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Hits: 7924
The physicochemical properties of the carboxyl cation exchanger Tokem-200, sulfonic cation exchanger Tokem-140 and their selectivity with respect to the Ca ion
2+ under equilibrium conditions were investigated, the sol-gel method from solutions synthesized spherical biomaterials based on Tokem- 200. The framework of the material is represented by TiO
2 -SiO
2 , and the inner part is filled with Ca
2+ oxide (sample TiO
2 - SiO
2 / CaO). Carboxyl cation exchanger Tokem-200 has the highest selectivity for Ca
2+ ions in contrast to Tokem-140, which makes it promising for the creation of biomaterials. It was found that the solutions are suitable for obtaining materials for up to 5 days.
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Hits: 9071
Introduction to the impregnating suspension based on hydroxyapatite powder, heat-treated at 800 ° C, 10 - 50 ° C; (by weight) of brushite powder heated at 50 ° C, after firing at 1200 ° C leads to partial decomposition of hydroxyapatite to tricalcium phosphate of the & # 945; - and & # 946; - modifications. The presence of the tricalcium phosphate phase in calcium phosphate foam ceramics contributes to an increase in porosity from 40 to 60 & # 37; and the degree of resorption with a significant decrease in static strength from 3 - 7 to 0.3 MPa
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Hits: 9304
A study of the process of removing the organic component from composites (photopolymer / calcium phosphate) of complex architecture, obtained by 3D printing for the creation of personalized bioceramic implants, has been carried out. Ceramic materials with a complex pore space organization were obtained by stereolithographic printing. The effect of the degree of polymerisation of the composite on the final density of calcium phosphate ceramic materials of complex architecture is shown.
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Hits: 10791
A method for obtaining X-ray contrast bioglass by pyrolysis of organic solutions containing tetraethoxysilane, tributyl phosphate, sodium oleate and calcium oleate in turpentine, as well as tungsten extract in a benzene solution of tri-n-octylamine. The method makes it possible to obtain tungsten-containing X-ray contrast glasses both in the form of powder materials and in the form of coatings on various porous carriers.
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Hits: 11095
To obtain resorbable ceramics in the Ca system (PO
3 )
2 -Ca
2 P
2 O
7 used powder mixtures prepared using mechanical activation from synthetic hydrated calcium acid phosphates Ca (H
2 PO
4 )
2 .
2 O and CaNRO
4 .
2 N
2 O. The phase composition of the ceramics after firing in the range 700 - 1000 & # 176; C was represented by biocompatible and bioresorbable phases: calcium polyphosphate Ca (PO
3 )
2 , thromlite Ca
4 P
6 O
19 and calcium pyrophosphate Ca
2 P
2 O
7 < / sub>. The obtained materials can be used for the manufacture of resorbable implants used in regenerative methods for the treatment of bone tissue defects.
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Hits: 11794
The results of X-ray diffraction and infrared analyzes of powders of zinc-substituted hydroxyapatite and tricalcium phosphate are presented, and the technology of plasma spraying of coatings based on them is presented. Structural-morphological and physicochemical characteristics of the obtained coatings were investigated, and their adhesion strength and degree of hydrophilicity were determined.
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Hits: 12025
From an aqueous solution of calcium acetate and a mixed-anionic (HPO
4 2- / CO
3 2- ) aqueous solution containing ammonium hydrogen phosphate and ammonium carbonate, an X-ray amorphous powder was synthesized at room temperature without pH adjustment. Powders synthesized from a mixed-anionic (HPO
4 2- / CO
3 2- ) solution can be recommended for the manufacture of composite materials with a polymer matrix or for the production of ceramics containing tricalcium-phosphate and calcite phases at a firing temperature of no more than 600 ° C
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Hits: 12638
The processes occurring at the stages of mechanical activation of powders and firing of samples pressed from calcium phosphate nanopowders with a molar ratio of Ca / P = 1.25 have been studied. Washing the nanopowder in distilled water and alcohol after mechanical activation led to the removal of ammonium phosphates, and only hydroxyapatite and tricalcium phosphate were present in the ceramics. To preserve the molar ratio Ca / P = 1.25 in the ceramics, washing should not be carried out, then after firing, in addition to the indicated phases, calcium pyrophosphate is also present in the ceramics.
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Hits: 12862
The influence of the mass content of Al
2 O
3 on the stability of the phase composition and the strength of the ceramics of the Al
2 O
3 -3Y system has been determined. -ZrO
2 prepared according to industrial technology. It is shown that the introduction of aluminum oxide has a positive effect on the stability of the tetragonal phase of zirconium dioxide under conditions of accelerated aging. At the same time, an increase in the mass content of aluminum oxide from 15 to 80 & # 37; does not lead to a further significant change in the t-ZrO
2 / m-ZrO
2 ratio. It was found that after 5 hours aging, all materials containing alumina exhibit an increase in strength.
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Hits: 13098
The study of the rheological properties of highly concentrated calcium phosphate suspensions for the creation of bioceramics of complex shape by slip casting and 3D printing has been carried out. Macroporous bioceramics with a gyroid architecture were made by casting water slips into polymer molds with a gyroid geometry, produced by thermal extrusion and stereolithographic 3D printing. The limitations of this technology in the reproduction of fine details are shown in comparison with direct 3D stereolithography of ceramic suspensions.
