Aluminum Powder Research Articles

Utilization of Cement Power Plant Beds for Aerated Concrete Thermal Blocks

<p>Nowadays cement industry power plant bed wastes can be used to create aerated concrete blocks for widespread usage in the construction sector instead of sand. The optimum materials for building enclosures for a variety of uses include aerated concretes. To enhance the physical and mechanical qualities of Non-Autoclaved Aerated Concrete (NAAC) blocks, bed material is introduced in this study as a superior alternative material. The non-autoclaved concrete blocks in this study are made with cement, bed materials, fly ash, gypsum, and a consistent amount of 0.65 grams of aluminium powder. The mix preparation and method employed for manufacturing NAAC blocks, the composition of mix specimens and the dosing and mixing processes have been expounded upon, shedding light on the critical steps in the production. According to the suggested method in IS 2185 (Part III) of 1984, the proportion of bed materials was taken by volume of compacted dry material for NAAC of Size 22cm x 10.5cm x 7cm. Experiments into the NAAC block's compressive strength plus water absorption of the bed materials were followed by comparisons of these characteristics with clay and fly ash bricks sold in the market. As a result, NAAC blocks met the 6 MPa strength criteria specified by Indian Standard code IS2185 (Part III): 1984. However, the strength of the aforementioned NAAC brick at 28 days was 7.28 MPa for Sample T5. A more in-depth presentation of the testing methods, focusing on the compressive strength tests was conducted at various intervals (7, 14, 21, and 28 days). The density values and water absorption rates for each test sample (T1 to T5) are now presented with additional insights into the observed trends. According to the research, blocks manufactured with NAAC bed materials tend to be stronger and lighter than those made with conventional clay bricks. They also produce non-autoclaved concrete blocks. Therefore, the creation of such inexpensive blocks can be employed for extensive production.</p>

Investigation of Mechanical and Wear Behaviour of Al5056-Carbon Nanotube -Graphene Hybrid MMCs using Powder Metallurgy Route

Composites containing metal at least in two constituent parts are metal matrix composites. Another material may also be used like organic compounds or ceramics, in addition to a different metal. In the current work Al5056 aluminium powder is used as the matrix material having an average particle size was about 35±5 μm and Carbon Nanotube (CNT) and Graphene (Gr) are used as reinforcement materials. Hybrid composites are developed using an advanced powder metallurgy technique process. Also, in the existing work microstructure characterization was performed using advanced techniques. Hardness, Tensile and wear tests are conducted as per ASTM standards. Mechanical properties improved with the increase in amalgams in the matrix. The wear surface morphology of Al alloy shows a rough surface with more grooves and ridges compared to the wear surface morphology of Al5056/CNT-Gr hybrid composites. Wear debris results of Al alloy show more debris chips out of the material compared to Al5056/CNT-Gr hybrid composites.

Application of microencapsulated fibrous carrier inhibitors in suppressing flake aluminum dust explosion: Performance and mechanism

Flake aluminum powder (FAl), due to its larger specific surface area and higher reactivity, posing a potential threat to the process safety of involved enterprises. To mitigate the explosion caused during the production of FAl, a green composite inhibitor, Sep@CS@PA-Na, was successfully prepared in the aqueous phase using microencapsulation technology with sepiolite (Sep), chitosan (CS), and sodium phytate (PA-Na) as raw materials. The suppression of FAl explosions in a vertical combustion duct system by inhibitors with different inerting ratios (α) was investigated. The results showed that after adding Sep@CS@PA-Na with an α of 0.75, the maximum flame propagation velocity (Vmax), the average flame velocity (Vavg), and the velocity of the flame reaching the pipeline top (Vtop) decreased by 79.6%, 75.1%, and 86.2%, respectively, and the reduction of the maximum flame front pressure (Pmax) and the maximum flame pressure rise rate ((dP/dt)max) were 90.4% and 89.8%, respectively, and the peak temperature (Tp) dropped to 505°C. Combined with TG-DSC and explosion product analysis, Sep@CS@PA-Na possessed both gas-phase reaction and surface reaction suppression functions, which were mainly reflected in the dilution effect, quenching effect, and barrier effect. This work will provide technical support for the emergency prevention and control of energetic metal dust explosions.

An enhanced DPC model for metal powder incorporating yield strength of solid-state

The Drucker-Prager/Cap (DPC) Model has a significant drawback in metal powder metallurgy simulations, which is the potential for the von Mises stress to exceed the yield strength of the solid state. To address this issue, this paper introduces a novel hardening law that effectively restricts the von Mises stress within the yield strength of solid alloy. As the powder becomes denser, the yield surface of the DPC model gradually approach towards the von Mises yield surface. To validate the proposed model, both micro-scale finite element simulations and published experimental data were used. The effectiveness of the proposed model was demonstrated through its application in the simulation of two scenarios: cold die compaction of aluminum powder and hot isostatic pressing of a Nickel based superalloy. The results indicate that the proposed model outperforms the original DPC model and is more suitable for powder metallurgy simulations.

Pore structure regulation of aluminum powder as a filler for high energy solid propellants

Aluminum (Al) powder, as a high-energy metal combustible agent, has advantages such as high calorific value and low cost. It has important research value in energetic materials. However, due to the Al2O3 layer on the surface of Al powder, the contact area between Al powder and oxidant components is reduced, resulting in a decrease in its energy release performance. In this paper, a modified Al powder with porous structure was prepared by chemical corrosion method to solve the problem that its small contact area with oxidant components affects its energy release performance. The study found that when the concentration of HF solution is 3.0 wt%, the removal effect of the oxide layer of Al powder is most effective, with a surface O element content of only 0.6 wt% and a uniform porous structure on the surface of Al powder. In addition, experiments have shown that nano CuO can be well filled into the pore structure of modified Al, increasing the contact area between Al powder and oxidant. This work provides a novel and simple research approach for effectively improving the energy release performance of Al based energetic materials.

Effect of Source Type on Pore Structure and Properties of Aerated Geopolymer Concrete

A study has been carried out to produce environmentally friendly lightweight concrete by substituting cement with alternative geopolymer binders. Fly ash and silica fume (waste materials) were used as source materials and their effect on pore structure and properties of aerated geopolymer concrete was evaluated. Autoclaved aerated concrete, locally known as thermostone, was supplied from the market and tested as a reference mix. Three aerated geopolymer concrete mixes (around 550 kg/m3 density) were produced by mixing source materials (fly ash and silica fume), activator solution (sodium silicate and sodium hydroxide), and aeration agent (aluminum powder). It was found that by not only enhancing the pore structure but also improving the binder medium, the aerated geopolymer mixes were stronger and less absorbed than the autoclaved aerated concrete mix. However, the thermal insulation of the aerated concrete mix was better than those of aerated geopolymer concrete mixes. In terms of the source material, it was found that usage of fly ash helped in enhancing the strength by about 100% of autoclaved aerated concrete. In addition, unless its lowest density, aerated geopolymer mix made with fly ash and silica fume in combination absorbed less water than the other investigated mixes. Adding superplasticizer to the geopolymer mix helped in enhancing its pore structure by making the pores smaller, their irregularity lesser, and their number higher. In general, an environmentally friendly lightweight material with strength and absorption better than those of autoclaved aerated concrete was produced by adopting a geopolymerization process.

Efficient and eco-friendly cadmium ion recycling: Ultrasonic enhancement of aluminum powder replacement for low-temperature industrial applications

Replacing cadmium ions in cadmium-containing solutions with aluminum powder is beneficial for cadmium resource recycling and environmental protection. However, the conventional aluminum powder replacement method requires harsh temperatures and prolonged conditions. In this study, the effect and mechanism of ultrasound on the replacement of cadmium with aluminum powder were investigated at low temperatures. Ultrasound has been proven to promote the etching of alumina films through the use of TEM and XPS, providing mechanistic support for the superiority of the new process. A degree of Cd replacement as high as 95.08 % is achieved at a low temperature (60 ℃) and in a short time (20 min) when using ultrasonicated aluminum powder replacement, which is 42.17 % higher than that of conventional aluminum powder. Compared with conventional aluminum powder replacement conditions with the same effect, the introduction of ultrasound can reduce the temperature by 30℃ and shorten the replacement time by 2/3, which has significant advantages in reaction efficiency and safety. The strengthening mechanism of ultrasound on the replacement effect of aluminum powder at low temperatures is revealed through detailed discussions on the corrosion of alumina films, agglomeration of aluminum powder, and adhesion of replacement products to the surface of aluminum powder, dissolved oxygen in the solution, and redissolution of cadmium. Therefore, a new approach for replacing aluminum powder in solutions with high Cd2+ concentrations at low temperatures is proposed in this work, which is expected to solve the existing harsh and dangerous problems of industrial aluminum powder replacement.

ПЕРСПЕКТИВНАЯ ТЕХНОЛОГИЯ УТИЛИЗАЦИИ АЛЮМИНИЙСОДЕРЖАЩИХ ПОЛИМЕРНЫХ ОТХОДОВ

According to the Ministry of Natural Resources and Environment of the Russian Federation, about 70 million tonnes of solid municipal waste are generated annually in Russia, which contain up to 50% of polymer packaging material that has a negative impact on the environment. The amount of waste increases every year by more than 3%, destroying the fragile ecological balance in nature. Along with this there is a problem with utilisation of polymer multi-component wastes, of which there are more than 400 different types, differing from each other by compositions and technologies of processing and utilisation. Recycling of polymer wastes acquires topical importance not only from the point of view of environmental protection, but also due to the fact that in conditions of polymer raw materials deficit plastic wastes become a powerful raw material and energy resource. In order to prevent negative impact on the environment and rational use of natural resources the technology of multi-component aluminium-containing polymer waste recycling has been developed. The technological line was designed and implemented by the limited liability company "ReDevelopment". The initial raw material is complex two-layer blisters from medicines, representing a cellular plate of polymer with glued aluminium foil. In the course of operation of the technological line for processing aluminium-containing polymer waste, two types of products are formed: powder from a mixture of aluminium and polymer waste and powder of plastic waste based on different polymers. Aluminium powder is used to form aluminium briquettes, which are marketable products.

Effect of microstructure on functional force and air explosion performance of CL-20-based aluminum-containing explosive

A solvent–non-solvent approach was used to create a CL-20-based aluminum-containing explosive with a composite structure. The SEM results demonstrate that the aluminum powder is equally embedded on the surface of the CL-20 crystal in the CL-20/Al explosive with a composite structure but the aluminum powder in the mechanically mixed CL-20/Al explosive is agglomerated and spread unevenly. The maximum expansion velocity of the composite structure CL-20/Al explosive was 17.74% higher than that of the mechanically mixed explosive in the cylinder test, and the acceleration ability of the CL-20/Al explosive with a composite structure to the cylinder wall is superior to that of the mechanically mixed explosive. In the air explosion test, the shock wave overpressure and impulse of the CL-20/Al explosive with a composite structure are superior to those of the mechanically mixed explosive, but as the distance increases, the gap between the two explosives gradually narrows until it is flat. The results of interfacial particle velocity show that the length of the reaction zone and duration of CL-20/Al explosives with composite structures are longer than those of mechanically mixed structures, and the interfacial particle velocity of CL-20/Al explosives with composite structures is higher than that of mechanically mixed structures.

Physico-chemical analysis and characterization of the flammability of metallic powders

When fine particles known as flammable powders are suspended in the air under specific circumstances, they have the potential to explode. There could be many serious fatalities, injuries, and structural damage as a result of a dust explosion. By being aware of the flammability parameters and the physico-chemical analysis for flammable powders and taking additional protective measures as a result of the occurrence of these kinds of catastrophic mixes, the risk of such incidents can be decreased. The goal of this study was to determine the flammability characteristics of two combustible powders, magnesium and aluminum powder. These characteristics included the lowest ignition temperature of the dust cloud and dust layer as well as certain physicochemical studies of the composition.

Development of cellular construction material-based flax shives: Physico-mechanical and thermal characterisation

The reduction of energy consumption in construction, production of thermal insulation materials, and the solution of environmental problems by recycling by-product derived several industrial sectors are becoming greater problems. In this context, vegetable by-products are an excellent alternative product to substitute mineral aggregates because they are easily available and renewable low-cost raw materials, and have higher advantage for economy and environment concerns. The viability of using vegetable materials such as flax shives for developing a sustainable Lightweight Cellular Construction Material (LCCM) is investigated in this paper. The produced material containing different volumes of flax shives (0V (control specimen), 1V, and 2V) was lightened by creating a porous structure in the matrix through a chemical reaction between Aluminium powder and free lime from pre-formulated Tradical PF70 binder. A study conducted on hardened material properties has indicated a significant reduction in sample unit weight, thereby resulting in a level of compressive strength compatible with a load-bearing wall. The reduction in flexural strength was lower than that in compressive strength. This study has also highlighted the effect of the porous structure on the thermal conductivity that lead to provide a high degree of thermal insulation. These results show that the cellular material based on flax particle can be used as suitable insulated load-bearing walls.

Oxidation of fine aluminum particles: thermally induced transformations in particle shells and kinetics of oxide nucleation.

This paper investigates the process of oxidation of fine aluminum powder, consisting of spherical Al particles of 'metal core/oxide shell' type, when heated in air at temperatures below 550 °C. The highly dispersed aluminum powder 'Alex' used in this work (particle size: 0.05-1.5 μm and number average particle diameter (DN): 0.11 μm) was produced by electric explosion of a thin Al wire in argon with subsequent passivation in an oxygen-containing atmosphere. For the first time, the influence of the particle size on the oxidation process has been identified. During the reaction, individual γ-Al2O3 oxide nuclei grow at the surface of Al particles with diameters less than 300 nm without laterally overlapping to form a protective passivating layer, as typically occurs during the oxidation of micron-sized particles or bulk metal. The localization of γ-Al2O3 nuclei is determined by the regions where peeling of the primary amorphous oxide film from the surface of the metal core of an Al particle occurs due to the thermal decomposition of aluminum hydroxides (T ≈ 350 °C) present within the particle shells. A significant increase in the contributions of the following factors leads to a high oxidation rate: the diffusion within the disordered structure of a particle core and the surface diffusion of cations (Ea = 80.6 ± 5.3 kJ mol-1, 400-450 °C), the surface and grain boundary diffusion of oxygen during the growth of γ-Al2O3 crystallites (Ea = 108.3 ± 11.2 kJ mol-1, 470-500 °C) and the surface and grain boundary transport of anions through an amorphous and underlying nanocrystalline oxide layer with a constant thickness (Ea = 205.1 ± 8.6 kJ mol-1, 520-550 °C). The results obtained make it possible to expand the theoretical understanding of the manifestations of the size effect in solid-phase reactions and take into account its influence in practice.

High-throughput centrifugal evaporation for mesoporous alumina powder synthesis via evaporation-induced self-assembly (EISA).

The evaporation-induced self-assembly (EISA) process is commonly employed to synthesise mesoporous materials, such as mesoporous alumina. Typically, recovering mesoporous alumina in powder form takes several days due to the need for controlled solvent evaporation conditions. The mesostructure obtained from the EISA process is highly sensitive to these conditions, which can sometimes hinder reproducibility. This paper presents an improved EISA method using a centrifugal evaporator, which enables the rapid recovery of mesoporous alumina powder (approximately 2 h) from multiple precursor solutions under controlled evaporation conditions. The advantages of using a centrifugal evaporator over traditional vacuum evaporation methods include: (1) the reduction of bumping and foaming due to centrifugal force; (2) resistance to evaporated gaseous HCl; and (3) the ability to evaporate multiple samples simultaneously. This enhanced EISA process is expected to accelerate the research progress of powdery mesoporous materials.

Current prospect of dental zirconia recycling: A scoping review.

This scoping review aimed to identify and discuss the recyclability of dental zirconia residuals along with the factors influencing the properties of dental recycled zirconia. In vitro studies written in both English and Chinese that evaluated the recyclability of dental zirconia residue were selected. A literature search was conducted in Medline, PubMed, Web of Science, and Cochrane Library databases with no restrictions on the publication year. Sixteen studies were included in this review. Residual dental zirconia can be recycled. Cold isostatic pressing improved the density of recycled zirconia compared with uniaxial pressing. Recycled zirconia powder with fine particles enhanced the performance of recycled zirconia compared with coarse particles. A presintering temperature of 950 to 1100°C was suitable for preparing recycled zirconia presintered bodies. Recycled zirconia may require a higher sintering temperature (≥1500°C) compared with commercially available zirconia. Additionally, recycled zirconia powder can enhance the properties of polymethylmethacrylate as a reinforcing filler and can be combined with alumina powder to obtain an alumina/zirconia composite material. Despite a limited body of literature, the recycling and reutilization of dental zirconia residuals are feasible and reliable, and can reduce economic and environmental losses. Nevertheless, several factors influence the recycling effect, including the particle size, molding techniques, and sintering parameters. In addition, recycled zirconia powder can act as a reinforcing filler, potentially enhancing the mechanical properties of other materials. To realize commercially viable recycled zirconia materials, further studies are essential to comprehensively explore and understand their recycling performance.

Сравнительный анализ структуры и свойств керамик на основе оксида алюминия, полученных методами свободного и электроимпульсного плазменного спекания

The effect of the initial size of alumina particles on the density, microstructure, hardness, and fracture toughness of ceramics obtained by conventional and spark plasma sintering (SPS) has been studied. We studied ceramics obtained from commercial Al2O3 powders with an initial particle size of 40 – 50 nm, 0.2 mm, and 1 mm, and domestic fine powders with an initial particle size of 0.2 – 3 mm, and Al2O3 + 0.25 vol. % MgO and Al2O3 + 10 vol. % ZrO2. It is shown that the density of alumina ceramics nonmonotonically depends on the initial size of Al2O3 powder particles. It has been established that an increase in the grain size leads to a nonmonotonic change in the hardness of alumina ceramics. It has been established that the addition of 0.25 vol. % MgO accelerates the sintering of alumina. The addition of 10 vol. % ZrO2 makes it possible to provide an optimal combination of hardness and fracture toughness. It is shown that fine-grained ceramics obtained by the SPS method have a higher hardness. It has been suggested that SPS of submicron alumina powders with an amorphous layer on the surface, additionally stabilized by zirconia particles, is promising for further increasing the hardness of alumina ceramics.

HYDROGEN ABSORBERS BASED ON POROUS CERAMICS SYNTHESIZED IN A SOLAR FURNACE

In this study, we investigated the processes of hydrogen absorption in porous ceramic materials sythesized in a solar furnace. We used burning additives inserted into ceramic materials and melted in a solar furnace in a high-density stream of concentrated solar radiation (200 W/cm<sup>2</sup>). The melt was cooled by pouring it into water at a cooling rate of 10<sup>3</sup>-10<sup>4</sup> degree/s. The castings were characterized by a fine-grained microstructure (in which the grain size did not exceed 10 µm). The crushed and molded samples were fired at a temperature of 1150°C for 2 hours. Thr results obtained showed that the sodium aluminosilicate zeolite ceramic porous material based on a mixture of aluminum powder, quartz sand, and polyvinyl alcohol exhibited high hydrogen absorption-up to 13% (at temperature = 250°C and pressure = 13 atm).

Analysis of the Effect of the Addition of Aluminum Powder on Polyester-Glass Composite Properties in Tensile and Hardness Test

The study aimed to analyse the influence of aluminum powder on the mechanical properties of polyester-glass composites. Composite materials were made of glass fibres with random fibre direction and polyester resin with the addition of aluminum powder as a filler. The strength parameters of materials obtained during the static tensile test and hardness test were compared. The results were subjected to statistical analysis, taking into account the change in the amount of filler, microstructure was also observed using optical microscopy. An analysis of the results showed that the addition of aluminum powder amounting to 2% of the weight of the composites reduces their hardness and, at the same time, the longitudinal modulus of elasticity.The addition of aluminum powder amounting to 5% and 10% of the weight of the composites increased the hardness of the composites while reducing the Young's modulus. The values of hardness measurements were subjected to statistical analyses at significance level α = 95. The Shapiro-Wilk test confirmed that the hardness variables for all tested samples were in normal distributions, and therefore the most powerful parametric tests were used to test the differences. Using the Student's t-test, it was confirmed that between pairs of variables in configurations: a standard sample with a modified sample, for all tested samples there are significant statistical differences in the distributions of hardness values. Studies have shown that the modification of the mechanical and strength properties of composite materials, through the use of an aluminum filler, makes it possible to obtain materials with variable parameters that can be useful and attractive in many new areas, depending on the application and user requirements.

ИССЛЕДОВАНИЕ ИЗНОСОСТОЙКОСТИ ГИЛЬЗ ЦИЛИНДРОВ, ВОССТАНОВЛЕННЫХ КЕРАМИЧЕСКИМ ПОКРЫТИЕМ

The results of the study of the workability and wear resistance of the combined coating of the restored cylinder liners obtained by applying a layer of aluminum powder to the cast-iron base by cold gas-dynamic spraying with subsequent treatment by microarc oxidation were presented. (Research purpose) The research purpose is a comparative analysis of the tribotechnical properties of the conjugations "sleeve coated with cold gas-dynamic spraying and treatment with microarc oxidation-counter-sample 100Cr6" and "sleeve (SH25 in the delivery state)-counter-sample 100Cr6" (reference pairing). (Materials and methods) Conducted a study of the workability of materials of the reference and reconstructed conjugations according to RD 50-662-88 "Guidelines. Methods of experimental evaluation of frictional compatibility of materials of friction conjugations". Comparative bench tests were performed on the wear resistance of the reference and restored conjugates according to GOST 23.224-86 "Ensuring the wear resistance of products. Methods for assessing the wear resistance of restored parts". (Results and discussion) The optimal modes of long-term operation and the limits of the interface operability were determined during the stepwise loading of the reference and restored tribo-couplings. The run-in coefficient and the wear factor of the couplings were calculated. It was found that the restored coupling "sleeve coated with cold gas-dynamic spraying and microarc oxidation treatment-counter-sample 100Cr6" has similar run-in rates with the reference coupling, and its wear resistance exceeds the wear resistance of the reference coupling by more than two times. (Conclusions) High indicators of workability and wear resistance of the restored interface "sleeve coated with cold gas-dynamic spraying and microarc oxidation treatment-counter-sample 100Cr6" in comparison with the reference sleeve (from SCH25 in the state of delivery) provide an increase in its durability and indicate the expediency of using the combined method in the restoration of cylinder liners.

Effect of silver inhibition on the ceramic foam as flame suppression

Aluminium dust explosions pose significant safety and economic challenges in various industrial processes. Due to this, the current research explores an innovative approach by inhibiting the silver nanoparticles (Ag NPs) to ceramic porous form substrate as a flame suppressant in order to mitigate the risks associated with these explosions. The antimicrobial and non-toxic qualities of silver are also attractive to be applied in medical and food technology. However, the interfacial adhesion between the metallic (nanosilver) and non-metallic (silica-based-ceramic) is still vaguely studied due to the mechanical and surface energy mismatch between the organic surface and the inorganic layers. From this study, the physicochemical and mechanical properties of the silver-coated ceramic foam were analyzed using X-ray diffraction, field emission scanning electron microscopy with energy dispersive X-ray, thermogravimetric analysis, and compression test. From the mechanical testing, it was found that the percentage increase of maximum load for silver-ceramic foam from the original ceramic foam was about 60%. The results indicate that silver-coated foam has a better compressive strength of 0.93 MPa as compared to 0.58 MPa by the original ceramic. The inhibition effect of Ag NPs powder on the explosion pressure evolution and flame spread mechanism of aluminium powder at different concentrations and particle sizes was tested using the Hartmann experimental system.

Properties of ceramic coatings in engine cylinder liners restoration using combined technology

In the course of vehicle operation with internal combustion engines, due to various reasons, defects occur on the cylinder mirror, resulting in the need for repair work to eliminate them. For non-cylinder blocks most often requires replacement with a new block, which is economically very costly. The technologies of liner restoration are very diverse and their application depends on the available equipment and material of the liner. The aim of the work is to develop a new combined technology for the restoration of liners and cylinder blocks regardless of the material for their manufacture. As a technology of restoration of the geometry of the mirror of the liner the method of cold gas dynamic spraying with the use of aluminum powder is considered. Subsequent application of the plasma electrolytic oxidation (PEO) technology makes it possible to obtain on the mirror a ceramic coating with thickness of 80-100 microns, which is sufficient for long-term operation of the internal combustion engine. On the basis of GZ-195N liner the technology of cylinder mirror restoration was worked out and the process of plasma electrolytic oxidation (PEO) was carried out. Research has shown that the hardening of the coating occurs to the depth of 100 microns required by the technology. The wear resistance of the coating exceeds the wear resistance of the reference sample, its wear factor is 1.27 times less than that of the reference pair. The possibility of using the technology of aluminum coating by cold spray on any metal makes the combined technology of cylinder liner repair applicable to achieve the desired result - to restore the performance of the cylinder block or liner and increase their wear resistance. The obtained positive results require the development of industrial technology of combined coating and experimental testing on a running engine.