Ukwakheka kwengilazi
Izakhiwo ze-physicochemical zengilazi azinqunywa kuphela ukwakheka kwamakhemikhali, kodwa futhi zihlobene eduze nesakhiwo sayo. Kuphela ngokuqonda ubudlelwano bangaphakathi phakathi kwesakhiwo, ukwakheka, ukwakheka nokusebenza kwengilazi, ungakwazi ukwenza izinto zengilazi noma imikhiqizo enezici ze-physicochemical ezinqunywe kusengaphambili ngokushintsha ukwakheka kwamakhemikhali, umlando oshisayo noma ukusebenzisa ezinye izindlela zokwelapha ngokomzimba namakhemikhali.
Izici zengilazi
I-Glass iyigatsha le-amorphous solid, okuyi-amorphous material enezakhiwo eziqinile zemishini. Kuvame ukubizwa ngokuthi "i-supercooled liquid". Emvelweni, kunezimo ezimbili zento eqinile: isimo esihle nesingesihle. Okubizwa ngokuthi isimo esingakhiqizi isimo sezinto eziqinile ezitholwa ngezindlela ezihlukene futhi ezibonakala ngokuphazamiseka kwesakhiwo. I-Glassy state iwuhlobo oluqinile olungajwayelekile. Ama-athomu engilazini awanalo uhlelo olu-oda lwebanga elide esikhaleni njengekristalu, kodwa ayafana noketshezi futhi anohlelo olu-oda lwebanga elifushane. Ingilazi ingakwazi ukugcina isimo esithile njengesiqinile, kodwa hhayi njengoketshezi olugeleza ngaphansi kwesisindo salo. Izinto ezingilazi zinezimpawu ezisemqoka ezilandelayo.
(1) Ukuhlelwa kwezinhlayiya zezinto eziyingilazi ze-isotropic akuvamile futhi kufana ngokwezibalo. Ngakho-ke, lapho kungekho ukucindezeleka kwangaphakathi engilazini, izakhiwo zayo ezingokwenyama namakhemikhali (njengokuqina, i-modulus elastic, i-coefficient yokwandisa ukushisa, ukuqhutshwa kwe-thermal, inkomba ye-refractive, conductivity, njll.) iyafana kuzo zonke izinkomba. Kodwa-ke, lapho kunengcindezi engilazini, ukufana kwesakhiwo kuzobhujiswa, futhi ingilazi izobonisa i-anisotropy, njengomehluko osobala wendlela yokubona.
(2) I-Metastability
Isizathu sokuthi kungani ingilazi isesimweni sokumetastable ukuthi ingilazi itholakala ngokupholisa ngokushesha kokuncibilika. Ngenxa yokwanda okubukhali kwe-viscosity ngesikhathi senqubo yokupholisa, izinhlayiya azikho isikhathi sokwenza ukuhlelwa okujwayelekile kwamakristalu, futhi amandla angaphakathi esistimu awekho inani eliphansi kakhulu, kodwa esimweni se-metastable; Kodwa-ke, nakuba ingilazi isesimweni esiphezulu samandla, ayikwazi ukuguqula ngokuzenzakalelayo ibe umkhiqizo ngenxa ye-viscosity yayo ephezulu ekamelweni lokushisa; Kuphela ngaphansi kwezimo ezithile zangaphandle, okusho ukuthi, kufanele sinqobe umgoqo ongase ube khona wezinto ezibonakalayo kusukela esimweni seglasi kuya esimweni se-crystalline, ingilazi ingahlukaniswa. Ngakho-ke, ngokombono we-thermodynamics, isimo sengilazi asizinzile, kodwa kusukela ekubukeni kwe-kinetics, sizinzile. Yize inomkhuba wokuzikhulula kokushisa okuguqukayo kube yikristalu enamandla angaphakathi aphansi, amathuba okuthi iguqukele esimweni sekristalu mancane kakhulu kuzinga lokushisa elilingana negumbi, ngakho-ke ingilazi isesimweni sokumetastable.
(3) Alikho iphuzu elincibilikayo elingaguquki
Ukuguqulwa kwento eyingilazi isuka eqinile iye oketshezini yenziwa ebangeni elithile lokushisa (izinga lokushisa lokushintsha), elihlukile kunento ecwebezelayo futhi alinayo indawo yokuncibilika engaguquki. Lapho into iguqulwa isuka ekuncibilikeni iye ekuqineni, uma kuyinqubo ye-crystallization, izigaba ezintsha zizokwakhiwa ohlelweni, futhi izinga lokushisa le-crystallization, izakhiwo nezinye izici eziningi zizoshintsha kungazelelwe.
Njengoba izinga lokushisa liyancipha, i-viscosity yokuncibilika iyanda, futhi ekugcineni kwakhiwa ingilazi eqinile. Inqubo yokuqinisa iqedwa ebangeni lokushisa elibanzi, futhi awekho amakristalu amasha akhiwayo. Izinga lokushisa lokushintsha ukusuka ekuncibilikeni ukuya engilazini eqinile lincike ekwakhekeni kwamakhemikhali engilazi, ngokuvamile aguquguqukayo abe ngamashumi kuya kumakhulu amadigri, ngakho ingilazi ayinayo indawo yokuncibilika engaguquki, kodwa izinga lokushisa elithambile kuphela. Kulolu hlu, ingilazi ishintsha kancane kancane isuka ku-viscoplastic iye ku-viscoelastic. Inqubo yokushintsha kancane kancane yalesi sakhiwo iyisisekelo sengilazi enokucubungula okuhle.
(4) Ukuqhubeka nokubuyiselwa emuva koshintsho lwesakhiwo
Inqubo yokuguqulwa kwempahla yezinto eziyingilazi isuka kusimo sokuncibilika iye esimweni esiqinile iyaqhubeka futhi iyabuyiseleka emuva, lapho kunesigaba sesifunda sokushisa okuyipulasitiki, esibizwa ngokuthi “uguquko” noma isifunda “esingavamile”, lapho izakhiwo zinezinguquko ezikhethekile.
Endabeni ye-crystallization, izakhiwo ziyashintsha njengoba kuboniswe ku-curve ABCD, t. Yindawo yokuncibilika kwezinto. Lapho ingilazi yakhiwe ngokupholisa okukhulu, inqubo iyashintsha njengoba kukhonjisiwe ku-abkfe curve. T yizinga lokushisa lokushintsha kwengilazi, t izinga lokushisa elithambile lengilazi. Ngengilazi ye-oxide, i-viscosity ehambisana nalawa manani amabili cishe i-101pa · s kanye ne-1005p · s.
Ithiyori yesakhiwo yengilazi ephukile
“Isakhiwo sengilazi” sibhekisela ekumisweni kwejiyomethri kwama-ion noma ama-athomu emkhathini kanye nezakhiwo ezakhayo engilazini. Ucwaningo ngesakhiwo sengilazi seluveze imizamo ebuhlungu nobuhlakani bososayensi abaningi bezingilazi. Umzamo wokuqala wokuchaza ingqikithi yengilazi ngu-g. I-Tamman's supercooled liquid hypothesis, ebamba ukuthi ingilazi iwuketshezi olupholile kakhulu, Inqubo yokuqiniswa kwengilazi ukusuka ekuncibilikeni kuya kokuqinile kuyinqubo engokwenyama kuphela, okungukuthi, ngokuncipha kwezinga lokushisa, ama-molecule engilazi asondela kancane kancane ngenxa yokuncipha kwamandla e-kinetic. , futhi amandla okusebenzelana akhula kancane kancane, okwenza izinga lengilazi likhule, futhi ekugcineni kwakhe into eqinile eqinile futhi engajwayelekile. Abantu abaningi benze umsebenzi omningi. Imibono enethonya kakhulu yesakhiwo sengilazi yesimanje yilezi: ithiyori yomkhiqizo, ithiyori yenethiwekhi engahleliwe, ithiyori yejeli, ithiyori ye-engeli emihlanu yokulinganisa, ithiyori ye-polymer nokunye. Phakathi kwabo, incazelo engcono kakhulu yengilazi iyinkolelo yomkhiqizo kanye nenethiwekhi engahleliwe.
I-Crystal theory
U-Randell l wabeka phambili i-crystal theory ye-glass structure ngo-1930, ngoba iphethini ye-radiation yezinye izibuko ifana naleyo yamakristalu okwakheka okufanayo. Wayecabanga ukuthi ingilazi yakhiwe nge-microcrystalline kanye ne-amorphous material. I-microproduct inokuhlelwa kwe-athomu evamile kanye nomngcele osobala onempahla ye-amorphous. Usayizi we-microproduct ngu-1.0 ~ 1.5nm, futhi okuqukethwe kwawo kubala ngaphezu kuka-80%. Ukuma kwe-microcrystalline kuphazamisekile. Ekutadisheni ukumbozwa kwengilazi ye-silicate optical, u-Lebedev wathola ukuthi kube noshintsho olungazelelwe ejikeni lenkomba yengilazi ye-refractive enezinga lokushisa elingu-520 ℃. Wachaza lesi simo njengoshintsho olulinganayo lwe-quartz "microcrystalline" engilazini engu-520 ℃. U-Lebedev wayekholelwa ukuthi ingilazi yakhiwe "amakristalu" amaningi, ahluke ku-microcrystalline, Ukuguqulwa kusuka "ku-crystal" kuya esifundeni se-amorphous kuqedwa isinyathelo ngesinyathelo, futhi akukho mngcele ocacile phakathi kwabo.
Isikhathi sokuthumela: May-31-2021