Izinqubo ezine ze-sintering ze-silicon carbide ceramics

I-Silicon carbide ceramics inamandla okushisa aphezulu, ukumelana nokushisa okuphezulu kwe-oxidation, ukumelana okuhle kokugqoka, ukuzinza okuhle kokushisa, i-coefficient encane yokwanda kwe-thermal, ukuqhutshwa kokushisa okuphezulu, ukuqina okuphezulu, ukumelana nokushisa ukushisa, ukumelana nokugqwala kwamakhemikhali nezinye izakhiwo ezinhle kakhulu.Isetshenziswe kabanzi kwezezimoto, emishinini, ekuvikelweni kwemvelo, ezobuchwepheshe be-aerospace, ulwazi lwe-elekthronikhi, amandla kanye neminye imikhakha, futhi isiphenduke i-ceramic yesakhiwo engenakushintshwa esebenza kahle kakhulu emikhakheni eminingi yezimboni.Manje ake ngikubonise!

Sintering ngaphandle kwengcindezi

I-sinterlessless sintering ibhekwa njengendlela ethembisa kakhulu ye-SiC sintering.Ngokuya ngezindlela ezihlukene zokucwilisa, i-sintering engenangcindezi ingahlukaniswa ibe yi-solid-phase sintering kanye ne-liquid-phase sintering.Ngokusebenzisa i-ultra-fine β- Inani elifanele le-B ne-C (okuqukethwe kwe-oksijeni ngaphansi kwe-2%) yengezwe ku-SiC powder ngesikhathi esifanayo, kanye ne-s.I-proehazka yacwiliswa emzimbeni we-SiC sintered ngobuningi obungaphezu kwama-98% ngo-2020 ℃.A. Mulla et al.I-Al2O3 ne-Y2O3 zisetshenziswe njengezithasiselo futhi zafakwa ku-1850-1950 ℃ ku-0.5 μ m β-SiC (i-particle surface iqukethe inani elincane le-SiO2).Ukuminyana okuhlobene kwama-ceramics e-SiC atholakele kukhulu kuno-95% we-theoretical density, futhi usayizi wokusanhlamvu mncane futhi usayizi ojwayelekile.Ingama-microns angu-1.5.

I-Hot press sintering

I-Pure SiC ingafakwa kuphela ngokuhlangene ekushiseni okuphezulu kakhulu ngaphandle kwanoma yiziphi izithasiselo ze-sintering, ngakho-ke abantu abaningi basebenzisa inqubo yokucindezela okushisayo ye-SiC.Kube nemibiko eminingi ngokucindezela okushisayo kwe-SiC ngokwengeza izinsiza zokucula.U-Alliegro et al.Ufunde umphumela we-boron, i-aluminium, i-nickel, i-iron, i-chromium nezinye izithasiselo zensimbi ku-SiC densification.Imiphumela ibonisa ukuthi i-aluminiyamu nensimbi iyizithasiselo ezisebenza kahle kakhulu zokukhuthaza i-SiC hot pressing sintering.I-FFlange ifunde umphumela wokwengeza inani elihlukile le-Al2O3 kuzakhiwo ze-SiC ecindezelwe okushisayo.Kucatshangwa ukuthi ukuminyana kwe-SiC ecindezelwe okushisayo kuhlobene nendlela yokuhlakazeka kanye nemvula.Kodwa-ke, inqubo ye-hot press sintering ingakhiqiza izingxenye ze-SiC ezinomumo olula.Ubuningi bemikhiqizo ekhiqizwa inqubo yesikhathi esisodwa yokufaka i-hot press sintering encane kakhulu, engahambisani nokukhiqizwa kwezimboni.

Ukucindezela okushisayo kwe-isostatic sintering

Ukuze kunqotshwe ukushiyeka kwenqubo ye-sintering yendabuko, uhlobo lwe-B nohlobo lwe-C lusetshenziswe njengezithasiselo kanye nobuchwepheshe bokucindezela bokucindezela kwe-isostatic obushisayo bamukelwa.Ngo-1900 ° C, kwatholakala ama-ceramics e-crystalline amahle anomthamo omkhulu kuno-98, futhi amandla okugoba ekamelweni lokushisa angafinyelela ku-600 MPa.Yize i-isostatic pressing sintering eshisayo ingakhiqiza imikhiqizo yesigaba esiminyene enomumo oyinkimbinkimbi kanye nezakhiwo ezinhle zemishini, i-sintering kufanele ivalwe, okunzima ukufeza ukukhiqizwa kwezimboni.

Ukusabela sintering

I-Reaction sintered silicon carbide, eyaziwa nangokuthi i-self bonded silicon carbide, ibhekisela kunqubo lapho i-billet enezimbotshana isabela khona negesi noma isigaba soketshezi ukuze kuthuthukiswe ikhwalithi ye-billet, kuncishiswe ukuqina, kanye nemikhiqizo eqediwe ye-sinter enamandla athile nokunemba kobukhulu.thatha i-α- SiC powder kanye negraphite kuxutshwe ngesilinganiso esithile futhi kushiswe cishe ku-1650 ℃ ukuze kwakhiwe i-billet yesikwele.Ngesikhathi esifanayo, ingena noma ingene ku-billet ngokusebenzisa i-Gaseous Si futhi iphendule nge-graphite ukuze yakhe i-β-SiC, ihlanganiswe nezinhlayiya ezikhona ze-α-SiC.Lapho u-Si engene ngesinyenyela ngokuphelele, umzimba osabelayo onobunzima obuphelele nosayizi onganciphisi ungatholwa.Uma kuqhathaniswa nezinye izinqubo ze-sintering, ukuguqulwa kosayizi we-reaction sintering enqubweni yokuminyana kuncane, futhi imikhiqizo enosayizi onembile ingalungiselelwa.Kodwa-ke, ukuba khona kwenani elikhulu le-SiC emzimbeni we-sintered kwenza izici zokushisa eziphezulu ze-reaction sintered SiC ceramics zibe zimbi nakakhulu.