A method for disentangling β-Si3N4 seeds obtained by SHS

The manufacture of β-Si3N4 seeds by self-propagating high temperature synthesis (SHS) presents some advantages, such as the low production costs, compared to other preparation methods based on sintering of α-Si3N4 powders and subsequent leaching out of the glassy phase. However, SHS process produces seed clusters that must be disentangled before use as reinforcing particles. Different mechanical and chemical treatments were tried to achieve good seed dispersion, proving that a combined treatment based on a hot basic etching and a short time attrition milling gave almost agglomerate-free particles with adequate features for seeding use.

Graphical abstractScanning electron micrograph of the SHS β-Si3N4 seeds after BEM treatment. The combination of basic etching and short-time milling allows achieving almost agglomerate-free β-Si3N4 seeds with an adequate aspect ratio distribution and an impurity content within the range of the most commonly used commercial α-Si3N4 powders. That confirms the potential of this type of seeds to fabricate highly anisotropic reinforced Si3N4 materials.Figure optionsDownload full-size imageDownload as PowerPoint slide