Speaker
Description
The industrial production of advanced Mn-Zn ferrites often faces unique challenges that determine its upscaling success. These range from controlling fundamental properties such as thermal expansion to meeting broader goals of innovation and sustainability. The present work aims to address key material design challenges and strategic development approaches to these goals.
One of the critical cost factors of Mn-Zn ferrite production is the loading efficiency of the sintering furnaces. However, the thermal expansion of the ferrite during the early stages of sintering may cause sticking of the neighbouring ferrite cores, if positioned too close on the sintering plate. To minimize this risk, a systematic investigation of the expansion characteristics of Mn-Zn ferrites of various Zn contents was done, in relation to the atmosphere during prefiring and sintering. Phase identification during the two thermal processes, combined with their magnetic response, led to the determination of the optimal temperature and atmosphere parameters to avoid product sticking while preserving optimal magnetic performance.
Beyond conventional ferrite core production, however, innovation through the development of ferrite powders is in growing demand, aiming to exploit their inductive performance in the design of thermally activated processes and applications, as at the micro range, the ferrite particles are multi-domain, exhibiting intra-particle domain walls. The primary goal being to establish a correlation between the magnetic performance of sintered cores and powders, Mn-Zn and Mg-Mn ferrite materials were prepared following the ceramic method and were structurally, morphologically and magnetically characterized. A direct correlation between the two states was achieved through $B$-$H$ loop acquisition and VSM measurements, while the heating ability of the prepared powders provided further insights. Several granulation techniques shed light on the flexibility of ferrite powders in terms of granulate size and inductive response.
Regardless of specific application requirements, sustainability has become a fundamental priority in modern industrial production, driving the need for resource-efficient materials. In this context, a high-value spinel Mn-Zn ferrite was successfully developed through the targeted conversion of an industrial solid waste, electrolytic MnO$_2$. Material design was based on the optimal treatment of the waste starting from constituents’ separation, combined with a proper process design to fit the conventional ceramic technique and a targeted compositional adjustment. The lab-developed Mn-Zn ferrite was upscaled to a semi-pilot plant for tile-shaped products, which were successfully implemented as magnetic shielding couplers on a prototype wireless charging unit. The achieved $23\%$ increase in the current intensity flow demonstrates the potential of circular economy principles in advancing sustainable ferrite technology.
