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1、AZ91D鎂合金在SO?薄液膜下的腐蝕行為研究*林翠肖志陽匕2,梁健能彳(1.南昌航空大學(xué)“輕合金加工科學(xué)與技術(shù)”國防重點(diǎn)學(xué)科實(shí)驗(yàn)室,南昌330063;2.南昌航空犬學(xué)材料學(xué)院,南昌330063;3.中國電器科學(xué)研究院,廣東廣州510300)摘要:利用自建厚度控制和大氣腐蝕薄液膜電化學(xué)測試裝賈,運(yùn)用極化曲線以及交流阻抗譜,探討AZ91D鎂合金在含SO?薄液膜下的腐蝕電化學(xué)行為,并采用金相顯微鏡和掃描電鏡觀察薄液膜下的腐蝕形貌。結(jié)果表明:薄液膜厚度和SO?對鎂合金陰陽極化率都有影響。SO2的加入使陰陽極化率降低,加速鎂合金在薄液膜下的腐蝕。隨著薄液膜的減薄,腐蝕加速,5
2、0pn下出現(xiàn)最大值;但在極薄液膜下腐蝕產(chǎn)物的形成阻礙02的擴(kuò)散,腐蝕減緩。極限擴(kuò)散電流密度隨薄液膜厚度的增大先增加后減小,薄液膜悍度小于50pm,腐蝕產(chǎn)物的堆積使陽極過程受到抑制。鎂合金在SO2薄液膜下的阻抗圖由個(gè)高頻容抗弧和一個(gè)低頻擴(kuò)散阻抗組成,表現(xiàn)為兩個(gè)吋間常數(shù)。隨著腐蝕的進(jìn)行,陷不斷增加,腐蝕速率降低。在不同厚度SO?薄液膜卜腐蝕傾向的順序?yàn)?50
3、xm>20
4、im>200
5、im>300
6、xmo關(guān)鍵詞:AZ91D鎂合金;薄液膜;SO2;電化學(xué)行為;腐蝕中圖分類號:TG172.3文獻(xiàn)標(biāo)識碼:A文章編號:CorrosionofAZ91DMagnesiumAlloyU
7、nderThinElectrolyteLayerContainingSO2LINCuiu,XIAOZhi-yangL2,LIANGJian-neng3(1.NationalDefenceKeyDisciplineLaboratoryofLightAlloyProcessingScienceandTechnology,NanchangHangkongUniversity,Nanchang33(X)63;2.SchoolofMaterialScienceandTechnology,NanchangHangkongUniversity,Nanchang330063;3.Ch
8、inaNationalElectricApparatusResearchInstitute,Guangzhou510300)Abstract:Theself-builtthinelectrolytelayerthicknesscontrollingandelectrochemicalmeasurementsystemwasutilizedtoinvestigatethecorrosionelectrochemicalbehaviorofAZ91DmagnesiumalloyunderthinelectrolytelayercontainingSO2bymeansofp
9、olarizationcurveandelectrochemicalimpedancespectium,furthermorethemorphologieswereinvestigatedbyopticalmicroscopeandscanningelectronmicroscopy.ThethicknessofthinelectrolytelayerandSO2hadsomeeffectsonanodic,cathodicpolarizationslope?SO2enabledanodic,cathodicpolarizationslopetodrop,indica
10、tingtheaccelerationofcorrosionofmagnesiumalloy.Withthedecreaseofthethicknessofthinelectrolytelayer,thecorrosionrateincrease.Themaximumvaluewasfoundat50
11、imthicknessofthinelectrolytelayercontainingSO2.Theformationofcorrosionproductsunderelectrolytelayerwithverythinthicknessblockedtheoxyge
12、ndiffusion,leadingtotheslowingdownofcorrosion.Thelimiteddiffusioncurrentdensityfirstlyincreasedandthendecreasedwiththeincreaseinthethicknessofthinelectrolytelayer.Whenthethicknessof收稿日期:2012-05-21;修訂日期:2013-03-28基金資助:國家自然科學(xué)基金資助項(xiàng)H(50601012);江西省自然科學(xué)基金資助項(xiàng)H(2009GQC0110)作者簡介:林翠(1976