Wear resistant composite ceramic nanostructured material and method of its obtaining
SUBSTANCE: claimed ceramic material based on aluminium oxide with a volume content of components: Al2O3 63-82%, TiCN 16-34%, ZrO2 2-3%, contains a phase of titanium carbonitride TiCN on boundaries of aluminium oxide grains and nanosize particles of zirconium dioxide inside aluminium oxide. The phase of titanium carbonitride is presented by the nanosize particles and particles of submicron size. The nanosize particles of TiCN and ZrO2 are additionally present on the boundaries of aluminium oxide grains and particles of TiCN phase of submicron size. The claimed method of the ceramic material obtaining, includes stages of milling, mixing of components after milling and sintering of the obtained mixture, with a speed of mixture heating to a temperature of sintering being supported constant in the range of 50-400 degree/min, and sintering being realised at temperatures from 1450 to 1600°C, under an impact of electric and/or electromagnetic fields under pressure.
EFFECT: high indices of strength, hardness, wear resistance of the material, including that at increased temperatures.
5 cl, 11 ex, 2 tbl, 1 dwg
The invention relates to the field of technical ceramics, in particular the wear-resistant composite ceramic nanostructured material (hereinafter material) on the basis of aluminum oxide (Al2O3), having high strength, hardness, wear resistance, including at elevated temperatures, as well as to a method for producing this material. The proposed material can be used for the manufacture of cutting tools with high service life and wear-resistant parts for machinery.
The main material properties of the cutting tool, which determine the parameters of the machining process such as cutting speed and feed, depth of cut, the type of material to be processed, the application in conditions of semi finishing and interrupted cutting, tool life)are hardness, strength, heat resistance, wear resistance, including resistance to crater wear. For machining cast irons sufficient level of hardness Hv10the material of the cutting tool is 16.5-17.5 HPa, and for hardened steels required hardness Hv10not less 21-22 HPa, and the possibility of intermittent processing is provided by the tensile strength in bending of at least 800 MPa, .
Development carried out in this area and directed the on solving these problems, associated with the search for the optimum of the compositions and methods of forming the special microstructures.
Known composite materials based on Al2O3containing carbonitride or carbide of titanium and zirconium dioxide (ZrO2), which are currently used for obtaining cutting tool for finishing of cast iron and hardened steel with a hardness of 50 to 65 HRC .
Introduction titanium carbonitride (TiCN) in the composition containing aluminum oxide, increases the hardness and wear resistance, and supplements ZrO2increase his strength and crack resistance. While the impact of these two components mutually opposite: the higher the content of one of them weakens the quality, improve the presence of the other. For example, in the range of developments achieved a high level of strength, due to the high content of zirconium dioxide, however, the level of hardness Hv is in the range of 12.5 to 13.5 GPA [4, 5]. At low concentrations of Zirconia high hardness combined with moderate strength (for example, about 700 HPa), which does not allow to use the material in cutting tools for operations with intermittent processing and reduces the tool life . Thus, we can conclude that a higher level of performance by varying the composition, as a result reaches a certain limit.
Properties of ceramic composites based on aluminum oxide are largely determined by the microstructure, in particular the uniformity of distribution of the introduced components relative to the phase of Al2O3and uniformity of distribution of the particle (grain) size. Special advantages of the formation of compositions containing nano-sized particles, at least one of the phases, which can be located inside and/or on the limits of the larger grains of different phases . Such a microstructure can achieve higher hardness, in addition to cement grains  and interphase boundaries, which increases the wear resistance of the material, in particular resistance to crater wear. Development of nanostructured composites is achieved through the use of nanopowders and prevent grain growth during sintering.
In the formation of nanostructures in composites play an important role technological parameters of the sintering process: the lower the sintering temperature, shorter cycle time and higher the heating rate, the greater the probability that the grain size of the starting components at the nanoscale. There are modern technologies that use the activating influence of electric and electromagnetic fields, such as: induction heating under uniaxial pressure, the method of electrical discharge Spokane the method (SPS) and other These technologies allow to carry out the sintering at much lower temperatures and shorter cycles and higher heating rate compared to traditional methods. However, to realize these benefits conditions of heat and properties of mixtures should ensure uniformity of the temperature field in the whole volume of sintered blanks. The latter condition occurs when a volume of sintered mixture of heat and electrically conductive cluster.
A known material with high strength . The material consists of emery-zirconium matrix (particle size 0.3 to 0.5 μm)containing 30-50% of zirconium dioxide by volume of the matrix, and carbonitride of titanium in the amount of 20% of the volume of the material. A lack of material, from the point of view of the problems to be solved in the framework of this invention are: the uneven distribution of TiCN particles in the matrix, and insufficient for use in cutting tools, the level of hardness (Hv≤18 HPa). The main cause moderate level of hardness is high content of ZrO2 (30 vol.%. in the matrix, which corresponds to 24% of the total material). The disadvantages of the method are: the complexity of the process associated with the use of mortar technology and the prevailing content of the powders in the mixture that promotes their aglomerirovanie, complicates dispergirovany the initial components and homogeneous distribution in the microstructure of the material, and also may enhance the grain growth during sintering. In addition, in this method the traditional method of hot pressing, which is characterized by a relatively low heating rate and long-term exposure at the maximum sintering temperature, which also contributes to the growth of grain.
Closest to the present invention is a technical solution for the application JP 7097255 (A) (SV 35/10) , related to material with a matrix of aluminum oxide, which has been allocated one or two additional phases (in particular, TiCN and ZrO2) in the form: (1) particles inside the grains phases of Al2O3(the so-called "dispersed phase") and (2) particles located at grain boundaries of Al2O3(the so-called "intergranular phases"). The content of grains of Al2O3the material is 85-99,5 vol.%, the particle size of the disperse phase" is smaller than the grains of aluminum oxide and, according to the description corresponds to nanoreno. According to the description of examples, "intergranular phase" is only represented by particles with sizes of 0.2-0.4 microns, exceeding nanorover (0.1 ám), i.e., are in accordance with generally accepted terminology, "submicron level (between 0.1 and 1 μm), and the grain size of the alumina is from 1.5 to 2.5 μm.
To obtain the material at the specified invention previously perform SIP the La and mixing the alumina with the input components, with the possible use of pre-application on grain Al2O3coating, for example of titanium carbonitride, by physical or chemical vapour deposition. For sintering the prepared mixtures using free sintering, hot pressing or hot isostatic pressing at temperatures in the range from 1600 to 1850°C.
The disadvantage of the material of the prototype is a low content of titanium carbonitride, not exceeding 15%vol., that is not sufficient to provide the desired level of hardness (21-22 HPa). In addition, the content of TiCN is insufficient to create a thermally conductive cluster in the volume of the sintered mixture, which excludes conditions quick and uniform heating (achieving a homogeneous and fine-grained microstructure). The strength, hardness and fracture toughness of the material obtained in the description of this invention are not given. The level of resistance exhibited by the time full production resource tool, is not sufficiently high to achieve the objectives of the claimed invention. The disadvantage of the microstructure of a material is the lack of nanoscale particles in the intergranular phase. While it is known that the presence of nanoparticles on the phase boundaries in Zn is significant extent strengthens these boundaries, preventing their destruction and increasing strength, crack resistance and wear resistance of the material .
The main disadvantages of the method of obtaining material of the prototype is the use of high temperature sintering (between 1,600 and 1,850°C) and the traditional ways of heating, paired with a lasting effect of temperature on sintered mixture, which leads to grain growth of alumina and particles of the intergranular phase during sintering. The disadvantage of this method is the use of a preliminary high-temperature phase coating on the grains of aluminium oxide, which increases material cost and complicates the process.
The invention relates to wear-resistant composite ceramic nanostructured material based on aluminum oxide containing carbonitride titanium and zirconium dioxide, for use in cutting tools with increased service life and extended nomenclature of the processed metal alloys, as well as for the manufacture of wear-resistant structural parts.
The present invention is the creation of a composite ceramic material having high tensile strength in bending (not less than 800 MPa), hardness (21-22 HPa) and durability for use in the manufacture of cutting tools with high time the service is s and advanced applications, including hardened steel and operations intermittent treatment manufactured by a process suitable for mass production, which ensures the homogeneous microstructure containing nano-sized particles introduced components both inside and along the grain boundaries of the main phase of Al2O3.
This problem is solved by creating a wear-resistant composite ceramic nanostructured material based on aluminum oxide containing phase titanium carbonitride on the grain boundaries of the aluminum oxide and nano-sized particles of Zirconia inside the grains of aluminum oxide, in which the phase of the titanium carbonitride presents nano-particles and sub-micron size level. In addition nano-sized particles of titanium carbonitride and Zirconia are present at grain boundaries of the aluminum oxide and particles of submicron size level phase titanium carbonitride. Volumetric component content, %: Al2O3- 62-83; TiCN - 15-35, ZrO2- 2.0 to 3.0.
To create a material with these characteristics, a method for receiving comprising a stage of grinding, mixing the components after milling and sintering the mixture, in which the rate of heating to the sintering temperature constant support in the range is the area from 50 to 400 deg/min, and the sintering is carried out at temperatures ranging from 1450 to 1600°C, when exposed to electric and/or electromagnetic fields under pressure. To achieve the microstructure close to submicron, the grinding of titanium carbonitride is carried out to obtain the metric d50not more than 600 nm, while the volumetric content of particles less than 100 nm in titanium carbonitride after grinding is from 2 to 5%. Phase mixing of the components may be carried out under the action of ultrasonic vibrations.
In the proposed material based on aluminum oxide containing carbonitride titanium and zirconium dioxide, a technical effect is achieved, on the one hand, due to composition, in which a sufficiently high content of titanium carbonitride provides high hardness and wear resistance of the material, and the presence of phase t-ZrO2with its low content provides enough padding without the effect of reducing the hardness. The above-mentioned hardening is realized due to the fact that at the time of occurrence of defects (cracks) in the operation of the product in the material mechanism is implemented so-called "transformation hardening," in which the tetragonal phase t-ZrO2transforms into monoclinic m-ZrO2the particles of Zirconia, located in the front of propagation of cracks, which is accompanied by some increase in the volume and leads to "heal" this crack.
On the other hand, the technical effect achieved by creation of a special microstructure in which the grain of the aluminum oxide reinforced with nanoparticles ZrO2and interfacial grain boundaries of Al2O3and sub-micron particles TiCN reinforced with nanoparticles ZrO2and TiCN. Strengthening crystal boundaries nanoparticles increases the level of mechanical properties of the material, including at elevated temperatures (created when cutting hard materials with high speeds), improves the resistance of the cutting tool wear, in particular to the crater. In addition, the obtained microstructure is fine-grained and homogeneous, where it achieves a homogeneous distribution of the components, and particle size, which is also reflected in the increased mechanical properties of the material.
It should be noted that the mentioned high content and uniform distribution of the phase TiCN is also a necessary condition for the implementation of the proposed retrieval method. This component, because of its relatively high thermal conductivity and electric conductivity), capable of rapid and uniform heating, especially in the presence of electric and/or electromagnetic fields. This enables not only high speed to heat the mixture after grinding up to the sintering temperature, but also to maintain the speed constant and conduct sintering in a short time (3-15 min) with high reproducibility. The alignment of the temperature field for the harvest and the effect of heating due to internal heat sources activates sintering, reducing operating temperature. Under the influence of an electric field during electric discharge sintering (SPS-method) there is an additional activation of the sintering process and further improve the uniformity of the temperature field by creating in the volume of the electrically conductive workpiece cluster of particles TiCN. The sintering time in the SPS method is minimal (3-5 min). These factors help to prevent grain growth.
The presence of nano-sized ZrO2 particles and TiCN at the grain boundaries of Al2O3and TiCN also helps curb the growth of these grains in the sintering process.
Content TiCN less than 16% vol. is insufficient to achieve the desired level of hardness and wear resistance of the material, as it is a component of the material makes the most significant contribution in the indicator toughness. In addition, the content of TiCN is insufficient for the formation of the sintered billet heat and electrically conductive cluster, increase the uniformity of heating and activating the sintering process at high heating rate and reduced temperatures. In this case not provided the necessary conditions for effective prevention of grain growth and, as the result is s, decrease the hardness and wear resistance of the material, at the same time not reached the hardening effect due to the presence of nanosized grains.
When the content TiCN more than 34% in the sintered billet unnecessarily increases the share of contacting grains of this phase, the sintering them difficult (compared to the sintering of grains involving aluminum oxide) and requires a higher temperature, which causes excessive grain growth and, consequently, deterioration of the hardness and wear resistance of the material and also the reduction of the hardening effect due to the presence of nanosized grains. In addition, a material with a high content of TiCN is more expensive.
The content of Al2O3in the composition of the material and mutually connected with the content of TiCN. Thus, the material containing more than 82% Al2O3, characterized by the lack of content TiCN (less than 16%vol.) and the corresponding deterioration. Similarly, the material containing less than 63% Al2O3, characterized by the excessive content of TiCN (34%) and the corresponding deterioration, according to the above description.
The content of ZrO2less than 2.0 vol.% is insufficient to realize the desired effect transformation hardening of the grains of Al2O3and interphase boundaries. Besides, with what you learn in due measure is not realized the effect of the ZrO2 nanoparticles, present at the interphase boundaries on the growth of the grains of the Al2O3and TiCN particles during sintering. These circumstances are accompanied by a decrease in strength, hardness and wear resistance of the material.
When the content of ZrO2more than 3.0 vol.% becomes noticeable effect of this component is to reduce the hardness of the material. As the source of zirconium dioxide is used in the form of a nanopowder, in this case also increases the total content of nanoparticles in the original mixture, which makes the dispersion and mixing, increases the probability of formation of agglomerates and, therefore, promotes the growth of particles ZrO2and the formation of heterogeneous structures, deteriorating properties of the material.
In a preferred embodiment of the invention all the grains in the microstructure is smaller than 1.5 μm, which contributes to the achievement of the highest hardness and wear resistance.
In the proposed method of obtaining material heated to a temperature of the sintering is carried out at a high speed. The heating rate is less than 50 deg/min is sufficient to prevent the grain growth. In this case, is not achieved sufficient hardening effect of the grain boundaries of the nanoparticles, and the microstructure may be heterogeneous, containing large grains. These factors lead to reduction of hardness, strength, and and the nososticta material. At a heating rate of more than 400 deg/min is not ensured the formation of a homogeneous field of temperature on the volume of the workpiece. In addition, the duration of the heating in this case is too small for the normal formation of grain boundaries, which complicates the sintering. These factors lead to inhomogeneous microstructure and deterioration of material properties.
When using sintering temperatures below 1450°C degrades the density, strength and wear resistance of the material, as these temperatures are not sufficient for sintering the particles TiCN. Sintering temperature above 1600°C lead to excessive grain growth, thereby reducing the effect of strengthening nanoparticles, hardness and wear resistance of the material.
If the grinding of the original TiCN powder is carried out to obtain the metric d50not more than 600 nm, the structure of the material becomes more homogeneous and fine-grained, which further increases the hardness and wear resistance of the material.
When the content in the hammer carbonitride particle size of less than 100 nm (i.e. nanoparticles) in an amount of not less than 2 vol.% additionally improve the contacts between the TiCN particles when forming the heat - conductive cluster in the sintered mixture and, therefore, further increases the uniformity of the temperature field during sintering, contributing to improved homogeneity microstruc the tours of the material. It also improves the hardening effect of interphase boundaries due to the presence of nanoparticles. The limitations of the content of nanoparticles TiCN in the hammer carbonitride not more than 5 vol.%, allows you to avoid agglomeration of TiCN particles in the mixture and, consequently, their growth during sintering.
If the mixing is carried out under the action of ultrasonic vibrations, it is additionally improves the homogeneity of the mixture, decreases the probability of presence of agglomerates, therefore, uniformity.
The invention is new, involves an inventive step, applicable on an industrial scale. The invention can be implemented using well-known equipment, such as SINTER plants SPS - 625 (Sumitomo) and NNR D 25 (FCT Systeme GmbH).
Produce the original grinding powder of titanium carbonitride in a vibratory mill in the environment of isopropyl alcohol to the final dispersion are given in table 1. Milled powder of titanium carbonitride is mixed with alumina powder (company Almatis, mark ST 3000 SDP), a powder of zirconium dioxide (Pangea International brand C-3YB) in the ratio: 64% aluminum oxide, 34% carbonitride titanium, 2% vol. Zirconia, in a ball mill with grinding bodies of titanium carbonitride in an environment of isopropyl alcohol in the presence of surfactants (oleic acid) for 12 hours.
Ready shytobuy mesh is sintered by hot pressing with induction heating-rate sintering of 100 deg/min in argon at a temperature of 1600°C.
The microstructure of the resulting material examined using scanning electron microscopy and optical electron microscopy. The phase composition is determined by the method of x-ray phase analysis. Hardness Vickers determined under a load of 10 kgf, the bend test is conducted by the method of three-point bending. Determination of wear resistance material spend time developing a resource tool. Tests are carried out on the plate SNMN 120408. Samples tested continuous turning under the following conditions: machined steel jug (HRC 60~62), the cutting speed of 150 m/min, depth of cut 0.5 mm, feed 0.1 mm/Rev. Trials continue until the complete exhaustion of the resource samples. Full production of cutting plates appreciate in excess of abrasive wear on the rear surface values are 0.3 mm or the occurrence of surface defects, chips, etc.
Figure 1 shows fractorama the surface of the destruction of a sample of the material obtained in the field of view scanning electron microscope, showing the microstructure of the material. The properties of the material obtained are shown in table 2.
The powder of titanium carbonitride in example 1 is mixed with powders of aluminum oxide and zirconium dioxide as described in example 1 in the ratio: 83% aluminum oxide, 15 vol.%, carbonitride titanium, 2% vol. on the zirconium oxide. Sintering is conducted as described in example 1.
The properties of the material obtained are shown in table 2.
The powder of titanium carbonitride in example 1 is mixed with powders of aluminum oxide and zirconium dioxide as described in example 1 in the ratio: 58% vol. aluminum oxide, 40% vol. carbonitride titanium, 2% vol. Zirconia. Sintering is conducted as described in example 1. The properties of the material obtained are shown in table 2.
Powders of titanium carbonitride, aluminum oxide, zirconium dioxide according to example 1 are mixed in a reactor with stirrer when exposed to ultrasound (ultrasonic power generator 4 kW) in distilled water in the presence of oxidation inhibitor metamax 115 and surface-active substances (surfactants) for 2 hours. Sintering is conducted as described in example 1. The properties of the material obtained are shown in table 2.
Powders of titanium carbonitride, aluminum oxide, zirconium dioxide according to example 1 are mixed as described in example 4. Sintering is conducted by SPS method in argon at a temperature of 1450°C. the Properties of the material obtained are shown in table 2.
The powder of titanium carbonitride in example 1 is mixed with powders of aluminum oxide and zirconium dioxide as described in example 1 in the ratio: 65% aluminum oxide, 34 vol.%. carbonitride titanium, 1% vol. dioxide CID is one. Sintering is conducted as described in example 1. The properties of the material obtained are shown in table 2.
Produce a milled powder of titanium carbonitride in a vibratory mill in the environment of isopropyl alcohol, to the final dispersion in which the particle content of less than 0.8 μm is 50 vol.%, and the content of particles with a size not exceeding 100 nm - 1% vol. (table 1).
The powder of titanium carbonitride is mixed with powders of aluminum oxide and zirconium dioxide as described in example 1 in the ratio: 64% aluminum oxide, 34% carbonitride titanium, 2% vol. Zirconia. Sintering is conducted as described in example 1. The properties of the material obtained are shown in table 2.
The powder of titanium carbonitride in example 1 is mixed with powders of aluminum oxide, zirconium dioxide, as described in example 1 at a ratio of 90 vol.% aluminum oxide, 8% vol. carbonitride titanium, 2% vol. Zirconia. Sintering is conducted as described in example 1. The properties of the material obtained are shown in table 2.
The powder of titanium carbonitride in example 1 is mixed with powders of aluminum oxide and zirconium dioxide as described in example 1 in the ratio as in example 2. Sintering is conducted as described in example 5. The properties of the material obtained are shown in table 2.
The powder of titanium carbonitride on PR is a measure 1 is mixed with powders of aluminum oxide and zirconium dioxide as described in example 4 in the ratio as in example 2. Sintering is conducted as described in example 5.
The properties of the material obtained are shown in table 2.
The powder of titanium carbonitride in example 1 is mixed with powders of aluminum oxide and zirconium dioxide in the ratio as in example 1. Sintering is conducted by the traditional method of hot pressing sintering (resistive heating) speed sintering of 20 deg/min in argon at a temperature of 1600°C.
|# example||The blending method*||The time of mixing, h||Composition, vol.%||TiCN, d50nm||Method of sintering**||Speed spainiard/min||The sintering temperature, °C||The sintering time, min|
|The total content||Including <100 nm)|
|Notes: *BL - ball mill, ULTRASONIC ultrazvukova mill;|
**GP - hot pressing
|No. sample||ρ, g/cm3||Flexural strength, MPa||The time for complete development, min|
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. Xu C., C. Huang, X. Ai Cutting behavior and related cracks in wear and fracture of ceramic tool materials // Int. J. Adv. Manuf. Technol. - 2007. - V.32: - P.1083-1089
. Barry, J., Byrne G. Cutting tool wear in the machining of hardened steels: Part I: alumina/TiC cutting tool wear // Wear. - 2001. - V.247, Is.2. - P.139-15
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. Dong Qian. Al2O3-TiC-ZrO2 nanocomposites fabricated by combustion synthesis followed by hot pressing / Qian Dong, Qing Tang, Wenchao Li // Materials Science and Engineering: A. - 2008. - V.475, No..1-2. - P.68.
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 Dyatlovo AG Instrumental based ceramic composition Al2O3-ZrO2-TiCN / AG Dyatlova, S. Agafonov, HE Boykov, S. of Ordanian, V. Rumyantsev // Powder metallurgy. - 2010, No. 11/12. - R-83
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1. Wear-resistant composite ceramic nanostructured material based on aluminum oxide containing phase titanium carbonitride on the grain boundaries of the aluminum oxide and nano-sized particles of Zirconia inside the grains of aluminum oxide, characterized in that the phase of the titanium carbonitride presents nano-particles and sub-micron size level, with advanced nano-sized particles of titanium carbonitride and Zirconia are present at grain boundaries of the aluminum oxide and particles of submicron size level phase titanium carbonitride, and a volumetric component content, %:
TiCN - 16-34;
ZrO2- 2.0 to 3.0.
2. The material according to claim 1, in which the grain size of the aluminum oxide is less than 1.5 mm.
3. A method of obtaining a material according to claim 1, which includes stages of grinding, mixing the components after milling and sintering the mixture, wherein the heating rate of the mixture to a temperature of the sintering support constant in the range from 50 to 400 deg/min, and sintering the implementation of the presentations at temperatures from 1450 to 1600°C, when exposed to electric and/or electromagnetic fields under pressure.
4. The method according to claim 3, in which the grinding of titanium carbonitride is carried out to obtain the metric d50not more than 600 nm, while the volumetric content of particles less than 100 nm in titanium carbonitride after grinding is from 2 to 5%.
5. The method according to claim 3, in which the stage of mixing the components is performed under the action of ultrasonic vibrations.
SUBSTANCE: boron suboxide-based composite material contains boron suboxide and a second phase in bound form, the second phase containing a boride and uniformly distributed in the boron suboxide. The composite material has crack resistance of more than 3.5 MPa·m0.5, and hardness of more than 25 GPa. The borides are selected from a group comprising borides of group IV-VIII transition metals and borides of platinum group metals. In particular, the boride can be selected from a group comprising borides of iron, cobalt, nickel, titanium, tungsten, hafnium, tantalum, zirconium, rhenium, molybdenum, chromium, manganese and niobium. The boride can also be a boride of a platinum group metal, preferably palladium boride. Furthermore, the second phase can contain one or more oxides. According to the disclosed method of producing the composite material, a boron suboxide source is brought into contact with a boride or source thereof and the obtained mass is sintered at temperature of 1750-1900°C.
EFFECT: obtaining boron suboxide-based materials with high strength and crack resistance.
22 cl, 22 ex, 1 tbl, 4 dwg
FIELD: process engineering.
SUBSTANCE: proposed invention relates to production of diamond composite materials consisting of dense bulk of diamond crystals bonded by binder. Method comprises bringing layer of diamond powder and layer of binder in contact, subjecting them to pressure and heat and impregnating with binder of the following composition, in wt %: Si - 50÷70; Ni - 25÷45 and Ti - 3÷10. Compaction of diamond powder layer and impregnation with binder are performed at 2.0÷4.0 GPa and 1000÷300°C.
EFFECT: impregnation at lower pressure and temperature, high-strength and impact-resistant material.
FIELD: construction industry.
SUBSTANCE: invention refers to manufacturing method of fluorescent ceramics having general formula Gd2O2S alloyed with the element chosen from the group consisting of Ce, Pr, Eu, Tb, Yb, Dy, Sm and/or Ho. Manufacturing method of fluorescent ceramic material includes the following stages: a) selection of powder-like pigment Gd2O2S alloyed with M, and M is at least the element chosen from the group containing Eu, Tb, Yb, Dy, Sm, Ho, Ce and/or Pr; at that, grain size of the above powder used for hot pressing is 1 mcm to 20 mcm, hot pressing and annealing. Hot pressing is performed at temperature of 1000°C to 1400°C and/or pressure of 100 MPa to 300 MPa, annealing - in vacuum at temperature of 1000 to 1400°C during 0.5-30 hours, and then -in the air at temperature of 700°C to 1200°C during 0.5-30 hours.
EFFECT: possibility of being used in ionising-radiation detectors.
21 ex, 2 tbl
FIELD: technological processes.
SUBSTANCE: invention may be used for production of parts and cutting tools for processing of wear resistant materials, in particular, silicon-containing aluminium alloys. Layers of diamond powder and material of impregnation that are in contact are placed layer by layer on charge. Layer of diamond powder is divided into two layers. In one of the layers, which contacts with impregnation material, diamond powder is used with size of particles from 20/14 to 2/1 mcm. Additionally detonating diamond powder is introduced with size of particles in the range from 1 to 100 nanometers in the amount from 1 to 30 percents from the volume of diamond powder of this layer. In the second layer, which contacts the first one, diamond powder is used with size of particles in the range from 40/28 to 28/20 mcm, at that height of this layer in respect to the first one amounts from 2:1 to 3:1. As impregnation material silicon or silicon-containing materials are used, for example, mixture of silicon powders, flaked graphite and detonating diamond. Stock prepared by this method is affected with high pressure - from 3 to 8 GPa and temperature of 1200 - 2000°C, for 40 - 120 sec. Prior to effect of high pressure and temperature stock may be shaped in round, square, rhombic, triangular, hexagonal and other forms. Ultrahard compact is prepared with high cutting ability and output of serviceable products.
EFFECT: permits to provide high purity of processed materials surface.
2 cl, 2 dwg, 1 tbl, 6 ex
FIELD: powder metallurgy, namely manufacture of powder articles such as technical ceramics and refractory parts.
SUBSTANCE: method comprises steps of molding blank of article; subjecting it to hot pressing between two punches and soaking at final values of temperature and pressure while lateral surfaces of pressed article are remained free. Temperature and pressure values are increased simultaneously at rate respectively 60 - 150°C/min and 4 - 8 MPa/min. Final temperature of hot pressing consists 0.3 - 0.5 of melting temperature of powder material. Soaking at final temperature is performed for 15 - 30 min.
EFFECT: possibility for providing minimum changes in structure of initial powder materials and for keeping their fine grain structure, improved strength and density of articles.
SUBSTANCE: charge for manufacturing of ceramics contains silicon carbide, α-oxide of aluminium and an oxide-containing additive, which is a mixture of oxides. According to the first version, the charge contains, wt %: silicon carbide 30-40, α-oxide of aluminium 34-50, silicon dioxide 11.8-25.2, iron oxide (III) 0.25-0.4, calcium oxide 0.2-0.4, titanium dioxide 0.2-0.4, magnesium oxide 0.02-0.4, potassium oxide 1.2-3.8, sodium oxide 0.3-1.2. According to the second version, the charge contains components at the following ratio, wt %: silicon carbide 20-35, α-oxide of aluminium 30-60, calcium oxide 5.0-15.0, zirconium dioxide 5.0-15.0, kaolin 10.0-17.0.
EFFECT: development of charge for manufacturing of a ceramic material with hardness and strength, sufficient to resist impact of impact-dynamic loads.
2 cl, 6 ex
SUBSTANCE: ceramic material has the following chemical composition: 24 to 25.5 wt % ZrO2, from 0.26 to 0.35 wt % Cr2O3, from 0.50 to 0.60 wt % Y2O3 with respect to ZrO2, from 0.7 to 0.85 wt % SrO, from 0 to 0.5 wt % TiO2 and from 0 to 0.5 wt % MgO, as well as Al2O3 additionally to 100 wt %. In composition of baked product in aluminium oxide matrix there are inclusions of zircon oxide and lamellar crystals of strontium aluminate.
EFFECT: increase of crack and damage resistance, increase of material solidity.
12 cl, 2 tbl
SUBSTANCE: invention relates to obtaining a porous material from ceramic based on aluminium oxide and can be used in chemical industry, including in aggressive media at high temperatures, for making catalyst supports, in water treatment as well as in medicine for making porous ceramic implants. GN alumina is ground and mixed with 0.3-2.0% magnesium carbonate in a ball mill. After grinding and mixing, the powder mixture is emptied into a sagger and sintered in a furnace at 1000-1500°C. The cooled sinter is loaded into a ball mill and ground until a powder with grain size of 1.5-2.5 mcm is obtained, mixed with zirconium oxide stabilised yttrium oxide, aluminium hydroxide, aluminium oxide nanopowder in gamma-phase with specific surface area S=245 m2/g, ammonium carbonate, glelatine and polyvinyl alcohol. The obtained powder is moulded by uniaxial pressing and fired. The porous ceramic material has the following characteristics: open porosity 25-45%, pore size from 10 mcm to 600 mcm, compression strength of up to 70 MPa.
EFFECT: obtaining a porous structure of an alumina ceramic with differential distribution of micropores.
3 cl, 1 tbl, 3 dwg
SUBSTANCE: invention relates to production of zirconia alumina used in making an abrasive tool on a flexible base and grinding wheels on an organic bond. The method of producing zirconia alumina involves preparation of a mixture, loading said mixture into an electric melting furnace, melting and pouring the melt into a slit-type crystalliser for intense cooling of the melt. The alumina-containing component of the mixture used is high-alumina industrial wastes from natural gas processing, and the stabiliser and degasifying agent used is wastes from mechanical processing titanium metal.
EFFECT: low cost of the obtained articles.
1 ex, 2 tbl
SUBSTANCE: invention relates to biochemistry and can be used to control biochemical reactions in vitro and in vivo. Control is carried out by exposing a magnetic nanosuspension containing a bioactive macromolecule, attached directly or through a ligand to single-domain magnetic nanoparticles, to an external low-intensity low-frequency alternating magnetic field which provides deformation and/or change in conformation of bioactive macromolecules participating in the reaction.
EFFECT: invention provides measured action on a specific metabolism link responsible for a pathologic condition.
13 cl, 11 dwg
SUBSTANCE: when producing a mixture with high size homogeneity of particles that are doped with a sintering additive, the starting MgAl2O4 spinel in form of a size-homogenous nanopowder with particle size of 10-70 nm is mixed with a concentrated alcohol solution of boric acid and held for 1 hour, wherein a uniform layer of boric acid forms on the surface of each nanoparticle. The method of producing an optical nanoceramic based on a MgAl2O4 spinel includes heat treatment of a portion of the doped powder of said mixture, which is subjected to uniaxial hot pressing to obtain a dense transparent nanoceramic.
EFFECT: producing optical ceramic with high homogeneity and high optical transmission.
4 cl, 2 dwg, 3 ex
SUBSTANCE: invention relates to production of superhard composite material based on cubic boron nitride (CBN) in the presence of synthesis catalysts and additional reactants in a high-pressure chamber. The invention can be used to make cutting parts of a machining tool that are in direct contact with the workpieces. The composite polycrystalline material based on CBN is obtained via secondary synthesis of CBN powder from hexagonal boron nitride powder in a high-pressure chamber in the presence of a catalyst in form of a boride or nitride of an alkali or alkali-earth metal. To this end, CBN powder, obtained in advance using nitride catalysts, is mixed with a boride catalyst. If CBN powder obtained using boride catalysts is used, nitride catalysts are used for secondary synthesis. To neutralise residual reaction products and bind said products in a matrix into a harder phase, aluminium metal powder is added to the charge mixture and mechanical alloying is carried out. After mechanical alloying of CBN particles by mixing and rubbing them with aluminium, powdered carbides of refractory metals are added to the mixture, followed by pressing and subjecting the workpiece to pressure and temperature of 5-5.5 GPa and 1300-1600°C for 15 s to 20 min.
EFFECT: high chemical wear resistance and heat resistance of the composite.
25 cl, 6 ex
SUBSTANCE: method includes heating a mixture of components - 0.01 mol phenylacetylene, 0.01 mol iodobenzene (aryl iodide), 0.0006 g copper nanopowder and 0.002 g CuI at temperature of 110-120°C for 3 hours; after cooling, the reaction mass is poured into 100 ml cold water while stirring, followed by extraction with ethyl acetate, purification on a column with silica gel, elution with a solvent mixture with ratio of ethyl acetate to hexane of 1:6 and then distilling off the solvent to obtain pure products.
EFFECT: use of the present method enables to obtain end products with high output with considerable simplification of the process.
SUBSTANCE: inventions can be used in the field of nanotechnologies and inorganic chemistry. The method of production of boride nanofilm or nanowire comprises depositing on the alumina nanowire or on fiberglass of low-melting glass in vacuum the multiple alternating layers of titanium and boron, after which the resulting composition is gradually heated to a temperature of 1500°C. In another embodiment, the method of production of boride nanofilm comprises depositing of titanium boride layer of nanothickness on alumina nanofilm of the gas phase comprising titanium halogenide and boron.
EFFECT: inventions enable to obtain boride nanostructures.
4 cl, 2 ex
SUBSTANCE: coating is based on titanium carbonitride with addition of additional elements which provide the required set of mechanical and tribological properties, as well as biologically active and antibacterial properties. Overall concentrations of basic and additional elements are in the following ratio:
EFFECT: coating has high hardness, low modulus of elasticity, high value of elastic recovery, low coefficient of friction and rate of wear in different physiological media.
1 tbl, 2 ex
SUBSTANCE: invention relates to the application of a solid medicinal product, which is heated under the impact of an alternating magnetic field, for further therapeutic treatment after surgical ablation of tumours and cancerous ulcers. The medicinal product represents a surgical implant, presented in the form of a physiologically acceptable fabric, sponge or film. The medicinal product contains magnetic particles, which generate heat when excited by an impact of the alternating magnetic field, and in this way, heat the medicinal product.
EFFECT: invention ensures considerable improvement of further treatment after operation on cancerous tumour in comparison with chemotherapy.
21 cl, 14 ex