Ua ntej delving rau hauv kev lag luam saw thiab daim ntawv thov ntawm cov hlau chromium, peb yuav tsum xub to taub cov hlau nws tus kheej - nws los ntawm qhov twg, dab tsi nws muaj, thiab nyob rau hauv dab tsi cov ntaub ntawv nws muaj nyob rau hauv lub industrial ntiaj teb no.
1. Cov Khoom Siv Yooj Yim: Ib qho "xim muaj xim" tawv
Chromium (tshuaj cim Cr, atomic naj npawb 24) yog ib qho kev hloov pauv hlau nrog nyiaj - xim dawb thiab lub ntuj me ntsis - xiav tint. Nws "hardness" nyob rau hauv nws lub koob npe nrov - nws yog cov hlau hardest nyob rau hauv cov xwm. Ntshiab chromium muaj ductility zoo, tab sis muaj chromium muaj impurities yog tawv thiab nkig.
Chromium muaj qhov melting point ntawm 1907 degree, qhov kub ntawm 2679 degree, thiab qhov ceev ntawm kwv yees li 7.19 g / cm³. Nyob rau hauv chav tsev kub, nws yog ruaj khov tiv thaiv oxygen thiab noo noo, raws li ib tug ntom chromium oxide zaj duab xis sai sai rau ntawm nws nto, tiv thaiv corrosion ntxiv. Txawm li cas los xij, thaum qhov kub thiab txias (piv txwv li, siab dua 1200 degree), cov yeeb yaj kiab tiv thaiv no raug rhuav tshem.
Yuav luag tag nrho cov chromium tebchaw tso saib cov xim zoo nkauj - chromium sulfate yog ntsuab, potassium dichromate yog txiv kab ntxwv -liab, thiab lead chromate yog daj. Vim li no, thaum Fabkis chemist Vauquelin nrhiav pom nws hauv xyoo 1797, nws tau muab nws lub npe los ntawm Greek lo lus "chroma" (lub ntsiab lus "xim").
2. Keeb Kwm thiab Tsis Paub: Muab zais tob hauv lub ntiaj teb Crust, tseem zoo kawg li tam sim no ntawm Ancient Qin Swords
Chromium tso nyiaj rau tsuas yog 0.01% ntawm lub ntiaj teb lub crust, qeb 17 nyob rau hauv ntau. Nws yog xim hlau chromium tsis muaj nyob hauv lub xeev dawb hauv qhov xwm txheej; nws yog tsuas yog "pob" nyob rau hauv chromite ore.
Interestingly, bronze swords unearthed from the No. 2 Pit of the Terracotta Army of China's Qin Dynasty tseem tsis muaj xeb thiab ci li tshiab tom qab 2,000 xyoo. Kev soj ntsuam kev tshawb fawb pom tau tias cov hniav ntaj muaj oxide zaj duab xis uas muaj 2% chromium. Cov txheej txheem chromate hloov dua siab tshiab no yog cov txheej txheem niaj hnub qib siab - Lub teb chaws Yelemees thawj zaug tsim nws hauv xyoo 1937, thiab Tebchaws Meskas hauv xyoo 1950, nrog cov ntaub ntawv patent tom qab ntawd. Cov txuj ci casting ntawm cov neeg Qin yog qhov xav tsis thoob tiag.
3. Ob hom kev lag luam
Nws yog xim hlau chromium uas tsim industrially tuaj nyob rau hauv ob lub ntsiab:
Aluminothermic chromium: nyob rau hauv daim ntawv, ci silvery nyob rau hauv cov xim nrog ib tug metallic luster, nrog ib tug chromium ntsiab lus> 98%.
Electrolytic chromium: in flake form, with a dark brown surface; after hydrogen refining, the surface becomes bright, with higher purity (> 99%).
Tuam Tshoj pib tsim cov hlau chromium nyob rau hauv 1958, thiab Jinzhou Ferroalloy Cog tsim lub teb chaws thawj aluminothermic chromium chaw tsim khoom nyob rau hauv thaum ntxov 1960s.
