Cov qauv tshwj xeeb xeb ntawm titanium screws!
Cov ntsia hlau titanium alloy (xws li TC4) paub txog lawv qhov kev tiv thaiv xeb zoo heev, tab sis qhov no tsis tau txhais hais tias lawv "yeej tsis xeb" nyob rau hauv txhua qhov xwm txheej. Hauv qee qhov chaw tshwj xeeb thiab hnyav, cov ntsia hlau titanium yuav muaj cov qauv tshwj xeeb ntawm kev xeb.
Kev nkag siab txog cov qauv tshwj xeeb ntawm kev xeb no yog qhov tseem ceeb rau kev xaiv thiab kev teeb tsa cov titanium screws kom raug.
Lub hauv paus ntsiab lus: "Passivation zaj duab xis" ntawm titanium
Qhov kev tiv thaiv xeb ntawm titanium los ntawm ib daim zaj duab xis oxide nyias heev (kwv yees li 3-5 nanometers) tab sis tsis ruaj khov thiab ruaj khov (feem ntau yog TiO₂) ntawm nws qhov chaw. Daim "zaj duab xis passivation" no tuaj yeem kho nws tus kheej hauv feem ntau ib puag ncig thiab tiv thaiv cov hlau sab hauv. Txawm li cas los xij, nyob rau hauv cov xwm txheej tshwj xeeb hauv qab no, daim zaj duab xis no yuav raug puas tsuaj, ua rau xeb.
Ntau hom xeb tshwj xeeb ntawm titanium ntsia hlau
1. Kev xeb sib txawv
Qhov no yog hom kev xeb hauv zos tshaj plaws thiab txaus ntshai tshaj plaws ntawm cov titanium alloys hauv cov chaw muaj chlorine.
Cov xwm txheej tshwm sim:
- Muaj cov qhov sib nrug nqaim (feem ntau ntawm 0.025mm thiab 0.1mm ntawm qhov dav).
- Muaj cov tshuaj tiv thaiv corrosive uas tsis txav chaw nyob rau hauv qhov sib txawv (tshwj xeeb tshaj yog cov kua dej uas muaj chloride ions, xws li dej hiav txwv, dej ntsev, thiab cua ntsev tsuag uas ntub dej)
Vim li cas nws thiaj tshwm sim:
- Nws nyuaj heev rau cov pa oxygen kom kis mus rau sab hauv los ntawm qhov sib txawv thiab tsis tuaj yeem tswj tau qhov concentration oxygen uas xav tau rau zaj duab xis passivation.
- Qhov concentration ntawm chloride ions hauv qhov sib txawv nce ntxiv, thiab tus nqi pH txo qis (acidity ua zog dua)
- Thaum tus nqi pH ib puag ncig qis dua qee qhov tseem ceeb (kwv yees li 1-2 rau titanium alloys), zaj duab xis passivation yuav raug puas tsuaj thiab dhau los ua kev yaj.
Cov kev pheej hmoo tshwj xeeb cuam tshuam nrog cov ntsia hlau:
- Nruab nrab ntawm lub hau ntswj thiab qhov chaw sib cuag ntawm cov khoom.
- Nyob rau hauv qhov sib txawv ntawm kev sib koom tes threaded.
- Qhov chaw sib cuag ntawm lub tshuab ntxhua khaub ncaws hauv qab lub taub hau ntsia hlau.
- Txhua qhov chaw dig muag uas cov electrolytes yooj yim sib sau ua ke.
2. Kev xeb galvanic
Kuj tseem hu ua "kev sib txhuam sib cuag" lossis "kev sib txhuam hlau sib txawv". Qhov no yog qhov chaw yooj yim tshaj plaws los ua yuam kev thaum txhim kho cov ntsia hlau titanium.
Cov xwm txheej tshwm sim:
Cov ntsia hlau titanium sib chwv ncaj qha nrog cov hlau uas muaj peev xwm tsis zoo (active), xws li txhuas lossis carbon hlau, hauv cov electrolyte.
Leej twg yuav raug kev puas tsuaj:
Qhov tseem ceeb yog tias titanium nws tus kheej yuav raug tiv thaiv, thaum cov hlau reactive uas kov nws (xws li cov thav duab txhuas thiab cov khoom magnesium) yuav ua rau xeb sai dua!
Vim li cas nws thiaj tshwm sim:
Titanium muaj peev xwm zoo (ntau dua "inert") ntawm cov hlau uas siv ntau, sib npaug rau "cathode". Aluminium, hlau, thiab lwm yam khoom siv yog "anodes". Thaum lawv tsim ib lub voj voog los ntawm electrolyte, lub anode yuav ua kom cov dej yaj sai dua los tiv thaiv cathode.
Cov kev pheej hmoo tshwj xeeb cuam tshuam nrog cov ntsia hlau:
- Kev ntsia hlau titanium ncaj qha rau hauv cov qhov uas muaj xov ntawm cov thav duab txhuas tuaj yeem ua rau xeb sai thiab lwj ntawm cov qhov uas muaj xov txhuas hauv cov chaw noo noo, thaum kawg ua rau cov xov tsis ua haujlwm thiab cov ntsia hlau xoob.
- Kev sib cuag ntawm cov ntsia hlau titanium thiab cov hlau carbon washers lossis qhov chaw
3. Hydrogen embrittlement
Qhov no yog ib hom kev ua tsis tiav loj heev uas yuav ua rau pob txha tawg tam sim ntawd.
Cov xwm txheej tshwm sim:
- Cov titanium atoms yooj yim nqus cov hydrogen atoms.
- Thaum titanium nyob rau hauv cov chaw hauv qab no, hydrogen yuav nkag mus rau hauv:
- Kev tiv thaiv cathodic ntau dhau: Piv txwv li, hauv galvanic corrosion, titanium ua cathode yuav dhau los ua hydrogen evolution reaction.
- Hauv kev txo cov kua qaub xws li hydrochloric acid thiab sulfuric acid.
- Ib puag ncig hydrogen kub thiab siab siab.
- Kev pleev xim lossis kev kho qhov chaw tsis zoo (xws li kev ntxuav kua qaub nrog hydrogen uas muaj kua qaub).
4. Kev tawg ntawm kev ntxhov siab
Kev tawg yooj yim tshwm sim nyob rau hauv kev ua ke ntawm cov ib puag ncig corrosive thiab kev ntxhov siab tensile.
Cov xwm txheej tshwm sim:
Cov xov xwm tshwj xeeb corrosive: Rau titanium alloys, cov tseem ceeb yog fuming nitric acid, methanol, halogen elements, solid chlorides, thiab lwm yam. TC4 titanium alloy muaj kev tiv thaiv kev ntxhov siab zoo heev hauv huab cua ib txwm lossis dej hiav txwv.
Kev ntxhov siab tas mus li: Nws tuaj yeem yog qhov thauj khoom sab nraud lossis kev ntxhov siab sab hauv uas tsim tawm thaum lub sijhawm zawm ntsia hlau.
Kev pheej hmoo ntawm cov ntsia hlau:
Nws yuav tshwm sim hauv cov chaw tshwj xeeb heev (xws li cov khoom siv tshuaj lom neeg), tab sis rau cov ntawv thov txhua hnub xws li tsheb kauj vab roob, qhov kev pheej hmoo yog qis heev.