Cov ntsiab lus carbon ntawm txhua qhov sintered specimen fracture yog txawv, nrog cov ntsiab lus carbon ntawm A-2.5 awt.% nyob rau hauv qhov ntau, tsim cov khoom siv ntom ntom uas yuav luag tsis muaj qhov hws, uas yog tsim los ntawm cov khoom sib xyaw ntawm silicon carbide thiab dawb silicon. Nrog kev nce ntawm cov pa roj carbon ntxiv, cov ntsiab lus ntawm cov tshuaj tiv thaiv-sintered silicon carbide nce zuj zus, qhov loj me ntawm silicon carbide nce, thiab silicon carbide txuas nrog ib leeg hauv cov pob txha pob txha. Txawm li cas los xij, cov ntsiab lus carbon ntau dhau tuaj yeem ua rau cov pa roj carbon seem nyob hauv lub cev sintered. Thaum cov pa roj carbon dub ntxiv mus rau 3a, sintering ntawm cov qauv tsis tiav, thiab cov "interlayers" dub tshwm hauv.
Thaum cov pa roj carbon reacts nrog molten silicon, nws ntim expansion tus nqi yog 234%, uas ua rau lub microstructure ntawm cov tshuaj tiv thaiv-sintered silicon carbide ze ze rau cov ntsiab lus carbon nyob rau hauv lub billet. Thaum cov ntsiab lus carbon nyob rau hauv billet me me, silicon carbide tsim los ntawm silicon-carbon cov tshuaj tiv thaiv tsis txaus los sau cov pores nyob ib ncig ntawm cov hmoov carbon, uas ua rau muaj ntau ntawm silicon dawb hauv cov qauv. Nrog rau kev nce ntawm cov ntsiab lus ntawm cov pa roj carbon monoxide, cov tshuaj tiv thaiv-sintered silicon carbide tuaj yeem ua tiav cov pores nyob ib puag ncig cov hmoov carbon thiab txuas cov thawj silicon carbide ua ke. Lub sijhawm no, cov ntsiab lus ntawm silicon dawb hauv cov qauv txo qis thiab qhov ceev ntawm sintered lub cev nce. Txawm li cas los xij, thaum muaj cov pa roj carbon ntau nyob rau hauv lub billet, qhov thib ob silicon carbide tsim los ntawm cov tshuaj tiv thaiv ntawm cov pa roj carbon monoxide thiab silicon sai sai nyob ib puag ncig lub toner, ua rau nws nyuaj rau molten silicon hu rau toner, ua rau cov pa roj carbon seem hauv lub cev sintered.
Raws li cov txiaj ntsig XRD, theem muaj pes tsawg leeg ntawm cov tshuaj tiv thaiv-sintered sic yog α-SiC, β-SiC thiab silicon dawb.
Nyob rau hauv cov txheej txheem ntawm kev kub siab sintering, carbon atoms migrate mus rau thawj lub xeev ntawm SiC nto β-SiC los ntawm molten silicon α-secondary tsim. Txij li thaum cov tshuaj tiv thaiv silicon-carbon yog cov tshuaj tiv thaiv exothermic nrog ntau cov tshuaj tiv thaiv tshav kub, cua txias sai tom qab lub sij hawm luv luv ntawm cov tshuaj tiv thaiv kub kub ua rau kom cov pa roj carbon diluted hauv cov kua silicon, kom cov β-SiC particles precipitated hauv lub daim ntawv ntawm cov pa roj carbon, yog li txhim kho cov khoom siv kho tshuab ntawm cov khoom. Yog li ntawd, theem nrab β-SiC grain refinement yog qhov zoo rau kev txhim kho kev khoov lub zog. Hauv Si-SiC composite system, cov ntsiab lus ntawm silicon dawb hauv cov khoom txo qis nrog qhov nce ntawm cov ntsiab lus carbon hauv cov khoom siv raw.
Xaus:
(1) Lub viscosity ntawm npaj reactive sintering slurry nce nrog qhov nce ntawm cov pa roj carbon dub; Tus nqi pH yog alkaline thiab maj mam nce.
(2) Nrog rau qhov nce ntawm cov ntsiab lus carbon hauv lub cev, qhov ceev thiab khoov lub zog ntawm cov tshuaj tiv thaiv-sintered ceramics npaj los ntawm nias txoj kev ua ntej nce thiab tom qab ntawd txo qis. Thaum tus nqi ntawm cov pa roj carbon dub yog 2.5 npaug ntawm qhov pib, peb lub ntsiab lus dabtsi yog khoov lub zog thiab qhov ntom ntom ntawm cov xim ntsuab tom qab cov tshuaj tiv thaiv sintering siab heev, uas yog 227.5mpa thiab 3.093g / cm3, feem.
(3) Thaum lub cev nrog cov pa roj carbon ntau dhau yog sintered, cov kab nrib pleb thiab cov "sandwich" dub yuav tshwm sim hauv lub cev ntawm lub cev. Yog vim li cas rau qhov tawg yog tias cov roj silicon oxide tsim nyob rau hauv cov txheej txheem ntawm cov tshuaj tiv thaiv sintering tsis yooj yim rau kev tso tawm, maj mam sib sau, lub siab nce, thiab nws cov nyhuv jacking ua rau tawg ntawm cov pob zeb. Hauv cheeb tsam dub "sandwich" hauv sinter, muaj ntau cov pa roj carbon monoxide uas tsis koom nrog cov tshuaj tiv thaiv.
Post lub sij hawm: Lub Xya hli ntuj-10-2023