Yuav Ua Li Cas Thiaj Muaj Oxidizing Ions (Fe³⁺, Cu²⁺) nyob rau hauv 5% Sulfuric Acid ntawm 60℃Extend lossis txo qhov Passive Range ntawm Titanium Qib 2 cua sov Tubes?
Tso lus
Qib 2 titanium nyob ze rau nws cov nquag ua haujlwm -passive hloov hauv 5% H2SO4 ntawm 60℃. Qib 2. Nws yuav ua kom muaj zog hauv cov kua qaub deaerated ntawm tus nqi ntawm 0.5 mus rau 2.0 hli ib xyoo. Nyob rau hauv lub xub ntiag ntawm yaj oxygen los yog oxidizing ions (Fe³⁺, Cu²⁺, Cr⁶⁺) titanium passivates thiab tus nqi corrosion yog qis dua 0.01 hli / xyoo. Tab sis cov oxidizing ions tuaj yeem ua rau ntau dhau passivation lossis pitting ntawm ntau qhov ntau. Cov txiaj ntsig ntawm Fe3+ thiab Cu{15}} ntawm qhov txuas ntxiv lossis txo qis ntawm qib passive ntawm Qib 2 hauv 5% H2SO4 ntawm 60℃tau tham hauv kab lus no.
Passivation Mechanism los ntawm Oxidizing Ion Source
Cov tshuaj oxidizing txo qis yog ferric (Fe3+) thiab cupric (Cu2+) ions. Lawv qhov kev txo qis ntawm titanium nto muab cov cathodic tam sim no uas polarizes titanium mus rau hauv cheeb tsam passive: Fe3+ + e- → Fe2+ (E0=+0.77 V vs. SHE) Cu2+ + 2e- → Cu0 (E0=+0.34 V % kev thuam rau HE) H2SO4 yog ~-0.2 rau 0 V vs. SCE. Ob leeg Fe 3+ thiab Cu 2+ tsim kom txaus cathodic tam sim no kom dhau qhov teeb meem no.
Cov teebmeem ntawm Concentration
Qib 2 xeem hauv 5% H2SO4 ntawm 60℃ntawm qhov sib txawv ntawm Fe3+ thiab Cu2+:
Tsis muaj oxidizing ions (deaerated): Active corrosion 1.0-2.0 hli / xyoo.
Fe³⁺ 10 ppm Passivation tshwm sim. Corrosion tus nqi txo mus rau 0.02-0.05 mm / xyoo. Passive ntau yog nthuav.
50–500 ppm Fe3+ ruaj khov passivation. Corrosion tus nqi 0.01-0.03mm / xyoo. Qhov zoo tshaj plaws.
Fe3+ 1,000–5,000 ppm: Tseem tsis muaj zog, tab sis qhov kev pheej hmoo ntawm pitting nce nyob rau hauv muaj cov chlorides.
Fe³⁺ 5,000 ppm: tuaj yeem tsim dhau -passivation ntawm qhov kub siab dua (tab sis tsis nyob ntawm 60℃).
Rau Cu 2+ : Tib cov tshuaj tiv thaiv , tab sis Cu 2+ tuaj yeem tso cov hlau tooj liab ntawm titanium ( Cu 2+ + 2}e − → Cu 0 ). Copper deposits yog galvanic cells, uas yog qhov zoo yog tias lawv tsis sib xws, tab sis phem yog nodular.
Synergistic thiab Antagonistic Ua
Fe³⁺ + Cu²⁺ ua ke: Kev ruaj ntseg passivation zoo dua li ib leeg. Nyob rau hauv lub xub ntiag ntawm Fe3+, qhov sib xyaw muaj peev xwm yog nruab nrab thiab cov tooj liab tso nyiaj ntau dua.
Oxidizing ions + chlorides: Thaum muaj oxidizing ions, chlorides (txawm tias 10-50 ppm) tuaj yeem ua rau pitting. Passivation plus aggressive anion yog qhov zoo tshaj plaws combo rau pitting corrosion.
Oxidizing ions + txo cov neeg ua haujlwm Yog tias txo cov neeg ua haujlwm (SO₂, H₂S, organic teeb meem) siv Fe³⁺ passivation ploj. Xyuas Fe3+ concentration.
Ntsuas Corrosion Rate
Oxidizing Ion Concentration Corrosion Rate (mm / xyoo) Passive? Pitting Danger
Tsis muaj (deaerated) 0 ppm 1.0-2.0 Tsis muaj (muaj zog corrosion)
Fe3+10 ppm0.02-0.05YesLowFe3+100 ppm0.01-0.02YesLowFe3+1,000 ppm0.01-0.03YesLow (yog Cl- 10 ppm)
Cu²⁺ 10 ppm 0.03 - 0.08Yog (Nrog Cu tso nyiaj) Nruab Nrab Cu2+ 100 ppm 0.02-0.05 Yog Nruab Nrab (Nodular Cu)
Fe³⁺ + Cu²⁺ (1: 1) 100 ppm txhua 0.01-0.02 Yog Tsawg Fe³⁺ + 50 ppm Cl⁻ 100 ppm 0.02-0.05 (pitting) Yog (tab sis pitting) High Application Matrix rau Qib 2⁻ ntawm 5% H.
Kev Pabcuam Kev Kho Mob Qib ntawm Oxidizing IonChloride Theem Xav Tau Qib 2 Kev Ua Haujlwm Zoo Pom Zoo Ua Haujlwm
Deaerated acid Tsis muaj Ib qho kev ua haujlwm corrosion (1-2 mm / xyoo) Ntxiv Fe3+ lossis siv Qib 7
Cua SpargingO₂ (8 ppm)<10 ppm Passive (0.01-0.03 mm/yr)Not Acceptable
Fe3+ los ntawm cov txheej txheem (xws li steel pickling) 50-500 ppm<10 ppmExcellent passive (0.01mm/year) Mint condition
Fe3+ + chlorides e.g. HCl pollution 100 ppm 50 ppm Pitting (0.1-0.3 mm/year pits) Add Fe3+ >500 ppm lossis qis dua Cl- Cu2+ los ntawm cov khoom siv tooj liab 100 ppm<10 ppmPassive with Cu depositionCheck copper thickness Clean once a year
Qib 2 cua sov raj hauv 5% H 2 SO 4 ntawm 60℃nrog rau qhov sib ntxiv ntawm 10-500 ppm Fe 3+ qhia qhov nce hauv qhov tsis muaj zog nrog cov nqi corrosion<0.03 mm/year compared to >1 hli / xyoo. Fe³⁺ yog qhov zoo thiab yog tias ua tau yuav tsum tau tswj xyuas. Cu²⁺ kuj tseem txhawb nqa kev ua kom tsis muaj zog tab sis tuaj yeem tso cov hlau nplaum tooj liab- cov khoom tso nyiaj ib txwm muaj kev tiv thaiv, cov nyiaj tso nyiaj nodular ua rau muaj kev ua phem galvanic. Cov oxidizing ions ua ke nrog chlorides thiab ua rau pitting. Khaws Fe³⁺ siab tshaj 500 ppm kom tsis txhob pitting los ntawm chlorides. Rau cov txheej txheem tshiab, xav txog ntxiv 50-100 ppm Fe3+ (raws li Fe2(SO4)3) kom ntseeg tau tias muaj kev nkag mus. Yog tias oxidizing ions tsis tuaj yeem khaws cia, qhia qib 7 titanium. Rau cov cua sov uas twb muaj lawm nrog kev ua haujlwm corrosion, Fe3+ tshuaj txhaj tshuaj txav lub rhaub rau hauv qhov tsis muaj zog; Qhov kev cuam tshuam qis qis no tuaj yeem txuas ntxiv lub neej ntawm lub tshuab cua sov los ntawm lub hlis mus rau xyoo.
