{"id":1368,"date":"2024-10-25T08:34:58","date_gmt":"2024-10-25T08:34:58","guid":{"rendered":"https:\/\/nbaem.com\/?p=1368"},"modified":"2024-10-25T08:36:15","modified_gmt":"2024-10-25T08:36:15","slug":"how-to-make-ndfeb-magnet","status":"publish","type":"post","link":"https:\/\/nbaem.com\/cs\/how-to-make-ndfeb-magnet\/","title":{"rendered":"Jak vyrobit NdFeB magnet"},"content":{"rendered":"
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Neodymov\u00fd magnet<\/a> <\/span>st\u00e1le je nejv\u00fdkonn\u011bj\u0161\u00edm a nej\u010dast\u011bji pou\u017e\u00edvan\u00fdm vz\u00e1cn\u00fdm zemn\u00edm pevn\u00fdm magnetem v sou\u010dasnosti. Magnet z neodymu lze rozd\u011blit na sinterovan\u00fd magnet z neodymu, v\u00e1zan\u00fd magnet z neodymu a za tepla stla\u010den\u00fd magnet z neodymu podle v\u00fdrobn\u00edho procesu. Ka\u017ed\u00e1 forma m\u00e1 odli\u0161n\u00e9 magnetick\u00e9 vlastnosti, jejich p\u0159ekr\u00fdvaj\u00edc\u00ed se pou\u017eit\u00ed je proto omezen\u00e9 a maj\u00ed sp\u00ed\u0161e dopl\u0148kov\u00fd vztah. U\u017eivatel\u00e9 magnet\u016f se ptaj\u00ed, jak jsou magnety z neodymu vyr\u00e1b\u011bny. Sinterovan\u00fd magnet z neodymu je vyr\u00e1b\u011bn tradi\u010dn\u00edm pr\u00e1\u0161kov\u00fdm metalurgick\u00fdm procesem a zauj\u00edm\u00e1 absolutn\u00ed p\u0159evahu na trhu.<\/span><\/p>\n<\/div>\n<\/div>\n

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Jak se vyr\u00e1b\u011bj\u00ed neodymov\u00e9 magnety?<\/strong><\/p>\n

Sinterovan\u00fd neodymov\u00fd magnet je p\u0159ipraven tak, \u017ee suroviny jsou roztaveny pod vakuem nebo inertn\u00ed atmosf\u00e9rou v induk\u010dn\u00ed peci, pot\u00e9 zpracov\u00e1ny v p\u00e1sov\u00e9 lince a ochlazeny za vzniku p\u00e1su slitiny Nd-Fe-B. P\u00e1sy slitiny jsou drceny na jemn\u00fd pr\u00e1\u0161ek s pr\u016fm\u011brem n\u011bkolika mikron\u016f. Tento jemn\u00fd pr\u00e1\u0161ek je n\u00e1sledn\u011b zhutn\u011bn v orienta\u010dn\u00edm magnetick\u00e9m poli a sintrov\u00e1n do hust\u00fdch t\u011bles. T\u011blesa jsou pot\u00e9 obr\u00e1b\u011bna do po\u017eadovan\u00fdch tvar\u016f, povrchov\u011b upravena a magnetizov\u00e1na.<\/p>\n

V\u00e1\u017een\u00ed<\/strong><\/p>\n

V\u00e1\u017een\u00ed kvalifikovan\u00e9ho surov\u00e9ho materi\u00e1lu je p\u0159\u00edmo spojeno s p\u0159esnost\u00ed slo\u017een\u00ed magnetu. \u010cistota surov\u00e9ho materi\u00e1lu a stabilita chemick\u00e9ho slo\u017een\u00ed jsou z\u00e1kladem kvality v\u00fdrobku. Sinterovan\u00fd neodymov\u00fd magnet obvykle vol\u00ed vz\u00e1cn\u00e9 zeminov\u00e9 slitiny jako Praseodym-Neodym Pr-Nd mischmetal, Lanthanum-Cerium La-Ce mischmetal a Dysprosium-\u017delezo Dy-Fe slitinu jako materi\u00e1l z d\u016fvodu n\u00e1kladov\u00e9 efektivnosti. Vy\u0161\u0161\u00ed bod t\u00e1n\u00ed maj\u00ed prvky jako Bor, Molybden nebo Niob, kter\u00e9 jsou p\u0159id\u00e1v\u00e1ny ve form\u011b ferroaloy. Vrstva rzi, inkluze, oxidy a ne\u010distoty na povrchu surov\u00e9ho materi\u00e1lu mus\u00ed b\u00fdt odstran\u011bny pomoc\u00ed mikrobrusn\u00e9ho stroje. Nav\u00edc by m\u011bl b\u00fdt surov\u00fd materi\u00e1l ve vhodn\u00e9 velikosti, aby byla zaji\u0161t\u011bna \u00fa\u010dinnost v n\u00e1sledn\u00e9m tav\u00edc\u00edm procesu. Neodym m\u00e1 n\u00edzk\u00fd parci\u00e1ln\u00ed tlak a aktivn\u00ed chemick\u00e9 vlastnosti, proto vz\u00e1cn\u00e9 zeminov\u00e9 kovy b\u011bhem taven\u00ed podl\u00e9haj\u00ed ur\u010dit\u00e9mu \u00fabytku odpa\u0159ov\u00e1n\u00edm a oxidac\u00ed, a proto by v\u00e1\u017een\u00ed sinterovan\u00e9ho neodymov\u00e9ho magnetu m\u011blo zohlednit p\u0159id\u00e1n\u00ed dal\u0161\u00edho vz\u00e1cn\u00e9ho zeminov\u00e9ho kovu, aby byla zaji\u0161t\u011bna p\u0159esnost slo\u017een\u00ed magnetu.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

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Taven\u00ed a odl\u00e9v\u00e1n\u00ed p\u00e1sovou technologi\u00ed<\/strong><\/p>\n<\/div>\n<\/div>\n

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Taven\u00ed a odl\u00e9v\u00e1n\u00ed p\u00e1sovou technologi\u00ed je kl\u00ed\u010dov\u00e9 pro slo\u017een\u00ed, krystalickou strukturu a rozlo\u017een\u00ed f\u00e1z\u00ed, a t\u00edm ovliv\u0148uje n\u00e1sledn\u00fd proces a magnetickou v\u00fdkonnost. Surov\u00e1 hmota je zah\u0159\u00edv\u00e1na na tavn\u00fd stav pomoc\u00ed st\u0159edofrekven\u010dn\u00edho a n\u00edzkofrekven\u010dn\u00edho induk\u010dn\u00edho taven\u00ed za vakuov\u00fdch nebo inertn\u00edch podm\u00ednek. Odl\u00e9v\u00e1n\u00ed lze prov\u00e1d\u011bt, kdy\u017e se slitina roztav\u00ed, dos\u00e1hne homogenizace, odplyn\u011bn\u00ed a odstra\u0148ov\u00e1n\u00ed strusky. Dobr\u00e1 mikrostruktura odlitku by m\u011bla m\u00edt dob\u0159e rostouc\u00ed a jemnozrnnou sloupcovou krystalickou strukturu, p\u0159i\u010dem\u017e f\u00e1ze bohat\u00e1 na Nd by m\u011bla b\u00fdt rozlo\u017eena pod\u00e9l hranic zrn. Nav\u00edc mikrostruktura odlitku by m\u011bla b\u00fdt bez f\u00e1ze \u03b1-Fe. Diagram f\u00e1zov\u00e9 rovnov\u00e1hy Re-Fe nazna\u010duje, \u017ee tern\u00e1rn\u00ed slitina vz\u00e1cn\u00fdch zemin je nevyhnuteln\u00e1 pro vznik f\u00e1ze \u03b1-Fe p\u0159i pomal\u00e9m ochlazov\u00e1n\u00ed. Magnetick\u00e9 vlastnosti p\u0159i pokojov\u00e9 teplot\u011b f\u00e1ze \u03b1-Fe v\u00e1\u017en\u011b naru\u0161uj\u00ed magnetickou v\u00fdkonnost magnetu, a proto mus\u00ed b\u00fdt inhibov\u00e1ny rychl\u00fdm ochlazov\u00e1n\u00edm. Aby bylo mo\u017en\u00e9 dos\u00e1hnout po\u017eadovan\u00e9ho efektu rychl\u00e9ho ochlazen\u00ed a potla\u010dit tvorbu f\u00e1ze \u03b1-Fe, vyvinula spole\u010dnost Showa Denko K. K. technologii p\u00e1sov\u00e9ho odl\u00e9v\u00e1n\u00ed, kter\u00e1 se brzy stala rutinn\u00ed technologi\u00ed v odv\u011btv\u00ed. Rovnom\u011brn\u00e9 rozlo\u017een\u00ed f\u00e1ze bohat\u00e9 na Nd a jej\u00ed inhibi\u010dn\u00ed \u00fa\u010dinek na f\u00e1zi \u03b1-Fe mohou efektivn\u011b sn\u00ed\u017eit celkov\u00fd obsah vz\u00e1cn\u00fdch zemin, co\u017e je p\u0159\u00edzniv\u00e9 pro v\u00fdrobu vysoce v\u00fdkonn\u00fdch magnet\u016f a sni\u017eov\u00e1n\u00ed n\u00e1klad\u016f.<\/p>\n

Degradace vod\u00edkem<\/strong><\/p>\n<\/div>\n<\/div>\n

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Chov\u00e1n\u00ed hydrogenace vz\u00e1cn\u00fdch zemin, slitin nebo intermetalick\u00fdch slou\u010denin a fyzik\u00e1ln\u011b-chemick\u00e9 vlastnosti hydridu byly v\u017edy d\u016fle\u017eit\u00fdmi ot\u00e1zkami p\u0159i vyu\u017eit\u00ed vz\u00e1cn\u00fdch zemin. Tavenina slitiny Nd-Fe-B tak\u00e9 vykazuje velmi silnou tendenci k hydrogenaci. Atomy vod\u00edku vstupuj\u00ed do mezist\u011bnn\u00e9ho m\u00edsta mezi hlavn\u00ed f\u00e1z\u00ed intermetalick\u00e9 slou\u010deniny a f\u00e1z\u00ed zrn bohatou na Nd a vytv\u00e1\u0159ej\u00ed mezist\u011bnnou slou\u010deninu. Pot\u00e9 se zv\u00fd\u0161\u00ed vzd\u00e1lenost mezi atomy a roz\u0161\u00ed\u0159\u00ed se m\u0159\u00ed\u017ekov\u00fd objem. V\u00fdsledn\u00e9 vnit\u0159n\u00ed nap\u011bt\u00ed zp\u016fsob\u00ed prask\u00e1n\u00ed zrn (mezizrnn\u00e9 prask\u00e1n\u00ed), prask\u00e1n\u00ed krystal\u016f (transkrystalick\u00e9 prask\u00e1n\u00ed) nebo ductiln\u00ed prask\u00e1n\u00ed. Tato prask\u00e1n\u00ed, doprov\u00e1zen\u00e1 prask\u00e1n\u00edm, jsou zn\u00e1m\u00e1 jako hydrogenace. Proces hydrogenace sinterovan\u00e9ho neodymiov\u00e9ho magnetu je tak\u00e9 ozna\u010dov\u00e1n jako HD proces. Prask\u00e1n\u00ed zrn a prask\u00e1n\u00ed krystal\u016f vznikaj\u00edc\u00ed p\u0159i procesu hydrogenace zp\u016fsobuj\u00ed NdFeB pr\u00e1\u0161kov\u00fd kurz velmi k\u0159ehk\u00fd a vysoce v\u00fdhodn\u00fd pro n\u00e1sledn\u00fd proces trysk\u00e1n\u00ed. Krom\u011b zv\u00fd\u0161en\u00ed \u00fa\u010dinnosti procesu trysk\u00e1n\u00ed je proces dekrepitace vod\u00edkem tak\u00e9 p\u0159\u00edzniv\u00fd pro \u00fapravu pr\u016fm\u011brn\u00e9 velikosti pr\u00e1\u0161ku jemn\u00e9ho pr\u00e1\u0161ku.<\/span><\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

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Tryskov\u00e9 mlet\u00ed<\/strong><\/p>\n

Tryskov\u00e9 mlet\u00ed se uk\u00e1zalo jako nejprakti\u010dt\u011bj\u0161\u00ed a nejefektivn\u011bj\u0161\u00ed \u0159e\u0161en\u00ed v procesu pr\u00e1\u0161kov\u00e1n\u00ed. Tryskov\u00e9 mlet\u00ed vyu\u017e\u00edv\u00e1 vysokorychlostn\u00ed proud inertn\u00edho plynu k urychlen\u00ed hrub\u00e9ho pr\u00e1\u0161ku na supersonickou rychlost a k n\u00e1razu pr\u00e1\u0161ku do sebe navz\u00e1jem. Z\u00e1kladn\u00edm c\u00edlem procesu pr\u00e1\u0161kov\u00e1n\u00ed je hled\u00e1n\u00ed vhodn\u00e9 pr\u016fm\u011brn\u00e9 velikosti \u010d\u00e1stic a rozlo\u017een\u00ed velikosti \u010d\u00e1stic. Rozd\u00edly v\u00fd\u0161e uveden\u00fdch vlastnost\u00ed se projevuj\u00ed odli\u0161n\u00fdmi charakteristikami na makroskopick\u00fdch \u0161k\u00e1l\u00e1ch, co\u017e p\u0159\u00edmo ovliv\u0148uje pln\u011bn\u00ed pr\u00e1\u0161ku, orientaci, zhutn\u011bn\u00ed, demont\u00e1\u017e a mikrostrukturu vznikaj\u00edc\u00ed p\u0159i sinterov\u00e1n\u00ed, a t\u00edm pak citliv\u011b ovliv\u0148uje magnetickou v\u00fdkonnost, mechanick\u00e9 vlastnosti, termoelektrick\u00e9 vlastnosti a chemickou stabilitu sinterovan\u00e9ho magnetu na Neodymu. Ide\u00e1ln\u00ed mikrostruktura je jemn\u00e1 a jednotn\u00e1 hlavn\u00ed f\u00e1ze zrn obklopen\u00e1 hladkou a tenkou p\u0159\u00eddavnou f\u00e1z\u00ed. Krom\u011b toho by m\u011bla b\u00fdt snadn\u00e1 orientace magnetiza\u010dn\u00edho sm\u011bru hlavn\u00edho zrna v souladu s orienta\u010dn\u00edm sm\u011brem co nejv\u00edce. Dutiny, velk\u00e1 zrna nebo m\u011bkk\u00e1 magnetick\u00e1 f\u00e1ze povedou k v\u00fdrazn\u00e9mu sn\u00ed\u017een\u00ed vnit\u0159n\u00ed koercivity. Remanence a \u010dtvercov\u00fd tvar k\u0159ivky demagnetizace se sou\u010dasn\u011b sn\u00ed\u017e\u00ed, pokud se orienta\u010dn\u00ed sm\u011br zrna odch\u00fdl\u00ed od sm\u011bru orientace. Proto by m\u011bly b\u00fdt slitiny rozdrceny na jednosm\u011brn\u00e1 zrna o pr\u016fm\u011bru od 3 do 5 mikron\u016f.<\/p>\n

Zhutn\u011bn\u00ed<\/strong><\/p>\n<\/div>\n<\/div>\n

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Orientace magnetick\u00e9ho pole p\u0159i kompaktaci se ozna\u010duje jako vyu\u017eit\u00ed interakce mezi magnetick\u00fdm pr\u00e1\u0161kem a vn\u011bj\u0161\u00edm magnetick\u00fdm polem k zarovn\u00e1n\u00ed pr\u00e1\u0161ku pod\u00e9l sm\u011bru snadn\u00e9ho magnetizace a k zaji\u0161t\u011bn\u00ed shody s kone\u010dn\u00fdm sm\u011brem magnetizace. Orientace magnetick\u00e9ho pole p\u0159i kompaktaci je nejb\u011b\u017en\u011bj\u0161\u00ed cestou k v\u00fdrob\u011b anizotropn\u00edho magnetu. Slitina Nd-Fe-B byla v p\u0159edchoz\u00edm procesu tryskac\u00edho mlet\u00ed rozdrcena na \u010d\u00e1stice monokrystalick\u00e9ho typu. Monokrystalick\u00e1 \u010d\u00e1stice m\u00e1 uniaxi\u00e1ln\u00ed anizotropii a ka\u017ed\u00e1 z nich m\u00e1 pouze jeden snadn\u00fd sm\u011br magnetizace. Magnetick\u00fd pr\u00e1\u0161ek se p\u0159i p\u016fsoben\u00ed vn\u011bj\u0161\u00edho magnetick\u00e9ho pole p\u0159em\u011bn\u00ed z v\u00edcedom\u00e9nov\u00e9ho na jedno dom\u00e9nov\u00e9. Magnetick\u00e9 pole po voln\u00e9m napln\u011bn\u00ed do formy, pot\u00e9 upravit sm\u011br snadn\u00e9 magnetizace osy c tak, aby byl v souladu s vn\u011bj\u0161\u00edm magnetick\u00fdm polem prost\u0159ednictv\u00edm ot\u00e1\u010den\u00ed nebo posunu. Osa c slitiny pr\u00e1\u0161ku v podstat\u011b zachovala sv\u016fj uspo\u0159\u00e1d\u00e1n\u00ed b\u011bhem procesu zhutn\u011bn\u00ed. Zhutn\u011bn\u00e9 d\u00edly by m\u011bly p\u0159ed demont\u00e1\u017e\u00ed podstoupit demagnetiza\u010dn\u00ed o\u0161et\u0159en\u00ed. Nejv\u00fdznamn\u011bj\u0161\u00edm ukazatelem procesu zhutn\u011bn\u00ed je stupe\u0148 orientace. Stupe\u0148 orientace sintrovan\u00fdch magnet\u016f neodymu je ur\u010den r\u016fzn\u00fdmi faktory, v\u010detn\u011b intenzity orienta\u010dn\u00edho magnetick\u00e9ho pole, velikosti \u010d\u00e1stic, zd\u00e1nliv\u00e9 hustoty, metody zhutn\u011bn\u00ed, tlaku zhutn\u011bn\u00ed atd.<\/span><\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

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Sinterov\u00e1n\u00ed<\/strong><\/p>\n<\/div>\n<\/div>\n

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Hustota zhutn\u011bn\u00e9 \u010d\u00e1sti m\u016f\u017ee po procesu sinterov\u00e1n\u00ed za vysok\u00e9ho vakua nebo \u010dist\u00e9 inertn\u00ed atmosf\u00e9ry dos\u00e1hnout v\u00edce ne\u017e 95% teoretick\u00e9 hustoty. Proto jsou vylou\u010deny vzduchov\u00e9 mezery v sinterovan\u00e9m Nd magnetu, co\u017e zaji\u0161\u0165uje jednotnost magnetick\u00e9ho toku a chemickou stabilitu. Jeliko\u017e jsou permanentn\u00ed magnetick\u00e9 vlastnosti sinterovan\u00e9ho Nd magnetu \u00fazce spjaty s jeho mikrostrukturou, je tepeln\u00e9 zpracov\u00e1n\u00ed po procesu sinterov\u00e1n\u00ed tak\u00e9 kl\u00ed\u010dov\u00e9 pro \u00fapravu magnetick\u00e9ho v\u00fdkonu, zejm\u00e9na vnit\u0159n\u00ed koercivity. F\u00e1ze na hranici zrn bohat\u00e1 na Nd slou\u017e\u00ed jako kapaln\u00e1 f\u00e1ze, kter\u00e1 m\u016f\u017ee podporovat sinterovac\u00ed reakci a obnovovat povrchov\u00e9 defekty na hlavn\u00edm zrnku f\u00e1ze. Teplota sinterov\u00e1n\u00ed Nd magnetu se obvykle pohybuje od 1050 do 1180 stup\u0148\u016f Celsia. P\u0159\u00edli\u0161 vysok\u00e1 teplota povede ke zv\u011bt\u0161en\u00ed zrn a sn\u00ed\u017een\u00ed vnit\u0159n\u00ed koercivity. Pro dosa\u017een\u00ed ide\u00e1ln\u00ed vnit\u0159n\u00ed koercivity, rovnosti k\u0159ivky demagnetizace a vysokoteplotn\u00ed nevratn\u00e9 ztr\u00e1ty je obvykle nutn\u00e9 prov\u00e9st dvoustup\u0148ov\u00e9 tempera\u010dn\u00ed tepeln\u00e9 zpracov\u00e1n\u00ed p\u0159i 900 a 500 stupn\u00edch Celsia.<\/p>\n

Obr\u00e1b\u011bn\u00ed<\/strong><\/p>\n

Krom\u011b b\u011b\u017en\u00e9ho tvaru st\u0159edn\u00ed velikosti je sintrovan\u00fd neodymov\u00fd magnet obt\u00ed\u017en\u00e9 p\u0159\u00edmo dos\u00e1hnout po\u017eadovan\u00e9ho tvaru a rozm\u011brov\u00e9 p\u0159esnosti najednou kv\u016fli technick\u00fdm omezen\u00edm v procesu orientace magnetick\u00e9ho pole p\u0159i kompakci, a proto je obr\u00e1b\u011bn\u00ed nevyhnuteln\u00fdm procesem u sintrovan\u00e9ho neodymov\u00e9ho magnetu. Jako typick\u00fd keramick\u00fd materi\u00e1l je sintrovan\u00fd neodymov\u00fd magnet pom\u011brn\u011b tvrd\u00fd a k\u0159ehk\u00fd, a proto je mo\u017en\u00e9 jej obr\u00e1b\u011bt pouze \u0159ez\u00e1n\u00edm, vrt\u00e1n\u00edm a brou\u0161en\u00edm. pou\u017eiteln\u00e9 pro jeho obr\u00e1b\u011bn\u00ed mezi konven\u010dn\u00edmi obr\u00e1b\u011bc\u00edmi technologiemi. N\u016f\u017eky na \u0159ez\u00e1n\u00ed obvykle vyu\u017e\u00edvaj\u00ed diamantov\u00e9 nebo CBN pota\u017een\u00e9 \u010depele. \u0158ez\u00e1n\u00ed dr\u00e1tem a laserov\u00e9 \u0159ez\u00e1n\u00ed jsou vhodn\u00e9 pro obr\u00e1b\u011bn\u00ed speci\u00e1ln\u011b tvarovan\u00fdch magnet\u016f, av\u0161ak jsou kritizov\u00e1ny za n\u00edzkou v\u00fdrobn\u00ed efektivitu a vysok\u00e9 n\u00e1klady na zpracov\u00e1n\u00ed. Proces vrt\u00e1n\u00ed sintrovan\u00e9ho neodymov\u00e9ho magnetu prim\u00e1rn\u011b vyu\u017e\u00edv\u00e1 diamant nebo laser. Je nutn\u00e9 zvolit proces trepanning, kdy\u017e je vnit\u0159n\u00ed otvor prstence v\u011bt\u0161\u00ed ne\u017e 4 mm. Jako vedlej\u0161\u00ed produkt v procesu trepanningu lze pou\u017eit\u00fd j\u00e1dro trepanned pou\u017e\u00edt k v\u00fdrob\u011b jin\u00fdch vhodn\u00fdch men\u0161\u00edch magnet\u016f, \u010d\u00edm\u017e se v\u00fdrazn\u011b zv\u00fd\u0161\u00ed vyu\u017eit\u00ed materi\u00e1lu. Brusn\u00fd kotou\u010d pro kop\u00edrov\u00e9 brou\u0161en\u00ed je vyr\u00e1b\u011bn na z\u00e1klad\u011b brusn\u00e9ho povrchu.<\/span><\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

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Povrchov\u00e1 \u00faprava<\/strong><\/p>\n<\/div>\n<\/div>\n

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Ochrann\u00e1 povrchov\u00e1 \u00faprava je nezbytn\u00fdm krokem u neodymov\u00fdch magnet\u016f, zejm\u00e9na u sintrovan\u00fdch neodymov\u00fdch magnet\u016f. Sintrovan\u00fd neodymov\u00fd magnet m\u00e1 v\u00edcef\u00e1zovou mikrostrukturu a skl\u00e1d\u00e1 se z hlavn\u00ed f\u00e1ze Nd2Fe14B, Nd bohat\u00e9 f\u00e1ze a B bohat\u00e9 f\u00e1ze. Nd bohat\u00e1 f\u00e1ze vykazuje velmi silnou tendenci k oxidaci a bude tvo\u0159it prim\u00e1rn\u00ed baterii s hlavn\u00ed f\u00e1z\u00ed za vlhk\u00e9ho prost\u0159ed\u00ed. Mal\u00e9 mno\u017estv\u00ed substitu\u010dn\u00edch prvk\u016f m\u016f\u017ee zv\u00fd\u0161it chemickou stabilitu magnet\u016f, av\u0161ak za cenu sn\u00ed\u017een\u00ed magnetick\u00fdch vlastnost\u00ed. Proto je ochrana sintrovan\u00e9ho neodymov\u00e9ho magnetu prim\u00e1rn\u011b zam\u011b\u0159ena na jeho povrch. Povrchov\u00e1 \u00faprava sintrovan\u00e9ho neodymov\u00e9ho magnetu m\u016f\u017ee b\u00fdt rozd\u011blena na mokrou a suchou metodu. Mokr\u00e1 metoda znamen\u00e1, \u017ee magnety jsou zpracov\u00e1v\u00e1ny s povrchovou ochranou v \u010dist\u00e9 vod\u011b nebo roztoku. Mokr\u00e1 metoda zahrnuje fosf\u00e1tov\u00e1n\u00ed, elektrolytick\u00e9 pokovov\u00e1n\u00ed, chemick\u00e9 pokovov\u00e1n\u00ed, electrophoretick\u00e9 pokovov\u00e1n\u00ed, st\u0159\u00edk\u00e1n\u00ed a pono\u0159en\u00ed. Such\u00e1 metoda znamen\u00e1, \u017ee magnety jsou zpracov\u00e1v\u00e1ny povrchovou ochranou prost\u0159ednictv\u00edm fyzik\u00e1ln\u00edch nebo chemick\u00fdch proces\u016f bez kontaktu s roztokem. Such\u00e1 metoda obvykle zahrnuje fyzik\u00e1ln\u00ed depozici par (PVD) a chemickou depozici par (CVD).<\/p>\n

Magnetizace<\/strong><\/p>\n<\/div>\n<\/div>\n

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V\u011bt\u0161ina permanentn\u00edch magnet\u016f je p\u0159ed pou\u017eit\u00edm magnetizov\u00e1na. Proces magnetizace spo\u010d\u00edv\u00e1 v aplikaci magnetick\u00e9ho pole ve sm\u011bru orientace permanentn\u00edho magnetu a dosa\u017een\u00ed technick\u00e9 saturace s rostouc\u00ed vn\u011bj\u0161\u00ed magnetickou silou. Ka\u017ed\u00fd typ permanentn\u00edho magnetick\u00e9ho materi\u00e1lu pot\u0159ebuje odli\u0161nou magnetickou s\u00edlu k dosa\u017een\u00ed technick\u00e9 saturace v magnetiza\u010dn\u00edm sm\u011bru. Remanence a vnit\u0159n\u00ed koercivita budou ni\u017e\u0161\u00ed ne\u017e jejich odpov\u00eddaj\u00edc\u00ed hodnoty, pokud vn\u011bj\u0161\u00ed magnetick\u00e1 s\u00edla nedos\u00e1hne technick\u00e9 saturace. Permanentn\u00ed magnet lze rozd\u011blit na isotropn\u00ed a anizotropn\u00ed podle toho, zda m\u00e1 snadn\u00fd magnetiza\u010dn\u00ed sm\u011br nebo ne. Jako anizotropn\u00ed magnet s vysokou vnit\u0159n\u00ed koercivitou je sintrovan\u00fd neodymov\u00fd magnet nutno magnetizovat impulzn\u00ed magnetizac\u00ed. Kondenz\u00e1tor bude nabit po usm\u011brn\u011bn\u00ed, pot\u00e9 elektrick\u00e1 energie v kondenz\u00e1toru okam\u017eit\u011b vybije do magnetiza\u010dn\u00edho za\u0159\u00edzen\u00ed. Magnetiza\u010dn\u00ed za\u0159\u00edzen\u00ed m\u016f\u017ee generovat pulzn\u00ed magnetick\u00e9 pole b\u011bhem okam\u017eit\u00e9ho pr\u016fchodu siln\u00e9ho proudu. Proto bude permanentn\u00ed magnet v c\u00edvce magnetizov\u00e1n. Na sintrovan\u00e9m neodymov\u00e9m magnetu lze dos\u00e1hnout r\u016fzn\u00fdch vzor\u016f magnetizace, pokud nejsou v rozporu s jeho orienta\u010dn\u00edm sm\u011brem.<\/span><\/p>\n<\/div>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"

Neodymov\u00fd magnet je st\u00e1le nejsiln\u011bj\u0161\u00ed a nej\u010dast\u011bji pou\u017e\u00edvan\u00fd vz\u00e1cnozemn\u00ed permanentn\u00ed magnetick\u00fd materi\u00e1l v sou\u010dasnosti. Neodymov\u00fd magnet lze rozd\u011blit na sinterovan\u00fd neodymov\u00fd magnet, v\u00e1zan\u00fd neodymov\u00fd magnet a za tepla stla\u010den\u00fd neodymov\u00fd magnet podle v\u00fdrobn\u00edho procesu. Ka\u017ed\u00e1 forma m\u00e1 odli\u0161n\u00e9 magnetick\u00e9 vlastnosti, pak jejich p\u0159ekryv [\u2026]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_mi_skip_tracking":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-1368","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/nbaem.com\/cs\/wp-json\/wp\/v2\/posts\/1368","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nbaem.com\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nbaem.com\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nbaem.com\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/nbaem.com\/cs\/wp-json\/wp\/v2\/comments?post=1368"}],"version-history":[{"count":3,"href":"https:\/\/nbaem.com\/cs\/wp-json\/wp\/v2\/posts\/1368\/revisions"}],"predecessor-version":[{"id":1371,"href":"https:\/\/nbaem.com\/cs\/wp-json\/wp\/v2\/posts\/1368\/revisions\/1371"}],"wp:attachment":[{"href":"https:\/\/nbaem.com\/cs\/wp-json\/wp\/v2\/media?parent=1368"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nbaem.com\/cs\/wp-json\/wp\/v2\/categories?post=1368"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nbaem.com\/cs\/wp-json\/wp\/v2\/tags?post=1368"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}