Ubume beglasi
Iimpawu ze-physicochemical zeglasi azinqunywanga kuphela ngokubunjwa kweekhemikhali, kodwa zihambelana ngokusondeleyo nesakhiwo sayo.Kuphela ngokuqonda ubudlelwane bangaphakathi phakathi kwesakhiwo, ukubunjwa, ukwakheka kunye nokusebenza kweglasi, ngaba kunokwenzeka ukwenza izinto zeglasi okanye iimveliso ezineempawu ze-physicochemical ezichazwe kwangaphambili ngokuguqula ukubunjwa kweekhemikhali, imbali yokushisa okanye ukusebenzisa ezinye iindlela zonyango lomzimba kunye neekhemikhali.
Iimpawu zeglasi
I-Glass lisebe le-amorphous solid, eyi-amorphous material eneempawu eziqinileyo zoomatshini.Idla ngokubizwa ngokuba “yi-supercooled liquid”.Kwindalo, kukho iimeko ezimbini zemiba eqinileyo: imo elungileyo kunye nemeko engalunganga.Into ebizwa ngokuba yimeko engavelisiyo yimeko yento eqinileyo efunyenwe ngeendlela ezahlukeneyo kwaye ibonakaliswe ngokuphazamiseka kwesakhiwo.Imeko yeglasi luhlobo oluqinileyo olungelulo umgangatho.Iiathom ezikwiglasi azinaludwe olucwangcisiweyo olude kwisithuba esifana nekristale, kodwa ziyafana nolwelo kwaye zine-odolo yoluhlu olufutshane.Iglasi inokugcina imilo ethile njengento eqinileyo, kodwa ingafani nolwelo oluqukuqelayo phantsi kobunzima bayo.Izinto zeglasi zinezi mpawu zilandelayo.
(1) Ukulungelelaniswa kwamasuntswana eglasi ye-isotropic ayiqhelekanga kwaye ayifani ngokwezibalo.Ngoko ke, xa kungekho uxinzelelo lwangaphakathi kwiglasi, iimpawu zayo zomzimba kunye neekhemikhali (ezifana nobunzima, i-elastic modulus, i-coefficient yokwandisa i-thermal, i-thermal conductivity, i-index refractive, i-conductivity, njl.) iyafana kuzo zonke iindlela.Nangona kunjalo, xa kukho uxinzelelo kwiglasi, ukufana kwesakhiwo kuya kutshatyalaliswa, kwaye iglasi iya kubonisa i-anisotropy, njengomahluko ocacileyo wendlela yokubona.
(2) I-Metastability
Isizathu sokuba iglasi ikwimeko ye-metastable kukuba iglasi ifunyenwe ngokupholisa ngokukhawuleza kokunyibilika.Ngenxa yokunyuka okubukhali kwe-viscosity ngexesha lokupholisa, iinqununu azikho ixesha lokwenza ilungiselelo eliqhelekileyo leekristale, kwaye amandla angaphakathi enkqubo ayikho kwixabiso eliphantsi, kodwa kwi-metastable state;Nangona kunjalo, nangona iglasi ikwimeko ephezulu yamandla, ayikwazi ukuguqula ngokuzenzekelayo kwimveliso ngenxa ye-viscosity ephezulu kwiqondo lokushisa;Kuphela phantsi kweemeko ezithile zangaphandle, oko kukuthi, kufuneka sinqobe umqobo wezinto eziphathekayo ukusuka kwi-glassy state ukuya kwi-crystalline state, iglasi inokuhlukaniswa.Ngoko ke, ukusuka kwindawo yokujonga i-thermodynamics, i-glass state ayizinzile, kodwa ukusuka kwinqanaba le-kinetics, lizinzile.Nangona inomkhwa wokukhulula ubushushu obuguqukayo bube yikristale ngamandla aphantsi angaphakathi, amathuba okuba aguquke abe yicrystal state incinci kakhulu kwiqondo lobushushu begumbi, ngoko ke iglasi ikwimo enokumetastable.
(3) Akukho ndawo yokunyibilika ezinzileyo
Ukuguqulwa kwezinto zeglasi ukusuka kwisigxina ukuya kulwelo lwenziwa kwiqondo elithile lobushushu (uluhlu lweqondo lokushisa lokuguqulwa), olwahlukileyo kwi-crystalline substance kwaye ayinayo indawo edibeneyo yokunyibilika.Xa i-substance iguqulwa ukusuka kwi-melt ukuya kwisiqina, ukuba yinkqubo ye-crystallization, izigaba ezintsha ziya kwenziwa kwinkqubo, kunye nobushushu bekristallisation, iipropati kunye nezinye izinto ezininzi ziya kutshintsha ngokukhawuleza.
Njengoko iqondo lokushisa liyancipha, i-viscosity ye-melt iyanda, kwaye ekugqibeleni iglasi eqinile yenziwe.Inkqubo yokuqinisa igqitywe kuluhlu olubanzi lweqondo lokushisa, kwaye akukho zikristali ezintsha ezenziweyo.Uluhlu lwamaqondo obushushu otshintsho ukusuka kwinyibilika ukuya kwiglasi eqinileyo luxhomekeke kukwakheka kweekhemikhali zeglasi, ezithi ziguquguquka ngokubanzi kumashumi ukuya kumakhulu eedigri, ngoko ke iglasi ayinayo indawo yokunyibilika ezinzileyo, kodwa luluhlu lobushushu obuthambileyo kuphela.Kolu luhlu, iglasi iguquka ngokuthe ngcembe ukusuka kwi-viscoplastic ukuya kwi-viscoelastic.Inkqubo yokutshintsha ngokuthe ngcembe le propati isisiseko seglasi enokuqhubekeka kakuhle.
(4) Ukuqhubekeka kunye nokuguqulwa kokutshintshwa kwepropati
Inkqubo yokutshintshwa kwepropati yezinto zeglasi ukusuka kwimeko yokunyibilika ukuya kwisimo esiqinileyo siyaqhubeka kwaye sibuyiselwa umva, apho kukho icandelo lommandla weqondo lokushisa eliyiplastiki, elibizwa ngokuba yi "transformation" okanye "engaqhelekanga" ummandla, apho iipropati zineenguqu ezikhethekileyo.
Kwimeko ye-crystallization, iipropati zitshintsha njengoko kuboniswe kwi-curve ABCD, t.Yindawo yokunyibilika kwezinto.Xa iglasi yenziwe yi-supercooling, inkqubo iyatshintsha njengoko kubonisiwe kwijika le-abkfe.T yiglasi yotshintsho lobushushu, t bubushushu obuthambileyo beglasi.Kwiglasi ye-oxide, i-viscosity ehambelana nala maxabiso mabini malunga ne-101pa · s kunye ne-1005p · s.
Ithiyori yesakhiwo seglasi eyaphukileyo
"Ulwakhiwo lweglasi" lubhekiselele kubume bejometri yeeyoni okanye iiathom ezisesithubeni kunye nezakheko zazo ezakha kwiglasi.Uphando malunga nesakhiwo seglasi luye lwabonakalisa iinzame ezibuhlungu kunye nobulumko beenzululwazi ezininzi zeglasi.Inzame yokuqala yokuchaza undoqo weglasi ngu g.I-tamman's supercooled liquid hypothesis, ebambe ukuba iglasi ilulwelo olupholileyo kakhulu, Inkqubo yokuqina kweglasi ukusuka kwinyibilika ukuya kwisiqina yinkqubo yomzimba kuphela, oko kukuthi, ngokuncipha kwamaqondo obushushu, iimolekyuli zeglasi zisondela ngokuthe ngcembe ngenxa yokuncipha kwamandla ekinetic. , kwaye amandla okunxibelelana ayanda ngokuthe ngcembe, okwenza iqondo leglasi linyuke, kwaye ekugqibeleni lenze into eqinileyo kunye nengaqhelekanga.Abantu abaninzi benze umsebenzi omninzi.Ezona ngqikelelo zinempembelelo kakhulu kwisakhiwo seglasi yale mihla zezi: ithiyori yemveliso, ithiyori yenethiwekhi engacwangciswanga, ithiyori yejeli, ithiyori ye-engile ezintlanu, ithiyori yepolymer njalo njalo.Phakathi kwabo, ukuchazwa kakuhle kweglasi yinkcazo yemveliso kunye nenethiwekhi engahleliwe.
Ithiyori yeCrystal
URandell wabeka phambili ithiyori yekristale yesakhiwo seglasi ngo-1930, kuba ipateni yemitha yezinye iiglasi iyafana naleyo yeekristale zokwakheka okufanayo.Wayecinga ukuba iglasi yenziwe nge-microcrystalline kunye ne-amorphous material.I-microproduct inelungiselelo le-athomu rhoqo kunye nomda ocacileyo kunye nempahla ye-amorphous.Ubungakanani be-microproduct yi-1.0 ~ 1.5nm, kwaye umxholo wayo ubalelwa ngaphezu kwe-80%.Ukuqhelaniswa ne-microcrystalline kuphazamisekile.Ekufundeni ukufakwa kweglasi ye-silicate optical glass, uLebedev wafumanisa ukuba kukho utshintsho olukhawulezileyo kwigophe leglasi ebonisa ubushushu obukwi-520 ℃.Wachaza le nto njengenguqu ye-quartz "microcrystalline" kwiglasi kwi-520 ℃.U-Lebedev wayekholelwa ukuba iglasi iqulethwe "iikristale" ezininzi, ezahlukileyo kwi-microcrystalline, Ukutshintsha ukusuka "kwi-crystal" ukuya kwindawo ye-amorphous kugqitywe ngesinyathelo ngesinyathelo, kwaye akukho mda ocacileyo phakathi kwabo.
Ixesha lokuposa: May-31-2021