Nanopatterned calcium phosphate ceramic material on basis of threecalciumphosphate-hydroxyapatite system for reconstruction of osteal defects
FIELD: medicine, pharmaceutics.
SUBSTANCE: it is described a nanopatterned calcium phosphate material on the basis of threecalciumphosphate-hydroxyapatite system for reconstruction of osteal defects. The invention concerns to the calcium phosphate ceramic materials intended for manufacturing of osteal implants and-or replacement of defects at various osteal pathologies. The material on the chemical compound is close to a natural osteal tissue (the structure corresponds to the threecalciumphosphate-hydroxyapatite system). The unique ultradisperse structure of a material is formed at the expense of use of initial calcium phosphate nanopatterned powders and the additive.
EFFECT: reception of a ceramic material with uniform structure with the average size of particles less than 100 nanometres.
1 tbl, 3 ex
The invention relates to medicine, in particular calcium phosphate ceramic materials intended for the manufacture of bone implants and/or replacement of defects in various bone pathologies.
Calcium phosphates are the main elements of the bone and are widely used as materials for bone regeneration and production of solid bone implants used in orthopedic, maxillofacial surgery, etc. To the most used in medicine to calcium phosphates include tricalcium phosphate - CA3(RHO4)2(TCP) and hydroxyapatite - CA5(PO4)3HE (HA) or bi-phase materials based on the system TKF-HA. Biological and mechanical properties of calcium phosphate ceramics are determined by the phase composition and structure, which mainly depend on the firing temperature and the size of the original particles of the ceramic powder. One method to improve mechanical properties and reduce the sintering temperature of ceramics is the use of ceramic ultrafine powders with a particle size less than 1 micron.
(A.Tampieri, G.Celotti, F.Szontagh and E.Landi "Sintering and characterization of HA and TCP bioceramics with control of their strength and phase purity" J. of Materials Sciance: Materials in Medicine 8 (1997) 29-37) were obtained calcium phosphate materials based on TCP and HA powders with an average crystal size of 0.5 is km. The obtained materials were characterized by a crystalline structure with an average crystal size of 1-2 microns, a porosity of less than 7%. The disadvantage of this material was high firing temperature 1220-1300°C. in Addition, at temperatures above 1250°C, the decrease of the strength and partial decomposition of HA with the formation of toxic calcium oxide.
The closest technical solution and the achieved effect is calcium phosphate-based materials system tricalcium phosphate-hydroxyapatite (S.Raynaud, E.Champion*, D.Bernache-Assollant "Calcium phosphate apatites with variable Ca/P atomic ratio II. Calcination and sintering", Biomaterials 23 (2002) 1073-1080) obtained by sintering of nanocrystalline powders at a temperature of 1100-1150°C. In this work to reduce the sintering temperature managed through the use of nanocrystalline powders and method of hot pressing. This has resulted in bi-phase materials system TKF-HA, which was characterized by a fine structure with an average crystal 200 nm. The disadvantage of this pottery is a high firing temperature and the application of the method of hot pressing, resulting in a considerable rise in prices of finished products.
The technical result of the invention is the obtaining of nanostructured ceramic material on the basis of HA-TCP medium p is smarami particles is not more than 100 nm, fusible to a dense state (open porosity of less than 4%) at temperatures up to 700°C.
To achieve a technical result of the proposed calcium phosphate ceramics on the basis of a system of HA-TCP 80-99,5 wt.% and supplements of 0.5-20 wt.%. The additive has the following composition, wt.%: potassium carbonate and 80%lithium carbonate up to 80% and the calcium carbonate up to 60%. The ceramic material of the composition is unknown.
When firing additive (a mixture of carbonates of potassium, lithium and calcium) dissociates with the formation of cations and carbonation, when interacting with a lattice of sintered material formed numerous defects, both the anion and the cation, which promotes sintering by solid phase mechanism at lower temperatures. In addition, the sintering being on liquid-phase mechanism, because the mixture of salts, potassium carbonate, sodium and calcium forms a low-temperature melts, which also reduces the sintering temperature of the material. With the introduction of additives in amounts of less than 0.5 wt.% the material was characterized by high porosity and toast to a dense state above 700-750°C. the use of additives is higher than 20 wt.% the pottery was deformed. Introduction in addition to the carbonates of potassium, more than 80 wt.%, lithium more than 80 wt.% and calcium more than 60 wt.% leads to increasing sintering temperature over 700°C and growth of poristost is more than 5%.
Example. 1 Powder-based systems HA-TKF with an atomic ratio of CA/P, equal 1,66-1,68, with a specific surface area of 120 m2/g is mixed with the additive in an amount of 7 wt.% composition: carbonate potassium - 40 wt.%, lithium carbonate 40 wt.% and calcium carbonate 20 wt.%. Then the powder mixture is molded in the form of beams of size 50×6×6. Molded samples calcined at 640°C. the result is 100% HA ceramic samples with a porosity of not more than 1% and with an average particle size of about 60 nm.
Example 2. The blood samples were obtained analogously to example 1. Difference is the use of powder-based systems HA-TKF with an atomic ratio of CA/P, equal 1,49-1,51, with a specific surface area of 130 m2/g and an additive in the amount of 0.5 wt.%, this Supplement consists of lithium carbonate 20 wt.% and potassium carbonate 80 wt.%. Sintering was carried out at 680°C. the result is 100% TKF ceramic samples with a porosity of not more than 4% and an average particle size of about 70 nm.
Example 3. The blood samples were obtained analogously to example 1. The difference is the use of a powder system HA-TKF with calculated atomic ratio CA/P, equal 1,52-1,54, and a specific surface area of 115 m /g and an additive in an amount of 10 wt.%, this Supplement consists of lithium carbonate 80 wt.% and calcium carbonate 20 wt.%. Sintering was carried out at 650°C. the result is a ceramic samples. containing 76-80 wt.%TKF and 20-24 wt.% HA with a porosity of not more than 3% and with an average particle size of about 90 nm.
Were produced samples of ceramics having compositions within the stated and defined their properties in comparison with the prototype. The results obtained are summarized in table.
Nanostructured calcium phosphate-based material system tricalcium phosphate-hydroxyapatite for reconstruction of bone defects, wherein the tricalcium phosphate-hydroxyapatite ceramics includes the additional additive is potassium carbonate and/or lithium carbonate and/or calcium carbonate with the following ratio of components in ceramics, wt.%:
|Hydroxyapatite and/or tricalcium phosphate||80-99,5|
in the following ratio of components in the additive, wt.%:
|Cabinet potassium and/or lithium||up to 80|
|lithium carbonate||up to 80|
FIELD: technical ceramics and refractory materials, possible use for manufacturing products used in electric engineering, mechanical engineering, chemical, metallurgic and other industrial branches.
SUBSTANCE: method for producing ceramic mass includes low-temperature annealing of plasma-chemical powders of metal oxides at temperature of 800-1000°C during 1 hour, mechanical activation by means of grinding during 25-50 hours in ball mill with addition of 0,25-0,5 mass.% sodium chloride in form of water solution as surfactant, mixing of plasma-chemical powders of metal oxides and organic connective - 12-15 weight.% of paraffin, containing 2-3 weight.% of beeswax. Plasma-chemical powders of oxides of aluminum, magnesium, yttrium, calcium, cerium, zirconium dioxide and their mixtures are used.
EFFECT: possible production of ceramic mass on basis of ultra-dispersion plasma-chemical powders of metal oxides with reduced content of organic connective and preserved structure of nano-powders with high values of casting capability.
3 ex, 1 tbl
FIELD: technology for preparing heat building-up materials.
SUBSTANCE: invention relates to manufacturing heat building-up materials. Method for preparing heat building-up materials based on talc-magnesite involves preparing 30-60% an aqueous suspension of talc-magnesite by grinding talc-magnesite, its mixing with water, additional addition to the suspension 5-15 wt.-% of iron oxides, 0.5-4 wt.-% of water glass, 0.05-7 wt.-% of cement followed by treatment in cavitational device at the rotor rate 3000-12000 rev/min, at temperature 15-70°C and number of treatment cycles 5-50, and molding the prepared mass under pressure and its thermal treatment. Invention provides enhancing the specific heat value of talc-magnesite-base material.
EFFECT: improved preparing method, improved properties of materials.
FIELD: manufacture of refractory materials of corundum composition; manufacture of articles for lining of different thermal units working at high temperatures.
SUBSTANCE: charge includes synthetic corundum modified with readily decomposing additive of aluminate composition (for example, aluminum nitrate, aluminum formiate, bauxite, etc.) in the amount of 1-5 mass-% and phosphate binder. Used as phosphate binder is aluminum-boro-phosphate binder at the following composition of components, mass-%: modified corundum, 90-93 and phosphate binder, 7-10. Proposed charge makes it possible to reduce its sintering temperature and porosity of articles at enhanced strength and heat resistance and additional residual change in sizes at heating (by 1-13%).
EFFECT: enhanced efficiency.
1 tbl, 4 ex
SUBSTANCE: invention relates to manufacture of molded ceramic materials for use as propping agent in production of liquid and gaseous fluids from bored wells. Method comprises briquetting and heat treatment of aluminosilicates kaolin at 1150-1250оС. Resulting mix is ground to average grain size 3-5 μm and loaded into granulator. Before granulation, 1.2-3.0% mineralizer and 5-10% plasticizer are added. Mix is moistened with dozed amount of organic binder and stirred to form granules. At the end of granulation, fired ground material for powdering granules is added in amount 1.2-3.0%. Granules are dried and screened to isolate desired fraction, which is subjected to final firing at 1370-1450оС for 30-60 min and then re-screened into commercial fractions.
EFFECT: enabled manufacture of granules having low loose density and high strength allowing their use at depths up to 14000 feet (4200 m).
3 cl, 1 dwg, 1 tbl, 3 ex
SUBSTANCE: method of phosphate ore processing includes one-step counterflow process of phosphate ore decomposition, characterised by P2O5 content exceeding 20% in weight, by processing it with water solution of hydrochloric acid, which has HCl concentration lower than 10% in weight, with formation of processing solution, consisting of water phase, in which calcium phosphate is in dissolved state, and of solid phase, which contains admixtures; preliminary neutralisation of processing solution, containing calcium phosphate in solution, to first pH value, which is lower than pH value, at which essential part of said dissolved calcium phosphate precipitates in form of calcium monohydrophosphate (DCP), with precipitation of admixtures; first separation of insoluble solid phase and water phase of processing solution; repeated neutralisation of water phase obtained during first separation to second pH value, exceeding said first pH value, with DCP precipitation; and second separation of repeatedly neutralised water medium, which represents water solution of calcium chloride and precipitated DCP.
EFFECT: method allows optimising ratio between dissolved P2O5 output and purity degree of final product and ensure economically profitable process, which can be realised on simple equipment.
14 cl, 3 dwg, 2 tbl, 1 ex
SUBSTANCE: nano-sized highly-pure hydroxylapatite (HAP) is obtained in form of alcohol colloid solution (gel), which can be used for production of medicinal preventive preparations in stomatology, for applying bioactive coating on bone implants. Method includes hydroxylapatite synthesis by adding solution of orthophosphoric acid to calcium hydroxide solution and exposure to ultrasound impact, and ethyl or isopropyl alcohol is added to colloid of highly-pure nano-sized hydroxylapatite with concentration from 5% to 40±2% in order to obtain concentration of hydrooxylapatite in alcohol from 0.2 to 20%. After that alcohol mixture is processed with ultrasound with frequency 10-50 kHz during 1-2 hours.
EFFECT: alcohol colloid of nano-sized hydroxylapatite with high stability.
2 cl, 3 ex
SUBSTANCE: invention relates to technology of obtaining inorganic materials, namely to methods of obtaining nanosized highly pure hydroxylapatite (HAP) in form of colloid solution or gel, which can be used for production of medico-preventive preparations for stomatology, for application on bone implants. Method of obtaining nanosized colloid hydroxylapatite includes synthesis of hydroxylapatite in saturated solution of calcium hydroxide, decanted after 24-hour settling from sedimented aggregates Ca(OH)2, by adding at rate 1.5-2.2 ml/min per litre of alkali solution 10-20% solution of orthophosphoric acid with constant mixing until pH value of reaction mixture is not lower than 10.5±0.5. Mixture is mixed during 20-30 minutes, settled during 1-2 hours and decanted until liquid phase stops forming on the surface. Obtain product represents colloid solution of highly pure hydroxylapatite with concentration 1.5-2%. Increase of hydroxylapatite concentration within the range from 2 to 30% is carried out by evaporation at temperature not higher than 60°C, and for obtaining nanosized hydroxylapatite with concentration 40±2% initial colloid solution is subjected to complete freezing with further unfreezing at temperature not more than 60°C and liquid phase decanting.
EFFECT: obtaining stable product with set in advance concentration, possessing higher penetrating ability and biochemical activity.
3 cl, 4 ex
SUBSTANCE: method of processing of residual products containing phosphoric acid to calcium phosphates comprises its mixing with calcium-containing compounds, separation of derived slurry with filtration and drying. The limestone is used as calcium-containing compound, initially it is fed for mixing in quantity necessary for monocalcium phosphate, then derived slurry is divided to two flows in ratio 1:(1.5-4), the major flow is mixed with lime taken in quantity necessary for dicalcium phosphate formation, derived slurry is separated with filtration and minor flow of monocalcium phosphate slurry is added to separated dicalcium phosphate before drying and granulating. Preparation of monocalcium phosphate slurry is carried out in two stages, at first stage the phosphoric acid is mixed with limestone up to mixture pH =2.9-3.1, at second stage - up to mixture pH =3.5-3.7, during mixing of monocalcium phosphate slurry with lime pH is maintained in the range 5.4-5.6. Drying and granulating are carried out at the same time in drum granulator-dryer.
EFFECT: method enables to process the residual products to granulated calcium phosphates with usage the lowest-cost raw materials.
3 cl, 1 tbl, 1 ex
FIELD: paint and varnish industry.
SUBSTANCE: anticorrosive pigment comprises , in mass per cents, 3.0-4.7 of calcium chromate and waterless dicalciumphosphate as the balance.
EFFECT: improved anticorrosion capabilities.
FIELD: production of pure phosphoric acid and calcium monohydrophosphate.
SUBSTANCE: proposed method includes decomposition of phosphate ore by first hydrochloric acid solution at concentration not exceeding 10 mass-%, separation of liquid decomposition product into insoluble solid phase containing admixtures and separate aqueous phase containing phosphate, chloride and calcium ions in form of solution, neutralization of aqueous phase separated from liquid decomposition product by adding calcium compound for obtaining insoluble settled-out calcium phosphate by means of phosphate ions, separation of neutralized aqueous phase into aqueous phase containing calcium and chloride ions in form of solution and settled solid phase on base of water-insoluble calcium phosphate and dissolving of at least part of separated settled solid phase in second aqueous hydrochloric acid solution containing hydrochloric acid in the amount exceeding its content in first hydrochloric acid solution, thus forming aqueous solution containing phosphate, chloride and calcium ions extracted by organic extracting agent at extraction in "liquid-liquid" system. Proposed method makes it possible to avoid fine grinding or roasting of ore.
EFFECT: enhanced efficiency of extraction for production of pure concentrated phosphoric acid solution with no contamination of surrounding medium.
24 cl, 2 dwg, 1 tbl, 4 ex
FIELD: inorganic chemistry, chemical technology.
SUBSTANCE: invention relates to technology for preparing fodder calcium phosphates, namely to producing monocalcium phosphate. Method involves mixing wet-process phosphoric acid with a calcium-containing component in the presence of recycle, granulation and drying the product. Mixing process is carried out for two stages. At the first stage wet-process phosphoric acid with the concentration 62-65% of P2O5 is fed and process is carried out at recycle index = 1:(0.3-0.5) up to decomposition degree of calcium-containing raw = 0.89-0.92 at this stage. The second stage is combined with granulation and carried out its in high-speed mixer in water addition to obtain moisture in mixture 9.5-13%. The rate and time for mixing are regulated to provide the decomposition degree of calcium-containing raw = 0.93-0.99, and temperature at the next drying stage is maintained in the level 105-115°C. Method provides simplifying the process, reducing energy consumption and preparing product with the high content of P2O5 in water-soluble form and low content of fluorine.
EFFECT: improved method for preparing.
2 cl, 3 ex
FIELD: industrial inorganic synthesis.
SUBSTANCE: monocalcium phosphate, widely applied in agriculture, is prepared by mixing extraction phosphoric acid with calcium-containing component followed by granulation and drying of product. During mixing of components, appropriate temperature and moisture are maintained to ensure viscosity of mixture 3-7 mPa*s, and granulation and drying are carried out simultaneously in drum-type granulator drier. Calcium-containing component is either calcium carbonate or mixture thereof with limestone, whose does not exceed 15% of total weight of calcium-containing raw material. Moisture content in worked out drying agent leaving drum-type granulator drier equals 70-80 g per 1 kg dry air.
EFFECT: simplified process flowsheet, enabled granule size control, and increased strength of granules.
3 cl, 3 ex
SUBSTANCE: invention is related to the field of scientific instrument-making and is intended for application in scanning probing microscopes and nanotechnological plants for object micromotions. Device for object micromotions comprises base, magnet with magnetic conductors, holder with collet spring, object holder, bracket, three coils and piezoelectric tube. On the basis the following components are fixed: magnet with magnetic conductors, and also one end of piezoelectric tube, the other end of which is equipped with holder with collet spring and holder of displaced object installed in spring. Magnetic conductors create magnetic gap, in which three coils are installed, at that the first coil is placed on holder of displaced object, and the second and third coils are placed on bracket connected to holder.
EFFECT: increased accuracy of micromotions object positioning due to damping of dying oscillations and improvement of extent of friction force negative effect compensation.