About Determing the Microhardness of Composite Coatings

2021 ◽  
Vol 1037 ◽  
pp. 486-493
Author(s):  
Sergey Y. Zhachkin ◽  
Anatoly I. Zavrazhnov ◽  
Nikita A. Penkov ◽  
George V. Kudryavtsev ◽  
Paul V. Tsisarenko
Keyword(s):  
Composite Coating ◽  
Mechanical Treatment ◽  
Composite Coatings ◽  
Operational Parameters ◽  
Deposition Parameters ◽  
Cylinder Liners ◽  
High Degree ◽  
Applied Coating ◽  
Positive Effect ◽  
Selection Of

One of the fundamental tasks in restoring the operability of cylinder liners is the application of a composite coating with a predetermined microhardness value. The authors have developed a technology for applying composite coatings based on iron on cylindrical surfaces, which makes it possible to vary the physical, mechanical and operational parameters of the formed iron-containing coating due to the planned selection of the deposition parameters. This eliminates the need for mechanical treatment of the applied coating, which is the reason for the high degree of rejection parts that undergo the iron-on operation. Contact interaction of the working tool with the formed layer of the composite coating has a positive effect on the value of its roughness.

scholarly journals Isothermal Oxidation Performance of Laser Cladding Assisted with Preheat (LCAP) Tribaloy T-800 Composite Coatings Deposited on EN8

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 843
Author(s):  
Sipiwe Trinity Nyadongo ◽  
Sisa Lesley Pityana ◽  
Eyitayo Olatunde Olakanmi
Keyword(s):  
Iron Oxide ◽  
Composite Coating ◽  
Laser Cladding ◽  
Composite Coatings ◽  
Parabolic Rate Constant ◽  
Mass Gain ◽  
Isothermal Oxidation ◽  
Operational Parameters ◽  
Temperature Oxidation ◽  
Service Environments

It is anticipated that laser cladding assisted with preheat (LCAP)-deposited Tribaloy (T-800) composite coatings enhances resistance to structural degradation upon exposure to elevated-temperature oxidation service environments. The oxidation kinetics of LCAP T-800 composite coatings deposited on EN8 substrate and its mechanisms have not been explored in severe conditions that are similar to operational parameters. The isothermal oxidation behaviour of the T-800 composite coating deposited on EN8 via LCAP was studied at 800 °C in air for up to 120 h (5 × 24 h cycles) and contrasted to that of uncoated samples. The mass gain per unit area of the coating was eight times less than that of the uncoated EN8 substrate. The parabolic rate constant (Kp) for EN8 was 6.72 × 10−12 g2·cm−4·s−1, whilst that for the T-800 composite coating was 8.1 × 10−13 g2·cm−4·s−1. This was attributed to a stable chromium oxide (Cr2O3) layer that formed on the coating surface, thereby preventing further oxidation, whilst the iron oxide film that formed on the EN8 substrate allowed the permeation of the oxygen ions into the oxide. The iron oxide (Fe2O3) film that developed on EN8 spalled, as evidenced by the cracking of oxide when the oxidation time was greater than 72 h, whilst the Cr2O3 film maintained its integrity up to 120 h. A parabolic law was observed by the T-800 composite coating, whilst a paralinear law was reported for EN8 at 800 °C up to 120 h. This coating can be used in turbine parts where temperatures are <800 °C.

scholarly journals Microstructure of the coating obtained by magnetron sputtering of a Ni-Cr-B4C composite target

2021 ◽  
Vol 2124 (1) ◽  
pp. 012021
Author(s):  
S V Zaitsev ◽  
D S Prokhorenkov ◽  
M S Ageeva ◽  
A A Skiba
Keyword(s):  
Magnetron Sputtering ◽  
Composite Coating ◽  
Composite Coatings ◽  
Thermal Spraying ◽  
Rf Magnetron Sputtering ◽  
Columnar Structure ◽  
Columnar Crystal ◽  
Composite Target ◽  
Combined Use ◽  
Positive Effect

Abstract This paper presents data on obtaining a composite coating by radio frequency (RF) magnetron sputtering of a Ni-Cr-B4C composite target in an inert gas (argon) environment. To make the target, Ni-Cr-B4C composite powder was applied to the copper base of the target by detonation gas-thermal spraying. The obtained targets served as a source of coating material during high-frequency magnetron sputtering. This method of coating production ensures the reproducibility of their properties, as well as the uniformity of coating thickness and good adhesion to various target backings. The data of the study of the structure and morphology of the composite coating are presented. The resulting composite coating Ni-B/Cr7C3 with a thickness of 2 microns has a dense homogeneous structure with expressed textured polycrystallinity. The surface of the resulting coating is represented by nanoscale and homogeneous grains. There is no columnar crystal growth in the coating, which has a positive effect, as the columnar structure reduces the mechanical characteristics of the coatings due to faster oxygen diffusion along the grain boundaries. It is established that the combined use of the Ni-B and Cr7C3 binary phases in composite coatings leads to an increase in operational properties.

A Study of Different Methodologies Helpful in the Identification of Offline Handwritten Script

2018 ◽  
Vol 6 (6) ◽  
pp. 307
Author(s):  
Manish M. Kayasth ◽  
Bharat C. Patel
Keyword(s):  
Feature Extraction ◽  
Character Recognition ◽  
Recognition Rate ◽  
Recognition System ◽  
Post Processing ◽  
Classification Technique ◽  
Scanned Image ◽  
Gujarati Language ◽  
High Degree ◽  
Selection Of

The entire character recognition system is logically characterized into different sections like Scanning, Pre-processing, Classification, Processing, and Post-processing. In the targeted system, the scanned image is first passed through pre-processing modules then feature extraction, classification in order to achieve a high recognition rate. This paper describes mainly on Feature extraction and Classification technique. These are the methodologies which play an important role to identify offline handwritten characters specifically in Gujarati language. Feature extraction provides methods with the help of which characters can identify uniquely and with high degree of accuracy. Feature extraction helps to find the shape contained in the pattern. Several techniques are available for feature extraction and classification, however the selection of an appropriate technique based on its input decides the degree of accuracy of recognition. 

scholarly journals Influence of Pulse Current Forward-Reverse Duty Cycle on Structure and Performance of Electroplated W–Cu Composite Coatings

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1233
Author(s):  
Yuchao Zhao ◽  
Nan Ye ◽  
Haiou Zhuo ◽  
Chaolong Wei ◽  
Weiwei Zhou ◽  
...  
Keyword(s):  
Composite Coating ◽  
Duty Cycle ◽  
Electrode Materials ◽  
Pulse Current ◽  
Electrical Discharge Machining ◽  
Composite Coatings ◽  
Electrical Contact ◽  
Pulse Plating ◽  
Fusion Welding ◽  
Raw Material

Tungsten-copper (W–Cu) composites are widely used as electrical contact materials, resistance welding, electrical discharge machining (EDM), and plasma electrode materials due to their excellent arc erosion resistance, fusion welding resistance, high strength, and superior hardness. However, the traditional preparation methods pay little attention to the compactness and microstructural uniformity of W–Cu composites. Herein, W–Cu composite coatings are prepared by pulse electroplating using nano-W powder as raw material and the influence of forward-reverse duty cycle of pulse current on the structure and mechanical properties is systematically investigated. Moreover, the densification mechanism of the W–Cu composite coating is analyzed from the viewpoints of forward-pulse plating and reverse-pulse plating. At the current density (J) of 2 A/dm2, frequency (f) of 1500 Hz, forward duty cycle (df) of 40% and reverse duty cycle (dr) of 10%, the W–Cu composite coating rendered a uniform microstructure and compact structure, resulting in a hardness of 127 HV and electrical conductivity of 53.7 MS/m.

scholarly journals Preparation and Degradation Characteristics of MAO/APS Composite Bio-Coating in Simulated Body Fluid

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 667
Author(s):  
Zexin Wang ◽  
Fei Ye ◽  
Liangyu Chen ◽  
Weigang Lv ◽  
Zhengyi Zhang ◽  
...  
Keyword(s):  
Simulated Body Fluid ◽  
Composite Coating ◽  
Body Fluid ◽  
Composite Coatings ◽  
Degradation Process ◽  
Ceramic Coatings ◽  
Immersion Test ◽  
Substrate Material ◽  
Atmospheric Plasma

In this work, ZK60 magnesium alloy was employed as a substrate material to produce ceramic coatings, containing Ca and P, by micro-arc oxidation (MAO). Atmospheric plasma spraying (APS) was used to prepare the hydroxyapatite layer (HA) on the MAO coating to obtain a composite coating for better biological activity. The coatings were examined by various means including an X-ray diffractometer, a scanning electron microscope and an energy spectrometer. Meanwhile, an electrochemical examination, immersion test and tensile test were used to evaluate the in vitro performance of the composite coatings. The results showed that the composite coating has a better corrosion resistance. In addition, this work proposed a degradation model of the composite coating in the simulated body fluid immersion test. This model explains the degradation process of the MAO/APS coating in SBF.

scholarly journals Rural Financial Development Impacts on Agricultural Technology Innovation: Evidence from China

2021 ◽  
Vol 18 (3) ◽  
pp. 1110
Author(s):  
Yuyu Liu ◽  
Duan Ji ◽  
Lin Zhang ◽  
Jingjing An ◽  
Wenyan Sun
Keyword(s):  
Economic Development ◽  
Financial Development ◽  
Agricultural Development ◽  
Technology Innovation ◽  
Agricultural Technology ◽  
Rural Finance ◽  
Rural Economic Development ◽  
High Degree ◽  
The Impact ◽  
Positive Effect

Agricultural technology innovation is key for improving productivity, sustainability, and resilience in food production and agriculture to contribute to public health. Using panel data of 31 provinces in China from 2003 to 2015, this study examines the impact of rural financial development on agricultural technology innovation from the perspective of rural financial scale and rural finance efficiency. Furthermore, it examines how the effects of rural financial development vary in regions with different levels of marketization and economic development. The empirical results show that the development of rural finance has a significant and positive effect on the level of agricultural technology innovation. Rural finance efficiency has a significantly positive effect on innovation in regions with a low degree of marketization, while the rural financial scale has a significantly positive effect on technological innovation in regions with a high degree of marketization. Further analysis showed that improving the level of agricultural technology innovation is conducive to rural economic development. This study provides new insights into the effects of rural financial development on sustainable agricultural development from the perspective of agricultural technology innovation.

Development of a Performance-Related Framework for Asphalt Mixture Design for the Illinois Tollway

2021 ◽  
pp. 036119812110148
Author(s):  
Behnam Jahangiri ◽  
Punyaslok Rath ◽  
Hamed Majidifard ◽  
William G. Buttlar
Keyword(s):  
Asphalt Mixture ◽  
Field Performance ◽  
Compact Tension ◽  
T Test ◽  
Novel Approach ◽  
Final Adjustment ◽  
Development And Validation ◽  
High Degree ◽  
Selection Of

Various agencies have begun to research and introduce performance-related specifications (PRS) for the design of modern asphalt paving mixtures. The focus of most recent studies has been directed toward simplified cracking test development and evaluation. In some cases, development and validation of PRS has been performed, building on these new tests, often by comparison of test values to accelerated pavement test studies and/or to limited field data. This study describes the findings of a comprehensive research project conducted at Illinois Tollway, leading to a PRS for the design of mainline and shoulder asphalt mixtures. A novel approach was developed, involving the systematic establishment of specification requirements based on: 1) selection of baseline values based on minimally acceptable field performance thresholds; 2) elevation of thresholds to account for differences between short-term lab aging and expected long-term field aging; 3) further elevation of thresholds to account for variability in lab testing, plus variability in the testing of field cores; and 4) final adjustment and rounding of thresholds based on a consensus process. After a thorough evaluation of different candidate cracking tests in the course of the project, the Disk-shaped Compact Tension—DC(T)—test was chosen to be retained in the Illinois Tollway PRS and to be presented in this study for the design of crack-resistant mixtures. The DC(T) test was selected because of its high degree of correlation with field results and its excellent repeatability. Tailored Hamburg rut depth and stripping inflection point thresholds were also established for mainline and shoulder mixes.

Cybersecurity Standards in the Context of Operating System

2021 ◽  
Vol 54 (3) ◽  
pp. 1-36
Author(s):  
Syed Wasif Abbas Hamdani ◽  
Haider Abbas ◽  
Abdul Rehman Janjua ◽  
Waleed Bin Shahid ◽  
Muhammad Faisal Amjad ◽  
...  
Keyword(s):  
Organizational Context ◽  
Cyber Attacks ◽  
Fine Tuning ◽  
Security Vulnerabilities ◽  
Compliance Testing ◽  
Depth Analysis ◽  
Minimum Requirements ◽  
Security Standards ◽  
High Degree ◽  
Selection Of

Cyber threats have been growing tremendously in recent years. There are significant advancements in the threat space that have led towards an essential need for the strengthening of digital infrastructure security. Better security can be achieved by fine-tuning system parameters to the best and optimized security levels. For the protection of infrastructure and information systems, several guidelines have been provided by well-known organizations in the form of cybersecurity standards. Since security vulnerabilities incur a very high degree of financial, reputational, informational, and organizational security compromise, it is imperative that a baseline for standard compliance be established. The selection of security standards and extracting requirements from those standards in an organizational context is a tedious task. This article presents a detailed literature review, a comprehensive analysis of various cybersecurity standards, and statistics of cyber-attacks related to operating systems (OS). In addition to that, an explicit comparison between the frameworks, tools, and software available for OS compliance testing is provided. An in-depth analysis of the most common software solutions ensuring compliance with certain cybersecurity standards is also presented. Finally, based on the cybersecurity standards under consideration, a comprehensive set of minimum requirements is proposed for OS hardening and a few open research challenges are discussed.

Using Cluster Analysis to Improve Marketing Experiments

1971 ◽  
Vol 8 (3) ◽  
pp. 340-347 ◽  
Author(s):  
George S. Day ◽  
Roger M. Heeler
Keyword(s):  
Cluster Analysis ◽  
Space Representation ◽  
Reduced Space ◽  
High Degree ◽  
Degree Of Similarity ◽  
Sensitive Experiment ◽  
Selection Of

When the selection of a sample of stores or cities requires a high degree of similarity among the test units in order to ensure a sensitive experiment, the sample may no longer represent the market. These conflicting requirements can be satisfied by choosing the sample from clusters displayed in a reduced space representation of the market.

SHELL MATERIAL'S PERFORMANCE OF THE MICROCAPSULE FOR ELECTROLYTIC CO-DEPOSITION

2010 ◽  
Vol 24 (15n16) ◽  
pp. 3124-3130 ◽  
Author(s):  
HUI CONG LIU ◽  
XIU QING XU ◽  
WEI PING LI ◽  
YAN HONG GUO ◽  
LI-QUN ZHU
Keyword(s):  
Composite Coating ◽  
Methyl Cellulose ◽  
Water Vapor Permeability ◽  
Core Material ◽  
Vapor Permeability ◽  
Shell Material ◽  
The Core ◽  
Surface Performance ◽  
The Stability ◽  
Positive Effect

The shell material of microcapsules has an important effect on the electrolytic co-deposition behavior, the release of core material and the surface performance of composite coating. This paper discussed the tensile property and the stability of three shell materials including polyvinyl alcohol (PVA), gelatin and methyl cellulose (MC). It is found that these three shell materials have good mechanical strength and flexibility which are favorable to electrolytic co-deposition and stability of microcapsules in composite coating and that MC has well permeability and porosity which has a positive effect on the release of the core material in composite coating. Moreover, the study of the thermal properties and water vapor permeability of the three shell materials showed that their permeability improved with increase of temperature and humidity. In addition, the composite copper coating containing microcapsules with PVA, gelatin or MC as shell material was prepared respectively.

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