Multifunctional Smart Nanocomposite Based on Aluminum Oxide Nanopowder and Sialon

Goal: Production of a nanocomposite with high impact strength and crack resistance. Method: SiALON with porosity of 13% - 15% was synthesized at 1400˚C using the metallothermic and reactive sintering methods in a nitrogen atmosphere. It was then SiAlON milled in an attritor and in composition with aluminium oxide nanopowder (Table 1), hot pressed and received nanocomposite in the Al2O3-SiAlON system. Aluminum oxide nanopowder with an average dispersion of 435 nanometers, produced by the German ALCOA company, was used. For the technology and research, hot pressing was used at 1650˚C. Thermal treatment was conducted for 40 minutes, under pressure 30 MPa, with an 8-minute hold at the final temperature. Studies were performed using micro- and macromechanical methods, as well as structural-optical methods with an AmScope MT300 3.1 MP and electron microscopy techniques. The structural-morphological and elemental composition analysis of the samples was performed using a scanning electron microscope (SEM) JSM-6510LV from the Japanese company JEOL, equipped with an energy-dispersive X-ray spectrometer (EDX) X-MaxN from the British company OXFORD INSTRUMENTS. Result: The obtained material is characterized by high operational properties. A dense material with a water absorption rate of 0.O1%, and total porosity—0.13 % was obtained. The bending strength is 470 MPa, while the compressive strength is 1923 MPa. Micro-mechanical analysis showed that no cracks are formed in the sialon matrix during the loading process. Conclusion: The high operational properties of the composite were confirmed through the application of Kovziridze’s formulas: the dependence of the mechanical modulus and macromechanical properties on the content of the porous phase in the matrix, and the determination of micro- and macromechanical properties, depending on the content of the crystalline phase in the matrix.