Direct transformation of waste printed circuit boards to nano-structured powders through mechanical alloying

Publication date: 5 March 2018
Source:Materials & Design, Volume 141
Author(s): Rasoul Khayyam Nekouei, Farshid Pahlevani, Ravindra Rajarao, Rabeeh Golmohammadzadeh, Veena Sahajwalla
Identifying a solution to directly transform waste printed circuit boards (PCBs) to useful alloys will save energy, conserve our valuable resources, and contribute to preservation of our environment. In this study a solid state mechanical alloying was used to directly convert waste PCBs to a homogenous nanostructured alloy (Cu79-Zn13-Fe3-Sn3-Ni1). Electron microscopy analysis showed 10h milling time after a short period of cryomilling was enough to obtain a homogenous alloy and SAED ring pattern confirmed the nano-structure, although just a portion of particles size of the power was in nano-scale (<100nm). Lattice parameter, strain and grain size were calculated using XRD analysis. The grain size was 40nm with a strain of 0.73%. High resolution XPS analysis confirmed minor surface oxidation of produced alloy. The UV–Vis analysis showed a broad peak between 350 and 650nm indicating the chemical homogeneity of the surface. Also the calculation of input energy confirmed the formation of a nano-structured material during mechanical alloying. Finally, a promising application was investigated as nanofluid after dispersion of the synthesised powder in DI water followed by characterization of pH and conductivity variation. The conductivity of the sample was about 10 times higher than DI water. These results, for the first time, introduce a concept for directly transform waste PCBs to metallic alloys without using any heat or solutions.

Graphical abstract

http://ift.tt/2BGyN0Q