Qhov sib txawv tseem ceeb ntawm nanocrystalline thiab polycrystalline yog cov ntaub ntawv nanocrystalline yog ua los ntawm cov khoom hauv nanometer-scale whereas polycrystalline cov ntaub ntawv yog ua los ntawm cov khoom loj.
Cov khoom peb paub tuaj yeem muab faib ua cov chav sib txawv nyob ntawm seb qhov loj me lossis los ntawm saib lawv cov pob zeb siv lead ua. Cov khoom siv nanocrystalline thiab cov khoom siv polycrystalline yog ob chav kawm.
Nanocrystalline yog dab tsi?
Nanocrystalline cov ntaub ntawv yog cov uas muaj cov khoom siv lead ua uas muaj qhov ntev ntawm nanometer nplai. Cov ntaub ntawv no zoo li ua rau qhov sib txawv ntawm cov khoom siv amorphous, yog li cov pob zeb siv lead ua no tau teem caij tsis muaj qhov ntev ntev. Yog li ntawd, nanocrystalline cov ntaub ntawv yog cov pa coarse-grained cov ntaub ntawv. Feem ntau, muaj qee qhov txawv me ntsis ntawm cov ntaub ntawv nanocrystalline. Txawm li cas los xij, cov khoom siv uas muaj cov hmoov nplej uas muaj qhov ntev hauv qab 100 nm feem ntau suav tias yog cov khoom siv nanocrystalline. Ntxiv mus, crystal grains muaj qhov ntev ntawm 100 mus rau 500 nm yog hu ua "ultrafine" nplej. Peb tuaj yeem sau cov ntaub ntawv nanocrystalline li NC.
Daim duab 01: Nanocrystalline
X-ray diffraction yog cov txheej txheem loj uas peb siv los ntsuas cov khoom siv lead ua loj ntawm NC cov khoom. Cov ntaub ntawv nrog cov khoom siv lead ua me me qhia pom dav dav diffraction peaks. Qhov dav peaks no tuaj yeem siv los txiav txim siab cov nplej loj siv Scherrer kab zauv thiab Williamson-Hall zaj duab xis. Los yog lwm yam, peb tuaj yeem siv ntau txoj hauv kev xws li Warren-Averbach txoj kev lossis kev ua qauv hauv computer ntawm tus qauv diffraction.
Thaum xav txog kev sib txuas ntawm NC cov khoom, muaj ntau txoj hauv kev. Cov txheej txheem no yog nyob ntawm theem ntawm cov teeb meem. Piv txwv li, muaj qee cov tswv yim rau NC ntau lawm xws li kev ua haujlwm hauv lub xeev, kev ua kua, kev ua vapour-theem, thiab kev daws teeb meem.
YPolycrystalline yog dab tsi?
Polycrystalline cov ntaub ntawv yog cov uas muaj cov khoom siv lead ua uas muaj qhov ntev tshaj qhov ntsuas nanometer. Cov ntaub ntawv no feem ntau tshwm sim thaum txias. Cov khoom siv lead ua hauv cov ntaub ntawv polycrystalline hu ua "crystallites". Kev taw qhia ntawm cov crystallites hauv cov khoom siv feem ntau yog random yam tsis muaj kev taw qhia tshwj xeeb, kev ntxhib los mos, thiab lwm yam. Peb tuaj yeem sau cov ntaub ntawv polycrystalline li PC.
Cov khoom organic feem ntau peb paub yog cov ntaub ntawv polycrystalline. Qee qhov piv txwv muaj xws li ceramics, pob zeb, dej khov, thiab lwm yam. Cov qib ntawm crystallization hauv PC cov khoom yog qhov tseem ceeb hauv kev txiav txim siab cov khoom ntawm cov ntaub ntawv no. Piv txwv li, leej faj tuaj yeem pom nyob rau hauv cov ntaub ntawv sib txawv uas cov allotropes muaj cov khoom sib txawv raws li qib ntawm crystallinity.
Qhov loj ntawm crystallite tuaj yeem ntsuas tau siv cov txheej txheem X-ray diffraction. Qhov loj ntawm cov nplej kuj tuaj yeem txiav txim siab siv lwm txoj hauv kev xws li kis tau tus mob electron microscopy. Qee zaum, cov ntaub ntawv muaj ib qho loj loj crystallite uas tuaj yeem ua tau yooj yim.
Qhov txawv ntawm Nanocrystalline thiab Polycrystalline yog dab tsi?
Cov ntaub ntawv uas peb paub tuaj yeem muab faib ua cov chav sib txawv nyob ntawm seb qhov loj me lossis los ntawm kev saib cov hmoov nplej. Cov khoom siv nanocrystalline thiab cov khoom siv polycrystalline yog ob chav kawm. Cov ntaub ntawv uas muaj cov khoom siv lead ua nrog qhov ntev hauv qab 100 nm feem ntau suav tias yog cov khoom siv nanocrystalline thaum cov ntaub ntawv uas muaj cov hmoov nplej nrog qhov ntev tshaj 100 nm feem ntau suav tias yog cov ntaub ntawv polycrystalline. Yog li, qhov sib txawv tseem ceeb ntawm nanocrystalline thiab polycrystalline yog cov ntaub ntawv nanocrystalline yog ua los ntawm cov khoom hauv nanometer-scale whereas polycrystalline cov ntaub ntawv yog ua los ntawm cov khoom loj.
Hauv qab infographic qhia txog qhov sib txawv ntawm nanocrystalline thiab polycrystalline.
Summary – Nanocrystalline vs Polycrystalline
Cov ntaub ntawv tuaj yeem muab faib ua ob chav sib txawv raws li cov khoom siv nanocrystalline thiab cov khoom siv polycrystalline, nyob ntawm seb qhov loj me lossis los ntawm saib cov khoom siv lead ua. Qhov sib txawv tseem ceeb ntawm nanocrystalline thiab polycrystalline yog cov ntaub ntawv nanocrystalline yog ua los ntawm cov khoom hauv nanometer-scale whereas polycrystalline cov ntaub ntawv yog ua los ntawm cov khoom loj.
