Graphite yog ib yam khoom uas muaj kev ruaj ntseg zoo heev. Nws yuav luag chemically inert nyob rau hauv txo tej yam kev mob. Thaum nws tiv nrog lwm cov kua thiab cov khoom slags ntawm qhov kub thiab txias, nws yog ib qho nyuaj rau infiltrated thiab yaj los ntawm slag. Graphite muaj thermal conductivity, tsis tshua muaj thermal expansion coefficient, thiab zoo heev thermal shock kuj. Nws tuaj yeem siv tau zoo hauv cov txheej txheem smelting lub sijhawm ntawm cov hlau tsis muaj hlau ntawm 800 degree -1300 degree thaum ua rau hauv graphite crucibles.
Graphite khoom pib oxidize nyob rau hauv ib qho chaw oxidizing nrog kub siab tshaj 400 degree, thiab oxidation ceev yog ceev tshaj 800 degree, thiab nws yog heev yooj yim rau chemically react nrog oxidizing gases thiab yuav ablated. Decarburization yuav ua rau lub koom haum xoob, slag yaig tsis kam, thiab thermal shock kuj yuav txo tau zoo heev, thiab txawm tias kev puas tsuaj vim poob ntawm lub zog vim xoob qauv.
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Txhawm rau txhim kho oxidation tsis kam ntawm graphite cov ntaub ntawv, cov kws tshawb fawb tau ua ntau txoj kev tshawb fawb thiab tsim ntau yam kev tiv thaiv, ntawm cov txheej txheem txheej yog siv ntau dua.
Cov txheej txheem txheej yog txheej txheej txheej ntawm cov khoom siv graphite nrog oxidation-resistant txheej kom cais cov graphite cov khoom los ntawm cov roj oxidizing thiab tiv thaiv oxidation poob. Hom txheej txheej no yuav tsum muaj cov khoom nram qab no:
(1) Kub-kub tsis kam;
(2) Lub thermal expansion coefficient yog nyob ze thiab sib haum nrog cov pa roj carbon matrix;
(3) Zoo tshuaj ruaj khov, tsis yooj yim rau volatilize, muaj zog tiv thaiv slag yaig;
(4) Lub diffusion coefficient ntawm oxygen yog tsawg.
Cov hlau refractory tantalum muaj lub siab melting point thiab tuaj yeem tiv taus qhov yaig ntawm cov pa roj kub reactive, yog li nws yog ib qho khoom zoo los tiv thaiv ablation. Cov tantalum txheej thiab graphite muaj cov khoom sib txuas ntawm tus kheej, yog li lub zog sib txuas nrog cov graphite nto yog siab, uas tuaj yeem xyuas kom meej tias cov txheej txheem yuav tsis poob thaum lub sij hawm melting. Kev tsim kho thiab kev siv cov tantalum txheej tuaj yeem txhim kho lub neej kev pabcuam ntawm graphite crucibles, txuag nqi, thiab tuaj yeem tau txais txiaj ntsig zoo ntawm kev lag luam thiab kev ruaj ntseg lav.
