Hydrated alumina yog ib hom hydrated alumina compound dav siv hauv kev lag luam, khoom siv, kev tiv thaiv ib puag ncig, thiab tshuaj. Nws cov haujlwm tseem ceeb tuaj yeem raug sau tseg raws li hauv qab no:
nplaim retardant thiab muab tub lim muaj nuj nqi (feem ntau daim ntawv thov)
Hydrated alumina (tshwj xeeb tshaj yog trihydrated alumina Al(OH)₃) yog ib yam uas tsis yog - lom, halogen-dawb, ib puag ncig tus phooj ywg nplaim retardant, dav siv nyob rau hauv organic polymer cov ntaub ntawv xws li yas, roj hmab, cables, thiab unsaturated polyesters.
Nws nplaim retardant mechanism yog raws li nram no:
Endothermic decomposition: Thaum qhov kub siab tshaj 200 degree, hydrated alumina decomposes rau hauv alumina thiab dej (2Al(OH)₃ → Al₂O₃ + 3H₂O↑). Cov txheej txheem no absorbs ib tug loj npaum li cas ntawm tshav kub (kwv yees li 1967 kJ / kg), zoo inhibiting qhov kub ntawm cov khoom.
Dilution ntawm combustible gases: Cov dej vapor dilutes cov concentration ntawm oxygen thiab combustible gases, inhibiting kev sib kis ntawm combustion.
Tsim cov txheej txheej insulating: Residual alumina tsim ib txheej tuab inorganic ntawm cov khoom nto, cais cov pa oxygen los ntawm kev sib cuag nrog cov khoom sib txuas.
Tsis tas li ntawd, nws tseem ua haujlwm raws li kev muab tub lim, txhim kho cov khoom hardness, huab cua tsis kam, thiab kev ua haujlwm; cov nyiaj ntxiv tuaj yeem ncav cuag 30% -40%.
Kev npaj ntawm alumina ceramics thiab cov khoom siv ua haujlwm:
Hydrated alumina is a key precursor for preparing high-performance alumina ceramics. Through high-temperature calcination (>1273K), nws tuaj yeem hloov mus rau hauv -Al₂O₃, muaj cov thermal stability, siab zog, qis coefficient ntawm expansion, thiab zoo heev dielectric zog, thiab yog siv nyob rau hauv:
Electronic ceramics, cov ntaub ntawv refractory, sib tsoo xov xwm. Kev tswj tau ntawm nano-alumina, ua tiav los ntawm kev tswj cov txheej txheem kev npaj ntawm boehmite (boehmite monohydrate), tso cai rau kev tswj hwm ntawm qhov kawg alumina microstructure.
Catalysis thiab kev them nyiaj yug daim ntawv thov
Catalyst Supports: Hydrated alumina xws li boehmite thiab gibbsite muaj qhov tshwj xeeb ntawm qhov chaw thiab qhov porosity, thiab feem ntau yog siv los ua cov ntaub ntawv txhawb nqa catalyst hauv roj av catalytic cracking (FCC), automotive exhaust treatment, thiab hydrogenation reactions.
Activated Alumina Precursors: -Al₂O₃ (activated alumina), tau los ntawm dehydrating hydrated alumina, pom muaj zog adsorption thiab catalytic kev ua si thiab yog dav siv nyob rau hauv adsorbents, desiccants, catalyst txhawb, thiab lwm yam teb.
