N80钢CO2腐蚀产物膜研究

:2000211222;:2001204205:G19990650:,,1974,,N80CO21,22212(11710072;21710065):CO2,XRDEDSSEMN80,N80CO2,3,3(Fe,Ca)CO3:CO2N80:TG172:A:100524537(2002)03201432051CO2.CO2,FeCO3.CO2.N80FeCO3.2N80,1.72,1000#,,,.2.Cortest344.4105Pa,1.10h,,2h.,CO2,78,1MPa,1.2m/s.8h24h72h240h..,.FR-300MK,D/MAX-2400X-,JSM-5800,OXFORDISIS.32.,,,.N80CO2,,.Table1ChemicalcompositionofN80steel(mass%)CSiMnPSCrMoNiFe0.240.221.190.0130.0040.0360.0210.028bal.Table2ConcentrationofelectrolyteCl-SO2-4HCO-3Mg2+Ca2+Na+CO2-3g/L191.140.61.050.3911.990.12Fig.1Schematicofthecorrosionapparatus22320026JournalofChineseSocietyforCorrosionandProtectionVol122No13Jun12002Fig.2Variationofcorrosionweightlosswithtime3FeCO3.,FeCO3.8h(3a),FeCO3,,.,Fe2+,FeCO3.,FeCO3,FeCO3,FeCO3(3bc),FeCO3(3d).4240hSEM.3.FeCO3,FeCO3,.,,,;,;,,,.3.,FeCO3,FeCO3,.,,..,[13]:FeFe2++2e(1)Fe+2OH-Fe(OH)2+2e(2)Fe+HCO-3FeCO3+2e+H+(3)Fe+CO2-3FeCO3+2e(4)T=78,,.(1)(2)(3)(4):Ea1=-0.441+0.035lg[Fe2+](5)Ea2=-0.877-0.07lg[OH-](6)Ea3=-0.416+0.035(lg[H+]-lg[HCO-3])(7)Ea4=-0.775+0.035(-lg[CO2-3])(8)Fig.3GrowthofFeCO3grainsafterdifferentcorrosiontime(a)8h,(b)24h,(c)72h,(d)240h44122Fig.4Cross-sectionmorphologyofcorrosionscalecorrodedfor240h[HCO-3]=0.00984mol/L,[CO2-3]=0.002mol/L,CO2,CroletBouis[4]CO21MPa,[HCO-3]=0.01mol/LpH=4.8.pH=5[3],CO2H2CO3[HCO-3][CO2-3],[HCO-3]=0100984mol/L,[CO2-3]=0.002mol/L.FeCO3[Fe2+][CO2-3]=10-10.5,[Fe2+]=510-8.5mol/L,(5)(6)(7)(8):Ea1=-0.684VEa2=-0.345VEa3=-0.521VEa4=-0.661V(1)(3)(4),,[OH-],(2).FeCO3.,:(3)(4).FeCO3HCO-3CO2-3,.(1)Fe2+,[Fe2+][CO2-3]FeCO3,.3,,FeCO3..,,.3(c)FeCO3,.FeCO3,,FeCO3.,FeCO3,.,..,,FeCO3.PalaciosShadley[5],.,Fe2+.,.,..,[5];[2],:FeCO3(s)+HCO-3ZFe(CO3)22-+H+FeCO3(s)+H2CO3ZFe(HCO3)25.5a,.,FeCO3.,,.5b,..,.,FeCO,Ca4.08%,2.75%,0.27%.Ca4.08%,CaCO3,20%,X-.X-CaCO3Ca(6a).CaFeCO3Fe,(Fe,Ca)CO3.6bFeCO3(104),5413:N80CO2Fig.5MicrographofbreakageofFeCO3scalecorrodedfor240h(a)Surfacelayerscaleoftheinnerlayer(b)CorrosionproductfilmerodedbyelectrolyteFig.6X-raydiffractionanalysisofcorrosionscalea:surfacelayer,b:middlelayer,c:innerlayerCa,,.,Ca..(Fe,Ca)CO3.4(1)N80CO2,.(2),;,,.(3).(4)(Fe,Ca)CO3.:[1]LinterBR,BursteinGT.Reactionofpipelinesteelsincarbondiox2idesolutions[J].Corros.Sci.,1999,42(2):117-139.[2]DaviesDH,BursteinGT.Theeffectsofbicarbonateonthecorro2sionandpassivationofiron[J].Corrosion,1980,36(8):416-422[3]OgundeleGI,WhiteWE.Someobservationoncorrosionofcarbonsteelinaqueousenvironmentscontainingcarbondioxide[J].Corro2sion,1986,42(2):71-76.[4]CroletJL,BonisMR.PhmeasurementsinaqueousCO2solutionunderhighpressureandtemperature[J].Corrosion,1983,39(2):39-46.[5]PalaciosCA,ShadleyJR.CharacteristicsofcorrosionscalesonsteelsinCO2-saturatedNaClbrine[J].Corrosion,1991,47(2):122-127.64122STUDYOFCO2CORROSIONSCALESONN80STEELCHENChangfeng1,2,ZHAOGuoxian2,LUMinxu2,YANGYanqing1,LIHelin2(11SchoolofMaterialsScienceandEngineering,NorthwesternPolytechnicalUniversity,Xian710072;21TubularGoodsResearchCenterofCNPC,Xian710065)Abstract:WhilesimulatingtheenvironmentofCO2corrosioninoilfield,XRD,EDSandSEMtechniqueswereadoptedtostudytheformationanddevelopmentofCO2corrosionproductfilmonN80steel.Theresultsdemonstratedthatthecorro2sionscalescouldprotectmatrixofN80steelandthenreducethecorrosionrate.TherewerethreelayersinCO2corrosionproductfilm.Structuralcharacteristicsandformationmechanismofthefilmwerediscussedrespectively.Atthesametime,breakageofFeCO3scalewasstudied.TheCO2corrosionscalewas(Fe,Ca)CO3.Keywords:CO2corrosion,corrosionscale,N80steel7413:N80CO2