Iiceramics ezikhethekileyo zibhekisa kudidi lweeceramics ezineempawu ezikhethekileyo zoomatshini, zomzimba okanye zeekhemikhali, izinto ezisetyenzisiweyo kunye netekhnoloji yemveliso efunekayo zahluke kakhulu kwiiceramics eziqhelekileyo kunye nophuhliso. Ngokweempawu kunye nokusetyenziswa, iiceramics ezikhethekileyo zinokwahlulwa zibe ziindidi ezimbini: iiceramics zesakhiwo kunye neeceramics ezisebenzayo. Phakathi kwazo, iiceramics zesakhiwo zibhekisa kwiiceramics ezinokusetyenziswa njengezixhobo zesakhiwo zobunjineli, ezihlala zinamandla aphezulu, ubunzima obuphezulu, i-modulus ephezulu ye-elastic, ukumelana nobushushu obuphezulu, ukumelana nokuguguleka, ukumelana nokugqwala, ukumelana nokuxinana, ukumelana nokutshiswa kobushushu kunye nezinye iimpawu.
Kukho iintlobo ngeentlobo zeeseramikhi zesakhiwo, iingenelo kunye neengxaki, kwaye indlela yokusetyenziswa kweenzuzo kunye neengxaki zahlukile, phakathi kwazo "iiseramikhi ze-silicon nitride" ngenxa yokulinganisela ukusebenza kuzo zonke iinkalo, zaziwa njengowona msebenzi ubalaseleyo opheleleyo kusapho lweeseramikhi zesakhiwo, kwaye zinoluhlu olubanzi kakhulu lwezicelo.
Iingenelo ze-silicon nitride ceramics
I-silicon nitride (Si3N4) inokwahlulwa ibe zii-compounds ze-covalent bond, kunye ne-[SiN4] 4-tetrahedron njengeyunithi yesakhiwo. Iindawo ezithile zeeathomu ze-nitrogen kunye ne-silicon zinokubonwa kumfanekiso ongezantsi, i-silicon isembindini we-tetrahedron, kwaye iindawo zee-vertices ezine ze-tetrahedron zihlala ziiathomu ze-nitrogen, kwaye emva koko i-tetrahedron nganye ezintathu yabelana nge-athomu enye, ihlala isasazeka kwindawo enemilinganiselo emithathu. Ekugqibeleni, ulwakhiwo lwenethiwekhi luyenziwa. Iipropati ezininzi ze-silicon nitride zinxulumene nolu lwakhiwo lwe-tetrahedral.
Kukho izakhiwo ezintathu ze-silicon nitride ezi-crystalline, ezizii-α, β kunye ne-γ phases, apho ii-α kunye ne-β phases zezona ziqhelekileyo ze-silicon nitride. Ngenxa yokuba ii-athomu ze-nitrogen zidityaniswe ngokuqinileyo, i-silicon nitride inamandla aphezulu, ubunzima obuphezulu kunye nokumelana nobushushu obuphezulu, kwaye ubunzima bunokufikelela kwi-HRA91 ~ 93; Ukuqina okuhle kobushushu, kunokumelana nobushushu obuphezulu be-1300 ~ 1400℃; Impendulo encinci yekhemikhali ene-carbon kunye nezinto zesinyithi ikhokelela kwi-coefficient ephantsi yokungqubana; Iyazithambisa kwaye ngenxa yoko ayigugi; Ukumelana nokugqwala kunamandla, ukongeza kwi-hydrofluoric acid, ayisabelani nezinye ii-inorganic acids, ubushushu obuphezulu bukwanayo nokumelana ne-oxidation; Ikwanayo nokumelana okuhle nokutshayiswa kobushushu, ukupholisa okubukhali emoyeni kwaye emva koko ukufudumala okubukhali akuyi kudilika; Ukuqhekeka kweeseramikhi ze-silicon nitride kuncipha kubushushu obuphezulu, kwaye ukuguquguquka kweplastiki okucothayo kuncinci phantsi kwesenzo sobushushu obuphezulu kunye nomthwalo osisigxina.
Ukongeza, iiseramikhi ze-silicon nitride nazo zinamandla aphezulu athile, imo ethile ephezulu, ukuqhuba okuphezulu kobushushu, iipropati zombane ezibalaseleyo kunye nezinye iingenelo, ngoko ke inexabiso elikhethekileyo lokusetyenziswa kwindawo egqithisileyo efana nobushushu obuphezulu, isantya esiphezulu, imithombo yeendaba enamandla erhabaxa, kwaye ithathwa njengenye yezona zinto zeseramikhi zesakhiwo ezithembisayo zophuhliso kunye nokusetyenziswa, kwaye zihlala ziba lukhetho lokuqala kwizicelo ezininzi ekufuneka zivavanywe.
Ixesha lokuthumela: Agasti-15-2023