| 摘要 |
PURPOSE:To obtain Sr ferrite particles having superior dispersibility and a high magnetization value at the lowest reaction temp. under wide formation conditions by bringing a highly alkaline suspension contg. Sr ions and Fe (III) ions into a hydrothermal reaction in the presence of S. CONSTITUTION:A highly alkaline suspension of >pH12 contg. Sr ions mainly derived from Sr(NO3)2 and SrCl2 and partially derived from SrSO4, etc., and Fe (III) ions mainly derived from Fe(NO3)3 and FeCl3 and partially derived from Fe2(SO4)3 in 1:(6-10) atomic ratio of Sr:Fe and further contg. 1-10 S atoms or 1-10 SO4<2-> molecules per 1 Sr atom is hydrothermally treated at 100-320 deg.C, preferably 180-200 deg.C to obtain Sr ferrite particles having the crystal structure of SrFe12O19. The average particle size of the ferrite particles is <=1mum, the magnetization value is 40-57ems/g and the coercive force is 700-1,500Oe. |
