# Exploration of the Reduction Diffusion Temperature for Different Phases of Samarium–Cobalt Magnetic Particles

## TL;DR

This paper explores how to synthesize samarium–cobalt magnetic particles using a microwave method and identifies the best temperature for forming a specific magnetic phase.

## Contribution

The study identifies the optimal temperature for forming the 1:5 phase of samarium–cobalt particles using a novel microwave-assisted synthesis method.

## Key findings

- At 900 °C, a pure 1:5 phase of samarium–cobalt was formed with a coercivity of 35 kOe and a maximum energy product of 14 MGOe.
- The particle size increased with higher reduction temperatures, reaching approximately 800 nm at 900 °C.
- Microwave-assisted combustion combined with high-temperature reduction and diffusion effectively controls the phase transition of samarium–cobalt materials.

## Abstract

We report a method for synthesizing different phases of samarium–cobalt particles through microwave-assisted combustion combined with high-temperature reduction and diffusion, and identify the optimal temperature for forming the 1:5 phase using this approach. Initially, the samarium-to-cobalt ratio in a nitrate solution was determined. Using urea as both a reductant and fuel, samarium–cobalt oxides were synthesized via microwave-assisted combustion. The main components of the oxides were confirmed to be SmCoO3 and Co3O4. Subsequently, samarium–cobalt particles were synthesized at various diffusion temperatures. The results indicate that at 700 °C, the oxides were reduced to elemental Sm and Co. As the reduction temperature increased, the alloying of samarium and cobalt occurred, and the particle size gradually increased. At 900 °C, a pure 1:5 phase was formed, with particle sizes of approximately 800 nm, a coercivity of 35 kOe, and a maximum energy product of 14 MGOe. Based on the microwave-assisted combustion method, this study clarifies the transition temperatures of samarium–cobalt phases during the reduction and diffusion process, and further establishes the synthesis temperature for the 1:5 phase, providing new insights into the preparation and development of samarium–cobalt materials and potentially other rare earth materials.