Chii chinonzi corundum?

Corundum (Al2O3) ine zvakawanda zvakachengetwa zvakachengetwa, zvinotora chikamu che25% chehuremu hwepasi. Haidhuri uye ine zvinhu zvakawanda zvakanaka. Kune akawanda akasiyana makristasi eAl2O3, uye kune anopfuura gumi marudzi emhando dzakasiyana akashumwa, asi kune matatu makuru, anoti α-Al2O3, β-Al2O3, uye γ-Al2O3.

Tabular corundum

γ-Al2O3 is spinel structure, iyo isina kugadzikana pakupisa kwepamusoro uye haiwanzoshandiswa sechinhu chimwe chete. β-Al2O3 iine aluminate ine alkali simbi kana alkaline pasi simbi. Kemikari yaro inogona kuenzaniswa ne RO · 6Al2O3 uye R2O · 11Al2O3, hexagonal lattice, density 3.30 ~ 3.63g / cm3, 1400 ~ 1500 Inotanga kuora pa ℃ uye inoshandura kuita α-Al2O3 pa1600℃. α-Al2O3 imhando yepamusoro-yekushisa, ine tembiricha yakagadzikana yakakwira seyekunyungudika, uye density ye 3.96 ~ 4.01g / cm3, iyo inoenderana nekusachena kwemukati. Iyo unit cell iprism inopinza, iyo iripo muchimiro cheyakasikwa corundum, ruby ​​​​nesafire mune zvakasikwa. α-Al2O3 ine compact chimiro, yakaderera chiitiko, yakanaka magetsi zvivakwa, uye yakanakisa ma mechanical properties. Iyo Mohs yakaoma ndeye 9. α-Al2O3 ndeye hexagonal crystal system, corundum structure, a = 4.76, c = 12.99.

Al2O3 ine high mechanical simba. Iko kuchena kweAl2O3 kuumbwa, kunowedzera simba. Iyo yemagetsi simba inogona kushandiswa kugadzira mudziyo porcelain uye zvimwe zvemakanika zvikamu. Iyo resistivity yeAl2O3 yakakwirira, kushandiswa kwemagetsi ekudzivirira kwemagetsi kwakanaka, kupikisa pakupisa kwekamuri ndeye 1015Ω · cm, uye simba re dielectric 15kV / mm. Kushandisa kuvharwa kwayo uye simba, inogona kugadzirwa kuva substrates, sockets, spark plugs, circuit shells, etc. Al2O3 ine kuoma kwakanyanya, Mohs kuoma kwe9, pamwe nekunyanya kupfeka kusagadzikana, saka inoshandiswa zvakanyanya kugadzira zvishandiso, mavhiri ekukuya, mabrasives, kudhirowa kunofa, mabearings, kubereka makwenzi uye matombo anokosha. Al2O3 ine nzvimbo yakakwira yekunyungudika uye kushora. Iine nzvimbo yekunyungudika ye2050 ° C. Iine kumira zvakanaka pakukukurwa kwesimbi dzakanyungudutswa seBe, Sr, Ni, Al, V, Ti, Mn, Fe, CO uye sodium hydroxide, girazi, uye slag. Iyo inewo kupikisa kwakanyanya; haidyidzane neSi, P, Sb, Bi mumhepo inert, saka inogona kushandiswa sezvinhu zvinoramba, machubhu echoto, magirazi ekudhirowa macrucibles, mabhora asina maburi, fiber uye thermocouple inodzivirira inovhara, nezvimwe.

Al2O3 ine yakanakisa kugadzikana kwemakemikari. Mazhinji akaoma sulfides, phosphides, arsenides, chlorides, nitrides, bromides, iodides, yakaoma fluorides, sulfuric acid, hydrochloric acid, nitric acid, uye hydrofluoric acid haipindirani neAl2O3. Naizvozvo, inogona kugadzirwa kuita simbi yakachena uye imwechete yekristaro kukura crucibles, majoini evanhu, ekugadzira mapfupa, etc. Al2O3 ine optical properties uye inogona kugadzirwa kuva chiedza-transmitting zvinhu kugadzira Na vapor lamp tubes, microwave fairings, infrared windows uye laser. oscillation zvikamu. Iyo ionic conductivity yeAl2O3 inoshandiswa sechinhu chemasero ezuva uye mabhatiri ekuchengetedza. Al2O3 zvakare inowanzoshandiswa mune zvedongo pamusoro metallization tekinoroji.

Chikamu chikuru checrystalline chealumina-based fused corundum ndiyo chikamu checorundum ine saizi ye1.0-1.5mm uye makristasi akabatanidzwa. Mamwe ese anoteedzera huwandu hwerutile, alumina uye aluminium titanate, uye ari mukati mechikamu checorundum kana pakati pezvikamu zvekristaro. Chikamu chiduku chegirazi chikamu. MuChina, mushure memakore anopfuura gumi ekuedza kusingadzoreki, kunyungudutswa kwe bauxite-based fused corundum kwaita fambiro mberi huru, nehuwandu hwegore hwekugadzira hunopfuura matani 110,000. Bauxite-based fused corundum yakashandiswa zvakabudirira seyakagadzirwa kune dzakasiyana siyana zvidhinha zvakapfurwa uye zvisina kuumbwa zvimisikidzo. Semuenzaniso, inogona kutsiva dense corundum mukuputika kwevira remoto, uye inoshandiswa sematrix zvinhu uye granular zvinhu kugadzira yakaderera zvinokambaira. High alumina zvidhinha zvinoshandiswa kutsiva white corundum mune mamwe Al2O3-SiO2 refractories kugadzirira yakakwirira-inoshanda zvigadzirwa.

Brown corundum smelting inobva pamusimboti wekutanga wekuti aluminium ine hukama hukuru hweokisijeni kupfuura iron, silicon, titanium, nezvimwewo. Nokudzora huwandu hwekudzikisa agent, tsvina huru mubauxite inoderedzwa nekuderedza kunyunguduka, uye kusvibiswa kwakaderedzwa kunogadzira. ferrosilicon alloys. Inoparadzaniswa kubva kune corundum melt kuti iwane brown corundum ine crystal quality inosangana nezvinodiwa uye Al2O3 zvinyorwa zvakakura kudarika 94.5%. Fe2O3 yakaderedzwa kuti ibudise ferrosilicon alloy uye inobviswa panguva yekunyunguduka, asi shoma shoma yesimbi oxide uye alumina inogadzirwa spinel ichiri kusara muchigadzirwa. TiO2 yakaderedzwa zvishoma mu ferrosilicon alloy panguva yekunyungudutsa, uye chikamu chikuru chayo chinoramba chiri mubrown corundum, iyo ndiyo inonyanya kukosha mukuvara kwebrown corundum. CaO neMgO zvakaoma kudzikisa panguva yekunyungudika, uye mazhinji eCaO neMgO mune zvigadzirwa zvichiripo muchigadzirwa. Kunyange zvazvo Na2O neK2O inogona kunyungudika pakupisa kwepamusoro panguva yekunyunguduka, haigoni kuderedzwa uye inoramba iri mu corundum yebrown, iyo ine simba guru pahutano.

Brown corundum

Iyo mbishi yebrown corundum inoumbwa nea-alumina crystal tsanga uye diki chikamu chegirazi, α-alumina makristasi anoumbwa neAl2O3 yakasimba mhinduro ine Ti2O3, uye chikamu chegirazi chinonyanya kuumbwa titanium dioxide uye silicon dioxide nezvimwe. tsvaga oxidation iripo muchoto chemagetsi arc.物组合。 Material composition. Aya maokisisi anoumba chikamu chegirazi, uye anongova nekunyungudika kwakaderera muchimiro chekristaro chealumina tsanga. Ti2O3 ndiyo yega oxide iyo Ti inogona kunyungudika mualuminium tsanga. TiO2 ndiyo thermodynamically stable oxide yeTi. Munguva yekunyungudutswa uye kuderedzwa kwebrown corundum, chikamu cheTiO2 chinoderedzwa kuita sub-oxidation yetitanium. (Ti2O3), pamusoro pe1000 ℃, okisijeni inogona kupararira muGa-alumina tsanga, oxidize Ti2O3 muTiO2 yakagadzikana uye yobva yaiputira muiyo α-alumina tsanga, saka mazhinji etitanium dioxide i α-alumina Mhinduro yakasimba yekristaro. zviyo zviripo.

Iyo yakawandisa TiO2 mubrown corundum haigone kuramba iri muchikamu chegirazi, asi inopindirana nealuminium kuita aluminium titanate (TiO2 · Al2O3). Aluminium titanate ndiyo chikamu chechitatu pane interface pakati pe-α-alumina zviyo uye chikamu chegirazi; Kuoma kwebrown corundum kunowedzera nekukura kweTiO2 crystal nuclei. Iyo TiO2 chikamu chakapararira zvakafanana mu α-alumina crystal tsanga inoomesa iyo α-alumina zvidimbu. Brown corundum yakasimba mhinduro Ti2O3 inoita kuti brown corundum iite sebhuruu.

Iyo mbishi yebrown corundum inoumbwa nea-alumina crystal tsanga uye diki chikamu chegirazi, α-alumina makristasi anoumbwa neAl2O3 yakasimba mhinduro ine Ti2O3, uye chikamu chegirazi chinonyanya kuumbwa titanium dioxide uye silicon dioxide nezvimwe. tsvaga oxidation iripo muchoto chemagetsi arc.物组合。 Material composition. Aya maokisisi anoumba chikamu chegirazi, uye anongova nekunyungudika kwakaderera muchimiro chekristaro chealumina tsanga.

Ti2O3 ndiyo yega oxide iyo Ti inogona kunyungudika mualuminium tsanga. TiO2 ndiyo thermodynamically stable oxide yeTi. Munguva yekunyungudutswa uye kuderedzwa kwebrown corundum, chikamu cheTiO2 chinoderedzwa kuita sub-oxidation yetitanium. (Ti2O3), pamusoro pe1000 ℃, okisijeni inogona kupararira muGa-alumina tsanga, oxidize Ti2O3 muTiO2 yakagadzikana uye yobva yaiputira muiyo α-alumina tsanga, saka mazhinji etitanium dioxide i α-alumina Mhinduro yakasimba yekristaro. zviyo zviripo. Iyo yakawandisa TiO2 mubrown corundum haigone kuramba iri muchikamu chegirazi, asi inopindirana nealuminium kuumba aluminium titanate (TiO2 · Al2O3). Aluminium titanate ndiyo chikamu chechitatu pane interface pakati pe-α-alumina zviyo uye chikamu chegirazi; Kuoma kwebrown corundum kunowedzera nekukura kweTiO2 crystal nuclei. Iyo TiO2 chikamu chakapararira zvakafanana mu α-alumina crystal tsanga inoomesa iyo α-alumina zvidimbu. Brown corundum yakasimba mhinduro Ti2O3 inoita kuti brown corundum iite sebhuruu.