Upcycling copper chips into Cu–Fe alloys via coating-assisted plasma sintering

Researchers have devised a novel method to transform discarded copper chips into functional Cu–Fe alloys through a process called coated chip plasma sintering (CCPS). Copper chips generated during machining are first coated with iron using an arc physical vapor deposition technique. This coated material is then compressed cold and subsequently subjected to spark plasma sintering.

The initial machining process exposes the copper chips to severe plastic deformation, resulting in an ultrafine microstructure before the consolidation step. During the sintering process, the Fe coating and surface oxides are broken down, allowing for direct metal-to-metal contact and accelerated interfacial diffusion. This collaboration between the Fe coating and sintering conditions leads to effective densification and bonding of the alloy.

The resulting material features a mainly copper-rich matrix with a small addition of iron (~0.25 wt%) and displays noticeable strengthening properties. The alloy exhibits a yield strength of around 280 MPa, ultimate tensile strength of approximately 307.9 MPa, and hardness of about 116.5 HV. While elongation is reduced to roughly 11.6%, the alloy maintains relatively high electrical conductivity with only a minor increase in resistivity.

This CCPS approach offers an efficient and eco-friendly solution for converting copper waste into Cu-based alloys with desirable structural and electrical characteristics. The research was conducted without any financial backing and is published under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.