| 摘要 |
PURPOSE:To raise smoothness of the surface of a magnetic layer and to lower surface electric resistivity of said layer, by adding an SnO2 powder or a powder contg. it to the magnetic layer. CONSTITUTION:An SnO2 powder or a powder contg. it having 10-500nm average particle size is added to the magnetic layer formed on the surface of a nonmagnetic support. As said powder, SnO2 fine powder, fine powder obtd. by coating the surface of a powder, such as TiO2, and a colloidal dispersion of fine powder, such as BaSO4, and SNO2 powder, etc. are usable. As the fine powder on which SnO2 is coated, ZnO, SmO2, TiO2, CaCO3, lithopone, talc, etc. are used. The amt. of SnO2 powder to be added is 3-30wt% of magnetic material, preferably, 5-20wt%, and its average particle size is 10-1,000nm, preferably, 10-500nm. The addition of SnO2 powder can lower the surface resistivity of the magnetic layer and enhance the smoothness, video S/N ratio, and durability of the magnetic layer. |
