銅綠假單胞菌對(duì)CrCoNi中熵合金的微生物腐蝕行為研究

銅綠假單胞菌對(duì)CrCoNi中熵合金的微生物腐蝕行為研究摘要采用多種電化學(xué)實(shí)驗(yàn)手段及場(chǎng)發(fā)射掃描電子顯微鏡（FESEM）、金相顯微鏡（OM）等分析技術(shù)，結(jié)合活死細(xì)菌染色實(shí)驗(yàn)、點(diǎn)蝕坑深度分析等方法，以316L不銹鋼為對(duì)比，研究了CrCoNi中熵合金在含銅綠假單胞菌培養(yǎng)基中的微生物腐蝕行為。結(jié)果表明：銅綠假單胞菌能夠在CrCoNi中熵合金表面形成不均勻的生物被膜，導(dǎo)致開路電位下降、極化電阻減小、腐蝕電流密度增大；銅綠假單胞菌生物被膜一定程度上破壞了鈍化膜，導(dǎo)致浸泡在含銅綠假單胞菌培養(yǎng)基中的CrCoNi中熵合金的最大點(diǎn)蝕坑深（4.8μm）大于無(wú)菌培養(yǎng)基中（2.3μm）。與316L相比，CrCoNi中熵合金的開路電位較高、腐蝕電流密度和腐蝕速率較小，鈍化膜的修復(fù)能力較強(qiáng)，在含銅綠假單胞菌培養(yǎng)基中浸泡后的最大點(diǎn)蝕坑深度小于316L不銹鋼（5.8μm）。關(guān)鍵詞CrCoNi中熵合金，銅綠假單胞菌，微生物腐蝕，生物被膜，點(diǎn)腐蝕近年來(lái)，由多個(gè)等摩爾比或近等摩爾比組元組成的高熵合金引起了人們的廣泛關(guān)注ADDINEN.CITEADDINEN.CITE.DATA[1-3]。由于其優(yōu)異的強(qiáng)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]、良好的熱穩(wěn)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發(fā)展。其中，CrCoNi是一種僅含有三種元素的等摩爾比中熵合金，它是一種單相面心立方固溶體，具有超過(guò)大多數(shù)高熵合金和多相合金的強(qiáng)度和韌性ADDINEN.CITEADDINEN.CITE.DATA[6-10]。同時(shí)，本課題組研究發(fā)現(xiàn)，CrCoNi中熵合金在NaCl溶液中具有良好的耐腐蝕性能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]，與2205雙相不銹鋼相當(dāng)。因此，CrCoNi中熵合金可以作為基礎(chǔ)合金，發(fā)展性能更加優(yōu)異的工程合金金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]。微生物腐蝕是由微生物附著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]，它的腐蝕成本大約占所有金屬和建筑等材料腐蝕成本的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]。據(jù)2016年美國(guó)腐蝕工程師協(xié)會(huì)公布的全球腐蝕調(diào)研項(xiàng)目的結(jié)果，全球腐蝕成本大約占國(guó)民生產(chǎn)總值的3.4%ADDINEN.CITE<EndNote><Cite><Author>顧彩香</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%">顧彩香</style></author><author><styleface="normal"font="default"charset="134"size="100%">夏瑞</style></author><author><styleface="normal"font="default"charset="134"size="100%">朱冠軍</style></author><author><styleface="normal"font="default"charset="134"size="100%">朱云鵬</style></author></authors></contributors><auth-address><styleface="normal"font="default"charset="134"size="100%">上海海事大學(xué)商船學(xué)院</style><styleface="normal"font="default"size="100%">;</style></auth-address><titles><title><styleface="normal"font="default"charset="134"size="100%">不銹鋼海洋微生物腐蝕研究</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>不銹鋼</keyword><keyword>海洋微生物</keyword><keyword>腐蝕</keyword><keyword>腐蝕模型</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]，估算達(dá)2.5萬(wàn)億美元，其中海洋環(huán)境中腐蝕造成的經(jīng)濟(jì)損失約占總腐蝕成本的30%。在海洋環(huán)境中，由于存在多種微生物，暴露的金屬表面容易形成海洋微生物被膜，提高了發(fā)生微生物腐蝕的可能性，給許多行業(yè)帶來(lái)巨大的經(jīng)濟(jì)損失ADDINEN.CITE<EndNote><Cite><Author>Wikie?</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>Wikie?,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]。生物被膜除了會(huì)影響金屬表面電化學(xué)腐蝕的陽(yáng)極或陰極反應(yīng)，還會(huì)改變腐蝕反應(yīng)的類型，形成生物被膜內(nèi)腐蝕環(huán)境。同時(shí)微生物新陳代謝過(guò)程產(chǎn)生的侵蝕性物質(zhì)會(huì)改變金屬表面的膜電阻，微生物生長(zhǎng)和繁殖所建立的屏障層還會(huì)形成金屬表面的濃差電池等ADDINEN.CITEADDINEN.CITE.DATA[17-19]。銅綠假單胞菌是海洋中常見的好氧桿狀細(xì)菌，并且廣泛分布于土壤、沼澤等環(huán)境，它在代謝中會(huì)排出有機(jī)酸、二氧化碳和硫酸根離子。同時(shí)銅綠假單胞菌也是能夠形成生物被膜的典型菌種，研究表明它能加速碳鋼、不銹鋼等多種材料的腐蝕ADDINEN.CITEADDINEN.CITE.DATA[20-22]。但是，目前中高熵合金的微生物腐蝕行為未見報(bào)道，銅綠假單胞菌對(duì)其微生物腐蝕行為的影響機(jī)制也有待深入研究。本文利用電化學(xué)手段結(jié)合表面分析方法，以316L不銹鋼為對(duì)比，研究了在模擬海洋環(huán)境中銅綠假單胞菌對(duì)CrCoNi中熵合金的微生物腐蝕行為的影響規(guī)律，探討了在該微生物環(huán)境中的腐蝕機(jī)制，以期為CrCoNi中熵合金在海洋等領(lǐng)域的實(shí)際應(yīng)用提供理論依據(jù)和參考。1實(shí)驗(yàn)材料及方法1.1材料與實(shí)驗(yàn)介質(zhì)實(shí)驗(yàn)所用CrCoNi中熵合金和316L不銹鋼的化學(xué)成分如表1所示。從CrCoNi中熵合金和316L不銹鋼上切取尺寸為10mm×10mm×5mm的試樣，分別經(jīng)1150℃/2h和1050℃/1h固溶處理后，水冷至室溫。將試樣去除氧化皮并用1000#砂紙打磨后，用蒸餾水、無(wú)水乙醇清洗后烘干，然后用紫外燈滅菌30min。表1實(shí)驗(yàn)用鋼的化學(xué)成分Table1Chemicalcompositionsoftheexperimentalsteels(massfraction/%)SteelsCrCoNiCSiMnMoFeCrCoNiMEA30.5834.7134.71316LSS16.78-10.50.0210.431.182.09Bal.實(shí)驗(yàn)所用的測(cè)試溶液分別為無(wú)菌和含銅綠假單胞菌的2216E模擬海水液體培養(yǎng)基溶液，銅綠假單胞菌（MCCC1A00099）來(lái)自中國(guó)海洋微生物菌種保藏管理中心。2216E培養(yǎng)基的主要成分為：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檸檬酸鐵。用溫度為121℃的高壓滅菌鍋對(duì)培養(yǎng)基滅菌20min。接種后培養(yǎng)基中銅綠假單細(xì)胞的初始濃度約為106cell/mL。1.2電化學(xué)測(cè)試實(shí)驗(yàn)采用GamryReference600電化學(xué)工作站進(jìn)行開路電位（OCP）、線性極化電阻（LPR）、電化學(xué)阻抗譜（EIS）、電化學(xué)頻率調(diào)制（EFM）和循環(huán)極化曲線（CP）測(cè)試。電化學(xué)測(cè)試在37℃的2216E培養(yǎng)基中連續(xù)進(jìn)行14天。測(cè)試采用經(jīng)典的三電極體系，輔助電極為鉑電極（15mm×15mm鉑片），參比電極為飽和甘汞電極（SCE），工作電極為用環(huán)氧樹脂鑲嵌的CrCoNi中熵合金和316L不銹鋼試樣，工作面積為1cm2。在電化學(xué)測(cè)試中，開路電位的檢測(cè)時(shí)間為2000s，線性極化的掃描范圍為EOCP±5mV，掃描速率為0.125mV·s-1。EIS的擾動(dòng)電壓為5mV，頻率范圍為10-2～105Hz，測(cè)量結(jié)果用ZSimpWin軟件進(jìn)行擬合。循環(huán)極化從EOCP以下0.3V開始以0.3333mV·s-1的速率正向掃描，在電流密度達(dá)到1mAcm-2時(shí)反向掃描，當(dāng)達(dá)到保護(hù)電位（Eprot）后停止。循環(huán)極化測(cè)試結(jié)束后，采用OlympusDSX510金相顯微鏡觀察試樣的腐蝕形貌。1.3腐蝕形貌分析利用UltraPlus型場(chǎng)發(fā)射掃描電子顯微鏡（FESEM）觀察在含銅綠假單胞菌的培養(yǎng)基中分別浸泡7天和14天后試樣的生物被膜形貌。首先將浸泡后的CrCoNi中熵合金和316L不銹鋼試樣放入2.5%（體積分?jǐn)?shù)）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%的乙醇溶液脫水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]。在背散射模式下觀察試樣表面的細(xì)菌形貌，在二次電子模式下觀察試樣表面形貌。利用C2Plus型激光共聚焦掃描顯微鏡（CLSM）觀察在含銅綠假單胞菌培養(yǎng)基中分別浸泡7天和14天后試樣表面細(xì)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]。用去離子水清洗試樣表面，之后用染色劑（SYTO-9+PI(1:1)）對(duì)試樣表面的細(xì)菌進(jìn)行染色，染色后的活細(xì)胞和死細(xì)胞分別呈現(xiàn)綠色和紅色。利用LSM710型CLSM測(cè)量在無(wú)菌和含銅綠假單胞菌培養(yǎng)基中分別浸泡7天和14天后試樣表面的點(diǎn)蝕坑深度。首先在超聲波清洗器中依次用蒸餾水、無(wú)水乙醇對(duì)試樣進(jìn)行清洗，按照國(guó)家標(biāo)準(zhǔn)GB/T4334.4-2000用硝酸和氫氟酸的混合溶液去除腐蝕產(chǎn)物，之后用橡皮擦拭試樣表面，最后再次用蒸餾水、無(wú)水乙醇清洗試樣。將清洗后的試樣放到CLSM下，觀察試樣表面點(diǎn)蝕坑形貌，并統(tǒng)計(jì)點(diǎn)蝕坑深度。通常點(diǎn)蝕的發(fā)生是隨機(jī)的，每種試樣的點(diǎn)蝕坑深度并不是一個(gè)特定的值A(chǔ)DDINEN.CITEADDINEN.CITE.DATA[23,24]，而是不同深度的點(diǎn)蝕坑隨機(jī)分布在試樣表面。本實(shí)驗(yàn)中每種試樣的平均點(diǎn)蝕坑深度由隨機(jī)選取的10個(gè)點(diǎn)蝕坑求平均值得到。點(diǎn)蝕坑深度的累積概率可利用n/(N+1)計(jì)算得到ADDINEN.CITEADDINEN.CITE.DATA[25,26]，其中n是坑深從小到大排列的序號(hào)，N是選取的點(diǎn)蝕坑的總數(shù)。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]給出了點(diǎn)蝕坑深度Gumbel分布的公式：其中，F(xiàn)為概率，di為點(diǎn)蝕坑深度，μ為中心參數(shù)，α為尺度參數(shù)。張濤等人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]提出最大點(diǎn)蝕坑深度的概率可以用下列雙指數(shù)公式來(lái)描述：其中P表示點(diǎn)蝕坑尺寸的概率，R是點(diǎn)蝕坑的深度，S為試樣的總面積。本實(shí)驗(yàn)中試樣的總面積為1cm2，由公式(1)-(5)可得點(diǎn)蝕坑概率的簡(jiǎn)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實(shí)驗(yàn)結(jié)果2.1電化學(xué)測(cè)試結(jié)果（1）OCP、LPR、EFM結(jié)果CrCoNi中熵合金與316L不銹鋼在無(wú)菌及含銅綠假單胞菌培養(yǎng)基中EOCP隨時(shí)間的變化規(guī)律如圖1(a)所示。在無(wú)菌培養(yǎng)基中CrCoNi中熵合金的EOCP值較為穩(wěn)定，大約維持在-100mVvs.SCE。在含銅綠假單胞菌培養(yǎng)基中的CrCoNi中熵合金和316L不銹鋼的EOCP值分別在前4天和前3天內(nèi)急劇下降，其中CrCoNi中熵合金的EOCP值由-126.8mVvs.SCE降至-505.7mVvs.SCE，316L不銹鋼的EOCP值由-132.3mVvs.SCE降至-590.5mVvs.SCE。隨后兩種試樣的EOCP值在第3天至第8天內(nèi)逐漸上升，其中CrCoNi中熵合金的EOCP值升至-196.5mVvs.SCE，316L不銹鋼的EOCP值升至-205.2mVvs.SCE。最后6天CrCoNi中熵合金的EOCP值大約維持在-170mVvs.SCE，而316L不銹鋼的EOCP值大約維持在-200mVvs.SCE。CrCoNi中熵合金與316L不銹鋼在無(wú)菌及含銅綠假單胞菌培養(yǎng)基中線性極化電阻的倒數(shù)隨時(shí)間的變化規(guī)律如圖1(b)所示。根據(jù)Stern-Geary公式ADDINEN.CITEADDINEN.CITE.DATA[21,28-30]：其中，icorr為腐蝕速率，Rp為極化電阻，βa和βc分別為陽(yáng)極和陰極Tafel斜率?？芍猧corr與1/Rp成正比。由圖1(b)可以看出，在無(wú)菌培養(yǎng)基中CrCoNi中熵合金的腐蝕速率基本不變。在含銅綠假單胞菌培養(yǎng)基中CrCoNi中熵合金和316L不銹鋼的腐蝕速率先升高后降低，最終逐漸穩(wěn)定，并且CrCoNi中熵合金的腐蝕速率低于316L不銹鋼，此結(jié)果與EOCP的結(jié)果基本一致。CrCoNi中熵合金與316L不銹鋼在無(wú)菌及含銅綠假單胞菌培養(yǎng)基中腐蝕速率隨時(shí)間的變化規(guī)律如圖1(c)所示。從圖中可以看出，在無(wú)菌培養(yǎng)基中CrCoNi中熵合金的腐蝕速率在14天內(nèi)波動(dòng)較小，大約維持在0.0025mm·yr-1。在含銅綠假單胞菌培養(yǎng)基中CrCoNi中熵合金和316L不銹鋼的腐蝕速率在浸泡前期（第0天至第2天）急劇上升，分別升至0.0092mm·yr-1和0.0195mm·yr-1；在浸泡中期（第3天至第8天）分別下降至0.0027mm·yr-1和0.0054mm·yr-1；在浸泡后期分別大約維持在0.0025mm·yr-1和0.0050mm·yr-1，此結(jié)果與OCP、LPR測(cè)試結(jié)果基本一致。圖1CrCoNi中熵合金與316L不銹鋼在無(wú)菌及含銅綠假單胞菌培養(yǎng)基中的EOCP、1/Rp和腐蝕速率隨時(shí)間的變化規(guī)律Fig.1EOCP(a),1/Rp(b)andCorrosionrate(c)vs.exposuretimeforCrCoNiMEAand316LSSinsterilemediumandP.aeruginosamedium（2）EIS結(jié)果圖2(a-f)為CrCoNi中熵合金與316L不銹鋼在無(wú)菌及含銅綠假單胞菌培養(yǎng)基中浸泡第1、4、7和14天的Nyquist圖和Bode圖。由Nyquist圖可以看出，銅綠假單胞菌使CrCoNi中熵合金的Nyquist容抗弧半徑減小，表明降低了其耐腐蝕性能；此外，在含銅綠假單胞菌培養(yǎng)基中的CrCoNi中熵合金的Nyquist容抗弧半徑大于316L不銹鋼，表明CrCoNi中熵合金的耐微生物腐蝕性能優(yōu)于316L不銹鋼。圖2CrCoNi中熵合金與316L不銹鋼在無(wú)菌及含銅綠假單胞菌培養(yǎng)基中第1、4、7、10和14天的Nyquist圖和Bode圖Fig.2NyquistandBodeplotsofCrCoNiMEAinsterilemedium(a,b)andP.aeruginosamedium(c,d),and316LSSinP.aeruginosamedium(e,f)onthe1th,4th,7th,10thand14thday由圖2(a)可以看出，隨著時(shí)間的延長(zhǎng)，在無(wú)菌培養(yǎng)基中CrCoNi中熵合金的容抗弧半徑逐漸增大，尤其在第4天的增加幅度較大，而第7和14天的增加幅度較小，說(shuō)明隨著時(shí)間的推移，鈍化膜形成并逐漸變厚。由圖2(c)可以看出，除第7天外，在含銅綠假單胞菌培養(yǎng)基中CrCoNi中熵合金的容抗弧半徑隨時(shí)間的延長(zhǎng)不斷增大，表明表面形成鈍化膜和生物被膜并逐漸變厚。第7天容抗弧半徑的減小是由于銅綠假單胞菌使試樣發(fā)生腐蝕，導(dǎo)致鈍化膜受到了輕微破壞。由圖2(e)可以看出，在含銅綠假單胞菌培養(yǎng)基中316L不銹鋼的容抗弧半徑不斷波動(dòng)，這可能與氯離子引起的鈍化膜的破壞和修復(fù)有關(guān)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>