ИСТИНА

This work aimed to obtain a biocompatible ceramic material based on synthetic calcium phosphate powders and sodium silicate aqueous solution with a given phase composition in the Na2O-CaO-SiO2-P2O5 system intended for use in medicine. Pre-ceramic semi-finished products were obtained from highly concentrated suspensions consisting of synthetic calcium phosphate powders (hydroxyapatite, tricalcium phosphate and pyrophosphate) and the aqueous sodium silicate solution withthe silica module (SiO2/Na2O) = 2.87, both in the form of blocks by moulding in silicone rubber moulds and as simple 3-dimensional layered geometric shapes by extrusion moulding using a syringe.Ceramic materials after firing at 1000 included two biocompatible phases:sodium-calcium silicate Na6Ca3Si6O18 the main phase, and b-rhenanite b-NaCaPO4 in a small amount. The geometric density of materials for all samples after firing at 1000 was 0.76 - 0.78 g/cm3, and the compressive strength was 2.5-3.5 MPa.Thus, the highly concentrated suspensions based on synthetic calcium phosphate powders and the aqueous sodium silicate solution can be recommended for the preparation of porous composite biomaterials with both defined geometry and a porousarchitecture of implants using extrusion 3D printing. The approach proposed in the current work allows one to achieve a given phase composition of biocompatible ceramic materials in the Na2O CaO SiO2 P2O5 system.Acknowledgements: This work was supported by the Russian Foundation for Basic Research (project No 18-29-11079).