Protective coatings of alloy of the Ni–Cr–Mo system with a wide range of operating temperatures

2021 ◽  
pp. 74-79
Author(s):  
T. I. Bobkova ◽  
R. Yu. Bystrov ◽  
A. F. Vasilev ◽  
A. M. Makarov ◽  
B. V. Farmakovsky
Keyword(s):  
Protective Coatings ◽  
Experimental Studies ◽  
Wear Resistant ◽  
Wear Resistant Coatings ◽  
Wide Range ◽  
Operating Temperatures

This article presents the results of experimental studies of alloys of the Ni–Cr–Mo–Be–Re–Zr–Hf– Nb system for creating functional wear-resistant coatings on their basis by the method of microplasma spraying. The coating works efficiently in a wide range of positive (up to 1100°C) and negative (up to minus 196°C) temperatures.

scholarly journals Optimization of Coating Process from Cermet Powders by Plasma Spraying in Air

2021 ◽  
Vol 20 (5) ◽  
pp. 369-374
Author(s):  
V. A. Okovity ◽  
F. I. Panteleenko ◽  
V. V. Okovity ◽  
V. M. Astashinsky
Keyword(s):  
Plasma Spraying ◽  
Solid Phase ◽  
Protective Coatings ◽  
Composite Coatings ◽  
Polished Surface ◽  
Powder Materials ◽  
Wear Resistant ◽  
Wear Resistant Coatings ◽  
Contact Points ◽  
Plasma Coatings

The paper presents studies on the optimization of the process of applying coatings from cermet powders with different solid phase contents by plasma spraying in air to restore and harden parts of machines and mechanisms operating under adverse conditions. Such conditions are usually created in heavily loaded tribojoints when the mechanisms operate at a low speed of relative movement of surfaces during friction. At the same time, the destruction of the working surfaces is mainly due to the process of microcontact setting and subsequent detachment of the formed particles at their contact points. The application of special protective coatings with the required properties is possible with the manufacture of high-quality starting powder materials and optimization of the technology for their application. Such powders and powder compositions can be obtained by the method of agglomeration of a fine powder mixture with its subsequent high-temperature sintering. To identify the hardening mechanism of composite coatings made of cermet by gas-thermal spraying, important stages are the optimization of the deposition process parameters and the study of the properties of plasma coatings obtained in this case. When optimizing the technological parameters of plasma spraying of coatings, the utilization rate of the sprayed powder material has been taken into account as the main indicator of the process efficiency, the structure of the obtained layers, and the morphology of individual particles deposited on the polished surface. The paper provides data on the structural elements of sprayed materials for wear-resistant coatings obtained by plasma spraying at optimal conditions. Taking into account the processes that occur during the wear of tribological conjugations, the data indicate the existing prerequisites for the wear resistance of the studied composite coatings made of metal ceramics. Special wear-resistant coatings made of materials with a soft matrix hardened by solid inclusions Al2O3–TiO2–Ni–Cr–Al–Y are widely used in various industries. Based on the detailed analysis of the features of cermet plasma coatings, it can be stated that such powder compositions (complex oxides-metal component) are often used as wear-resistant plasma coatings. The research results can be taken into account in cases of application of wear-resistant plasma coatings made of metal-ceramics and compositions based on them, containing solid phases in the form of oxides, as well as the manufacture of a whole range of parts operating under conditions of intense wear.

scholarly journals Features of Machining Rotor Shafts of Diesel Engine Turbochargers with a Multilayer-Coated Tool

2021 ◽  
Vol 31 (4) ◽  
pp. 518-529
Author(s):  
Vladimir A. Skryabin
Keyword(s):  
Cutting Force ◽  
Experimental Studies ◽  
Titanium Carbonitride ◽  
Wear Resistant ◽  
Wear Resistant Coatings ◽  
Heat Resistant ◽  
Cutting Force Components ◽  
Alloy Steels ◽  
Force Components ◽  
Cutting Unit

Introduction. The paper presents the results of experimental studies of power parameters when hard alloy steels are machined with tools, the cutting units of which have multilayer hard, heat-resistant and wear-resistant coatings. The obtained data will make it possible to optimize machining hard-to-machine materials. Materials and Methods. The aim of the study is to measure the power parameters of turning products and to create experimental formulas of power parameters for different technological modes. For this purpose, a special measuring multicomponent complex was used to estimate the influence of the mode parameters on the change in the cutting force components. Results. The numerically controlled machine tool was retooled by combining it with a three-component dynamometer and tooling. The cutting unit of the tool was coated with a multi-layer hard, heat-resistant and wear-resistant coating. The tool was equipped with instruments connected to a personal computer for measuring and processing experimental data. According to the results of the study, there have been obtained graphical dependences and empirical formulas, which take into account the influence of the mode parameters on the cutting force components when machining the units of alloy steels of high hardness, heat resistance and wear resistance. Discussion and Conclusion.The study allowed us to obtain experimental formulas of cutting force components for different mode parameters when machining parts by the tool equipped with cutting plates. The plates are coated with multilayer hard and wear-resistant coatings of titanium carbonitride, aluminum oxide and nickel nitride. The coating increases significantly the hardness, heat and wears resistance of the tool cutting unit and provides quality machining.

Analysis of the results of medium-energy electrons on the protective and thermoregulatory coatings of high-orbit satellites

2018 ◽  
pp. 156-171
Author(s):  
A. M. Shamayev ◽  
M. D. Ozersky
Keyword(s):  
Structural Changes ◽  
Protective Coatings ◽  
Experimental Studies ◽  
Thermal Control ◽  
Space Vehicles ◽  
Medium Energy ◽  
Electrostatic Discharges ◽  
High Orbit ◽  
Thermal Control Coatings ◽  
Solar Batteries

The results of experimental studies of the effect of electron irradiation on K-208 and CMG glasses used for manufacturing protective coatings of solar batteries and thermal control coatings of space vehicles are analyzed. It is shown that the caused electrostatic discharges lead to structural changes in the surfaces of the glasses studied. The goals of further studies of the influence of proton and electronproton effects on the properties of such coatings are outlined. 

scholarly journals Image Statistics Preserving Encrypt-then-Compress Scheme Dedicated for JPEG Compression Standard

Entropy ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 421
Author(s):  
Dariusz Puchala ◽  
Kamil Stokfiszewski ◽  
Mykhaylo Yatsymirskyy
Keyword(s):  
Statistical Analysis ◽  
Image Encryption ◽  
Experimental Studies ◽  
Quality Measures ◽  
Input Image ◽  
Jpeg Compression ◽  
Image Statistics ◽  
Compression Stage ◽  
Wide Range ◽  
The Impact

In this paper, the authors analyze in more details an image encryption scheme, proposed by the authors in their earlier work, which preserves input image statistics and can be used in connection with the JPEG compression standard. The image encryption process takes advantage of fast linear transforms parametrized with private keys and is carried out prior to the compression stage in a way that does not alter those statistical characteristics of the input image that are crucial from the point of view of the subsequent compression. This feature makes the encryption process transparent to the compression stage and enables the JPEG algorithm to maintain its full compression capabilities even though it operates on the encrypted image data. The main advantage of the considered approach is the fact that the JPEG algorithm can be used without any modifications as a part of the encrypt-then-compress image processing framework. The paper includes a detailed mathematical model of the examined scheme allowing for theoretical analysis of the impact of the image encryption step on the effectiveness of the compression process. The combinatorial and statistical analysis of the encryption process is also included and it allows to evaluate its cryptographic strength. In addition, the paper considers several practical use-case scenarios with different characteristics of the compression and encryption stages. The final part of the paper contains the additional results of the experimental studies regarding general effectiveness of the presented scheme. The results show that for a wide range of compression ratios the considered scheme performs comparably to the JPEG algorithm alone, that is, without the encryption stage, in terms of the quality measures of reconstructed images. Moreover, the results of statistical analysis as well as those obtained with generally approved quality measures of image cryptographic systems, prove high strength and efficiency of the scheme’s encryption stage.

Desirability-Based Performance Optimization of Wear-Resistant Coatings by HVOF Sprayed WC-Co Experiments

2011 ◽  
Vol 189-193 ◽  
pp. 3633-3639
Author(s):  
Ming Der Jean ◽  
Yih Hwang Yang ◽  
Tzu Hsuan Chien
Keyword(s):  
Wear Rate ◽  
Performance Optimization ◽  
Desirability Function ◽  
High Velocity Oxygen Fuel ◽  
Wear Resistant ◽  
Wear Resistant Coatings ◽  
Designed Experiments ◽  
Control Factors ◽  
Desirability Analysis ◽  
Oxygen Fuel

This study presented the desirability function based on Taguchi designed experiments to solve multiple responses statistical optimal problems for the tungsten carbide/cobalt (WC-Co) coatings of high-velocity-oxygen-fuel (HVOF) processes. The eight control factors based on L18 arrays were conducted and the multi-responses of wear-resistant coatings such as hardness, deposited thickness and wear rate were evaluated simultaneously in the desirability-based experiments. Based on desirability analysis, the optimal settings have been identified, and the impacts of control factors are determined by analysis of variance on the multi-responses. Further, a confirmation run was conducted to validate the tests. Experimental results have shown that the hardness increased by 16.61% and the deposited thickness improved by 10.50%, while the wear rate decreased by 34.03%. It was clear that confirmation tests are greatly improved by way of the desirability-based multi-responses on HVOF WC-Co experiments, and these findings achieved the desired values on wear-resistant coatings. The proposed procedure was applied at HVOF sprayed WC-Co experiments, and the implementation results demonstrated its feasibility and effectiveness to maximize hardness, make a target of deposited thickness value and minimize wear rate by a HVOF.

Production of wear-resistant coatings on pump and fitting components by anodizing in a supercooled electrolyte

1990 ◽  
Vol 26 (9) ◽  
pp. 479-482
Author(s):  
E. E. Aver'yanov ◽  
R. M. Galimzyanov ◽  
K. Z. Gilyazova ◽  
V. A. Popov ◽  
A. V. Rabinovich ◽  
...  
Keyword(s):  
Wear Resistant ◽  
Wear Resistant Coatings

scholarly journals Effects of electrical stimulation on isolated rodent gastric smooth muscle cells evaluated via a joint computational simulation and experimental approach

2009 ◽  
Vol 297 (4) ◽  
pp. G672-G680 ◽  
Author(s):  
P. Du ◽  
S. Li ◽  
G. O'Grady ◽  
L. K. Cheng ◽  
A. J. Pullan ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Electrical Stimulation ◽  
Pulse Train ◽  
Pulse Width ◽  
Computational Simulation ◽  
Minimum Energy ◽  
Experimental Studies ◽  
Single Pulse ◽  
Plateau Phase ◽  
Wide Range

Gastric electrical stimulation (GES) involves the delivery of electrical impulses to the stomach for therapeutic purposes. New GES protocols are needed that are optimized for improved motility outcomes and energy efficiency. In this study, a biophysically based smooth muscle cell (SMC) model was modified on the basis of experimental data and employed in conjunction with experimental studies to define the effects of a large range of GES protocols on individual SMCs. For the validation studies, rat gastric SMCs were isolated and subjected to patch-clamp analysis during stimulation. Experimental results were in satisfactory agreement with simulation results. The results define the effects of a wide range of GES parameters (pulse width, amplitude, and pulse-train frequency) on isolated SMCs. The minimum pulse width required to invoke a supramechanical threshold response from SMCs (defined at −30 mV) was 65 ms (at 250-pA amplitude). The minimum amplitude required to invoke this threshold was 75 pA (at 1,000-ms pulse width). The amplitude of the invoked response beyond this threshold was proportional to the stimulation amplitude. A high-frequency train of stimuli (40 Hz; 10 ms, 150 pA) could invoke and maintain the SMC plateau phase while requiring 60% less power and accruing ∼30% less intracellular Ca2+ concentration during the plateau phase than a comparable single-pulse protocol could in a demonstrated example. Validated computational simulations are an effective strategy for efficiently identifying effective minimum-energy GES protocols, and pulse-train protocols may also help to reduce the power consumption of future GES devices.

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