Corrosion Daim Ntawv ntawm Titanium Hlau thiab Lawv Mechanisms

Titanium Corrosion Cwj Pwm: Ib Txheej Txheem

Titanium thiab nws cov alloys sib xyaw ua ke tsis tshua muaj siab, muaj zog tshwj xeeb, zoo corrosion kuj thiab cov yam ntxwv zoo tsim, uas ua rau lawv nyiam cov khoom siv rau aerospace engineering. Hauv kev pabcuam tiag tiag, txawm li cas los xij, ntau hom kev xeb tuaj yeem tshwm sim, thiab txhua tus muaj cov txheej txheem sib txawv thiab cov tshuaj sib txawv. Cov ntaub ntawv feem ntau ntsib yog crevice corrosion, pitting corrosion, hydrogen embrittlement thiab kev sib cuag, los yog galvanic, corrosion.

Crevice corrosion, tsav los ntawm stagnant electrolyte nyob rau hauv qhov khoob thiab pob qij txha.

Pitting corrosion, pib los ntawm lub zos tawg ntawm cov zaj duab xis passive.

Hydrogen embrittlement, tshwm sim los ntawm hydrogen absorbed rau hauv cov hlau.

Tiv tauj corrosion, generated thaum titanium yog txuas mus rau ib tug tsawg noble hlau.

Crevice Corrosion

Crevice corrosion pib nyob rau hauv qhov khoob, lub puab tsaig pob qij txha, cov kab gasket los yog qhov chaw nyob qhov twg cov electrolyte tsis tuaj yeem rov ua dua tshiab. Qhov kev daws teeb meem nyob rau hauv qhov crevice tsim ib qho hluav taws xob hluav taws xob nrog lub ntsej muag sab nraud, thiab kev tawm tsam hauv cheeb tsam tsim los ntawm qhov tshwm sim. Titanium yog qhov yooj yim dua rau kev tawm tsam hauv nruab nrab thiab cov kua qaub ntau dua li cov alkaline. Qhov kev tawm tsam tsis kis mus rau tag nrho cov crevice nto; nws concentrates ntawm tej qhov chaw thiab muaj peev xwm nyob rau hauv qhov kawg perforate lub tivthaiv, yog li ntawd lub zos phab ntsa thinning es tsis txhob ntawm cov hlau feem ntau yog cov qauv tsis ua hauj lwm.

Pitting Corrosion

Pitting yog tsis tshua muaj rau titanium nyob rau hauv feem ntau saline daws. Nws tshwm sim feem ntau hauv cov xov xwm tsis yog - aqueous media thiab hauv cov dej npau npau, cov tshuaj chloride ntau ntau. Halide ions nyob rau hauv cov kev daws teeb meem ua txhaum cov zaj duab xis passive ntawm lub titanium nto, thiab thaum lub zos tawg tau tshwm sim qhov chaw loj hlob nyob rau hauv lub hlau, yog li lub qhov qhib yog me dua nws qhov tob. Qee cov organic media uas muaj halogens tuaj yeem pib pitting. Hauv cov kev daws teeb meem halide, pitting ntawm titanium feem ntau yuav tsum muaj siab concentration thiab kub siab; nyob rau hauv sulphide- thiab chloride-cov kabmob ib puag ncig cov xwm txheej uas tsim pitting yog qhov tshwj xeeb thiab qhov kev tawm tsam tseem txwv. Vim hais tias cov pits yog nqaim thiab tob, lawv yog ib qho yooj yim kom tsis nco qab nyob rau hauv ib tug pom kev soj ntsuam thiab feem ntau yog kuaj los ntawm dye penetrant los yog ultrasonic txoj kev.

Hydrogen embrittlement

Hydrogen embrittlement, tseem hu ua hydrogen cracking los yog hydrogen puas, yog ib qho ntawm cov ua rau ntxov tsis ua hauj lwm ntawm titanium alloys. Cov zaj duab xis passive uas ua rau ntawm qhov chaw nce mus txog lub zog siab, thiab kev cuam tshuam rau hydrogen embrittlement nce nrog lub zog ntawm cov zaj duab xis passive, yog li titanium thiab nws cov alloys rhiab heev rau hydrogen uptake. Hydrogen absorbed los ntawm cov hlau precipitates raws li brittle hydride theem thiab txo ductility, thiab tsis ua hauj lwm tuaj yeem tshwm sim ntawm cov kev ntxhov siab zoo hauv qab lub zog tsim. Ib puag ncig uas tsim cov hydrogen, xws li kev tiv thaiv cathodic, acid pickling thiab txo qis acids, yog li yuav tsum tau tswj hwm, thiab cov ntsiab lus hydrogen ntawm cov hlau yuav tsum tau khaws cia rau hauv qhov tshwj xeeb.

Tiv tauj (Galvanic) Corrosion thiab Nws Tiv Thaiv

Lub passive oxide zaj duab xis nyob rau saum npoo hloov lub peev xwm ntawm titanium nyob rau hauv qhov zoo, noble kev taw qhia, thiab qhov no yog qhov tseeb uas muab titanium nws tsis kam mus tua nyob rau hauv acidic thiab aqueous xov xwm. Tib qhov kev hloov pauv txhais tau hais tias thaum titanium txuas rau lwm cov hlau ib qho hluav taws xob hluav taws xob hluav taws xob tau tsim thiab tiv thaiv corrosion tshwm sim. Ob hom ntawm ib puag ncig yog koom nrog. Thawj suav nrog cov dej hauv nroog, ntsev ntsev, dej hiav txwv, cua, nitric acid thiab acetic acid; ntawm no titanium nyob twj ywm passive thaum lub ruaj khov electrode muaj peev xwm ntawm cadmium, zinc thiab txhuas yog qhov tsis zoo tshaj li ntawm titanium, yog li tus nqi anodic corrosion ntawm cov hlau txuas ntxiv los ntawm ib qho ntawm kwv yees li rau rau rau caum. Hom thib ob npog txo cov acids xws li sulfuric acid thiab hydrochloric acid, uas titanium yuav passivate los yog nyob twj ywm; nyob rau hauv kev xyaum qhov kev sib tw ua ke yog ntsuas los ntawm thawj hom ib puag ncig. Anodizing feem ntau yog siv los tsim cov txheej txheem hloov kho ntawm lub substrate thiab yog li tiv thaiv kev sib cuag corrosion. Insulating gaskets, tsis yog -hlau ntxhua khaub ncaws thiab kev zam ntawm thaj chaw loj cathodic txheeb ze rau titanium anode yog kev ntsuas ntxiv.

FAQ: Corrosion ntawm titanium hlau

Q: Qhov twg crevice corrosion tshwm sim ntawm titanium?
Nyob rau hauv qhov khoob, lub puab tsaig pob qij txha, cov kab gasket thiab qhov chaw nyob qhov twg cov electrolyte stagnates. Kev tawm tsam yog nyob hauv zos, feem ntau yuav nyob rau hauv nruab nrab lossis acidic daws ntau dua li alkaline sawv daws yuav, thiab tuaj yeem perforate phab ntsa.

Q: Puas yog titanium ua rau pitting hauv dej hiav txwv?
Pitting yog tsis tshua muaj rau titanium nyob rau hauv feem ntau saline daws. Nws tshwm sim feem ntau hauv cov xov xwm uas tsis yog- aqueous media thiab hauv boiling, cov tshuaj chloride cov ntsiab lus siab ntawm qhov kub siab, qhov twg halide ions rhuav tshem cov zaj duab xis passive.

Q: Dab tsi ua rau hydrogen embrittlement hauv titanium?
Hydrogen absorbed rau hauv cov hlau ua nkig hydride theem thiab txo ductility. Susceptibility nce nrog lub zog ntawm cov zaj duab xis passive, yog li pickling, cathodic tiv thaiv thiab txo cov acids yuav tsum tau tswj.

Q: Vim li cas titanium sib txuas ua kom muaj zog ntawm cadmium, zinc lossis aluminium?
Vim tias cov hlau muaj qhov ruaj khov electrode muaj peev xwm tsis zoo dua li titanium. Titanium nyob twj ywm passive thiab ua raws li cathode, yog li anodic dissolution tus nqi ntawm cov hlau txuas ntxiv los ntawm kwv yees li rau rau rau caum zaus.

Q: Yuav tiv thaiv corrosion li cas?
Los ntawm anodising titanium nto los tsim cov txheej txheem hloov kho, los ntawm insulating qhov sib koom ua ke nrog cov tsis yog -hlau ntxhua khaub ncaws los yog gaskets, thiab los ntawm kev zam kom tsis txhob muaj qhov tsis zoo ntawm cheeb tsam ntawm cov tswv cuab cathodic thiab anodic.

Q: Qhov chaw twg yog qhov hnyav tshaj plaws rau titanium?
Stagnant nruab nrab los yog acidic chlorides rau crevice attack, boiling concentrated chlorides rau pitting, thiab hydrogen- tsim los yog xav kom txo cov xov xwm rau embrittlement thiab dav dav.