High deposition rate obtained for spin-sprayed Ni-Zn ferrite films without using ammonia ions

Spin-spray ferrite plating without using corrosive ammonia ions was developed and very high deposition rate of 60 nm/min of Ni-Zn ferrite films was achieved by spraying the reaction solution (FeCl/sub 2/+NiCl/sub 2/+ZnCl/sub 2/) and oxidizing solution (NaNO/sub 2/+KOCOCH/sub 3/) on the rotating glass substrate at 90/spl deg/C. The change of pH buffer from (NH/sub 4/)OCOCH/sub 3/ to KOCOCH/sub 3/ increased the pH in oxidizing solution from 6.8 to 7.6 and this higher pH expedited the ferrite film formation. The film surface observed in SEM image was smooth, and a large saturation magnetization M/sub s/ of 420 emu/cc and low coercivity H/sub c/ below 25 Oe were obtained. This film exhibited a high real permeability /spl mu/'/sub r/=45 and a high ferromagnetic resonance frequency f/sub r/=500 MHz. The deposition rate increased to 73 nm/min by increasing pH in oxidizing solution from 7.6 to 12.0. Although the film was porous, very high deposition rate of 230 nm/min was obtained for the film using oxidizing solution with high pH of 12.4. This film exhibited /spl mu//sub r/'=15 and f/sub r/=1 GHz, which were comparable to those of commercialized conducted noise suppressors.