Electroless Plating Of Ni-co-p Magnetic Recording Film

This paper studied the influence of preparation technics on electroless plating Ni-Co-P magnetic film's structure and magnetism, also studied the infullence of heat treatment on electroless plating Ni-P/Co-Ni-P thin film's structure and magnetism. Discussed the mechanism of film structure and magnetism changement caused by heat treatment, provides theory analyse and experiment data to improve the recording density. The major results obtained are summarized as follows:(1) Magnetic Ni-Co-P thin films were prepared by changing the concentration of alleviant. The result indicated that: The structure of the thin films change from β-Co to α-Co with the alleviant concentration increased. The coercivity of the thin film is only 1.1×10⁴A/m when the alleviant concentration is 0.1mol/L; the coercivity of the thin film can achieved to 5.7×10⁴A/m when the alleviant concentration is 0.5mol/L.(2) Magnetic Ni-Co-P thin films were prepared by changing the concentration of reducer. The result indicated that the structure of the thin film changed with the reducer concentration increased. There are α -Co and β-Co solid solution and Co₂P grain when the reducer concentration is 0.15mol/L, the two crystal phase coexistence make the coercivity of the thin film increased to 5.1×10⁴A/m;α-Co(101) diffraction disappear when the reducer concentration is 0.3mol/L, this cased the coercivity of the thin film decreased.(3) Magnetic Ni-P/Ni-Co-P thin film was prepared by electroless plating, and then, the heat treatments to the thin films at 100℃, 250℃ 350℃, 400℃, 500℃ were done in the high temperature vacuum tube. The result indicates that the heart treatments make the structure of the thin films change from α-Co to β-Co and the grain size of the films has a obvious change; The grain size grew to 30nm after heat treatment; The coercivity of the thin film increased to 5.57×10⁴A/m after heat treatment at 350℃; The squareness ratio increased to 0.28 afer heat treatment at 400℃.