切削液中类产碱假单胞菌对铝合金腐蚀行为的影响  

Microbially Influenced Corrosion Behavior of Aluminium Alloy in Metalcutting Fluid Containing Pseudomonas Pseudoalcaligenes

作　　者：李庆宏[1] 陈景浩 申媛媛[1] 郭章伟 董耀华[1] 张丽[1] 董丽华[1] LI Qing-hong;CHEN Jing-hao;SHEN Yuan-yuan;GUO Zhang-wei;DONG Yao-hua;ZHANG Li;DONG Li-hua(Shanghai Maritime University,Shanghai 201306,China;Beijing Institute of Petrochemical Technology,Beijing 102617,China)

机构地区：[1]上海海事大学,上海201306 [2]北京石油化工学院,北京102617

出　　处：《表面技术》2021年第5期269-280,共12页Surface Technology

基　　金：上海深远海洋装备材料工程技术研究中心项目(19DZ2253100);深水油气管线关键技术与装备北京市重点实验室开放课题(BIPT2019002);上海海事大学研究生创新基金项目(2017ycx003)。

摘　　要：目的从切削废液中分离出类产碱假单胞菌(Pseudomonas pseudoalcaligenes)菌株,研究该菌株对切削液的劣化,以及5754铝合金在含该菌株的切削液中的微生物腐蚀(MIC)行为。方法采用平板划线法,从切削废液中分离提纯出单一菌株,并通过16S rDNA进行菌株测序。将类产碱假单胞菌接种至切削液中,并将5754铝合金金浸泡于其中。通过定期检测细菌在切削液中的生长状况、切削液的p H值、乳液液滴粒径、溶解氧、总有机碳(TOC)、无机碳(IC)以及总氮(TN)含量变化,分析微生物对切削液的劣化行为。通过表征铝合金在含菌切削液中的微观腐蚀形貌与生物附着情况,并结合电化学手段,分析5754铝合金在含菌切削液中的电化学腐蚀行为。结果类产碱假单胞菌在切削液中具有良好的生长状况,微生物浓度维持在107 CFU/mL以上。切削液发生了严重的生物降解,在实验周期内,pH值由9.25降至7.39,乳液液滴粒径分布曲线从单峰分布(1.07μm)变为双峰分布(1.12、8.93μm),染色后的液滴有明显增大,并观测到了液滴间的聚结。切削液中TOC的质量浓度由15.42 g/L下降至9.69 g/L,IC由189.03 mg/L上升至485.50 mg/L,TN由564.77mg/L下降为142.16mg/L。5754铝合金在含菌切削液中浸泡10d时,表面出现了生物膜;浸泡15 d后,金属基体在生物膜下发生了严重的点蚀现象。极化曲线结果显示,腐蚀电位(Ecorr)发生了明显的负移,铝合金的腐蚀电流密度(Jcorr)由0.274μA/cm^(2)上升至0.477μA/cm^(2)。在15 d时,铝合金的腐蚀电流密度要比在无菌切削液中高出4.9倍。铝合金的击穿电位也不断负移,使得铝合金极易发生点蚀。EIS结果显示,随着浸泡时间的增加,5754铝合金的阻抗弧半径不断变小,铝合金的耐腐蚀性不断变差。结论类产碱假单胞菌将切削液中缓冲剂、乳化剂等含氮有机物优先降解为可溶性无机盐,使切削液pH降低,乳化剂保护效果下降,溶液导�We investigated the corrosion behavior of 5754 aluminium alloy in metalcutting fluid(MCF)containing P.pseudoalcaligenes which was isolated from a waste metalcutting fluid(WMCF).The single strain was purified and isolated by streak plate method and sequenced using 16S rDNA.P.pseudoalcaligenes was inoculated into the MCF and 5754 aluminium alloy specimen were immersed in the bio-contaminated MCF simultaneously.pH,emulsion droplets size distribution,dissolved oxygen,TOC,IC,and TN in the MCF were investigated to analysis the biodeterioration of MCF under the influence of P.pseudoalcaligenes.The microbially influenced corrosion behavior of 5754 aluminium alloy in the MCF was characterized by morphological characterization of metal and the attachment of biofilm.The polarization curves and EIS were applied to analyze the electrochemical behavior of aluminium alloy in the MCF containing P.pseudoalcaligenes.Remarkable growth of P.pseudoalcaligenes was showed in the MCF and the biomass remained at 107 CFU/mL.A severe biodegradation of MCF was observed,with the pH decreased from 9.25 to 7.39 and the curve of emulsion droplets size distribution transforming into bimodal(1.12μm,8.93μm)from monomodal(1.07μm).The coalescence between emulsion droplets was observed after the staining of droplets.The change of TOC and TN showed a decline from 15.42 g/L and 564.77 mg/L into 9.69 g/L and 142.16 mg/L,respectively.And the increase of IC was obtained during the biodegradation.A biofilm was occurred on the surface of 5754 aluminium alloy immersed in MCF containing P.pseudoalcaligenes for 10 days and a seriously pitting was observed in the matrix under the biofilm after immersion for 15 days.Results of polarization curve showed that the Ecorr shifted negatively under the microbial influence.The Jcorr of aluminium alloy immersed in MCF with microbes for 15 days increased from 0.274μA/cm^(2) to 0.477μA/cm^(2).The Jcorr of aluminium alloy immersed in bio-contaminated MCF for 15 days was 4.9-fold greater than in the absence of bacteria.

关 键 词：铝合金 切削液 微生物腐蚀 电化学测试 类产碱假单胞菌 

分 类 号：TG172[金属学及工艺—金属表面处理]