Tsarin gilashi
Abubuwan physicochemical na gilashi ba wai kawai an ƙaddara su ta hanyar sinadaran sinadaran ba, amma har ma suna da alaƙa da tsarinsa.Kawai ta hanyar fahimtar alaƙar ciki tsakanin tsari, abun da ke ciki, tsari da aikin gilashi, za'a iya yin yuwuwar yin kayan gilashi ko samfuran tare da ƙayyadaddun kaddarorin physicochemical ta hanyar canza tsarin sinadarai, tarihin zafi ko amfani da wasu hanyoyin jiyya na jiki da sinadarai.
Halayen gilashi
Gilashi reshe ne na amorphous m, wanda shi ne amorphous abu tare da m inji Properties.Yawancin lokaci ana kiransa "ruwa mai sanyi".A cikin dabi'a, akwai jihohi biyu na m kwayoyin halitta: kyakkyawan yanayi da kuma mara kyau.Abin da ake kira jihar da ba ta da amfani ita ce yanayin ƙayyadaddun kwayoyin halitta da aka samu ta hanyoyi daban-daban kuma suna da yanayin rashin tsari.Jihar Glassy wani nau'i ne na ƙaƙƙarfan da ba daidai ba.Atom ɗin da ke cikin gilashin ba su da tsari na dogon zango a sararin samaniya kamar crystal, amma suna kama da ruwa kuma suna da tsari na ɗan gajeren zango.Gilashi na iya kula da wani siffa kamar mai ƙarfi, amma ba kamar ruwa mai gudana ƙarƙashin nauyinsa ba.Abubuwan gilashi suna da manyan halaye masu zuwa.
(1) Tsarin barbashi na kayan gilashin isotropic ba daidai ba ne kuma daidaitattun ƙididdiga.Don haka, lokacin da babu damuwa na ciki a cikin gilashin, halayensa na zahiri da na sinadarai (kamar taurin, modules na roba, madaidaicin haɓakar thermal, thermal conductivity, refractive index, conductivity, da dai sauransu) iri ɗaya ne a dukkan kwatance.Duk da haka, lokacin da akwai damuwa a cikin gilashin, za a lalata tsarin tsarin, kuma gilashin zai nuna anisotropy, kamar bambancin hanya na gani.
(2) Metastability
Dalilin da ya sa gilashin ke cikin yanayin haɓaka shine cewa gilashin yana samuwa ta hanyar saurin sanyaya narke.Saboda kaifi karuwa na danko a lokacin da sanyaya tsari, da barbashi ba su da lokaci zuwa samar da na yau da kullum tsari na lu'ulu'u, da kuma ciki makamashi na tsarin ba a mafi ƙasƙanci darajar, amma a metastable jihar;Duk da haka, ko da yake gilashin yana cikin yanayi mafi girma na makamashi, ba zai iya canzawa da sauri zuwa samfurin ba saboda yawan danko a dakin da zafin jiki;Sai kawai a ƙarƙashin wasu yanayi na waje, wato, dole ne mu shawo kan yuwuwar shinge na kayan daga yanayin gilashi zuwa yanayin crystalline, gilashin za a iya raba.Sabili da haka, daga ra'ayi na thermodynamics, yanayin gilashin ba shi da tabbas, amma daga ra'ayi na motsi, yana da kwanciyar hankali.Ko da yake yana da dabi'ar sakewa da kansa zafi yana canzawa zuwa crystal tare da ƙarancin makamashi na ciki, yuwuwar canzawa zuwa yanayin crystal yana da ƙanƙanta a yanayin zafin jiki, don haka gilashin yana cikin yanayin daidaitacce.
(3) Babu tsayayyen wurin narkewa
Canjin abu mai gilashi daga mai ƙarfi zuwa ruwa ana aiwatar da shi a cikin wani takamaiman yanayin zafin jiki (canza yanayin zafin jiki), wanda ya bambanta da abu na crystalline kuma ba shi da tsayayyen wurin narkewa.Lokacin da wani abu ya canza daga narkewa zuwa ƙarfi, idan tsari ne na crystallization, za a samar da sababbin matakai a cikin tsarin, kuma zafin jiki na crystallization, kaddarorin da sauran abubuwa da yawa za su canza ba zato ba tsammani.
Yayin da zafin jiki ya ragu, danko na narkewa yana ƙaruwa, kuma a ƙarshe an kafa gilashi mai ƙarfi.An kammala tsarin ƙarfafawa a cikin kewayon zafin jiki mai faɗi, kuma ba a sami sabon lu'ulu'u ba.Yanayin zafin jiki na sauyawa daga narkewa zuwa gilashi mai ƙarfi ya dogara ne akan nau'in sinadarai na gilashi, wanda gabaɗaya yana canzawa cikin dubun zuwa ɗaruruwan digiri, don haka gilashin ba shi da tsayayyen wurin narkewa, amma kawai kewayon zafin jiki mai laushi.A cikin wannan kewayon, gilashin a hankali yana canzawa daga viscoplastic zuwa viscoelastic.Tsarin canji a hankali na wannan kadarorin shine tushen gilashi tare da kyakkyawan tsari.
(4) Ci gaba da jujjuyawar canjin dukiya
Tsarin canjin dukiya na kayan gilashi daga yanayin narkewa zuwa ƙasa mai ƙarfi yana ci gaba da juyawa, wanda akwai wani yanki na yankin zafin jiki wanda shine filastik, wanda ake kira "canji" ko "m" yanki, wanda dukiyar ke da canje-canje na musamman.
A cikin yanayin crystallization, kaddarorin suna canzawa kamar yadda aka nuna a cikin lanƙwasa ABCD, t.Ita ce wurin narkewar kayan.Lokacin da aka kafa gilashin ta hanyar sanyaya, tsarin yana canzawa kamar yadda aka nuna a cikin abkfe curve.T shine zafin canjin gilashin, t shine zafin jiki mai laushi na gilashin.Don gilashin oxide, danko mai dacewa da waɗannan dabi'u biyu shine kusan 101pa · s da 1005p · s.
Ka'idar tsari na fashe gilashi
"Tsarin Gilashin" yana nufin daidaitawar ions ko atom a sararin samaniya da kuma tsarin da suka kasance a gilashi.Binciken da aka yi kan tsarin gilashin ya haifar da ƙwazo da hikimar masana kimiyyar gilashi.Ƙoƙarin farko na bayyana ainihin gilashin shine g.Tamman's supercooled liquid hypothesis, wanda ke riƙe da cewa gilashin ruwa ne mai sanyi, Tsarin gilashin ƙarfafawa daga narkewa zuwa ƙarfi tsari ne kawai na jiki, wato, tare da raguwar zafin jiki, kwayoyin gilashin gilashin sannu a hankali suna gabatowa saboda raguwar makamashin motsa jiki. , kuma ƙarfin hulɗar yana ƙaruwa a hankali, wanda ke sa girman gilashin ya karu, kuma a ƙarshe ya samar da wani abu mai mahimmanci da maras kyau.Mutane da yawa sun yi ayyuka da yawa.Mafi rinjayen hasashe na tsarin gilashin zamani sune: ka'idar samfur, ka'idar cibiyar sadarwa bazuwar, ka'idar gel, ka'idar simmetry na kusurwa biyar, ka'idar polymer da sauransu.Daga cikin su, mafi kyawun fassarar gilashin shine ka'idar samfurin da cibiyar sadarwar bazuwar.
Ka'idar Crystal
Randell l ya gabatar da ka'idar tsarin gilashin a cikin 1930, saboda yanayin hasken wasu tabarau yana kama da na lu'ulu'u na abun da ke ciki.Ya yi tunanin cewa gilashin ya ƙunshi microcrystalline da amorphous abu.Microproduct yana da tsarin atomic na yau da kullun da bayyane iyaka tare da kayan amorphous.Girman microproduct shine 1.0 ~ 1.5nm, kuma abun ciki yana lissafin fiye da 80%.Matsakaicin microcrystalline ya lalace.A cikin nazarin ɓarkewar gilashin gani na silicate, Lebedev ya gano cewa an sami canji kwatsam a cikin madaidaicin ma'aunin gilashin da zafin jiki a 520 ℃.Ya bayyana wannan sabon abu a matsayin canjin kamanni na ma'adini "microcrystalline" a cikin gilashi a 520 ℃.Lebedev ya yi imanin cewa gilashin ya ƙunshi "crystals" da yawa, wanda ya bambanta da microcrystalline, an kammala sauyawa daga "crystal" zuwa yankin amorphous mataki-mataki, kuma babu wata iyaka a tsakanin su.
Lokacin aikawa: Mayu-31-2021