Kev kho graphitization feem ntau yuav tsum tau kub siab txij li 2300 txog 3000 ℃, nrog nws lub hauv paus ntsiab lus yog kev hloov pauv ntawm cov pa roj carbon los ntawm kev teeb tsa tsis sib xws mus rau cov qauv siv lead ua graphite los ntawm kev kho cua sov kub siab. Hauv qab no yog kev tshuaj xyuas ntxaws ntxaws:
I. Qhov Kub thiab Txias rau Kev Kho Mob Graphitization Ib Txwm Muaj
A. Cov Kev Cai Kub Yooj Yim
Kev siv graphitization ib txwm yuav tsum tau tsa qhov kub kom txog li ntawm 2300 txog 3000 ℃, qhov twg:
- 2500 ℃ yog lub sijhawm hloov pauv tseem ceeb, uas qhov sib nrug ntawm cov pa roj carbon atoms txo qis, thiab qib ntawm graphitization nce sai;
- Tshaj li 3000 ℃, kev hloov pauv maj mam zuj zus, thiab cov graphite siv lead ua los ze rau qhov zoo tshaj plaws, txawm hais tias qhov kub ntxiv nce ntxiv ua rau txo qis kev txhim kho me ntsis hauv kev ua tau zoo.
B. Kev cuam tshuam ntawm qhov sib txawv ntawm cov khoom siv rau qhov kub thiab txias
- Cov pa roj carbon uas yooj yim rau graphitize (piv txwv li, roj av coke): Nkag mus rau theem graphitization ntawm 1700 ℃, nrog rau qhov nce ntxiv ntawm qib graphitization ntawm 2500 ℃;
- Cov pa roj carbon uas nyuaj rau graphitize (piv txwv li, anthracite): Yuav tsum tau kub dua (yuav luag 3000 ℃) kom ua tiav kev hloov pauv zoo sib xws.
II. Txoj Kev Uas Kub Siab Txhawb Kev Txiav Txim ntawm Cov Pa roj Carbon
A. Theem 1 (1000–1800 ℃): Kev Tso Tawm Uas Hloov Pauv Tau Thiab Kev Txiav Txim Ob-Qhov Ntev
- Cov saw hlau aliphatic, CH, thiab C=O bonds tawg, tso tawm hydrogen, oxygen, nitrogen, sulfur, thiab lwm yam ntsiab lus hauv daim ntawv ntawm monomers lossis cov molecules yooj yim (piv txwv li, CH₄, CO₂);
- Cov txheej carbon atom nthuav dav hauv lub dav hlau ob-seem, nrog rau qhov siab microcrystalline nce ntxiv ntawm 1 nm mus rau 10 nm, thaum interlayer stacking tseem tsis hloov pauv ntau;
- Ob qho tib si endothermic (tshuaj lom neeg) thiab exothermic (cov txheej txheem lub cev, xws li kev tso tawm ntawm lub zog interfacial los ntawm microcrystalline boundary disappearance) cov txheej txheem tshwm sim tib lub sijhawm.
B. Theem 2 (1800–2400 ℃): Kev Txiav Txim Peb-Seem thiab Kev Kho Kom Zoo Ntawm Cov Nplej
- Kev nce ntxiv ntawm cov zaus co thermal ntawm cov pa roj carbon ua rau lawv hloov mus rau hauv peb-seem kev npaj, tswj hwm los ntawm lub hauv paus ntsiab lus ntawm lub zog tsawg kawg nkaus;
- Kev tawg thiab cov ciam teb ntawm cov pob zeb siv lead ua maj mam ploj mus, ua pov thawj los ntawm kev tshwm sim ntawm cov kab ntse (hko) thiab (001) hauv X-ray diffraction spectra, lees paub qhov tsim ntawm peb-seem kev npaj;
- Qee qhov tsis huv tsim cov carbides (piv txwv li, silicon carbide), uas lwj mus rau hauv cov hlau vapors thiab graphite ntawm qhov kub siab dua.
C. Theem 3 (Saum 2400 ℃): Kev Loj Hlob ntawm Cov Noob thiab Kev Rov Ua Dua Tshiab
- Qhov loj ntawm cov noob nplej nce ntxiv raws txoj kab a-axis mus rau qhov nruab nrab ntawm 10–150 nm thiab raws txoj kab c-axis mus txog kwv yees li 60 txheej (kwv yees li 20 nm);
- Cov pa roj carbon atoms raug kev kho kom zoo los ntawm kev sib hloov sab hauv lossis kev sib txuas ntawm cov molecule, thaum qhov nqi ntawm cov pa roj carbon evaporation nce ntxiv nrog rau qhov kub thiab txias;
- Kev sib pauv khoom siv nquag tshwm sim ntawm cov khoom khov thiab cov roj, ua rau muaj cov qauv siv lead ua graphite uas tau txiav txim siab zoo.
III. Kev Ua Kom Kub Zoo Dua Los Ntawm Cov Txheej Txheem Tshwj Xeeb
A. Kev ua kom cov duab zoo li catalytic
Kev ntxiv cov catalysts xws li hlau lossis ferrosilicon tuaj yeem txo qhov kub ntawm graphitization mus rau qhov ntau ntawm 1500–2200 ℃. Piv txwv li:
- Ferrosilicon catalyst (25% silicon cov ntsiab lus) tuaj yeem txo qhov kub ntawm 2500–3000 ℃ txog 1500 ℃;
- Cov tshuaj catalyst BN tuaj yeem txo qhov kub kom qis dua 2200 ℃ thaum txhim kho kev taw qhia ntawm cov carbon fibers.
B. Kev Ua Graphitization Kub Heev
Siv rau cov ntawv thov purity siab xws li nuclear-grade thiab aerospace-grade graphite, cov txheej txheem no siv cov cua sov induction nruab nrab lossis plasma arc cua sov (piv txwv li, argon plasma core kub ncav cuag 15,000 ℃) kom ua tiav qhov kub ntawm qhov chaw tshaj 3200 ℃ ntawm cov khoom;
- Qhov degree ntawm graphitization tshaj 0.99, nrog rau cov ntsiab lus tsis huv heev (cov ntsiab lus tshauv <0.01%).
IV. Kev cuam tshuam ntawm qhov kub thiab txias rau cov teebmeem graphitization
A. Kev Tiv Thaiv thiab Kev Ua Kub
Rau txhua qhov nce 0.1 hauv qib graphitization, qhov resistivity txo qis 30%, thiab thermal conductivity nce 25%. Piv txwv li, tom qab kho ntawm 3000 ℃, qhov resistivity ntawm graphite tuaj yeem poob rau 1/4–1/5 ntawm nws tus nqi pib.
B. Cov Khoom Siv Kho Tshuab
Qhov kub siab txo qhov sib nrug ntawm cov graphite mus rau qhov ze li ntawm qhov zoo tagnrho (0.3354 nm), ua rau muaj kev tiv thaiv thermal shock thiab kev ruaj khov ntawm tshuaj lom neeg (nrog rau kev txo qis ntawm 50% -80%), thaum tseem muab kev nplua thiab kev hnav tsis kam.
C. Kev Txhim Kho Kev Huv Si
Thaum 3000 ℃, cov tshuaj sib txuas hauv 99.9% ntawm cov khoom sib xyaw ua ke yuav tawg, ua rau cov khoom tsis huv tawm hauv daim ntawv gaseous thiab ua rau cov khoom huv ntawm 99.9% lossis siab dua.
Lub sijhawm tshaj tawm: Cuaj hlis-11-2025