Izinqubo ezine zokuhlanza ze-silicon carbide ceramics

I-silicon carbide ceramics inamandla okushisa aphezulu, ukumelana nokushiswa kwezinga lokushisa eliphezulu, ukumelana nokuguguleka okuhle, ukuzinza okuhle kokushisa, i-coefficient encane yokwanda kokushisa, ukuqhuba okuphezulu kokushisa, ubulukhuni obukhulu, ukumelana nokushaqeka kokushisa, ukumelana nokugqwala kwamakhemikhali nezinye izakhiwo ezinhle kakhulu. Isetshenziswe kabanzi ezimotweni, emishinini, ekuvikelweni kwemvelo, kubuchwepheshe bezindiza, kuma-elekthronikhi olwazi, emandleni nakwamanye amasimu, futhi isibe yi-ceramic yesakhiwo engenakuphikiswa esebenza kahle kakhulu emikhakheni eminingi yezimboni. Manje ake ngikubonise!

Ukushisa okungenangcindezi

Ukusinta ngaphandle kokucindezela kubhekwa njengendlela ethembisayo kakhulu yokusinta kwe-SiC. Ngokwezindlela ezahlukene zokusinta, ukusinta ngaphandle kokucindezela kungahlukaniswa kube ukusinta kwesigaba esiqinile kanye nokusinta kwesigaba soketshezi. Ngokusebenzisa i-β- Encane kakhulu Inani elifanele le-B kanye ne-C (okuqukethwe komoya-mpilo okungaphansi kuka-2%) kwenezelwa ku-SiC powder ngesikhathi esifanayo, kanti i-s. proehazka yasinta emzimbeni osinta we-SiC onobukhulu obungaphezu kuka-98% ngo-2020 ℃. U-A. Mulla et al. Al2O3 kanye no-Y2O3 basetshenziswa njengezithasiselo futhi basinta ku-1850-1950 ℃ ku-0.5 μ m β-SiC (ubuso bezinhlayiya buqukethe inani elincane le-SiO2). Ubuningi obuhlobene be-ceramics ye-SiC etholiwe bukhulu kuno-95% wobuningi bethiyori, kanti usayizi wezinhlamvu mncane futhi usayizi ojwayelekile. Ungama-microns ayi-1.5.

Ukushisa kokucindezela okushisayo

I-SiC emsulwa ingasikwa ibe yincane kuphela ekushiseni okuphezulu kakhulu ngaphandle kwezithasiselo zokusikwa, ngakho-ke abantu abaningi basebenzisa inqubo yokusikwa kwe-SiC ngokucindezela okushisayo. Kube nemibiko eminingi ngokusikwa kwe-SiC ngokucindezela okushisayo ngokufaka izinsiza zokusikwa. U-Alliegro nabanye. Bafunde umphumela we-boron, i-aluminium, i-nickel, i-iron, i-chromium nezinye izithasiselo zensimbi ekuqineni kwe-SiC. Imiphumela ikhombisa ukuthi i-aluminium ne-iron yizona zithasiselo eziphumelela kakhulu ukukhuthaza ukusikwa kwe-SiC ngokucindezela okushisayo. I-FFlange ifunde umphumela wokwengeza inani elihlukile le-Al2O3 ezimpahleni ze-SiC ecindezelwe ngokushisayo. Kucatshangwa ukuthi ukuminyana kwe-SiC ecindezelwe ngokushisayo kuhlobene nendlela yokuncibilika kanye nemvula. Kodwa-ke, inqubo yokusikwa kwe-SiC ngokucindezela okushisayo ingakhiqiza kuphela izingxenye ze-SiC ezinesimo esilula. Inani lemikhiqizo ekhiqizwa inqubo yokusikwa kwe-SiC ngesikhathi esisodwa lincane kakhulu, okuyinto engafanele ukukhiqizwa kwezimboni.

Ukucindezela kwe-isostatic okushisayo

Ukuze kunqotshwe ukushiyeka kwenqubo yendabuko yokusinta, uhlobo lwe-B nohlobo lwe-C kwasetshenziswa njengezithasiselo futhi kwamukelwa ubuchwepheshe bokusinta bokucindezela okushisayo kwe-isostatic. Ku-1900 ° C, kwatholakala izitsha zobumba ezicwebezelayo ezincane ezinobukhulu obungaphezu kuka-98, futhi amandla okugoba ekushiseni kwegumbi angafinyelela ku-600 MPa. Nakuba ukusinta okucindezelayo okushisayo kwe-isostatic kungakhiqiza imikhiqizo yesigaba esiminyene enezimo eziyinkimbinkimbi nezakhiwo ezinhle zemishini, ukusinta kumele kuvalwe, okunzima ukufeza umkhiqizo wezimboni.

Ukusabela okucasulayo

I-Reaction sintered silicon carbide, eyaziwa nangokuthi i-self bonded silicon carbide, ibhekisela enkambisweni lapho i-porous billet isabela khona ngegesi noma isigaba soketshezi ukuze kuthuthukiswe ikhwalithi ye-billet, kuncishiswe i-porosity, kanye nemikhiqizo eqediwe ye-sinter ngamandla athile kanye nokunemba okulinganayo. I-take α- SiC powder kanye ne-graphite kuxutshwa ngesilinganiso esithile futhi kushiswe cishe ku-1650 ℃ ukuze kwakhiwe i-square billet. Ngesikhathi esifanayo, ingena noma ingena ku-billet nge-gaseous Si futhi isabela ne-graphite ukuze yakhe i-β- SiC, kuhlanganiswe nezinhlayiya ze-α- SiC ezikhona. Uma i-Si ingeniswe ngokuphelele, umzimba we-reaction sintered onobukhulu obuphelele kanye nobungako obunganciphisi ungatholakala. Uma kuqhathaniswa nezinye izinqubo ze-sintering, ushintsho losayizi we-reaction sintering enkambisweni yokuqina luncane, futhi imikhiqizo enobukhulu obunembile ingalungiswa. Kodwa-ke, ukuba khona kwenani elikhulu le-SiC emzimbeni we-sintered kwenza izakhiwo zokushisa eziphezulu ze-reaction sintered SiC ceramics zibe zimbi kakhulu.