion of pure copper is mild at room temperature and serious at high temperature, showing the phenomenon of "reverse crevice corrosion". Pure titanium, nickel base alloy and stainless steel did not show crevice corrosion. Secondly, the effects of Cl-,SO42 and CO32- on the uniform corrosion rate and crevice corrosion depth of carbon steel and copper in underground aqueous solution were studied. In a single anionic solution, the crevice corrosion of carbon steel and copper is the most sensitive to SO42-, while in the complex groundwater simulation solution, Cl- plays a controlling role in the crevice corrosion process of carbon steel and copper. Thirdly, the corrosion mechanism of low alloy steel in underground aqueous solution is studied. The results of electrochemical measurements show that due to the difference of oxygen concentration in the upper and lower surfaces of the sample, the potential toward the top is more negative than that towards the bottom. During soaking, the anode is toward the top, and the FeOOH produced by anodic reaction can inhibit the deposition of CaCO3, so the corrosion product film is mainly composed of loose FeOOH and Fe304. The cathode is the cathode which is favorable to the deposition of CaCO3, so the corrosion product film is mainly composed of dense CaCO3 and Fe3O4. The difference of composition and structure of corrosion products resulted in higher corrosion degree on the upper surface of the sample than on the lower surface during soaking. Finally, the effect of alloying elements Cr and Cu on crevice corrosion of low alloy steel was studied. It was proved that the alloy elements Cr and Cu had synergistic effect in the process of crevice corrosion. When the steel contains Cr, the pitting corrosion pits will appear in the cracks, and the addition of Cu will accelerate the development of the pitting pits. Metallographic analysis shows that Cu promotes the enrichment of Cr in pearlite, which leads to pitting in the pearlite. Based on the study of corrosion behavior of typical metal materials in groundwater simulated solution, the behavior and mechanism of gap corrosion of different kinds of materials in geological disposal environment of Beishan area, Gansu Province, are preliminarily clarified in this paper. It provides theoretical and experimental basis for material selection of metal packaging container.
【學(xué)位授予單位】：北京科技大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：TG172
本文編號(hào)：2311394
[Abstract]:It is the safest, feasible and practical method to dispose high-level radioactive waste by deep underground burying. As the first artificial barrier to prevent the leakage of high-level radioactive waste, the metal packaging container may be damaged by groundwater erosion during the long term geological disposal. Beishan area of Gansu Province is one of the candidate sites for geological disposal repository in China. It is one of the urgent problems for geological disposal engineering of high-level radioactive waste in China to choose what metal as packaging container material in this environment. In this paper, long term immersion and electrochemical methods were used, and scanning electron microscope (SEM), (SEM), X ray spectrum, (EDS), X ray diffraction, (XRD), Raman spectroscopy and surface profilometer were used to analyze the results. The effects of environmental factors and alloying elements on gap corrosion of typical metal materials in simulated underground aqueous solution of Beishan were studied. First of all, the corrosion time of carbon steel (Q235), low alloy steel (16MnSSPHC-Corten A and CortenB), cast iron), aluminum alloy (20247B04), pure copper, pure titanium, nickel-base alloy (C22) and stainless steel (SUS 304SUS430316L) were studied. The crevice corrosion behavior of groundwater is simulated under different temperature and oxygen conditions. After one year immersion, no crevice corrosion was observed in carbon steel, low alloy steel and cast iron at room temperature, which may be related to the longer incubation period. Crack corrosion occurs in Corten steel at room temperature and oxygen free, and serious crevice corrosion occurs in carbon steel and low alloy steel at high temperature. Serious pitting and crevice corrosion occurred in aluminum alloy at room temperature. The crevice corrosion of pure copper is mild at room temperature and serious at high temperature, showing the phenomenon of "reverse crevice corrosion". Pure titanium, nickel base alloy and stainless steel did not show crevice corrosion. Secondly, the effects of Cl-,SO42 and CO32- on the uniform corrosion rate and crevice corrosion depth of carbon steel and copper in underground aqueous solution were studied. In a single anionic solution, the crevice corrosion of carbon steel and copper is the most sensitive to SO42-, while in the complex groundwater simulation solution, Cl- plays a controlling role in the crevice corrosion process of carbon steel and copper. Thirdly, the corrosion mechanism of low alloy steel in underground aqueous solution is studied. The results of electrochemical measurements show that due to the difference of oxygen concentration in the upper and lower surfaces of the sample, the potential toward the top is more negative than that towards the bottom. During soaking, the anode is toward the top, and the FeOOH produced by anodic reaction can inhibit the deposition of CaCO3, so the corrosion product film is mainly composed of loose FeOOH and Fe304. The cathode is the cathode which is favorable to the deposition of CaCO3, so the corrosion product film is mainly composed of dense CaCO3 and Fe3O4. The difference of composition and structure of corrosion products resulted in higher corrosion degree on the upper surface of the sample than on the lower surface during soaking. Finally, the effect of alloying elements Cr and Cu on crevice corrosion of low alloy steel was studied. It was proved that the alloy elements Cr and Cu had synergistic effect in the process of crevice corrosion. When the steel contains Cr, the pitting corrosion pits will appear in the cracks, and the addition of Cu will accelerate the development of the pitting pits. Metallographic analysis shows that Cu promotes the enrichment of Cr in pearlite, which leads to pitting in the pearlite. Based on the study of corrosion behavior of typical metal materials in groundwater simulated solution, the behavior and mechanism of gap corrosion of different kinds of materials in geological disposal environment of Beishan area, Gansu Province, are preliminarily clarified in this paper. It provides theoretical and experimental basis for material selection of metal packaging container.
【學(xué)位授予單位】：北京科技大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：TG172
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 楊武;A. Pourbaix;;鉻和鉬對(duì)鋼的局部腐蝕發(fā)展過(guò)程的影響[J];中國(guó)腐蝕與防護(hù)學(xué)報(bào);1983年01期
相關(guān)會(huì)議論文 前1條
1 董俊華;陽(yáng)靖峰;韓恩厚;柯偉;;模擬Yucca Mountain處置環(huán)境下C22合金縫隙腐蝕可能性的研究[A];第二屆廢物地下處置學(xué)術(shù)研討會(huì)論文集[C];2008年
相關(guān)碩士學(xué)位論文 前1條
1 賈恒磊;數(shù)字全息術(shù)研究碳鋼的縫隙腐蝕和鐵的陽(yáng)極電化學(xué)振蕩[D];山東大學(xué);2009年
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