めっき形磁気ディスク記録媒体下地用電解Ni-Pめっきの研究

抄録

Ni-P films electrodeposited on an aluminium alloy substrate have been investigated for the purpose of developing a plated magnetic recording disk. A plating equipment was designed to keep the plating solution thoroughly clean and to heighten the effect of air agitation at the plating surfaces. In addition, a cathodic shielding technique was employed to secure uniformity in film thickness and phosphorous content. The films obtained by using these techniques showed high Vickers hardness (Hv=600-700), low residual stress (σ=1.4-5.4kg/mm²), and high non-magnetic stability (activation energy E=1.78eV, relaxation time T=10³ years at 50°C), which are suitable for the substrate of the plated magnetic disk. Thickness deviation was within 5% irrespective of the film thickness. This uniformity developed a mechanical finishing efficiency of the plating surface. Signal errors under the read-write operation were avoided by using the non-defect plated substrate. The electrodeposited Ni-P films thus can be practically utilized for the plated magnetic recording disk and surely have an economical merit of high recording density.