公开(公告)号：DE1269446B

公开(公告)日：1968-05-30

申请号：DE1269446

申请日：1965-06-09

Applicant: IBM

Inventor： JUN WILLIAM NEVIUS DUNLAP ,  KORETZKY HERMAN ,  MCCABE HARRY DONOVAN

IPC: C23C18/36 ,  H01F41/24 ,  G11B5/62

Abstract: A magnetic Co film is electrolessly deposited on a substrate (e.g. of glass, ceramics, plastics such as polyethylene terephthalate, or of metal) from an aqueous solution of a Co salt, a hypophosphite such as sodium hypophosphite and a material which produces malonate ion in solution. A predetermined coercivity can be obtained by appropriately selecting the concentration of the malonate ion. The Co salt may be a chloride, sulphate, acetate or sulphamate, and the malonate may be malonic acid. The solution may contain the ammonium ion added e.g. as (NH4)2 SO4 and NH4OH. The pH is maintained at 8 to 11 by adding hydroxides, e.g. NH4OH, and ammonium salts such as (NH4)2SO4 or NH4Cl. The substrate may be a tape drum or disc. In an example a polyethylene terephthalate web is mechanically roughened, chemically etched and then sensitized by exposure to a Sn Cl2 solution and then to a Pd Cl2 solution with a water rinse after each exposure. The sensitized web, at this time having Pd on its surface, is then electrolessly coated with the Co. The coating bath may comprise:- .cobaltous ion.3.75 - 15.0 grams/litre .hypophosphite ion.3.0 - 24.5 grams/litre .malonate ion.15.0 - 200.0 grams/litre .ammonium ion.1.0 - 100.0 grams/litre