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    Process for stabilizing ferromagnetic chromium dioxide
    1.
    发明公开
    Process for stabilizing ferromagnetic chromium dioxide 失效
    一种用于稳定铁磁性二氧化铬的过程。

    公开(公告)号：EP0029687A1

    公开(公告)日：1981-06-03

    申请号：EP80304081.5

    申请日：1980-11-13

    申请人： Montedison S.p.A.

    发明人： Basile, Giampiero ,  Boero, Giancarlo ,  Mello Ceresa, Emiliano ,  Montino, Franco

    IPC分类号： H01F1/11 ,  C01G37/027

    CPC分类号： G11B5/70636 ,  C01G37/027 ,  C01P2006/42

    摘要： This invention relates to a process for stabilizing ferromagnetic chromium dioxide in respect of water and oxidable organic compounds which it may contact in the magnetic tapes.
    This process is applicable to a starting Cr0 2 having good magnetic properties, i.e. a coercive force not lower than about 400 Oersted, a maximum magnetic induction Bm not lower than about 2500 gauss and a magnetic induction Br not lower than about 1600 gauss. Cr0 2 is subjected to a heat treatment at a temperature ranging from 300 to 390°C in the presence of a gas stream not exerting any oxidizing or reducing action on the compounds of trivalent, tetravalent and hexavalent chromium. Suitable gases are, for example, nitrogen, helium and argon.

    Stabilized ferromagnetic chromium dioxide and a process for preparing it
    4.
    发明公开
    Stabilized ferromagnetic chromium dioxide and a process for preparing it 失效
    Stabilisiertes ferromagnetisches Chromdioxyd和Verfahren zu seiner Herstellung。

    公开(公告)号：EP0007764A1

    公开(公告)日：1980-02-06

    申请号：EP79301408.5

    申请日：1979-07-16

    申请人： Montedison S.p.A.

    发明人： Basile, Giampiero ,  Boero, Giancarlo

    IPC分类号： H01F1/11 ,  C04B35/26

    CPC分类号： G11B5/70636 ,  Y10S428/90 ,  Y10T428/2991

    摘要： A stabilized ferromagnetic chromium dioxide, CrO 2 , consists of particles of ferromagnetic chromium dioxide coated with a coating comprises a mixture of Fe 2 O 3 and MnO or of a mixture of a ferrite MeFe 2 O 4 with the oxides Fe 2 O 3 and MeO (wherein Me is Cu, Co, Zn or Mg) in which mixtures the molar ratio of Fe 2 O 3 : MnO or MeO is unity. The product is obtained by dispersing ferromagnetic chromium dioxide in water, co-precipitating Fe(OH) 3 and Mn(OH) 2 or Me(OH) 2 onto it, drying the resultant mixture at a temperature not exceeding 100°C and finally calcining the dried product at a temperature of from 250° to 350°C.

    摘要翻译： 稳定的铁磁二氧化铬CrO 2由涂覆有涂层的铁磁性二氧化铬颗粒组成，包括Fe 2 O 3和MnO的混合物或铁氧体MeFe 2 O 4与氧化物Fe 2 O 3和MeO的混合物（其中Me是Cu，Co，Zn或 Mg），其中Fe 2 O 3 :MnO或MeO的摩尔比为1。 该产物通过将铁磁性二氧化铬分散在水中，将Fe（OH）3和Mn（OH）2或Me（OH）2共沉淀在其上，在不超过100℃的温度下干燥所得混合物，最后煅烧 干燥产物在250-350℃的温度下进行。