METALL

METALL, fuluzot, moddahoi soddaeand, ki dar sharoiti muqarrari qobiliyati balandi elektr va garmiguzaroni, koeffisienti haroratii manfii elektrguzaroni, qobilityati ba khubi aks kardani mavjhoi elektrmagniti va khosiyati plastiki dorand. Metall dar holati sakht sokhta kristalli dorad, dar holati bur boshad, yakatoma ast. Hamai khosiyathoi nombarshuda ba sokhti elektronii Metall vobasta ast. Ziyoda az 80 moddai sodda va aksari khulahoi metalli doroi in khosiyathoyand. Metallho dar sistemai davrii elementhoi Mendeleev az tarafi chapi khati rosta az bor to astat guzaronidashuda va nometallho az tarafi rosti on joygirand. Elementhoi dar nazdi in khat joygirshuda khosiyathoi ham metalli va ham nometalli dorand (mas., As, Sb, Bi va g.; bazan inhoro nimmetall ham menomand).

Dar davrahoi qadim va asrhoi miyona 7 Metall (tillo, nuqra, mis, qalagi, surb, ohan va simob) malum bud. Kimyogaron (alkhimikho) gumon mekardand, ki Metallho dar qari zamin az tasiri sayyoraho paydo shuda, bagoyat ohista takomul yofta, okhir ba nuqravu tillo mubaddal shudaand. Avv. asri 18 tasavvurote vujud dosht, ki guyo Metall az zamin va flogiston nom mabdai suzish iborat boshad. Okhiri asri 18 A. L. Lavuaze in tasavvurotro rad karda nishon dod, ki Metall moddai sodda ast. Avvali asri 19 Metallhoi platini, ishqori va ishqorzamini kashf va hosil karda shudand; ba judo kardani Metallhoi nodirzamin asos guzoshta shud. Kashf karda shudani hodisai radioaktivi okhiri asri 19 baroi bo rohi suni hosil kardani yak qator Metallhoi radioaktivi, az on jumla elementhoi transurani, imkoniyat dod. Metall yak qator khosiyathoi umumi niz dorad, ki in khosiyatho natijai aloqai susti elektronhoi valenti bo yadroi atom meboshad. Mas., zuhuri valentnokii musbat, hosilkunii kationho, oksidho, gidroksidho va g. Hangomi az rui ziyodshavii potensiali muqarrari pay dar pay guzoshtani Metallho qatori shiddatnoki yo qatori faoliyatnokii onho hosil meshavad. Dar in qator kharakteri elektromusbatii Metallho az Metallhoi ishqori to Pt va Ai sust meshavad. Hamai Metallhoe, ki az N2 bol o joygir shudaand, gidrogenro az kislotai serob khorij mekunand. Metallhoe, ki az N2 poyon voqeand, dar kislotahoi oksigenhoi (Pt va Ai faqat dar shahsharob) hal meshavand. Metallhoi avvali qator az Li to Na bo oksigen dar khunuki, azohoi olidai qator (gayr az Ir, Pt va Ai) hangomi garm kardan ba reaksiya medaroyand. Oksidhoi darajai pasti Metallho khosiyati asosro dorand; oksidkhoi olii onho angidridi kislotaho meboshand. M.-ho valentnokii tagiiryobanda dorand. Dar borai digar khosiyathoi khimiyavii Metallho nig. Metallho, Gidriduo, Narbiduo va g.

Metall az sababi khosiyathoi mustahkami, sakhti, ustuvori ba korroziya, garmitobovari, qobiliyati balandi elektrguzaroni va g. doshtanashon dar tekhiikai imruza roli muhim mebozand. Hamai Metallho va khulahoi az onho hosilshudaro ba Metallhoi siyoh (ohan va khulahoi on) va rang (hamai Metallhoi boqimonda va khulahoi ohho judo mekunand. Metallhoi ranga niz dar navbati khud vobasta ba alomatho (khosiyathoi fiziki va khimiyavi, kharakteri dar qishri zamin joygirshavi)-yashon ba yakchand guruh judo meshavand: Metallhoi sabuk (Al, Mg), Metallhoi vaznin (Si, R va g.), Metallhoi dushvorgudoz (W, Mo va g.), Metallhoi asil (Au, Pt va r.), Metallhoi nodir (Sc, Y, La, lantanoidho) va g. Aloqamandii tarkib, sokht va khosiyati Metallho va khulaho, inchunin qonuniyati tagyirpazirii onhoro hangomi tasiri garmi, khimiyavi va mekhaniki metallshinosi meomuzad. Metall dar tabiat dar namudi madan, bazan dar holati khudruy (kholis) vomekhurad. Az Metallhoi baroi tekhnikai imruza muhimtarin dar qishri zamin Fe (4,65%), Al (8,8%), Mg (2,1%), Ti (0,63%) beshtar duchor meoyand. Dar borai hosilkunii Metall. nig. Metallurgiya.