Ceramics in the Ca2P2O7–Ca3(PO4)2 system were obtained from powder mixtures containing calcium hydroxyapatite Ca10(PO4)6(OH)2 and monocalcium phosphate monohydrate Ca(H2PO4)2· H2O. Fish scale powder was used as a natural source of natural calcium hydroxyapatite Ca10(PO4)6(OH)2. The molar ratios of Ca10(PO4)6(OH)2 /Ca(H2PO4)2· H2O in the initial powder mixture equal to 1/4, 3/5 and 2/1, respectively, ensured the formation after firing of ceramics having a desirable phase composition, including calcium pyrophosphate Ca2P2O7 and/or tricalcium phosphate Ca3(PO4)2 . The homogenization of the components was carried out by repeated passing of the powder mixture through a sieve with a mesh size of 200 μm. Plastic molding of the samples was carried out using ethyl alcohol as a binder. According to XRD data, the phase composition of all samples after the addition of alcohol, molding, and drying included monocalcium phosphate monohydrate Ca(H2PO4)2· H2O and calcium hydroxyapatite Ca10(PO4)6(OH)2. Monetite CaHPO4 and brushite CaHPO4· 2H2O were also present in the phase composition of the samples. The phase composition of prepared highly porous ceramic samples with relative density 27 – 55
The phase composition of the powder synthesized from aqueous solutions of sodium silicate Na2SiO3 and iron sulfate FeSO4 at the molar ratio Fe/Si = 2, as determined by x-ray diffraction (XRD) data, included hydrated sodium iron sulfate Na2Fe(SO4)2 · 4H2O and an x-ray amorphous product based on hydrated iron and silicon oxides. The phase composition of the powder obtained by fourfold washing of the synthesized powder in distilled water was represented by an x-ray amorphous product. Following firing in the air at temperatures ranging from 400 to 1200°C, hematite (Fe2O3) and cristobalite (SiO2) were identified in powder samples and the corresponding ceramics. Following firing at 900°C in graphite powder bedding, the phase composition of ceramic samples included magnetite (Fe3O4), laihunite (Fe4.74(SiO4)3), and fayalite (Fe2SiO4). The powder prepared from the product isolated from the mother liquor included hydrated sodium iron sulfate, Na2Fe(SO4)2 · 4H2O, and sodium iron sulfate hydroxide hydrate (metasideronatrite), Na4Fe2(SO4)4(OH)2 · 3H2O. Following heat treatment at 400°C, sodium iron sulfate (Na3Fe(SO4)3) was identified as the predominant phase in the powder. Powders resulting from the interaction of aqueous solutions of sodium silicate and iron sulfate can be used in the manufacture of high-temperature dyes and materials with magnetic properties, the creation of analogs of lunar or Martian regolith, as well as the development of functional (cathode) materials for Na-ion batteries.
The mixed-anionic solution synthesis was applied to obtain X-ray amorphous powder precursor of silicon-substituted hydroxyapatite (Si-HAp) for macroporous bioceramics fabrication. Proposed technique was proven to provide small particle size up to 1 mu m, as well as homogeneous components distribution in the final Si-HAp ceramics. A possible pathway of the Si-HAp formation under gradual heating up to 1000 degrees C was discussed.
Powders with a phase composition including syngenite (K2Ca(SO4)2·H2O) and/or calcium sulfate dihydrate (gypsum, CaSO4·2H2O) were synthesized from the powder of calcium carbonate (CaCO3) and water solutions of potassium hydrosulfate (KHSO4) of various concentrations (0.5 M, 1 M, and 2 M). A molar ratio of starting salts, KHSO4/CaCO3 = 2, was used to provide the formation of syngenite (K2Ca(SO4)2·H2O). But when using a 0.5 M water solution of potassium hydrosulfate (KHSO4), the phase composition of the synthesized powder was presented by calcium sulfate dihydrate (gypsum, CaSO4·2H2O). When using 1 M and 2 M water solutions of potassium hydrosulfate (KHSO4), the syngenite (K2Ca(SO4)2·H2O) was found as the predominant phase in synthesized powders. According to estimations made from thermal analysis data, powders synthesized using 1.0 M and 2.0 M water solutions of potassium hydrosulfate (KHSO4) contained no more than 7.9 and 1.9 mass % of calcium sulfate dihydrate (gypsum, CaSO4·2H2O), respectively. The phase composition of products isolated from mother liquors via water evaporation consisted of syngenite (K2Ca(SO4)2·H2O) and potassium sulfate (arcanite, K2SO4). Synthesized powders can be used in preparation of biocompatible bioresorbable materials with phase compositions in the K2O-CaO-SO3-H2O system; as matrix of thermo- or photo-luminescent materials; as components reducing the setting time and increasing the strength of sulfate cements; in the fertilizing industry; and also as components of Martian regolith simulants.
Composite cements containing brushite, monetite and newberyite as dominating phases were created and used as drug (vancomycin) carriers. Brushite-monetite-newberyite cement with variable composition was obtained by replacing Ca2+ ions with Mg2+ in the initial cement component. Starting powder mixtures for cement preparation synthesized via solid state reaction consisted of MgxCa(3-х)(PO4)2 (x = 0, 0.75, 1.5, 2.25, 3), monocalcium phosphate monohydrate Ca(H2PO4)2·H2O with and without vancomycin as antibacterial agent. 100 mg of powder of a pharmaceutical substance per 1 g of the dry cement powder was added before cement sample preparation. Mixing liquids used were water solutions containing sodium pyrophosphate hexahydrate Na4P2O7·10H2O and citric acid monohydrate C6H8O7·H2O as set-retarding additives. An increase in the concentration of Mg2+ ions entail an increase in pH during preparation and a decrease in porosity of cement sample. Incorporation of vancomycin at the stage of preparation of the cement mixture does not affect the strength characteristics, porosity and pH of the cement stone. The prolongation of the release of vancomycin depends on the composition and characteristics of the cement stone. The activity of vancomycin against Staphylloccoscus aureus and Escherichia coli the process of hydration of cement and its dissolution was confirmed by appropriate tests in vitro. In vivo studies confirm the biocompatibility, resorbability of cements, and the effectiveness of their use as carriers of vancomycin in the treatment of purulent-septic inflammation.
By firing polyurethane foam templates (“STR” brand, 12 pores per cm, China) with a porosity of ~ 65 % at 1200 °С, an open-pore calcium phosphate foam ceramics was obtained using a highly concentrated suspension based on synthetic hydroxyapatite, heat-treated at 800 °С, monocalcium phosphate monohydrate and 0.8 % polyvinyl alcohol. The resulting calcium phosphate foam ceramics after modification in the SBF (Simulated Body Fluid) solution concentrated 5 times (SBF×5) consisted of β-tricalcium phosphate, β-calcium pyrophosphate and biomimetic apatite, had a porosity of 53 – 59 % and a static strength of ~ 0.05 MPa. The formed biomimetic apatite, consisting of amorphous calcium phosphate Ca9(PO4)6 and apatite tricalcium phosphate Ca9HPO4(PO4)5OH, crystallizes into β-tricalcium phosphate at 1200 °С. Calcium phosphate foam ceramics modified with biomimetic apatite, after soaking in 5 % hydroxyapatite gel and SBF×5, which simulating a bone defect in vitro, in parallel with the formation of biomimetic apatite, is partially destroyed, which confirmed its high bioactivity and degradation.
Fine powders of brushite CaHPO4·2H2O, ardealite Ca(HPO4)x(SO4)1−x·2H2O (Ca(HPO4)0.5(SO4)0.5·2H2O), and calcium sulfate dihydrate CaSO4·2H2O—all containing sodium chloride NaCl as a reaction by-product—were synthesized from 0.5 M aqueous solution of calcium chloride CaCl2, sodium hydrophosphate Na2HPO4 and/or sodium sulfate Na2SO4. Powder of ardealite Ca(HPO4)x(SO4)1−x·2H2O (Ca(HPO4)0.5(SO4)0.5·2H2O) was synthesized by precipitation from aqueous solution of calcium chloride CaCl2 and mixed-anionic solution simultaneously containing the hydrogen phosphate anion HPO42− (Na2HPO4) and sulfate anion SO42− (Na2SO4). Sodium chloride NaCl, presenting in compacts based on synthesized powders of brushite CaHPO4·2H2O, ardealite Ca(HPO4)x(SO4)1−x·2H2O (Ca(HPO4)0.5(SO4)0.5·2H2O) and calcium sulfate dihydrate CaSO4·2H2O, was responsible for both low-temperature melt formation and the creation of phase composition of ceramics. Heterophase interaction of components led to the resulting phase composition of the ceramic samples during heating, including the formation of chlorapatite Ca5(PO4)3Cl in powders of brushite and ardealite. The phase composition of the ceramics based on the powder of brushite CaHPO4·2H2O containing NaCl as a by-product after firing at 800–1000 °C included β-Ca2P2O7, and Ca5(PO4)3Cl. The phase composition of ceramics based on the powder of ardealite Ca(HPO4)x(SO4)1−x·2H2O (Ca(HPO4)0.5(SO4)0.5·2H2O) containing NaCl as a by-product after firing at 800 and 900 °C included β-Ca2P2O7, CaSO4, and Ca5(PO4)3Cl; after firing at 1000 °C, it includedCaSO4, Ca5(PO4)3Cl and Ca3(PO4)2/Ca10Na(PO4)7, and after firing at 1100 °C, it included CaSO4 and Ca5(PO4)3Cl. The phase composition of ceramics based on powder of calcium sulfate dihydrate CaSO4·2H2O containing NaCl as a by-product after firing at 800–1100 °C included CaSO4 as the predominant phase. The phase composition of all ceramic samples under investigation consisted of biocompatible crystalline phases with different abilities to biodegrade. For this reason, the created ceramics can be recommended for testing as materials for treatment of bone defects using regenerative medicine methods.
Biomaterials based on hydroxyapatite with controllable composition and properties are promising in the field of regenerative bone replacement. One approach to regulate the phase composition of the materials is the introduction of biopolymer-based additives into the synthesis process. The purpose of present study was to investigate the formation of hydroxyapatite-based hybrid materials in the presence of 6-24% platelet-poor plasma (PPP) additive, at a [Ca2+]/[PO43-] ratio of 1.67, pH 11, and varying maturing time from 4 to 9 days. The mineral component of the materials comprised 53% hydroxyapatite/47% amorphous calcium phosphate after 4 days of maturation and 100% hydroxyapatite after 9 days of maturation. Varying the PPP content between 6% and 24% brought about the formation of materials with rather defined contents of amorphous calcium phosphate and biopolymer component and the desired morphology, ranging from typical apatitic conglomerates to hybrid apatite-biopolymer fibers. The co-precipitated hybrid materials based on hydroxyapatite, amorphous calcium phosphate, and PPP additive exhibited increased solubility in SBF solution, which defines their applicability for repairing rhinoplastic defects.
Powders of hydroxyapatite (HA) Ca10(PO4)6(OH)2 treated in 0.25M aqueous solutions of ammonium NH4H2PO4, sodium NaH2PO4 and potassium KH2PO4 dihydrophosphates for 1 hour under stirring were used for ceramics production. According to the XRD data, there was no changes in the phase composition of the powders after such treatment. After firing in the range of 900 – 1100 ?С, the phase composition of ceramics based on HA Ca10(PO4)6(OH)2 powder treated with an aqueous solution of NH4H2PO4 included ?-tricalcium phosphate ?-Ca3(PO4)2 and HA Ca10(PO4)6(OH)2; The phase composition of ceramics based on HA Ca10(PO4)6(OH)2 powder treated with NaH2PO4 aqueous solution included sodium-substituted tricalcium phosphate Ca10Na(PO4)7 and HA Ca10(PO4)6(OH)2; the phase composition of ceramics based on HA Ca10(PO4)6(OH)2 powder treated with an aqueous solution of KH2PO4 included potassium-substituted tricalcium phosphate Ca10K(PO4)7 and HA Ca10(PO4)6(OH)2. The formation of biphasic ceramics occurred due to a decrease in the molar ratio Ca/P of HA powder after treatment in aqueous solutions of ammonium NH4H2PO4, sodium NaH2PO4 and potassium KH2PO4 dihydrophosphates. HA-particle surface adsorption of cations and anions from the solution, slight dissolution of HA in solutions of dihydrophosphates with acidic pH, as well as ion exchange of cations and anions of HA for cations and anions from solutions, were possible processes providing change in the ratio of cations and anions in the HA powder. The resulting ceramic composites contain biocompatible phases, and can be recommended for the creation of bone implants.
Materials (cement stone samples) in the CaO-K2O-SO3-H2O system with the target phase compositions, including syngenite K2Ca(SO4)2·H2O and calcium sulfate dihydrate CaSO4·2H2O, were prepared from powder mixtures of calcium sulfate anhydrite CaSO4, and/or calciolangbeinite K2Ca2(SO4)3, and potassium sulfate K2SO4 via hydration reactions at a water/powder ratio within an interval of 0.5–0.9. It was revealed that samples with contents of 25, 50, 75 and 100 mol% of syngenite K2Ca(SO4)2·H2O demonstrated a nonlinear dependence of their respective microstructures on their phase compositions. The microstructures of samples with phase compositions of 25 and 75 mol% of syngenite K2Ca(SO4)2·H2O consisted of pillar crystals. The microstructures of samples with phase compositions of 50 and 100 mol% of syngenite K2Ca(SO4)2·H2O consisted of plate crystals. An explanation of microstructure formation was set forth, taking into account equilibria of the dissolution–crystallization processes during cement stone formation. Materials obtained in the CaO-K2O-SO3-H2O system consisting of biocompatible and resorbable (soluble in water) phases can be recommended for testing as potential substances for bone defect treatments.
Calcium phosphate materials and materials based on silicon dioxide have been actively studied for more than 50 years due to their high biocompatibility and bioactivity. Hydroxyapatite and tricalcium phosphate are the most known among calcium phosphate materials, and Bioglass 45S5 is the most known material in the Na2O–CaO–SiO2–P2O5 system. Each of these materials has its application limits; however, some of them can be eliminated by obtaining composites based on calcium phosphate and bioglass. In this article, we provide an overview of the role of silicon and its compounds, including Bioglass 45S5, consider calcium phosphate materials, talk about the limits of each material, demonstrate the potential of the composites based on them, and show the other ways of obtaining composite ceramics in the Na2O–CaO–SiO2–P2O5 system.
Synthesis from mixed-anionic aqueous solutions is a novel approach to obtain active powders for bioceramics production in the CaO-SiO2-P2O5-Na2O system. In this work, powders were prepared using precipitation from aqueous solutions of the following precursors: Ca(NO3)2 and Na2HPO4 (CaP); Ca(NO3)2 and Na2SiO3 (CaSi); and Ca(NO3)2, Na2HPO4 and Na2SiO3 (CaPSi). Phase composition of the CaP powder included brushite CaHPO4‧2H2O and the CaSi powder included calcium silicate hydrate. Phase composition of the CaPSi powder consisted of the amorphous phase (presumably containing hydrated quasi-amorphous calcium phosphate and calcium silicate phase). All synthesized powders contained NaNO3 as a by-product. The total weight loss after heating up to 1000 °C for the CaP sample—28.3%, for the CaSi sample—38.8% and for the CaPSi sample was 29%. Phase composition of the ceramic samples after the heat treatment at 1000 °C based on the CaP powder contained β-NaCaPO4 and β-Ca2P2O7, the ceramic samples based on the CaSi powder contained α-CaSiO3 and Na2Ca2Si2O7, while the ceramics obtained from the CaPSi powder contained sodium rhenanite β-NaCaPO4, wollastonite α-CaSiO3 and Na3Ca6(PO4)5. The densest ceramic sample was obtained in CaO-SiO2-P2O5-Na2O system at 900 °C from the CaP powder (ρ = 2.53 g/cm3), while the other samples had densities of 0.93 g/cm3 (CaSi) and 1.22 (CaPSi) at the same temperature. The ceramics prepared in this system contain biocompatible and bioresorbable phases, and can be recommended for use in medicine for bone-defect treatment.
Ceramic materials in Na2O-CaO-P2O5 system were obtained by firing cement-salt stone made from pastes based on powder mixtures including calcium citrate tetrahydrate Ca3(C6H5O7)2∙4H2O, monocalcium phosphate monohydrate (MCPM) Ca(H2PO4)2∙H2O and/or sodium dihydrogen phosphate NaH2PO4. The phase composition of the obtained samples of cement-salt stone after adding water, hardening and drying included brushite CaHPO4∙2H2O, monetite CaHPO4 and also unreacted Ca3(C6H5O7)2∙4H2O, Ca(H2PO4)2∙H2O and/or NaH2PO4. The phase composition of ceramics in Na2O-CaO-P2O5 system obtained by firing cement-salt stone was formed due to thermal conversion of hydrated salt and heterophase reactions between components presented in samples during firing. The phase composition of ceramic samples based on powder mixture of Ca3(C6H5O7)2∙4H2O and Ca(H2PO4)2∙H2O after firing at 900 °C included β-calcium pyrophosphate (CPP) β-Ca2P2O7. The phase composition of ceramic samples based on powder mixture of Ca3(C6H5O7)2∙4H2O, and NaH2PO4 after firing at 900 °C included β-sodium rhenanite β-CaNaPO4. The phase composition of ceramic samples based on powder mixture of Ca3(C6H5O7)2∙4H2O, Ca(H2PO4)2∙H2O and NaH2PO4 after firing at 900 °C included β-Ca2P2O7, β-CaNaPO4, double calcium-sodium pyrophosphate Na2CaP2O7, and Na-substituted tricalcium phosphate Сa10Na(PO4)7. Obtained ceramic materials in Na2O-CaO-P2O5 system including biocompatible and biodegradable phases could be important for treatments of bone tissue defects by means of approaches of regenerative medicine.
— β-Tricalcium phosphate (β-Ca 3 (PO 4 ) 2 ) based ceramics with a relative density of 20–21%, grain size from 200 to 600 nm, and compressive strength from 1.6 to 1.8 MPa have been produced by 1000°C firing of cement stone prepared from a powder mixture having a Ca/P molar ratio of 1.5 and consisting of hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ), calcium citrate tetrahydrate (Ca 3 (C 6 H 5 O 7 ) 2 ·4H 2 O), and calcium dihydrogen phosphate monohydrate (Ca(H 2 PO 4 ) 2 ·H 2 O). The mixing liquid used to initiate chemical binding reaction in the powder mixture was distilled water. The phase composition of the cement stone included brushite (CaHPO 4 ·2H 2 O) and unreacted starting materials. The presence of platelike calcium pyrophosphate (Ca 2 P 2 O 7 ) particles, formed from platelike brushite (CaHPO 4 ·2H 2 O) particles, impeded densification of the ceramics during firing and ensured the formation of an ultraporous structure. The submicron-grained microstructure and phase composition of the β-Ca 3 (PO 4 ) 2 -based ceramics resulted mainly from heterophase interactions between the products of thermal decomposition of cement stone components. Offering sufficient strength, biocompatible and bioresorbable ultraporous submicron-grained β-Ca 3 (PO 4 ) 2 -based ceramics can be recommended for use in regenerative medicine for bone tissue defect repair.
The development of electrospun nanofibers based on cellulose and its derivatives is an inalienable task of modern materials science branches related to biomedical engineering. The considerable compatibility with multiple cell lines and capability to form unaligned nanofibrous frameworks help reproduce the properties of natural extracellular matrix and ensure scaffold applications as cell carriers promoting substantial cell adhesion, growth, and proliferation. In this paper, we are focusing on the structural features of cellulose itself and electrospun cellulosic fibers, including fiber diameter, spacing, and alignment responsible for facilitated cell capture. The study emphasizes the role of the most frequently discussed cellulose derivatives (cellulose acetate, carboxymethylcellulose, hydroxypropyl cellulose, etc.) and composites in scaffolding and cell culturing. The key issues of the electrospinning technique in scaffold design and insufficient micromechanics assessment are discussed. Based on recent studies aiming at the fabrication of artificial 2D and 3D nanofiber matrices, the current research provides the applicability assessment of the scaffolds toward osteoblasts (hFOB line), fibroblastic (NIH/3T3, HDF, HFF-1, L929 lines), endothelial (HUVEC line), and several other cell types. Furthermore, a critical aspect of cell adhesion through the adsorption of proteins on the surfaces is touched upon.
Interest in calcium phosphate cements as materials for the restoration and treatment of bone tissue defects is still high. Despite commercialization and use in the clinic, the calcium phosphate cements have great potential for development. Existing approaches to the production of calcium phosphate cements as drugs are analyzed. A description of the pathogenesis of the main diseases of bone tissue (trauma, osteomyelitis, osteoporosis and tumor) and effective common treatment strategies are presented in the review. An analysis of the modern understanding of the complex action of the cement matrix and the additives and drugs distributed in it in relation to the successful treatment of bone defects is given. The mechanisms of biological action of functional substances determine the effectiveness of use in certain clinical cases. An important direction of using calcium phosphate cements as a carrier of functional substances is the volumetric incorporation of anti-inflammatory, antitumor, antiresorptive and osteogenic functional substances. The main functionalization requirement for carrier materials is prolonged elution. Various release factors related to the matrix, functional substances and elution conditions are considered in the work. It is shown that cements are a complex system. Changing one of the many initial parameters in a wide range changes the final characteristics of the matrix and, accordingly, the kinetics. The main approaches to the effective functionalization of calcium phosphate cements are considered in the review.
Hydroxyapatite (HA) Ca 10 (PO 4 ) 6 (OH) 2 powders kept for 1 h with stirring in 0.25 M aqueous solutions of dihydrogen phosphates of ammonium NH 4 H 2 PO 4 , sodium NaH 2 PO 4 , and potassium KH 2 PO 4 were used to obtain ceramics. According to XRD data, there were no changes in the phase compositions of powders after such treatment. After firing at 900 – 1100°C the phase composition of ceramics based on HA Ca 10 (PO 4 ) 6 (OH) 2 powder treated with an aqueous solution of NH 4 H 2 PO 4 included β-tricalcium phosphate β-Ca 3 (PO 4 ) 2 and HA Ca 10 (PO 4 ) 6 (OH) 2 ; the phase composition of ceramics based on HA powder Ca 10 (PO 4 ) 6 (OH) 2 treated with an aqueous solution of NaH 2 PO 4 included sodium-substituted tricalcium phosphate Ca 10 Na(PO 4 ) 7 and HA Ca 10 (PO 4 ) 6 (OH) 2 ; the phase composition of ceramics based on HA powder Ca 10 (PO 4 ) 6 (OH) 2 treated with an aqueous solution of KH 2 PO 4 included potassium-substituted tricalcium phosphate Ca 10 K(PO 4 ) 7 and HA Ca 10 (PO 4 ) 6 (OH) 2 . The formation of biphasic ceramics occurred because of reduction in the Ca/P molar ratio of HA Ca 10 (PO 4 ) 6 (OH) 2 powder after treatment in aqueous solutions of dihydrogen phosphates of ammonium NH 4 H 2 PO 4 , sodium NaH 2 PO 4 , and potassium KH 2 PO 4 . Adsorption of cations and anions from solutions on the surface of HA particles, slight dissolution of HA in aqueous solutions of dihydrogen phosphates with acidic pH, as well as ion exchange of cations and anions in the HA structure for cations and anions from solutions were possible processes effecting change in the ratio of cations and anions in HA powder. The resulting ceramic composites contain biocompatible phases and can be recommended for creating bone implants.
Composite powders were synthesized from the water solutions of sodium silicate and different calcium salts (nitrate, chloride, and acetate) at a Ca/Si molar ratio of 1.0. According to the XRD data, all the synthesized powders included hydrated calcium silicate Ca1,5SiO3,5·xH2O (Ca/Si molar ratio = 1.5) and calcium carbonate CaCO3 (Ca/Si molar ratio = ∞). The presence of H2SiO3 or SiO2·xH2O in the synthesized powders was assumed to be due to the difference between the Ca/Si molar ratio of 1.0 specified by the synthesis protocol and the molar ratio of the detected products. Reaction by-products (sodium nitrate NaNO3, sodium chloride NaCl, and sodium acetate NaCH3COO) were also found in the synthesized powders after filtration and drying. According to the XRD data phase composition of all powders after washing four times consisted of the quasi-amorphous phase and calcium carbonate in the form of calcite. Calcium carbonate in the form of aragonite was detected in powders synthesized from calcium chloride CaCl2 and calcium nitrate Ca(NO3)2 before and after washing. Synthesized powders containing reaction by-products and washed powders were used for the preparation of ceramics at 900, 1000, and 1100 °C. The phase composition of the ceramic samples prepared from the washed powders and powder containing NaCl after firing at 900 and 1000 °C consisted of β-wollastonite β-CaSiO3, and, after firing at 1100 °C, consisted of both β-wollastonite β-CaSiO3 and pseudo-wollastonite α-CaSiO3. The phase composition of the ceramic samples prepared from powders containing sodium nitrate NaNO3 and sodium acetate NaCH3COO after firing at 900, 1000, and 1100 °C consisted of calcium sodium silicates, i.e., Na2Ca2Si3O9 (combeite) and Na2Ca3Si2O8. Synthesized and washed composite powders can be used for the preparation of biocompatible materials, in the technology of construction materials, and as components of lunar soil simulants.
β-Tricalcium phosphate (β-Ca3(PO4)2) based ceramics with a relative density of 20–21
The introduction of 24 wt.% powder of monocalcium phosphate monohydrate after firing at 1200°C into an impregnating suspension based on hydroxyapatite powder heat-treated at 800°C effects the formation of calcium phosphate ceramic foam based on β-tricalcium phosphate and β-calcium pyrophosphate. Successive application of hydroxyapatite and biomimetic apatite to calcium phosphate ceramic foam effects greater strength and enrichment with α-tricalcium phosphate and hydroxyapatite. Multiphase calcium phosphate ceramic foam possesses porosity 35 – 60%, static strength to 0.08 MPa, and heightened bioactivity on account of the biomimetic apatite layer.