POLYMER MATERIALS REINFORCED WITH SILICON NITRIDE CERAMIC PARTICLES FOR 3D PRINTING

Abstract

Comprehensive research into the production of a ceramic-reinforced polymer material from high-density polyethylene or polypropylene and β-Si₃N₄ powder was conducted. The incorporation of Si3N4 ceramic particles (5 and 10 vol.%) into the polymers to make polymer–ceramic filaments was studied step by step. High-quality polypropylene–ceramic filaments could be obtained at an extrusion temperature of 150 ºC with an extrusion rate of 20 cm/min and polyethylene–ceramic filaments at 160 ºC and 30 cm/min. Data on the shape and size distribution of particles were used to simulate the elementary volume of the filaments to determine the mechanical properties of the composites applying a 2D finite-element model. The reinforcement of the polypropylene/polyethylene-matrix material by 10 vol.% Si₃N₄ was not sufficient since the composite elastic modulus increased insignificantly and the critical strain decreased substantially to incorporate a greater volume of hard particles to improve the elastic modulus. To assess the quality of the polymer–ceramic filaments, parts of different shape (washer and auger) from reinforced and unreinforced filaments were designed and printed. The printed polymer–ceramic parts demonstrated a smooth surface and did not have ledges or discontinuous areas. The mechanical (Vickers and Brinell hardness) and tribological (volume wear) properties of the filaments were examined. Wear tests of the polyethylene–Si₃N₄ composite showed that its wear resistance tended to improve with increasing ceramic content of the filament. The low abrasive wear of the Si3N4 ceramic-reinforced polypropylene/polyethylene material and the behavior of ceramic particles in contact with the indenter indicate that the composite material has high fracture resistance in 3D printing.