腐蚀与防护教学6

1„„„„234EMF5PtAuTiAgZr316317304430Ni70Cu30NiCuNiSnPb3163173042024Cd1100ZnMgMg6„7AaAcBaBciAaiAciBaiBcABAaAcBaBci’Aci’Baigi’Aai’BcABAaBaABAcBcABiAai’AaiBai’BaABiAci’AciBci’BcABigAB8ABABAγAcAaii=BcBaii=0'=Aai'''BcBaAcgiiii−==''''BcBaAaAcgiiiii−=−=BaBcgBaBaiiiii''+==γ9ElgiEAEBEgig=⏐i’Ac⏐=i’Ba-⏐i’Bc⏐iAa=⏐iAc⏐i’BaiBa=⏐iBc⏐i’Aci’BcEAEBABiAai’AaiBai’BaABiAci’AciBci’BcAB101122pH“”“”11iL3:AaAcBaBci’Aci’Baigi’Aai’BcS1S2AB12I’Ac+I’Bc=I’Bai’AcSA+i’BcSB=i’BaSBi’Ac=i’Bc=ili’Ba=il(1+SA/SB)BALBALBaBaSSiSSiii+=+==1)1('γIg=IAcigSB=ilSAig=ilSA/SBAABilγ131“”231415:161SPBSiCσ2“”171CrNiCr427816182σCrMo650850FeCrMoFeσσ19318Cr9Ni1050PSi20(1)TTSTemperatureTimeSensitivity18Cr9NiCr23C60.05%C1250H2SO4CuSO47506007006004502121CTTS2CrMoNiSiCrMoCNiSiCCC3TiNbTiNbTiNbCCrCCrTiCNbCCCr23C6TiNbTTS4B0.0040.005%BTTSBCP221,,2TiNbTiCNbCCr51030.060.0810501100700800TiNb43050188CrM23C62324:Zn25ZnCuZnZnCuZnZnCu26„„12Zn23Cu27„„eZnZn22+→+eCuCu+→+−→++OHeOHO222122222CuClCuClCu+→CueCu→++2228“”29303132StressCorrosionCracking—SCC33Intergranularstresscorrosioncrackingof316stainlesssteelStresscorrosionfracturesurfaceof316stainlessDuctilefracturesurfaceof316stainlesssteelSheardimplesintheshear-lipzoneof316stainlesssteelSCCof316stainlesssteelCrosssectionof316stainlesssteel3435SCCSCC:361SCCSCC2SCCSCCSCC37SCCNaOHH2SHClCOCO2H2OHCNNaClNH4+SO2NaCl290HCl1035H2SO467Cl2288346427N2O4O2NO2474KClK2CrO4HF383.391:90thSCC402.SCC413.:106103mm/min10610104.:42SCCSCCSCC431:a:SCCSCCSCC()bSCCcSCC442“”“”SCC453SCC4647SCCSCC48SCC:SCCSCC