Corrosion Mechanism ntawm NdFeB Permanent Magnet

Kev tiv thaiv corrosion ntawm NdFeB cov hlau nplaum ruaj khov yog vim qhov tseeb tias Nd yog ib qho ntawm cov khoom siv tshuaj lom neeg tshaj plaws. Ntawm qhov tod tes, cov hlau yog cov qauv multiphase nrog loj electrochemical theem sib txawv ntawm theem, uas tuaj yeem yooj yim ua rau electrochemical corrosion.

Tsis tas li ntawd, thaum lub sij hawm sintering txheej txheem ntawm NdFeB, tsis xws luag xws li micropores, xoob qauv, thiab ntxhib nto yog nquag tshwm rau sab hauv thiab nyob rau saum npoo ntawm cov hlau nplaum. Qhov chaw ua haujlwm ntawm NdFeB cov khoom siv hlau nplaum ruaj khov hauv kev siv feem ntau yog kub thiab av noo. Cov teeb meem no muab cov kev mob yooj yim rau NdFeB corrosion nyob rau hauv qhov kub thiab txias ib puag ncig.

(1) Kub kub ib puag ncig

Nyob rau hauv ib puag ncig qhuav, thaum kub qis dua 150 degree, oxidation tus nqi ntawm NdFeB mus tas li hlau nplaum yog qeeb heev. Txawm li cas los xij, ntawm qhov kub siab dua, cov tshuaj tiv thaiv hauv qab no yuav tshwm sim hauv thaj tsam Nd-nplua nuj: 4Nd + 3O2=2Nd2O3. Tom qab ntawd, Nd2Fe14B theem yuav decompose rau Fe thiab Nd2C3. Ntxiv oxidation tseem yuav tsim cov khoom xws li Fe2O3.

(2) Ib puag ncig sov thiab av noo

Nyob rau hauv cov huab cua sov thiab av noo, lub rhiab grain ciam theem nyob rau saum npoo ntawm NdFeB mus tas li hlau nplaum ua ntej reacts nrog cov dej vapor nyob rau hauv ib puag ncig raws li cov qauv hauv qab no. Lub H generated los ntawm cov tshuaj tiv thaiv nkag mus rau hauv grain ciam teb thiab ntxiv reacts nrog cov Nd-nplua nuj theem, ua rau grain ciam teb corrosion. Cov tiam ntawm NdH3 yuav ua rau kom lub ntim ntawm cov ciam teb nplej, ua rau grain ciam teb kev nyuaj siab thiab grain ciam kev puas tsuaj. Hauv cov xwm txheej hnyav, cov ciam teb yuav tawg thiab ua rau cov hlau nplaum pulverize.

Cov nyhuv ntawm ib puag ncig cov av noo ntawm corrosion kuj ntawm hlau nplaum yog ntau dua li qhov kub thiab txias. Qhov no yog vim hais tias cov khoom siv corrosion yog tsim los ntawm cov hlau nplaum nyob rau hauv ib puag ncig oxidizing qhuav yog qhov ntom ntom, uas rau qee yam cais cov hlau nplaum ntawm ib puag ncig thiab tiv thaiv oxidation ntxiv ntawm cov hlau nplaum.