Utilization of Industrial Solar Cells’ Scrap as the Base Material to Form Coatings

Abstract

The aim of this research is to find possible ways to recycle and re-use industrial solar cell scrap. The work is concentrated on cells which are broken, damaged or rejected during the manufacturing process, which accounts from 2 to 3 percent of whole production on average. Different chemical methods have been suggested for the recovery of pure valuable elements from damaged or worn cells, while the technology presented in this paper utilizes industrial solar cell scrap to produce secondary value products. Crushed industrial waste of different fraction sizes was analyzed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) methods. Tungsten inert gas welding (TIG) has been chosen as the coating formation process. Proper parameters: current 55 A, voltage 19 V, gas flow rate 5 l/min, torch tilt angle 80–85° were selected experimentally, as parameters of common welding are not suitable for the deposition. The chemical composition and transition of chemical elements towards the substrate showed sufficient adhesion and smooth distribution of elements. Alongside with aforementioned methods, mechanical tests were accomplished, showing that damaged solar cells industrial scrap could be used as a source of alloying elements to compose the coating. The hardness of produced coatings as deposited reached 39 HRC (microhardness 2 GPa) on average. Formed coatings could serve for various applications, however further in-depth research is necessary. As suggested, the wear test method is too aggressive for this type of surface. Nevertheless, coatings based on industrial solar cell scrap showed a mass loss two times lower on average than normalized structural steel S355 substrate in rough abrasive conditions.