Iinkqubo ezine ze-sintering ze-silicon carbide ceramics

I-Silicon carbide ceramics inamandla obushushu obuphezulu, ukumelana nobushushu obuphezulu be-oxidation, ukumelana nokunxiba kakuhle, ukuzinza okuhle kwe-thermal, i-coefficient encinci yokwandiswa kwe-thermal, i-thermal conductivity ephezulu, ubunzima obuphezulu, ukuxhathisa ubushushu, ukuxhathisa ukubola kweekhemikhali kunye nezinye iimpawu ezintle.Isetyenziswe ngokubanzi kwimoto, kumatshini, ukhuseleko lokusingqongileyo, itekhnoloji ye-aerospace, ulwazi lwe-elektroniki, amandla kunye namanye amasimi, kwaye iye yaba yi-ceramic yolwakhiwo engenakubuyiselwa kunye nokusebenza okugqwesileyo kumashishini amaninzi.Ngoku mandikubonise!

Sintering ngaphandle koxinzelelo

I-Sintering engenaxinzelelo ithathwa njengeyona ndlela ithembisayo ye-SiC sintering.Ngokweendlela ezahlukeneyo zokuntywila, i-sintering engenaxinzelelo inokwahlulwa ibe yi-slid-phase sintering kunye ne-liquid-phase sintering.Ngokusebenzisa i-ultra-fine β- Isixa esifanelekileyo se-B kunye ne-C (i-oxygen content ngaphantsi kwe-2%) yongezwa kwi-SiC powder ngexesha elifanayo, kunye ne-s.Iproehazka yacwiliswa kumzimba we-SiC sintered kunye noxinano olungaphezulu kwe-98% ngo-2020 ℃.A. Mulla et al.I-Al2O3 kunye ne-Y2O3 zisetyenziswe njengezongezo kunye ne-sintered kwi-1850-1950 ℃ ye-0.5 μ m β-SiC (i-particle surface iqukethe inani elincinci le-SiO2).Ubuninzi obunxulumene neekeramics ze-SiC ezifunyenweyo zikhulu kune-95% yoxinaniso lwethiyori, kwaye ubungakanani beenkozo buncinci kunye nobukhulu obuphakathi.Ziyi-1.5 microns.

I-Hot press sintering

I-SiC ecocekileyo inokufakwa kuphela ngokudibeneyo kubushushu obuphezulu kakhulu ngaphandle kokongeza izongezo, abantu abaninzi baphumeza inkqubo yokucinezela eshushu ye-SiC.Kukho iingxelo ezininzi malunga nokucofa okushushu kwe-SiC ngokongeza izixhobo zokuncedisa.Alliegro et al.Ufunde isiphumo se-boron, i-aluminiyam, i-nickel, isinyithi, i-chromium kunye nezinye izongezo zentsimbi kwi-SiC densification.Iziphumo zibonisa ukuba i-aluminiyam kunye nentsimbi zezona zongezo zisebenzayo ukukhuthaza i-SiC eshushu yokucinezela i-sintering.I-FFlange yafunda umphumo wokongeza inani elahlukileyo le-Al2O3 kwiipropati ze-SiC ecinezelekileyo.Kucatshangelwa ukuba ukuxinana kwe-SiC ecinezelweyo eshushu kuhambelana nendlela yokuchithwa kunye nemvula.Nangona kunjalo, inkqubo yokushicilela eshushu inokuvelisa kuphela iinxalenye zeSiC ezinemilo elula.Ubuninzi beemveliso eziveliswa yinkqubo yexesha elilodwa lokutshisa i-hot sintering encinci kakhulu, engabangeli ukuveliswa kwemveliso.

I-isostatic eshushu yokucofa sintering

Ukuze unqobe ukusilela kwenkqubo ye-sintering yendabuko, uhlobo lwe-B kunye nohlobo lwe-C lwasetyenziswa njengezongezo kunye ne-isostatic eshushu ye-sintering iteknoloji yamkelwa.Kwi-1900 ° C, ii-ceramics ze-crystalline ezintle ezinobuninzi obungaphezulu kwe-98 zifunyenwe, kwaye amandla okugoba kwiqondo lokushisa elingaphakathi angafikelela kwi-600 MPa.Nangona i-isostatic eshushu yokucinezela i-sintering inokuvelisa iimveliso zesigaba esishinyeneyo ezinemilo entsonkothileyo kunye neempawu ezilungileyo zoomatshini, i-sintering kufuneka itywinwe, ekunzima ukuyifezekisa imveliso yeshishini.

Reaction sintering

I-Reaction sintered silicon carbide, ekwaziwa ngokuba yi-self bonded silicon carbide, ibhekisa kwinkqubo apho i-porous billet isabela ngegesi okanye isigaba solwelo ukuphucula umgangatho webillet, ukunciphisa i-porosity, kunye neemveliso ezigqityiweyo ze-sinter ezinamandla athile kunye nokuchaneka komda.thatha i-α-SiC powder kunye negraphite zixutywe kumlinganiselo othile kwaye zifudunyezwe malunga ne-1650 ℃ ukwenza i-square billet.Ngelo xesha, ingena okanye ingena kwi-billet nge-Si ye-gaseous kwaye iphendule nge-graphite ukwenza i-β-SiC, idibaniswe kunye neengqungquthela ezikhoyo ze-α-SiC.Xa i-Si ifakwe ngokupheleleyo, i-reaction sintered body enoxinano olupheleleyo kunye nobukhulu obungancitshiyo bunokufumaneka.Xa kuthelekiswa nezinye iinkqubo sintering, utshintsho ubungakanani reaction sintering kwinkqubo densification incinci, kwaye iimveliso ezinobungakanani obuchanekileyo zingalungiswa.Nangona kunjalo, ubukho besixa esikhulu se-SiC kumzimba osikiweyo kwenza ukuba iipropathi zobushushu obuphezulu bokusabela kwi-sintered SiC ceramics zibe mandundu.