The American Chemical Society has discovered a ‘micro-recycling strategy’, which is able to convert old printed circuit boards and monitor components into a new type of metal coating.
Carefully calibrated high temperature-based processing can selectively break and reform chemical bonds in waste to form new, environmentally friendly materials. Researchers successfully turned a mix of glass and plastic into silica-containing ceramics. Now, this approach has been extended to extracting copper from circuit boards.
Based on the properties of recovered copper and silica compounds, researchers Veena Sahajwalla and Rumana Hossain suspected that they could combine them to create a durable new hybrid material ‘ideal’ for protecting metal surfaces.
First, the researchers heated glass and plastic powder from old computer monitors to 1500℃, generating silicon carbide nanowires. They subsequently combined the nanowires with ground-up circuit boards, put the mix on a steel substrate then heated it up again. This time the thermal transformation temperature selected was 1000℃, melting the copper to form a silicon-carbide enriched hybrid layer atop the steel.
‘Microscope images revealed that, when struck with a nanoscale indenter, the hybrid layer remained firmly affixed to the steel,’ the researchers note. ‘Without cracking or chipping.’ It also increased the steel’s hardness by 125%.
Sahajwalla refers to this selective, small-scale process as ‘material micro-surgery’. She believes it has the potential to transform used electronics into strong, ‘high performance’ surface coatings that could significantly improve corrosion and wear resistance.
‘This method could be a suitable alternative to conventional surface coatings and reduce the burden on raw material feedstocks,’ the researchers conclude.
Fuente: Recycling International