Fabrication of Si₂N₂O ceramic with silicon kerf waste as raw material

SiC and Si in silicon kerf waste of photo-voltaic (PV) industry produced by a slurry technology are difficult to be separated for recycling due to their similar density and particle sizes. In this work, silicon kerf waste after removing the glycol and metal was characterized, then used as raw material for producing Si₂N₂O ceramics. In the silicon kerf waste, besides SiC and Si, amorphous SiO₂ exist because of the reaction of Si with water during the storage time. Thermodynamic calculation showed that, ascribing to the reaction of Si, N₂ with SiO₂ and the reaction of SiC, N₂ with SiO₂ at high temperature in N₂ atmosphere, the Si was exhausted and the SiC was decreased to form the Si₂N₂O. With the content of sintering additives increasing, the porosity of the samples was decreased, the bulk density was increased, and the strength of the samples was increased. It would be a reasonable method for fully utilizing the silicon kerf waste to fabricate Si₂N₂O composite ceramic without separating the SiC and Si.