# Orthogonal Design Optimisation of the Sintering Process for MnZn Ferrites with Step-Sintering Verification

## TL;DR

This paper uses an orthogonal design to optimize the sintering process of MnZn ferrites, balancing magnetic permeability and power loss for power electronics.

## Contribution

A novel orthogonal-screening-plus-verification strategy is introduced for optimizing MnZn ferrite sintering parameters.

## Key findings

- Optimal sintering conditions for high permeability: 1250°C, 4h holding time, 3.5% oxygen partial pressure.
- Optimal sintering conditions for low power loss: 1250°C, 3.5h holding time, 5% oxygen partial pressure.
- XRD, SEM, and magnetic-loss separation confirm process-structure-property relationships.

## Abstract

MnZn ferrites for power electronics require a well-controlled sintering window to balance high initial permeability (µi) with low power loss (Pcv). Here, an L9 (33) orthogonal design was employed to quantify the main effects of sintering temperature, holding time, and oxygen partial pressure on µi and Pcv within the investigated processing window, enabling rapid mapping of feasible sintering windows. The orthogonal analysis identifies the relative significance of each factor and reveals a clear performance trade-off between µi and Pcv. For maximising µi, the optimal sintering condition was 1250 °C, 4 h holding time, and 3.5% oxygen partial pressure, yielding a µi of 3453 and a Pcv of 466 mW/cm3 at 100 kHz/200 mT. For minimising Pcv, the optimal condition was 1250 °C, 3.5 h holding time, and 5% oxygen partial pressure, resulting in a µi of 2678, with Pcv of 400 mW/cm3 at 100 kHz/200 mT and 182 mW/cm3 at 500 kHz/50 mT. Targeted verification together with XRD, SEM grain-size statistics, and magnetic-loss separation were used to strengthen the process-structure-property interpretation. Overall, the orthogonal-screening-plus-verification strategy provides a practical framework for predicting application-relevant performance trends of MnZn ferrites within a defined processing window.