Sintered hmoov

Hmoov sintering yuav nce qhov kub ntawm lub ntsuab compact, (nias hmoov ib feem), mus rau ib theem thiab ua kom nws nyob rau ntawm qhov kub ntawm lub sij hawm.Qhov kub ntawm sintering feem ntau yog nyob nruab nrab ntawm 70% thiab 90% ntawm lub melting point ntawm hmoov hlau.Qhov no yuav ua rau kev sib txuas cov txheej txheem tshwm sim ntawm cov hmoov uas tau nias ua ke hauv lub compact.Bonding nyob rau hauv ntsuab compact yog tsis muaj zog thiab no pressed unsintered ib feem feem ntau tsuas muaj txaus structural kev ncaj ncees los daws.Bonding uas tshwm sim thaum sintering zoo heev ntxiv dag zog rau ib feem.

Thaum lub sij hawm sintering, ib tug neeg particle qauv ploj thiab cov ntaub ntawv raws li ib tug loj.Pa sintering yuav tsis tshem tawm tag nrho cov porosity nyob rau hauv ib feem, tab sis nws txo cov porosity ntxiv.Ntxiv nrog rau kev txo qis hauv ntim, sintering kuj tseem tuaj yeem cais thaj chaw ntawm kev sib tshuam qhib porosity hauv ntsuab compact.Cov chaw sib cais no dhau los ua qhov porosity kaw, vim lawv raug txiav tawm ntawm ib puag ncig sab nraud.Sintering yog tus yam ntxwv ntawm kev hlawv tawm ntawm cov khoom ntxiv hauv cov hmoov uas tsim nyog rau cov txheej txheem ua ntej.Kev tshem tawm cov khoom tsis xav tau ntxiv lawm xws li lubricants, binders thiab deflocculates, yog qhov tseem ceeb los tswj cov khoom siv ntawm cov khoom kawg.Ntxiv nrog rau kev ua kom lub zog thiab qhov ntom ntom ntawm cov khoom siv, sintering kuj nce ductility, thermal conductivity thiab hluav taws xob conductivity.Shrinkage yuav tshwm sim thaum lub sij hawm sintering, tab sis yuav raug xam rau thaum tsim cov txheej txheem txheej txheem tswj.

Mechanisms uas ua rau kev sib raug zoo thaum lub sij hawm sintering yog varied thiab complex.Lub ntsiab mechanism los ntawm kev sib koom ua ke tshwm sim yog suav tias yog diffusion, cov txheej txheem yuav sib txawv raws li cov txheej txheem tsim khoom thiab cov yam ntxwv ntawm cov hmoov.Qee lwm cov txheej txheem uas yuav tshwm sim nrog rau kev sib kis yog cov yas ntws, recrystallization, kev loj hlob ntawm cov qoob loo, cov khoom ua kua theem thauj thiab vapor theem cov khoom thauj.Cov yam ntxwv ntawm lub cev ntawm ntau hom kev sib txuas yuav txawv.Particle sib txuas los ntawm ob lub tshuab sib txawv yog qhia hauv qab no.Lub diffusion bonding shrinks qhov kev ncua deb ntawm cov khoom, txo qhov chaw.Cov txheej txheem thauj khoom ntxiv cov khoom siv, thaum ua kom cov khoom sib nrug sib nrug.

Bonding mechanisms thaum lub sij hawm sintering yog qhov nyuaj thiab sib txawv, txawm li cas los xij, lub zog tsav tseem ceeb uas ua rau qhov kev sib txuas ntawm cov khoom no yog suav tias yog qhov txo qis ntawm lub zog vim qhov txo qis hauv cheeb tsam.Cov hmoov uas muaj thaj tsam loj dua yuav muaj lub zog tsav tsheb ntau dua rau kev sib txuas thiab txo qis ntawm lub peev xwm no.

Alloying ntawm cov hmoov hlau sib txawv kuj tshwm sim thaum sintering.Lub sintering kub yuav tsum ib txwm qis dua lub melting kub ntawm tsawg kawg yog ib tug ntawm cov hmoov constituents.Qee zaum, qhov kub ntawm sintering yog siab tshaj qhov melting point ntawm ib qho ntawm cov ntaub ntawv tab sis hauv qab lub melting point ntawm lwm yam.Qhov no yog hu ua kua theem sintering.Cov kua theem sintering tuaj yeem tshem tawm cov porosity thiab tsim cov khoom nrog cov khoom zoo heev.