Los ntawm qhov kev xav ntawm keeb kwm ntawm kev loj hlob ntawm cov khoom siv hlau nplaum ruaj khov, cov pa roj carbon hlau siv thaum kawg ntawm lub xyoo pua 19th muaj cov khoom siv hluav taws xob sib nqus (BH) max (lub cev muaj zog uas ntsuas qhov sib nqus zog ceev khaws cia hauv cov hlau nplaum ruaj khov) tsawg dua. 1MGOe (megagauge), thaum txawv teb chaws pawg tsim Nd-Fe -B cov khoom siv hlau nplaum ruaj khov, cov khoom siv hluav taws xob sib nqus tau mus txog ntau dua 50MGOe. Nyob rau hauv lub xyoo pua dhau los, qhov remanence Br ntawm cov khoom siv tau zoo dua me ntsis, thiab kev txhim kho ntawm cov khoom siv hluav taws xob yog vim qhov kev txhim kho ntawm lub zog quab yuam Hc. Kev txhim kho ntawm kev coercivity yog vim qhov kev nkag siab ntawm nws qhov xwm txheej thiab kev tshawb pom ntawm high magnetocrystalline anisotropy compounds, nrog rau kev nce qib ntawm kev npaj technology.
Thaum pib ntawm lub xyoo pua nees nkaum, tib neeg feem ntau siv cov pa roj carbon steel, tungsten steel, chromium steel thiab cobalt steel ua cov khoom siv hlau nplaum ruaj khov. Nyob rau xyoo 1930s, txoj kev vam meej ntawm AlNiCo cov khoom siv hlau nplaum ruaj khov ua rau daim ntawv thov loj ntawm cov khoom siv hlau nplaum ruaj khov. Nyob rau xyoo 1950, qhov tshwm sim ntawm barium ferrite tsis tsuas yog txo tus nqi ntawm cov hlau nplaum ruaj khov, tab sis kuj tau nthuav dav daim ntawv thov ntau yam khoom siv hlau nplaum mus tas li mus rau qhov chaw siab. Hauv xyoo 1960, qhov tshwm sim ntawm lub ntiaj teb tsis tshua muaj cobalt hlau nplaum ruaj khov tau qhib lub sijhawm tshiab rau kev siv cov hlau nplaum ruaj khov.
Xyoo 1967, Strnat ntawm University of Dayton hauv Tebchaws Meskas tau ua tiav SmCo5 cov hlau nplaum ruaj khov los ntawm kev sib txuas ntawm cov hmoov sib txuas, cim qhov tuaj txog ntawm lub sijhawm ntawm lub ntiaj teb tsis tshua muaj hlau nplaum ruaj khov. Txog tam sim no, lub ntiaj teb tsis tshua muaj cov hlau nplaum ruaj khov tau ntsib thawj tiam ntawm SmCo5, lub cim thib ob ntawm nag lossis daus hardening hom Sm2Co17, thiab kev txhim kho ntawm peb tiam ntawm Nd-Fe-B cov khoom siv hlau nplaum ruaj khov.
Tsis tas li ntawd, Cu-Ni-Fe, Fe-Co-Mo, Fe-Co-V, MnBi, A1MnC alloys, thiab lwm yam tau siv los ua cov khoom siv hlau nplaum ruaj khov hauv keeb kwm. Cov alloys no tsis tshua muaj siv nyob rau hauv ntau zaus vim lawv cov kev ua haujlwm qis thiab tus nqi qis. Thiab AlNiCo, FeCrCo, PtCo thiab lwm yam alloys kuj siv rau qee lub sijhawm tshwj xeeb. Tam sim no, Ba thiab Sr ferrites tseem yog cov khoom siv hlau nplaum ruaj khov tshaj plaws, tab sis ntau ntawm lawv cov ntawv thov tau maj mam hloov los ntawm Nd-Fe-B cov ntaub ntawv. Ntxiv mus, tam sim no cov txiaj ntsig ntawm cov khoom siv hlau nplaum tsis tshua muaj hauv ntiaj teb tau dhau los ntawm cov khoom siv hlau nplaum ferrite mus tas li, thiab cov khoom siv hlau nplaum tsis tshua muaj hauv ntiaj teb tau tsim rau hauv kev lag luam loj.
