Kuchuluka kwa kaboni m'chitsanzo chilichonse chophwanyika ndi kosiyana, ndi kuchuluka kwa kaboni kwa A-2.5 awt.% mu mtundu uwu, kupanga chinthu chokhuthala chomwe chilibe ma pores, chomwe chimapangidwa ndi tinthu ta silicon carbide tomwe timagawidwa mofanana komanso silicon yaulere. Ndi kuwonjezeka kwa kuwonjezera kwa kaboni, kuchuluka kwa silicon carbide yosakanikirana ndi reaction-sintered kumawonjezeka pang'onopang'ono, kukula kwa tinthu ta silicon carbide kumawonjezeka, ndipo silicon carbide imalumikizidwa wina ndi mnzake mu mawonekedwe a mafupa. Komabe, kuchuluka kwa kaboni kochulukirapo kungayambitse mosavuta kaboni wotsalira m'thupi lophwanyika. Pamene kaboni wakuda ukuwonjezeka kufika pa 3a, kuipitsidwa kwa chitsanzocho sikukwanira, ndipo "zolumikizana" zakuda zimawonekera mkati.
Mpweya ukakumana ndi silicon wosungunuka, kuchuluka kwake kwa voliyumu kumawonjezeka ndi 234%, zomwe zimapangitsa kuti kapangidwe kake ka silicon carbide yosakanikirana ndi reaction-sintered yogwirizana kwambiri ndi kuchuluka kwa kaboni mu billet. Pamene kuchuluka kwa kaboni mu billet kuli kochepa, silicon carbide yopangidwa ndi silicon-carbon reaction sikokwanira kudzaza ma pores ozungulira ufa wa kaboni, zomwe zimapangitsa kuti silicon yambiri yaulere ikhale mu chitsanzo. Ndi kuchuluka kwa kuchuluka kwa kaboni mu billet, silicon carbide yosakanikirana ndi reaction-sintered imatha kudzaza ma pores ozungulira ufa wa kaboni ndikulumikiza silicon carbide yoyambirira pamodzi. Pakadali pano, kuchuluka kwa silicon yaulere mu chitsanzo kumachepa ndipo kuchuluka kwa thupi losungunuka kumawonjezeka. Komabe, pamene pali kaboni wochulukirapo mu billet, silicon carbide yachiwiri yopangidwa ndi reaction pakati pa kaboni ndi silicon imazungulira toner mwachangu, zomwe zimapangitsa kuti silicon yosungunuka ikhale yovuta kukhudza toner, zomwe zimapangitsa kuti carbon yotsala m'thupi losungunuka ikhale yotsalira.
Malinga ndi zotsatira za XRD, kapangidwe ka gawo la reaction-sintered sic ndi α-SiC, β-SiC ndi free silicon.
Pakachitika kusintha kwa kutentha kwambiri, maatomu a kaboni amasamukira ku mkhalidwe woyambirira pamwamba pa SiC β-SiC pogwiritsa ntchito silicon yosungunuka α-secondary. Popeza silicon-carbon reaction ndi njira yodziwika bwino yochitira zinthu zosiyanasiyana yokhala ndi kutentha kwakukulu, kuzizira mwachangu pambuyo pa kanthawi kochepa kochita kutentha kwakukulu kodzidzimutsa kumawonjezera kusungunuka kwa kaboni wosungunuka mu silicon yamadzimadzi, kotero kuti tinthu ta β-SiC timapangika ngati kaboni, motero timawongolera mawonekedwe a makina a zinthuzo. Chifukwa chake, kukonzanso kwachiwiri kwa β-SiC tirigu kumathandiza pakukweza mphamvu yopindika. Mu dongosolo la Si-SiC composite, kuchuluka kwa silicon yaulere muzinthuzo kumachepa ndi kuchuluka kwa kaboni muzinthu zopangira.
Mapeto:
(1) Kukhuthala kwa slurry yokonzedwa bwino yothira madzi kumawonjezeka ndi kuchuluka kwa kaboni wakuda; pH ndi yamchere ndipo imawonjezeka pang'onopang'ono.
(2) Pamene kuchuluka kwa kaboni m'thupi kunawonjezeka, kuchuluka kwa mphamvu yopindika ndi yopindika ya zoumba zosakaniza zomwe zimapangidwa pogwiritsa ntchito njira yokanikiza kunayamba kukwera kenako kunachepa. Pamene kuchuluka kwa kaboni wakuda kuli nthawi 2.5 kuposa kuchuluka koyambirira, mphamvu yopindika ya mfundo zitatu ndi kuchuluka kwakukulu kwa billet yobiriwira pambuyo pa kupopera kwa kupopera kumakhala kwakukulu kwambiri, komwe ndi 227.5mpa ndi 3.093g/cm3, motsatana.
(3) Pamene mpweya wochuluka kwambiri wa kaboni wasungunuka m'thupi, ming'alu ndi madera akuda a "sandwich" amaonekera m'thupi la thupi. Chifukwa cha kuswekako ndichakuti mpweya wa silicon oxide womwe umapangidwa panthawi yochita zinthu zosokoneza siwophweka kutulutsa, pang'onopang'ono umasonkhana, kuthamanga kumakwera, ndipo mphamvu yake yothamanga imapangitsa kuti billet isweke. M'dera lakuda la "sandwich" mkati mwa sinter, muli mpweya wambiri wa kaboni womwe sukhudzidwa ndi zomwe zimachitika.
Nthawi yotumizira: Julayi-10-2023