铜绿假单胞菌对CrCoNi中熵合金的微生物腐蚀行为研究

铜绿假单胞菌对CrCoNi中熵合金的微生物腐蚀行为研究摘要采用多种电化学实验手段及场发射扫描电子显微镜（FESEM）、金相显微镜（OM）等分析技术，结合活死细菌染色实验、点蚀坑深度分析等方法，以316L不锈钢为对比，研究了CrCoNi中熵合金在含铜绿假单胞菌培养基中的微生物腐蚀行为。结果表明：铜绿假单胞菌能够在CrCoNi中熵合金表面形成不均匀的生物被膜，导致开路电位下降、极化电阻减小、腐蚀电流密度增大；铜绿假单胞菌生物被膜一定程度上破坏了钝化膜，导致浸泡在含铜绿假单胞菌培养基中的CrCoNi中熵合金的最大点蚀坑深（4.8µm）大于无菌培养基中（2.3µm）。与316L相比，CrCoNi中熵合金的开路电位较高、腐蚀电流密度和腐蚀速率较小，钝化膜的修复能力较强，在含铜绿假单胞菌培养基中浸泡后的最大点蚀坑深度小于316L不锈钢（5.8µm）。关键词CrCoNi中熵合金，铜绿假单胞菌，微生物腐蚀，生物被膜，点腐蚀近年来，由多个等摩尔比或近等摩尔比组元组成的高熵合金引起了人们的广泛关注ADDINEN.CITEADDINEN.CITE.DATA[1-3]。由于其优异的强度和延展性ADDINEN.CITE<EndNote><Cite><Author>Gao</Author><Year>2018</Year><RecNum>62</RecNum><DisplayText><styleface="superscript">[2]</style></DisplayText><record><rec-number>62</rec-number><foreign-keys><keyapp="EN"db-id="9twpvr2am9t5ebe0206paxphe9v5axxdpzp0"timestamp="1548121819">62</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Gao,Michael</author><author>Qiao,Junwei</author></authors></contributors><titles><title>High-EntropyAlloys(HEAs)</title><secondary-title>Metals</secondary-title></titles><periodical><full-title>Metals</full-title><abbr-1>Metals</abbr-1></periodical><pages>1-3</pages><volume>8</volume><number>2</number><section>108</section><dates><year>2018</year></dates><isbn>2075-4701</isbn><urls></urls><electronic-resource-num>10.3390/met8020108</electronic-resource-num></record></Cite></EndNote>[2]，以及高耐磨性ADDINEN.CITE<EndNote><Cite><Author>Jiang</Author><Year>2017</Year><RecNum>64</RecNum><DisplayText><styleface="superscript">[4]</style></DisplayText><record><rec-number>64</rec-number><foreign-keys><keyapp="EN"db-id="9twpvr2am9t5ebe0206paxphe9v5axxdpzp0"timestamp="1548123356">64</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Jiang,Hui</author><author>Jiang,Li</author><author>Qiao,Dongxu</author><author>Lu,Yiping</author><author>Wang,Tongmin</author><author>Cao,Zhiqiang</author><author>Li,Tingju</author></authors></contributors><titles><title>EffectofNiobiumonMicrostructureandPropertiesoftheCoCrFeNbxNiHighEntropyAlloys</title><secondary-title>JournalofMaterialsScience&Technology</secondary-title></titles><periodical><full-title>JournalofMaterialsScience&Technology</full-title><abbr-1>JMaterSciTechnol</abbr-1></periodical><pages>712-717</pages><volume>33</volume><number>7</number><keywords><keyword>Alloydesign</keyword><keyword>Microstructure</keyword><keyword>Mechanicalproperties</keyword><keyword>Wearresistance</keyword></keywords><dates><year>2017</year><pub-dates><date>2017/07/01/</date></pub-dates></dates><isbn>1005-0302</isbn><urls><related-urls><url>/science/article/pii/S1005030216301724</url></related-urls></urls><electronic-resource-num>/10.1016/j.jmst.2016.09.016</electronic-resource-num></record></Cite></EndNote>[4]、良好的热稳定性ADDINEN.CITE<EndNote><Cite><Author>Zhang</Author><Year>2016</Year><RecNum>65</RecNum><DisplayText><styleface="superscript">[5]</style></DisplayText><record><rec-number>65</rec-number><foreign-keys><keyapp="EN"db-id="9twpvr2am9t5ebe0206paxphe9v5axxdpzp0"timestamp="1548123396">65</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Zhang,Chuan</author><author>Zhang,Fan</author><author>Diao,Haoyan</author><author>Gao,MichaelC.</author><author>Tang,Zhi</author><author>Poplawsky,JonathanD.</author><author>Liaw,PeterK.</author></authors></contributors><titles><title>UnderstandingphasestabilityofAl-Co-Cr-Fe-Nihighentropyalloys</title><secondary-title>Materials&Design</secondary-title></titles><periodical><full-title>Materials&Design</full-title><abbr-1>MaterDes</abbr-1></periodical><pages>425-433</pages><volume>109</volume><keywords><keyword>High-entropyalloy</keyword><keyword>Phasestability</keyword><keyword>CALPHAD</keyword><keyword>Phasediagram</keyword><keyword>Atomprobetomography(APT)</keyword></keywords><dates><year>2016</year><pub-dates><date>2016/11/05/</date></pub-dates></dates><isbn>0264-1275</isbn><urls><related-urls><url>/science/article/pii/S026412751630973X</url></related-urls></urls><electronic-resource-num>/10.1016/j.matdes.2016.07.073</electronic-resource-num></record></Cite></EndNote>[5]，高熵合金得到了蓬勃的发展。其中，CrCoNi是一种仅含有三种元素的等摩尔比中熵合金，它是一种单相面心立方固溶体，具有超过大多数高熵合金和多相合金的强度和韧性ADDINEN.CITEADDINEN.CITE.DATA[6-10]。同时，本课题组研究发现，CrCoNi中熵合金在NaCl溶液中具有良好的耐腐蚀性能ADDINEN.CITE<EndNote><Cite><Author>Feng</Author><Year>2018</Year><RecNum>39</RecNum><DisplayText><styleface="superscript">[11]</style></DisplayText><record><rec-number>39</rec-number><foreign-keys><keyapp="EN"db-id="9twpvr2am9t5ebe0206paxphe9v5axxdpzp0"timestamp="1546479226">39</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Feng,Hao</author><author>Li,Huabing</author><author>Wu,Xiaolei</author><author>Jiang,Zhouhua</author><author>Zhao,Si</author><author>Zhang,Tao</author><author>Xu,Dake</author><author>Zhang,Shucai</author><author>Zhu,Hongchun</author><author>Zhang,Binbin</author><author>Yang,Muxin</author></authors></contributors><titles><title>Effectofnitrogenoncorrosionbehaviourofanovelhighnitrogenmedium-entropyalloyCrCoNiNmanufacturedbypressurizedmetallurgy</title><secondary-title>JournalofMaterialsScience&Technology</secondary-title></titles><periodical><full-title>JournalofMaterialsScience&Technology</full-title><abbr-1>JMaterSciTechnol</abbr-1></periodical><pages>1781-1790</pages><volume>34</volume><number>10</number><keywords><keyword>Medium-entropyalloy</keyword><keyword>Nitrogen</keyword><keyword>Pittingcorrosion</keyword><keyword>Passivefilm</keyword><keyword>Metastablepitting</keyword></keywords><dates><year>2018</year><pub-dates><date>2018/10/01/</date></pub-dates></dates><isbn>1005-0302</isbn><urls><related-urls><url>/science/article/pii/S1005030218300835</url></related-urls></urls><electronic-resource-num>/10.1016/j.jmst.2018.03.021</electronic-resource-num></record></Cite></EndNote>[11]，与2205双相不锈钢相当。因此，CrCoNi中熵合金可以作为基础合金，发展性能更加优异的工程合金金ADDINEN.CITE<EndNote><Cite><Author>Liu</Author><Year>2019</Year><RecNum>1</RecNum><DisplayText><styleface="superscript">[12]</style></DisplayText><record><rec-number>1</rec-number><foreign-keys><keyapp="EN"db-id="9twpvr2am9t5ebe0206paxphe9v5axxdpzp0"timestamp="1542162085">1</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Liu,X.W.</author><author>Laplanche,G.</author><author>Kostka,A.</author><author>Fries,S.G.</author><author>Pfetzing-Micklich,J.</author><author>Liu,G.</author><author>George,E.P.</author></authors></contributors><titles><title>ColumnartoequiaxedtransitionandgrainrefinementofcastCrCoNimedium-entropyalloybymicroalloyingwithtitaniumandcarbon</title><secondary-title>JournalofAlloysandCompounds</secondary-title></titles><periodical><full-title>JournalofAlloysandCompounds</full-title><abbr-1>JAlloyCompd</abbr-1></periodical><pages>1068-1076</pages><volume>775</volume><keywords><keyword>Mediumandhighentropyalloys</keyword><keyword>Grainrefinement</keyword><keyword>Castmicrostructure</keyword><keyword>Constitutionalundercooling</keyword><keyword>Mechanicalproperties</keyword></keywords><dates><year>2019</year><pub-dates><date>2019/02/15/</date></pub-dates></dates><isbn>0925-8388</isbn><urls><related-urls><url>/science/article/pii/S0925838818338611</url></related-urls></urls><electronic-resource-num>/10.1016/j.jallcom.2018.10.187</electronic-resource-num></record></Cite></EndNote>[12]。微生物腐蚀是由微生物附着在材料表面及形成生物被膜引起的ADDINEN.CITE<EndNote><Cite><Author>Xu</Author><Year>2013</Year><RecNum>11</RecNum><DisplayText><styleface="superscript">[13]</style></DisplayText><record><rec-number>11</rec-number><foreign-keys><keyapp="EN"db-id="9twpvr2am9t5ebe0206paxphe9v5axxdpzp0"timestamp="1542163775">11</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Xu,Dake</author><author>Li,Yingchao</author><author>Song,Fengmei</author><author>Gu,Tingyue</author></authors></contributors><titles><title>LaboratoryinvestigationofmicrobiologicallyinfluencedcorrosionofC1018carbonsteelbynitratereducingbacteriumBacilluslicheniformis</title><secondary-title>CorrosionScience</secondary-title></titles><periodical><full-title>CorrosionScience</full-title><abbr-1>CorrosSci</abbr-1></periodical><pages>385-390</pages><volume>77</volume><keywords><keyword>A.Carbonsteel</keyword><keyword>B.SEM</keyword><keyword>B.Weightloss</keyword><keyword>B.XRD</keyword><keyword>C.Microbiologicalcorrosion</keyword><keyword>C.Pittingcorrosion</keyword></keywords><dates><year>2013</year><pub-dates><date>2013/12/01/</date></pub-dates></dates><isbn>0010-938X</isbn><urls><related-urls><url>/science/article/pii/S0010938X13003545</url></related-urls></urls><electronic-resource-num>/10.1016/j.corsci.2013.07.044</electronic-resource-num></record></Cite></EndNote>[13]，它的腐蚀成本大约占所有金属和建筑等材料腐蚀成本的20%ADDINEN.CITE<EndNote><Cite><Author>Zhang</Author><Year>2015</Year><RecNum>12</RecNum><DisplayText><styleface="superscript">[14]</style></DisplayText><record><rec-number>12</rec-number><foreign-keys><keyapp="EN"db-id="9twpvr2am9t5ebe0206paxphe9v5axxdpzp0"timestamp="1542184702">12</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Zhang,Peiyu</author><author>Xu,Dake</author><author>Li,Yingchao</author><author>Yang,Ke</author><author>Gu,Tingyue</author></authors></contributors><titles><title>Electronmediatorsacceleratethemicrobiologicallyinfluencedcorrosionof304stainlesssteelbytheDesulfovibriovulgarisbiofilm</title><secondary-title>Bioelectrochemistry</secondary-title></titles><periodical><full-title>Bioelectrochemistry</full-title></periodical><pages>14-21</pages><volume>101</volume><keywords><keyword>Biofilm</keyword><keyword>Biocorrosion</keyword><keyword>SRB</keyword><keyword>Electrontransfer</keyword><keyword>Electronmediator</keyword></keywords><dates><year>2015</year><pub-dates><date>2015/02/01/</date></pub-dates></dates><isbn>1567-5394</isbn><urls><related-urls><url>/science/article/pii/S1567539414000929</url></related-urls></urls><electronic-resource-num>/10.1016/j.bioelechem.2014.06.010</electronic-resource-num></record></Cite></EndNote>[14]。据2016年美国腐蚀工程师协会公布的全球腐蚀调研项目的结果，全球腐蚀成本大约占国民生产总值的3.4%ADDINEN.CITE<EndNote><Cite><Author>顾彩香</Author><Year>2017</Year><RecNum>52</RecNum><DisplayText><styleface="superscript">[15]</style></DisplayText><record><rec-number>52</rec-number><foreign-keys><keyapp="EN"db-id="9twpvr2am9t5ebe0206paxphe9v5axxdpzp0"timestamp="1547464870">52</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author><styleface="normal"font="default"charset="134"size="100%">顾彩香</style></author><author><styleface="normal"font="default"charset="134"size="100%">夏瑞</style></author><author><styleface="normal"font="default"charset="134"size="100%">朱冠军</style></author><author><styleface="normal"font="default"charset="134"size="100%">朱云鹏</style></author></authors></contributors><auth-address><styleface="normal"font="default"charset="134"size="100%">上海海事大学商船学院</style><styleface="normal"font="default"size="100%">;</style></auth-address><titles><title><styleface="normal"font="default"charset="134"size="100%">不锈钢海洋微生物腐蚀研究</style></title><secondary-title><styleface="normal"font="default"charset="134"size="100%">船舶工程</style></secondary-title></titles><periodical><full-title>船舶工程</full-title></periodical><pages>57-61</pages><volume>39</volume><number>10</number><keywords><keyword>不锈钢</keyword><keyword>海洋微生物</keyword><keyword>腐蚀</keyword><keyword>腐蚀模型</keyword></keywords><dates><year>2017</year></dates><isbn>1000-6982</isbn><call-num>31-1281/U</call-num><urls></urls><remote-database-provider>Cnki</remote-database-provider></record></Cite></EndNote>[15]，估算达2.5万亿美元，其中海洋环境中腐蚀造成的经济损失约占总腐蚀成本的30%。在海洋环境中，由于存在多种微生物，暴露的金属表面容易形成海洋微生物被膜，提高了发生微生物腐蚀的可能性，给许多行业带来巨大的经济损失ADDINEN.CITE<EndNote><Cite><Author>Wikieł</Author><Year>2014</Year><RecNum>15</RecNum><DisplayText><styleface="superscript">[16]</style></DisplayText><record><rec-number>15</rec-number><foreign-keys><keyapp="EN"db-id="9twpvr2am9t5ebe0206paxphe9v5axxdpzp0"timestamp="1542196278">15</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Wikieł,AgataJ.</author><author>Datsenko,Iaryna</author><author>Vera,Mario</author><author>Sand,Wolfgang</author></authors></contributors><titles><title>ImpactofDesulfovibrioalaskensisbiofilmsoncorrosionbehaviourofcarbonsteelinmarineenvironment</title><secondary-title>Bioelectrochemistry</secondary-title></titles><periodical><full-title>Bioelectrochemistry</full-title></periodical><pages>52-60</pages><volume>97</volume><keywords><keyword>SRP</keyword><keyword>EPS</keyword><keyword>Biofilms</keyword><keyword>Carbonsteel</keyword><keyword>MIC</keyword></keywords><dates><year>2014</year><pub-dates><date>2014/06/01/</date></pub-dates></dates><isbn>1567-5394</isbn><urls><related-urls><url>/science/article/pii/S156753941300100X</url></related-urls></urls><electronic-resource-num>/10.1016/j.bioelechem.2013.09.008</electronic-resource-num></record></Cite></EndNote>[16]。生物被膜除了会影响金属表面电化学腐蚀的阳极或阴极反应，还会改变腐蚀反应的类型，形成生物被膜内腐蚀环境。同时微生物新陈代谢过程产生的侵蚀性物质会改变金属表面的膜电阻，微生物生长和繁殖所建立的屏障层还会形成金属表面的浓差电池等ADDINEN.CITEADDINEN.CITE.DATA[17-19]。铜绿假单胞菌是海洋中常见的好氧杆状细菌，并且广泛分布于土壤、沼泽等环境，它在代谢中会排出有机酸、二氧化碳和硫酸根离子。同时铜绿假单胞菌也是能够形成生物被膜的典型菌种，研究表明它能加速碳钢、不锈钢等多种材料的腐蚀ADDINEN.CITEADDINEN.CITE.DATA[20-22]。但是，目前中高熵合金的微生物腐蚀行为未见报道，铜绿假单胞菌对其微生物腐蚀行为的影响机制也有待深入研究。本文利用电化学手段结合表面分析方法，以316L不锈钢为对比，研究了在模拟海洋环境中铜绿假单胞菌对CrCoNi中熵合金的微生物腐蚀行为的影响规律，探讨了在该微生物环境中的腐蚀机制，以期为CrCoNi中熵合金在海洋等领域的实际应用提供理论依据和参考。1实验材料及方法1.1材料与实验介质实验所用CrCoNi中熵合金和316L不锈钢的化学成分如表1所示。从CrCoNi中熵合金和316L不锈钢上切取尺寸为10mm×10mm×5mm的试样，分别经1150℃/2h和1050℃/1h固溶处理后，水冷至室温。将试样去除氧化皮并用1000#砂纸打磨后，用蒸馏水、无水乙醇清洗后烘干，然后用紫外灯灭菌30min。表1实验用钢的化学成分Table1Chemicalcompositionsoftheexperimentalsteels(massfraction/%)SteelsCrCoNiCSiMnMoFeCrCoNiMEA30.5834.7134.71316LSS16.78-10.50.0210.431.182.09Bal.实验所用的测试溶液分别为无菌和含铜绿假单胞菌的2216E模拟海水液体培养基溶液，铜绿假单胞菌（MCCC1A00099）来自中国海洋微生物菌种保藏管理中心。2216E培养基的主要成分为：19.45g/LNaCl，5.89g/LMgCl2，3.24g/LNa2SO4，1.8g/LCaCl2，0.55g/LKCl，0.16g/LNa2CO3，0.08g/LKBr，0.034g/LSrCl2，0.08g/LSrBr2，0.022g/LH3BO3，0.004g/LNaSiO3，0.0024g/LNaF，0.0016g/LNH4NO3，0.008g/LNaH2PO4，5.0g/L蛋白胨，1.0g/L酵母膏和0.1g/L柠檬酸铁。用温度为121℃的高压灭菌锅对培养基灭菌20min。接种后培养基中铜绿假单细胞的初始浓度约为106cell/mL。1.2电化学测试实验采用GamryReference600电化学工作站进行开路电位（OCP）、线性极化电阻（LPR）、电化学阻抗谱（EIS）、电化学频率调制（EFM）和循环极化曲线（CP）测试。电化学测试在37℃的2216E培养基中连续进行14天。测试采用经典的三电极体系，辅助电极为铂电极（15mm×15mm铂片），参比电极为饱和甘汞电极（SCE），工作电极为用环氧树脂镶嵌的CrCoNi中熵合金和316L不锈钢试样，工作面积为1cm2。在电化学测试中，开路电位的检测时间为2000s，线性极化的扫描范围为EOCP±5mV，扫描速率为0.125mV·s-1。EIS的扰动电压为5mV，频率范围为10-2～105Hz，测量结果用ZSimpWin软件进行拟合。循环极化从EOCP以下0.3V开始以0.3333mV·s-1的速率正向扫描，在电流密度达到1mAcm-2时反向扫描，当达到保护电位（Eprot）后停止。循环极化测试结束后，采用OlympusDSX510金相显微镜观察试样的腐蚀形貌。1.3腐蚀形貌分析利用UltraPlus型场发射扫描电子显微镜（FESEM）观察在含铜绿假单胞菌的培养基中分别浸泡7天和14天后试样的生物被膜形貌。首先将浸泡后的CrCoNi中熵合金和316L不锈钢试样放入2.5%（体积分数）戊二醛溶液浸泡8h以固定生物被膜，然后依次用50%、60%、70%、80%、90%、95%、100%的乙醇溶液脱水10minADDINEN.CITE<EndNote><Cite><Author>Li</Author><Year>2016</Year><RecNum>22</RecNum><DisplayText><styleface="superscript">[21]</style></DisplayText><record><rec-number>22</rec-number><foreign-keys><keyapp="EN"db-id="9twpvr2am9t5ebe0206paxphe9v5axxdpzp0"timestamp="1542358510">22</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Li,Huabing</author><author>Zhou,Enze</author><author>Ren,Yibin</author><author>Zhang,Dawei</author><author>Xu,Dake</author><author>Yang,Chunguang</author><author>Feng,Hao</author><author>Jiang,Zhouhua</author><author>Li,Xiaogang</author><author>Gu,Tingyue</author><author>Yang,Ke</author></authors></contributors><titles><title>Investigationofmicrobiologicallyinfluencedcorrosionofhighnitrogennickel-freestainlesssteelbyPseudomonasaeruginosa</title><secondary-title>CorrosionScience</secondary-title></titles><periodical><full-title>CorrosionScience</full-title><abbr-1>CorrosSci</abbr-1></periodical><pages>811-821</pages><volume>111</volume><keywords><keyword>A.Stainlesssteel</keyword><keyword>B.EIS</keyword><keyword>C.Microbiologicalcorrosion</keyword><keyword>C.Pittingcorrosion</keyword></keywords><dates><year>2016</year><pub-dates><date>2016/10/01/</date></pub-dates></dates><isbn>0010-938X</isbn><urls><related-urls><url>/science/article/pii/S0010938X1630289X</url></related-urls></urls><electronic-resource-num>/10.1016/j.corsci.2016.06.017</electronic-resource-num></record></Cite></EndNote>[21]。在背散射模式下观察试样表面的细菌形貌，在二次电子模式下观察试样表面形貌。利用C2Plus型激光共聚焦扫描显微镜（CLSM）观察在含铜绿假单胞菌培养基中分别浸泡7天和14天后试样表面细菌的活性ADDINEN.CITE<EndNote><Cite><Author>Xia</Author><Year>2015</Year><RecNum>20</RecNum><DisplayText><styleface="superscript">[20]</style></DisplayText><record><rec-number>20</rec-number><foreign-keys><keyapp="EN"db-id="9twpvr2am9t5ebe0206paxphe9v5axxdpzp0"timestamp="1542357781">20</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Xia,J.</author><author>Yang,C.</author><author>Xu,D.</author><author>Sun,D.</author><author>Nan,L.</author><author>Sun,Z.</author><author>Li,Q.</author><author>Gu,T.</author><author>Yang,K.</author></authors></contributors><auth-address>aCollegeofChemistry,LiaoningUniversity,Shenyang,China.</auth-address><titles><title>Laboratoryinvestigationofthemicrobiologicallyinfluencedcorrosion(MIC)resistanceofanovelCu-bearing2205duplexstainlesssteelinthepresenceofanaerobicmarinePseudomonasaeruginosabiofilm</title><secondary-title>Biofouling</secondary-title></titles><periodical><full-title>Biofouling</full-title></periodical><pages>481-92</pages><volume>31</volume><number>6</number><edition>2015/07/22</edition><keywords><keyword>Anti-BacterialAgents/pharmacology</keyword><keyword>Biofilms/*drugeffects</keyword><keyword>Copper/adverseeffects/analysis</keyword><keyword>Corrosion</keyword><keyword>Microscopy,Fluorescence</keyword><keyword>Pseudomonasaeruginosa/*metabolism</keyword><keyword>StainlessSteel/*chemistry/*standards</keyword><keyword>2205Cu-DSS</keyword><keyword>Mic</keyword><keyword>Pseudomonasaeruginosa</keyword><keyword>antimicrobial</keyword><keyword>biofilm</keyword></keywords><dates><year>2015</year></dates><isbn>1029-2454(Electronic) 0892-7014(Linking)</isbn><accession-num>26194639</accession-num><urls><related-urls><url>/pubmed/26194639</url></related-urls></urls><electronic-resource-num>10.1080/08927014.2015.1062089</electronic-resource-num></record></Cite></EndNote>[20]。用去离子水清洗试样表面，之后用染色剂（SYTO-9+PI(1:1)）对试样表面的细菌进行染色，染色后的活细胞和死细胞分别呈现绿色和红色。利用LSM710型CLSM测量在无菌和含铜绿假单胞菌培养基中分别浸泡7天和14天后试样表面的点蚀坑深度。首先在超声波清洗器中依次用蒸馏水、无水乙醇对试样进行清洗，按照国家标准GB/T4334.4-2000用硝酸和氢氟酸的混合溶液去除腐蚀产物，之后用橡皮擦拭试样表面，最后再次用蒸馏水、无水乙醇清洗试样。将清洗后的试样放到CLSM下，观察试样表面点蚀坑形貌，并统计点蚀坑深度。通常点蚀的发生是随机的，每种试样的点蚀坑深度并不是一个特定的值ADDINEN.CITEADDINEN.CITE.DATA[23,24]，而是不同深度的点蚀坑随机分布在试样表面。本实验中每种试样的平均点蚀坑深度由随机选取的10个点蚀坑求平均值得到。点蚀坑深度的累积概率可利用n/(N+1)计算得到ADDINEN.CITEADDINEN.CITE.DATA[25,26]，其中n是坑深从小到大排列的序号，N是选取的点蚀坑的总数。Meng等人ADDINEN.CITE<EndNote><Cite><Author>Meng</Author><Year>2009</Year><RecNum>48</RecNum><DisplayText><styleface="superscript">[24]</style></DisplayText><record><rec-number>48</rec-number><foreign-keys><keyapp="EN"db-id="9twpvr2am9t5ebe0206paxphe9v5axxdpzp0"timestamp="1547120434">48</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Meng,Guozhe</author><author>Wei,Liyan</author><author>Zhang,Tao</author><author>Shao,Yawei</author><author>Wang,Fuhui</author><author>Dong,Chaofang</author><author>Li,Xiaogang</author></authors></contributors><titles><title>Effectofmicrocrystallizationonpittingcorrosionofpurealuminium</title><secondary-title>CorrosionScience</secondary-title></titles><periodical><full-title>CorrosionScience</full-title><abbr-1>CorrosSci</abbr-1></periodical><pages>2151-2157</pages><volume>51</volume><number>9</number><keywords><keyword>A.Aluminium</keyword><keyword>B.Polarization</keyword><keyword>B.SEM</keyword><keyword>C.Pittingcorrosion</keyword></keywords><dates><year>2009</year><pub-dates><date>2009/09/01/</date></pub-dates></dates><isbn>0010-938X</isbn><urls><related-urls><url>/science/article/pii/S0010938X09002558</url></related-urls></urls><electronic-resource-num>/10.1016/j.corsci.2009.05.046</electronic-resource-num></record></Cite></EndNote>[24]给出了点蚀坑深度Gumbel分布的公式：其中，F为概率，di为点蚀坑深度，μ为中心参数，α为尺度参数。张涛等人ADDINEN.CITE<EndNote><Cite><Author>Zhang</Author><Year>2008</Year><RecNum>51</RecNum><DisplayText><styleface="superscript">[27]</style></DisplayText><record><rec-number>51</rec-number><foreign-keys><keyapp="EN"db-id="9twpvr2am9t5ebe0206paxphe9v5axxdpzp0"timestamp="1547386694">51</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Zhang,Tao</author><author>Liu,Xiaolan</author><author>Shao,Yawei</author><author>Meng,Guozhe</author><author>Wang,Fuhui</author></authors></contributors><titles><title>ElectrochemicalnoiseanalysisonthepitcorrosionsusceptibilityofMg–10Gd–2Y–0.5Zr,AZ91Dalloyandpuremagnesiumusingstochasticmodel</title><secondary-title>CorrosionScience</secondary-title></titles><periodical><full-title>CorrosionScience</full-title><abbr-1>CorrosSci</abbr-1></periodical><pages>3500-3507</pages><volume>50</volume><number>12</number><keywords><keyword>A.Magnesium</keyword><keyword>A.Rareearthelements</keyword><keyword>B.Electrochemicalcalculation</keyword><keyword>C.Pittingcorrosion</keyword></keywords><dates><year>2008</year><pub-dates><date>2008/12/01/</date></pub-dates></dates><isbn>0010-938X</isbn><urls><related-urls><url>/science/article/pii/S0010938X08004198</url></related-urls></urls><electronic-resource-num>/10.1016/j.corsci.2008.09.033</electronic-resource-num></record></Cite></EndNote>[27]提出最大点蚀坑深度的概率可以用下列双指数公式来描述：其中P表示点蚀坑尺寸的概率，R是点蚀坑的深度，S为试样的总面积。本实验中试样的总面积为1cm2，由公式(1)-(5)可得点蚀坑概率的简化公式ADDINEN.CITE<EndNote><Cite><Author>Li</Author><Year>2016</Year><RecNum>22</RecNum><DisplayText><styleface="superscript">[21]</style></DisplayText><record><rec-number>22</rec-number><foreign-keys><keyapp="EN"db-id="9twpvr2am9t5ebe0206paxphe9v5axxdpzp0"timestamp="1542358510">22</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Li,Huabing</author><author>Zhou,Enze</author><author>Ren,Yibin</author><author>Zhang,Dawei</author><author>Xu,Dake</author><author>Yang,Chunguang</author><author>Feng,Hao</author><author>Jiang,Zhouhua</author><author>Li,Xiaogang</author><author>Gu,Tingyue</author><author>Yang,Ke</author></authors></contributors><titles><title>Investigationofmicrobiologicallyinfluencedcorrosionofhighnitrogennickel-freestainlesssteelbyPseudomonasaeruginosa</title><secondary-title>CorrosionScience</secondary-title></titles><periodical><full-title>CorrosionScience</full-title><abbr-1>CorrosSci</abbr-1></periodical><pages>811-821</pages><volume>111</volume><keywords><keyword>A.Stainlesssteel</keyword><keyword>B.EIS</keyword><keyword>C.Microbiologicalcorrosion</keyword><keyword>C.Pittingcorrosion</keyword></keywords><dates><year>2016</year><pub-dates><date>2016/10/01/</date></pub-dates></dates><isbn>0010-938X</isbn><urls><related-urls><url>/science/article/pii/S0010938X1630289X</url></related-urls></urls><electronic-resource-num>/10.1016/j.corsci.2016.06.017</electronic-resource-num></record></Cite></EndNote>[21]：2实验结果2.1电化学测试结果（1）OCP、LPR、EFM结果CrCoNi中熵合金与316L不锈钢在无菌及含铜绿假单胞菌培养基中EOCP随时间的变化规律如图1(a)所示。在无菌培养基中CrCoNi中熵合金的EOCP值较为稳定，大约维持在-100mVvs.SCE。在含铜绿假单胞菌培养基中的CrCoNi中熵合金和316L不锈钢的EOCP值分别在前4天和前3天内急剧下降，其中CrCoNi中熵合金的EOCP值由-126.8mVvs.SCE降至-505.7mVvs.SCE，316L不锈钢的EOCP值由-132.3mVvs.SCE降至-590.5mVvs.SCE。随后两种试样的EOCP值在第3天至第8天内逐渐上升，其中CrCoNi中熵合金的EOCP值升至-196.5mVvs.SCE，316L不锈钢的EOCP值升至-205.2mVvs.SCE。最后6天CrCoNi中熵合金的EOCP值大约维持在-170mVvs.SCE，而316L不锈钢的EOCP值大约维持在-200mVvs.SCE。CrCoNi中熵合金与316L不锈钢在无菌及含铜绿假单胞菌培养基中线性极化电阻的倒数随时间的变化规律如图1(b)所示。根据Stern-Geary公式ADDINEN.CITEADDINEN.CITE.DATA[21,28-30]：其中，icorr为腐蚀速率，Rp为极化电阻，βa和βc分别为阳极和阴极Tafel斜率。可知icorr与1/Rp成正比。由图1(b)可以看出，在无菌培养基中CrCoNi中熵合金的腐蚀速率基本不变。在含铜绿假单胞菌培养基中CrCoNi中熵合金和316L不锈钢的腐蚀速率先升高后降低，最终逐渐稳定，并且CrCoNi中熵合金的腐蚀速率低于316L不锈钢，此结果与EOCP的结果基本一致。CrCoNi中熵合金与316L不锈钢在无菌及含铜绿假单胞菌培养基中腐蚀速率随时间的变化规律如图1(c)所示。从图中可以看出，在无菌培养基中CrCoNi中熵合金的腐蚀速率在14天内波动较小，大约维持在0.0025mm·yr-1。在含铜绿假单胞菌培养基中CrCoNi中熵合金和316L不锈钢的腐蚀速率在浸泡前期（第0天至第2天）急剧上升，分别升至0.0092mm·yr-1和0.0195mm·yr-1；在浸泡中期（第3天至第8天）分别下降至0.0027mm·yr-1和0.0054mm·yr-1；在浸泡后期分别大约维持在0.0025mm·yr-1和0.0050mm·yr-1，此结果与OCP、LPR测试结果基本一致。图1CrCoNi中熵合金与316L不锈钢在无菌及含铜绿假单胞菌培养基中的EOCP、1/Rp和腐蚀速率随时间的变化规律Fig.1EOCP(a),1/Rp(b)andCorrosionrate(c)vs.exposuretimeforCrCoNiMEAand316LSSinsterilemediumandP.aeruginosamedium（2）EIS结果图2(a-f)为CrCoNi中熵合金与316L不锈钢在无菌及含铜绿假单胞菌培养基中浸泡第1、4、7和14天的Nyquist图和Bode图。由Nyquist图可以看出，铜绿假单胞菌使CrCoNi中熵合金的Nyquist容抗弧半径减小，表明降低了其耐腐蚀性能；此外，在含铜绿假单胞菌培养基中的CrCoNi中熵合金的Nyquist容抗弧半径大于316L不锈钢，表明CrCoNi中熵合金的耐微生物腐蚀性能优于316L不锈钢。图2CrCoNi中熵合金与316L不锈钢在无菌及含铜绿假单胞菌培养基中第1、4、7、10和14天的Nyquist图和Bode图Fig.2NyquistandBodeplotsofCrCoNiMEAinsterilemedium(a,b)andP.aeruginosamedium(c,d),and316LSSinP.aeruginosamedium(e,f)onthe1th,4th,7th,10thand14thday由图2(a)可以看出，随着时间的延长，在无菌培养基中CrCoNi中熵合金的容抗弧半径逐渐增大，尤其在第4天的增加幅度较大，而第7和14天的增加幅度较小，说明随着时间的推移，钝化膜形成并逐渐变厚。由图2(c)可以看出，除第7天外，在含铜绿假单胞菌培养基中CrCoNi中熵合金的容抗弧半径随时间的延长不断增大，表明表面形成钝化膜和生物被膜并逐渐变厚。第7天容抗弧半径的减小是由于铜绿假单胞菌使试样发生腐蚀，导致钝化膜受到了轻微破坏。由图2(e)可以看出，在含铜绿假单胞菌培养基中316L不锈钢的容抗弧半径不断波动，这可能与氯离子引起的钝化膜的破坏和修复有关ADDINEN.CITE<EndNote><Cite><Author>Li</Author><Year>2017</Year><RecNum>21</RecNum><DisplayText><styleface="superscript">[22]</style></DisplayText><record><rec-number>21</rec-number><foreign-keys><keyapp="EN"db-id="9twpvr2am9t5ebe0206paxphe9v5axxdpzp0"timestamp="1542358447">21</key><keyapp="ENWeb"db-id="">0</key></foreign-keys><ref-typename="JournalArticle">17</ref-type><contributors><authors><author>Li,Huabing</author><author>Yang,Chuntian</author><author>Zhou,Enze</author><author>Yang,Chunguang</author><author>Feng,Hao</author><author>Jiang,Zhouhua</author><author>Xu,Dake</author><author>Gu,Tingyue</author><author>Yang,Ke</author></authors></contributors><titles><title>MicrobiologicallyinfluencedcorrosionbehaviorofS32654superausteniticstainlesssteelinthepresenceofmarinePseudomonasaeruginosabiofilm</title><secondary-title>JournalofMaterialsScience&Technology</secondary-title></titles><periodical><full-title>JournalofMaterialsScience&Technology</full-title><abbr-1>JMaterSciTechnol</abbr-1></periodical>