Dav Davpiav qhia txog qhovKev tebCov SiC Sib Txuas
Cov khoom siv Reaction Bonded SiC muaj cov khoom siv kho tshuab thiab tiv taus oxidation. Nws tus nqi qis heev. Hauv lub zej zog tam sim no, nws tau nyiam ntau dua thiab ntau dua kev saib xyuas hauv ntau yam lag luam.
SiC yog ib qho kev sib txuas covalent muaj zog heev. Thaum sintering, qhov nrawm ntawm kev sib kis yog qis heev. Tib lub sijhawm, qhov chaw ntawm cov khoom me me feem ntau npog ib txheej oxide nyias nyias uas ua lub luag haujlwm ntawm qhov thaiv kev sib kis. SiC ntshiab tsis tshua muaj sintered thiab compact yam tsis muaj cov khoom ntxiv sintering. Txawm tias siv cov txheej txheem kub-nias, nws kuj yuav tsum xaiv cov khoom ntxiv tsim nyog. Tsuas yog thaum kub heev, cov ntaub ntawv tsim nyog rau kev tsim kho qhov ceev ze rau qhov ceev theoretical tuaj yeem tau txais uas yuav tsum nyob rau hauv qhov ntau ntawm 1950 ℃ txog 2200 ℃. Tib lub sijhawm, nws cov duab thiab qhov loj me yuav raug txwv. Txawm hais tias SIC composites tuaj yeem tau txais los ntawm kev tso pa tawm, nws tsuas yog txwv rau kev npaj cov ntaub ntawv qis lossis cov txheej nyias nyias. Vim nws lub sijhawm ntsiag to ntev, tus nqi ntawm kev tsim khoom yuav nce ntxiv.
Reaction Bonded SiC tau tsim los ntawm Popper xyoo 1950. Lub hauv paus ntsiab lus yog:
Nyob rau hauv qhov kev ua ntawm capillary force, kua silicon lossis silicon alloy nrog kev ua haujlwm reactive nkag mus rau hauv cov porous ceramics uas muaj carbon thiab tsim carbon silicon hauv qhov kev ua haujlwm. Cov silicon carbide tshiab tsim tau sib txuas nrog cov silicon carbide thawj hauv situ, thiab cov pores seem hauv qhov filler tau sau nrog tus neeg sawv cev impregnating kom ua tiav cov txheej txheem densification.
Piv nrog rau lwm cov txheej txheem ntawm silicon carbide ceramics, cov txheej txheem sintering muaj cov yam ntxwv hauv qab no:
Kub ua haujlwm tsawg, lub sijhawm ua haujlwm luv luv, tsis tas yuav siv cov khoom siv tshwj xeeb lossis kim;
Cov khoom sib txuas ua ke uas tsis muaj kev ntsws lossis hloov pauv loj;
Cov txheej txheem molding sib txawv (extrusion, txhaj tshuaj, nias thiab nchuav).
Muaj ntau txoj kev rau kev ua kom zoo nkauj. Thaum lub sijhawm sintering, cov khoom loj thiab cov khoom nyuaj tuaj yeem tsim tau yam tsis muaj kev nias. Cov thev naus laus zis Reaction Bonded ntawm silicon carbide tau kawm txog ib nrab xyoo pua. Cov thev naus laus zis no tau dhau los ua ib qho ntawm cov chaw tseem ceeb ntawm ntau yam kev lag luam vim nws cov txiaj ntsig tshwj xeeb.
Lub sijhawm tshaj tawm: Tsib Hlis-04-2018