Manganese zinc ferrite or nickel zinc ferrite core - with low signal-noise ratio in magnetic recording heads

摘要

Hot pressed ferrite core with high density, high abrasion resistance, and usable in a wide frequency range, esp. Mn-Zn ferrite (MZF) and Ni-Zn ferrite (NZF) cores for magnetic recording heats, where the ferrite has a large grain dize and uneven grain boundaries. The MZF has average grain size (AGS) =500 mu m, and the NZF an AGS =30 mu m. The initial oxide mixts. are pref. milled; opt. presintered; heated to 100-200 degrees C. Below the sintering temp.; heated to the sintering temp. heated to the sintering temp. under pressure then rapidly cooled without pressure. The large grain size reduces the initial permeability (ui), so the frequency ragne up to resonance is 5 MZF and over 10 MHz for NZF. The result is an esp. good signal to noise ratio, noticeable during read-out.