# Recycling of SmCo5 magnets by HD process

## TL;DR

This study introduces a novel hydrogen decrepitation process for recycling SmCo5 magnets, demonstrating effective powder production and improved microstructure, with comparable or enhanced magnetic properties compared to original magnets.

## Contribution

First application of hydrogen decrepitation for direct recycling of SmCo5 magnets, showing improved microstructure and magnetic performance.

## Key findings

- Recycled magnets have higher remanence and energy product.
- Microstructure is refined after recycling.
- Hydrogen decrepitation effectively produces usable powder.

## Abstract

Hydrogen decrepitation process has been applied for the first time for the direct recycling of SmCo5 magnets. Industrially produced sintered SmCo5 magnets were decrepitated by hydrogen gas at a pressure of 1 bar to 9.5 bar at room temperature in a planetary rotating jar. After decrepitation, the starting sintered magnets were reduced to a powder with a particle size of less than 200 microns. The produced powder was used for the preparation of recycled SmCo5 magnets. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction studies and magnetic measurements were used to follow the decrepitation and the sintering processes. The measured remanence and maximum energy product of the recycled magnet are 0.94 T and 171.1 kJ/m3, respectively, in comparison with 0.91 T and 156.8 kJ/m3, respectively for the original magnet before recycling. It was also observed that, there is refinement in the microstructure after recycling in comparison to the original magnet.

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Source: https://tomesphere.com/paper/1905.04829