Stress Analysis of Glass-Bonded Ferrite Recording Heads

Glass-bonded ferrite recording heads are subject to appreciable thermal stress because of the difference in thermal expansion between glass and ferrite in the temperature range of the glassing cycle. A theoretical analysis reveals the complexity of stress distributions in the structure and pinpoints the critically stressed areas in which a potential fracture or a magnetic degradation of the material may occur. It is found that the stresses are sensitive not only to the thermal mismatch of the component materials but also to the structural configuration. Low stress levels can be achieved by matching expansions of the materials and by proper head design, particularly in the optimization of fillet angle and fillet height.