Metal-ceramic Powders Research Articles

Повышение ресурса рабочих колес центробежных насосов шахтного водоотлива

Mining The article discusses the main failure causes of centrifugal pumps used in the mine dewatering plants. The factors causing intensive wear of the impellers used in centrifugal pumps of the CNS-33-66...330 type are analysed, as well as the ways of increasing their serviceability. The gas dynamic cold spraying is recognized as the most promising and efficient method of applying functional coatings, which makes it possible to improve the condition of the surface layer and eliminate surface defects of the initial impeller blanks, which have a significant impact on the serviceability of the parts. The main research trends are outlined in the studied area, and practical recommendations are provided on using the gas dynamic cold spraying methid both in the pump manufacturing process and in their overhaul. It is shown that one of the promising trends in development the gas dynamic cold spraying applications is the creation of multilayer coatings on the impeller blades based on compositions of various metal-ceramic powders. Along with the hardening treatment, this combination will allow to provide the impellers with a set of necessary functional characteristics for the hydro-abrasive wear conditions. technological process as a sequence of changing the natural state of the Earth's subsoil to obtain a certain quantity and quality of mineral products is characterized by departures from the specified normative parameter values, which is due to causes of different nature. Most of these causes are man-made, anf they are created during the performance of specific process operations by the personnel. The article presents an original approach to managing the control over the technological process parameters in a coal strip mine. To reduce the magnitude and probability of the process departures from the normative values, the authors propose to create technical and organizational control loops. Each loop is a closed chain of technical means and organizational tools, which secures up-keeping of the normative technological process state. Production risk is proposed to be used as a criterion to assess the efficiency of the control loops. The methodology allowing to calculate the risk is described. The results of the contour approach application to the technological process control at the Solntsevsky coal strip mine are presented.

Tribological Properties of a Friction Composition of MetalCeramic Powders and Carbon-Containing Additives on a Polymer Binder Material

Tribological Properties of a Friction Composition of MetalCeramic Powders and Carbon-Containing Additives on a Polymer Binder Material

Detonation Technology in Producing Metal–Ceramic Powder Targets for Magnetron Sputtering

Detonation Technology in Producing Metal–Ceramic Powder Targets for Magnetron Sputtering

Detonation Spraying of Composite Targets Based on Ni, Cr and B<sub>4</sub>C for Magnetron Multi-Functional Coating

The paper presents a method of producing a ceramic metal composite target by detonation gas-thermal spraying allowing spraying almost any powder compositions with high deposition efficiency of up to 90% and the possibility of spraying large areas at a relatively low cost, differentiation by coating thickness and size. The efficiency of detonation technology and related devices for the production of original composite cathodes for magnetron sputtering using the example of the powder composition Ni + Cr + B4C is justified. These materials make it possible to obtain composite coatings with a unique composition and characteristics using a magnetron. Magnetron sputtering is one of the most suitable methods for the industry. The influence of the process mode of metal ceramic powder application on copper substrate is considered. The structure of a metal-ceramic composite target was studied by scanning electron microscopy. It was shown that the target surface is dense without visible pores. The elemental composition of the powder is uniformly distributed over the target surface.

Metallographic Characterization of SiC-Ni-Ti Layer Reinforced on Austenitic Stainless Steel (AISI 316L) by Two-step Laser Fabrication

Industry X.0 is the new paradigm that is the driving phenomenon in the process of making things and the new method in which they are produced. In this work, we attempt to fabricate ceramic layer reinforced metal matrix composite (MMC) of AISI 316 L by a two-step laser process. The SiC-Ni-Ti layer on AISI316L serves to improve wear properties. The reinforcement of SiC-Ni-Ti on AISI316L modified the phase structure and microstructure. Coatings of metal-ceramic powders of 40 % SiC-40 %Ti-20 % Ni and 60 % SiC-30 %Ti-10 % Ni was preplaced on 316 L specimens. High power laser was used to irradiate the preplaced coatings to form MMCs of metal-ceramic particles. The composition of the MMC layer was studied by using optical emission spectroscopy (OES) and its microstructure of the MMC layers, phase analysis and its elemental analysis were characterized by optical and scanning electron microscopy (SEM), X-ray diffractometry, and image analyzing techniques, respectively. The formation of non-uniformity of coating thickness, microporous and crack formation at layer of MMC, revealed that a higher percentage of ceramic particles present in the MMC layer entails a particular disadvantage. The results confirmed the high hardness of the surface due to particle refinement with dispersion of hard SiC particle and precipitation of Cr2C3/Fe2Si in the matrix that results the improved wear resistance of laser clad material.

Cermet composite coating with a ductile Ni3Al binder phase and an in-situ Cr7C3 augmented phase

Boron doped Ni3Al intermetallic and in-situ Cr7C3 composite metal-ceramic powder were prepared by inert gas atomization method, and then the coating was prepared by HVOF. The Ni3Al alloys wet the in-situ ceramic particles well and form a continuous internal acicular crystalline phase. Mechanical property and wear performance testing showed the hardness, thermal shock performance and wear resistance of the coating are retained to temperatures of at least 700 °C. All mechanical properties in the range of 450–700 °C were found to be equal to or higher than comparable NiCr-based NiCr–Cr3C2 coating systems. Initial mechanism study shows that the small size and needle-like morphology of the ceramic particles are the important reasons for the good high temperature properties of the coating.

МОДЕЛЮВАННЯ ПРОЦЕСУ СФЕРОЇДИЗАЦІЇ ЧАСТИНОК ПОРОШКУ ПЛАЗМОВО-ДУГОВИМ МЕТОДОМ

Багато сучасних технологічних процесів вимагають використання металевих, керамічних та метало-керамічних порошків, частинки яких мають ідеальну сферичну форму. Отже, виникає задача ефективної сфероїдизації порошків, що використовуються. Найбільш ефективним способом сфероїдизації є обробка порошку в потоці низькотемпературної плазми. Для отримання частинок ідеальної сферичної форми необхідно, щоб до кінця дистанції частинка мала мінімальну швидкість і температуру, щоб уникнути деформації під час удару об поверхню для збору порошку. Крім того, в процесі польоту частинка повинна повністю розплавитись, але не досягати температури випаровування, а потім затвердіти. Задача моделювання процесу сфероїдизації частинок порошку плазмово-дуговим методом зводиться до визначення швидкості і температури частинки в потоці низькотемпературної плазми з урахуванням зміни її агрегатного стану. Визначення швидкості частинки проведено з урахуванням того, що єдиною силою, що діє на неї, є сила аеродинамічного опору. Швидкість плазмового потоку апроксимуємо експоненціальною функцією. В результаті, отримуємо неявний розв’язок диференціального рівняння для визначення швидкості частинки вздовж дистанції. Для дослідження температурного режиму розглядаємо п'ять ділянок дистанції. На першій з них (розігрів частинки до температури плавлення) використовуємо для визначення температури рівняння теплового балансу. Друга ділянка – процес плавлення частинки. Тут ми визначаємо час плавлення частинки, виходячи з рівняння теплового балансу, за умови відсутності теплового потоку на межі фазового переходу. Третя ділянка – політ частинки в розплавленому стані. Для моделювання процесу розв’язуємо крайову задачу для одновимірного рівняння теплопровідності для сферичного тіла, апроксимуючи температуру плазми кубічними сплайнами. Для четвертої ділянки (затвердіння частки) використана та ж модель, що і для другого. А на п'ятому (охолодження частки) - такий самий підхід, що й на третьому. На завершення наведені результати для частинок титану діаметром 10 мкм.

Application of 3d technologies for microwave range electronic components creating

This paper presents the results of the study of microwave radio-electronic components electrophysical parameters manufactured on a 3D printer. Laser sintering technologies for metal semiconductor and ceramic powders were used as experimental research methods. The resonant properties of one-sided surfaces in the form of a Mobius sheet made on the 3D printer are analyzed. An explanation of a traveling and standing wave formation in the oscillatory contours of the microwave range of one-sided surfaces in the form of a Mobius sheet is presented. The possibility to create digital active phased antenna arrays based on onesided surfaces in the form of a Mobius sheet is shown.

The Chemical Alloying by a Solution Combustion Process and Its Application to the Synthesis of the Nanocrystalline Alloy Powders.

Various nanocrystalline metal alloy powders were synthesized by solution combustion synthesis in a reducing atmosphere in which a spray pyrolysis process was modified. Miscible Cu-Ni alloy powder and immiscible Ag-Ni alloy powder were synthesized, along with Cu-Y₂O₃ metal-ceramic composite powder. X-ray diffraction, SEM and TEM observations showed that the synthesized powders were nanocrystalline and well alloyed. Alloying occurred via the chemical routes of the decomposition of the metal salts, as well as the oxidation, reduction and sintering processes.

Development of device for extrusion of metal-ceramic plates

The article is devoted to the issues of production of thin-walled plates from metal-ceramic powders, including the development of special equipment for extrusion of nanoscale powder materials exposed to subsequent sintering. The original device is proposed for production by direct extrusion of thin-walled plates from metal-ceramic powder blend by the radial expansion upsetting method, which improves the quality of the parts structure through the formation of additional lateral shear deformations on the contact of the workpiece with the walls of the rectangular die.

METALLOGRAPHIC STUDIES OF SAMPLES MADE OF 65G STEEL SUBJECTED TO COMPLEX TREATMENT BY ELECTROSPARK AND VIBRATION ARC DISCHARGES USING CERMET POWDERS

In this paper, some physical and mechanical properties of the surface layer of widely used steel 65G in mechanical engineering and agriculture, subjected to plasma treatment. The research is aimed at increasing the service life of parts and friction units of machinery and equipment. It is shown that vibroplasma surface treatment with the use of metal-ceramic powders allows to increase the hardness of the surface layer by more than 3 times. The elemental composition and microstructure of the sample surface were studied. The microstructure of the base material of the coated samples corresponds to the structure of the reference sample. The microstructure of the reference sample corresponds to the microstructure of low-carbon (pre-eutectoid) steel after annealing. Grained ferrite-pearlite structure with a predominance of ferrite. In the process of vibro plasma treatment in the surface layer of the sample is formed of 3 zones: the zone of deposited metal-ceramic material, a hardened area of the surface layer mixed with elements of the base and filler material and heat affected zone.

Features of electron-beam processing of metal-ceramic powders in the forevacuum

We present the results of sintering of a metal-ceramic sample consisting of alumina ceramics and titanium. Sintering has been conducted via the surface scanning by the electron beam generated by a plasma electron source. It has been shown that the bake-out temperature affects the formation of the layer with a uniform distribution of elements. We have determined the sintering regimes that enable fabrication of samples with uniformly distributed elements over volume.

Advanced methods for consolidation of powder materials by impulse electromagnetic fields

Advanced technologies for the production of new materials and, in particular, nanostructured materials, using powder technologies require fundamentally new approaches for the formation and preservation of a given structural-phase state. Precision control of the state of materials in the process of consolidating powders of nanomaterials can be carried out using pulsed electromagnetic fields. The aim of the project is to study the effect of high-voltage and low-voltage pulsed electromagnetic fields in the technologies of powder consolidation. The experimental devices of spark-plasma sintering, flash-sintering, high-voltage consolidation and magnetic-pulse compaction are used in our laboratory for the production of advanced materials from metal powders, ceramic and composite powders. We can produce boron carbide, silicon carbide, uranium nitride, tungsten carbide - cobalt - diamond composites, tungsten heavy alloys, and others by electromagnetic methods of powder consolidation. Experimental results to consolidation metal powders, ceramic and composites powders by electromagnetic methods presage fruitful results.

Production of titanium-containing metal-ceramic composites based on boron carbide in the nanocrystalline state

ABSTRACTThe results of the study of the production technology, phase composition, structure and physico-mechanical properties of metal-ceramic materials based on boron carbide and their components are presented. Boron carbide was obtained by direct synthesis from chemical elements using amorphous boron and carbon black. By mechanical dispersion, solid reagents were converted into an ultrafine state. Using a chemical method, nanoscale (70–80 nm) boron carbide was synthesised from suspension solutions of amorphous boron and liquid hydrocarbons. Boron carbide-based metal-ceramic composite powder B4C–(Co–Ni–Ti) was obtained by mechanical dispersion of the constituent components. Based on results of studying of the temperature-dependence of wetting angle of boron carbide with Co–Ni–Ti metallic alloy, the compacting modes of metal-ceramic composite powders by plasma-spark sintering and hot pressing have been developed. The influence of the component content of the binder metal (alloy) on some physico-mechanical properties (linear expansion coefficient, hardness, and bending strength) of hardmetal-ceramic materials based on boron carbide was studied. It was found that the optimum content of the metal component in the composite is ∼ 25 wt-%. In the temperature range 300–600°C, the materials obtained are characterised by stable dimensional factors, since in this temperature range the thermal conductivity coefficient does not depend much on temperature. At room temperature, their bending strength is about 1 GPa. A new method of chemical synthesis of nanocrystalline ceramic compositions of boron carbide and titanium diboride using suspension solutions for the preparation of powders and their spark plasma sintering was also developed to obtain a compacted material of composition B4C+30 wt-%TiB2, which has a high hardness of 95 HRA (with maximum microhardness 45.6 GPa) and sufficient strength (with a bending strength of 834 MPa).

Compaction Behaviour Modelling of Metal-Ceramic Powder Mixtures. A Review

Abstract Powder mixtures compaction behavior can be quantitatively expressed by densification equations that describe the relationship between densities - applied pressure during the compaction stages, using correction factors. The modelling of one phase (metal/ceramic) powders or two-phase metal-ceramic powder composites was studied by many researchers, using the most commonly compression equations (Balshin, Heckel, Cooper and Eaton, Kawakita and Lüdde) or relative new ones (Panelli - Ambrózio Filho, Castagnet-Falcão- Leal Neto, Ge Rong-de, Parilák and Dudrová, Gerdemann and Jablonski. Also, for a better understanding of the consolidation process by compressing powder blends and for better prediction of compaction behavior, it's necessary the modeling and simulation of the powder pressing process by computer numerical simulation. In this paper are presented the effect of ceramic particles additions in metallic matrix on the compressibility of composites made by P/M route, taking into account (a) the some of above mentioned powder compression equations and also (b) the compaction behavior modeling through finite element method (FEM) and discrete element modeling (DEM) or combined finite/ discrete element (FE/DE) method.

Densification Mechanism, Elastic-Plastic Deformations and Stress-Strain Relations of Compacted Metal-Ceramic Powder Mixtures (Review)

Abstract The basic purpose of compaction is to obtain a green compact with sufficient strength to withstand further handling operations. The strength of green compact is influenced by the characteristics of the powders (apparent density, particle size and shape, internal pores etc.), the processing parameters (applied force, pressing type, and temperature) and testing conditions (strain rate etc.) Successful powder cold compaction is determined by the densification and structural transformations of powders (metallic powders, ceramic powders and metal-ceramic powder mixtures) during the compaction stages. In this paper, for understanding the factors that determine a required strength of compacted metal-ceramic powder mixtures, we present the densification mechanisms of different mixtures according to densification theories of compaction, the elastic-plastic deformations of mixture powders, the stressstrain relations and the relaxation behavior of compacted metal-ceramic composite parts and the particularities of each of them.

Compaction of Metal-Ceramic Powder Mixtures. Part.2

Compaction of Metal-Ceramic Powder Mixtures. Part.2

Compaction of Metal-Ceramic Powder Mixture. Part.1

Compaction of Metal-Ceramic Powder Mixture. Part.1

Study on Cladding Performance, Coating Microstructure and Interfacial Bonding of Metal-base Coatings by Non-contact Cladding

Coating material and its cladding performance is the key to the preparation of high quality coating. In this paper, cladding performance, cladding coating morphology, interface diffusion and microstructure of typical alloy powder material were studied, such as self-melting alloy powder, coated composite powder and mixture metal ceramic powder by experiment. The results show that self-melting alloy prepared by atomization technology has well cladding performance which coating with compact microstructure. Composite alloy powder prepared by chemical method technology has poor cladding performance which loose microstructure. Mixed metal ceramic powder has well cladding performance which homogeneous microstructure. Fe-base alloy and Co-base alloy can be achieved diffusion metallurgical combination with the steel substrate.

Alkali Metal CO2 Sorbents and the Resulting Metal Carbonates: Potential for Process Intensification of Sorption-Enhanced Steam Reforming.

Sorption-enhanced steam reforming (SESR) is an energy and cost efficient approach to produce hydrogen with high purity. SESR makes it economically feasible to use a wide range of feedstocks for hydrogen production such as methane, ethanol, and biomass. Selection of catalysts and sorbents plays a vital role in SESR. This article reviews the recent research aimed at process intensification by the integration of catalysis and chemisorption functions into a single material. Alkali metal ceramic powders, including Li2ZrO3, Li4SiO4 and Na2ZrO3 display characteristics suitable for capturing CO2 at low concentrations (<15% CO2) and high temperatures (>500 °C), and thus are applicable to precombustion technologies such as SESR, as well as postcombustion capture of CO2 from flue gases. This paper reviews the progress made in improving the operational performance of alkali metal ceramics under conditions that simulate power plant and SESR operation, by adopting new methods of sorbent synthesis and doping with additional elements. The paper also discusses the role of carbonates formed after in situ CO2 chemisorption during a steam reforming process in respect of catalysts for tar cracking.