Kapangidwe ka galasi
Mawonekedwe a physicochemical a galasi samangotsimikiziridwa ndi kapangidwe kake, komanso kogwirizana kwambiri ndi kapangidwe kake.Pokhapokha pomvetsetsa ubale wamkati pakati pa kapangidwe kake, kapangidwe, kapangidwe ndi magwiridwe antchito agalasi, zitha kukhala zotheka kupanga zida zamagalasi kapena zinthu zokhala ndi zida zodziwikiratu za physicochemical posintha kapangidwe kake, mbiri yamatenthedwe kapena kugwiritsa ntchito njira zochizira thupi ndi mankhwala.
Makhalidwe a galasi
Galasi ndi nthambi ya amorphous solid, yomwe ndi chinthu cha amorphous chokhala ndi mawotchi olimba.Nthawi zambiri amatchedwa "supercooled liquid".M'chilengedwe, pali zigawo ziwiri za chinthu cholimba: mkhalidwe wabwino ndi wosakhala wabwino.Zomwe zimatchedwa kuti zopanda phindu ndi chikhalidwe cha zinthu zolimba zomwe zimapezedwa ndi njira zosiyanasiyana ndipo zimadziwika ndi chisokonezo cha structural.Galasi state ndi mtundu wosakhazikika olimba.Ma atomu omwe ali mugalasi alibe makonzedwe otalika ngati kristalo, koma amafanana ndi madzi ndipo amakhala ndi dongosolo lalifupi.Galasi imatha kukhala ndi mawonekedwe enaake ngati olimba, koma osati ngati madzi oyenda pansi pa kulemera kwake.Zinthu zamagalasi zili ndi mikhalidwe yayikulu iyi.
(1) Kapangidwe ka tinthu tating'ono ta magalasi a isotropic ndi osakhazikika komanso ofanana.Choncho, pamene palibe kupsinjika kwa mkati mu galasi, katundu wake wakuthupi ndi mankhwala (monga kuuma, zotanuka modulus, matenthedwe kukulitsa coefficient, matenthedwe madutsidwe, refractive index, conductivity, etc.) ndi chimodzimodzi mbali zonse.Komabe, pakakhala kupsinjika mugalasi, mawonekedwe ake amawonongeka, ndipo galasi imawonetsa anisotropy, monga kusiyana koonekeratu kwanjira.
(2) Metastability
Chifukwa chomwe galasilo liri losasunthika ndikuti galasilo limapezeka ndi kuzizira kofulumira kwa kusungunuka.Chifukwa cha kuwonjezereka kwamphamvu kwa mamasukidwe akayendedwe panthawi yozizira, tinthu tating'onoting'ono tating'ono tilibe nthawi yopanga ma kristalo nthawi zonse, ndipo mphamvu yamkati mwa dongosolo siili pamtengo wotsika kwambiri, koma m'malo osasunthika;Komabe, ngakhale galasi ili mu mphamvu yapamwamba, silingasinthe mwachisawawa kukhala mankhwala chifukwa cha kukhuthala kwake kwakukulu kutentha;Pokhapokha pazikhalidwe zina zakunja, ndiko kuti, tiyenera kuthana ndi chotchinga cha zinthu kuchokera ku magalasi kupita ku dziko la crystalline, galasi ikhoza kupatulidwa.Choncho, kuchokera ku lingaliro la thermodynamics, galasi la galasi ndi losakhazikika, koma kuchokera ku kinetics, ndilokhazikika.Ngakhale ili ndi chizolowezi chodzitulutsa yokha kutentha kusandulika kukhala kristalo ndi mphamvu yochepa yamkati, mwayi wosinthika kukhala crystal state ndi wocheperako kutentha wamba, kotero galasilo limakhala lokhazikika.
(3) Palibe malo osungunuka okhazikika
Kusintha kwa zinthu zamagalasi kuchokera ku zolimba kupita kumadzi kumachitika mumtundu wina wa kutentha (kusintha kwa kutentha), komwe kumakhala kosiyana ndi zinthu za crystalline ndipo alibe malo osungunuka.Chinthu chikasinthidwa kuchoka kusungunuka kupita ku cholimba, ngati ndi crystallization ndondomeko, magawo atsopano adzapangidwa mu dongosolo, ndipo kutentha kwa crystallization, katundu ndi zina zambiri zidzasintha mwadzidzidzi.
Pamene kutentha kumachepa, kukhuthala kwa kusungunuka kumawonjezeka, ndipo pamapeto pake galasi lolimba limapangidwa.Ntchito yolimbitsa thupi imatsirizidwa mu kutentha kwakukulu, ndipo palibe makhiristo atsopano omwe amapangidwa.Kutentha kwakusintha kuchokera kusungunuka kupita ku magalasi olimba kumadalira momwe magalasi amapangidwira, omwe nthawi zambiri amasinthasintha m'madigiri khumi mpaka mazana ambiri, kotero galasi ilibe malo osungunuka okhazikika, koma ndi kutentha kochepa chabe.Munjira iyi, galasi imasinthidwa pang'onopang'ono kuchokera ku viscoplastic kupita ku viscoelastic.Kusintha kwapang'onopang'ono kwa malowa ndi maziko a galasi ndi processability wabwino.
(4) Kupitiliza ndi kusinthika kwa kusintha kwa katundu
Njira yosinthira katundu wa zinthu zamagalasi kuchokera ku malo osungunuka kupita ku malo olimba ndi opitirira komanso osinthika, momwe muli gawo la dera la kutentha lomwe ndi pulasitiki, lotchedwa "kusintha" kapena "abnormal" dera, momwe katundu ali ndi kusintha kwapadera.
Pankhani ya crystallization, katundu amasintha monga momwe akuwonetsera pa ABCD, t.Ndiwo malo osungunuka a zinthu.Galasiyo ikapangidwa ndi supercooling, njirayo imasintha monga momwe abkfe curve akuwonekera.T ndi kutentha kwa galasi, t ndi kutentha kwa galasi.Kwa galasi la oxide, kukhuthala kofanana ndi mfundo ziwirizi ndi pafupifupi 101pa · s ndi 1005p · s.
Chiphunzitso cha kapangidwe ka galasi losweka
"Mapangidwe agalasi" amatanthauza kusinthika kwa ma ayoni kapena ma atomu mumlengalenga ndi momwe amapangira mugalasi.Kafukufuku wokhudza kapangidwe ka magalasi awonetsa khama komanso nzeru za asayansi ambiri agalasi.Kuyesera koyamba kufotokoza tanthauzo la galasi ndi g.tamman's supercooled liquid hypothesis, yomwe imatsimikizira kuti galasi ndi madzi ozizira kwambiri, Njira ya galasi yolimba kuchokera kusungunuka kupita ku yolimba ndizochitika zakuthupi, ndiko kuti, ndi kuchepa kwa kutentha, mamolekyu a galasi amayandikira pang'onopang'ono chifukwa cha kuchepa kwa mphamvu ya kinetic. , ndipo mphamvu yolumikizirana imawonjezeka pang'onopang'ono, zomwe zimapangitsa kuti mlingo wa galasi uwonjezeke, ndipo pamapeto pake umapanga chinthu cholimba komanso chosakhazikika.Anthu ambiri agwira ntchito zambiri.Malingaliro okhudzidwa kwambiri a kapangidwe ka magalasi amakono ndi awa: chiphunzitso chazinthu, chiphunzitso cha intaneti mwachisawawa, chiphunzitso cha gel, chiphunzitso cha ma angle symmetry asanu, chiphunzitso cha polima ndi zina zotero.Pakati pawo, kutanthauzira bwino kwa galasi ndi chiphunzitso cha mankhwala ndi maukonde mwachisawawa.
Chiphunzitso cha Crystal
Randell ndinaika patsogolo chiphunzitso cha kristalo cha kapangidwe ka galasi mu 1930, chifukwa ma radiation a magalasi ena ndi ofanana ndi makhiristo amtundu womwewo.Ankaganiza kuti galasi limapangidwa ndi microcrystalline ndi amorphous material.Microproduct imakhala ndi dongosolo la atomiki nthawi zonse komanso malire odziwikiratu okhala ndi zinthu za amorphous.Kukula kwa microproduct ndi 1.0 ~ 1.5nm, ndipo zomwe zili mkati mwake zimapitilira 80%.Maonekedwe a microcrystalline ndi osokonezeka.Powerenga ma annealing a silicate optical glass, Lebedev anapeza kuti panali kusintha kwadzidzidzi pamapindikira a galasi refractive index ndi kutentha pa 520 ℃.Iye anafotokoza chodabwitsa ichi monga kusintha homogeneous wa quartz "microcrystalline" mu galasi pa 520 ℃.Lebedev ankakhulupirira kuti galasi limapangidwa ndi "makristasi" ambiri, omwe ndi osiyana ndi microcrystalline, Kusintha kuchokera ku "crystal" kupita ku dera la amorphous kumatsirizidwa sitepe ndi sitepe, ndipo palibe malire oonekera pakati pawo.
Nthawi yotumiza: May-31-2021