scholarly journals Use of pulsed spray airflow for electric arc spraying of different types of wires

2021 ◽  
Vol 3 (1(59)) ◽  
pp. 23-27
Author(s):  
Vyacheslav Royanov ◽  
Irina Zakharova
Keyword(s):  
Chemical Composition ◽  
Adhesion Strength ◽  
Chemical Elements ◽  
Air Flow ◽  
Arc Spraying ◽  
Capital Costs ◽  
Burn Out ◽  
Sprayed Coating ◽  
Spraying Process

The object of research is the control of the process of formation of a spraying air flow and the transfer of particles of liquid metal from electrodes during arc spraying. One of the problem areas of the arc spraying process is the oxidation of the sprayed metal particles by the oxygen of the air flow during their transportation to the sprayed surface. This leads to the formation of a sufficiently large amount of oxides of chemical elements, which significantly deteriorate the adhesion strength and burn out alloying elements that are necessary to obtain a wear-resistant and corrosion-resistant coating. The suitability and durability of coatings during use depends on the strength of adhesion to the substrate. In the course of the study, methods were used to determine the adhesion strength of the coating to the base – the Steffens method and methods for studying the microstructure of coatings were taken as the basis. The data was processed and dependencies were plotted. The proposed method makes it possible to improve the quality of the resulting coating in terms of such an indicator as improvements in chemical composition. And also to influence the chemical composition by controlling the process of transfer of molten metal using a pulsating air flow. The obtained results of approbation of the method allow us to consider it effective, as evidenced by the quality of the obtained coatings. This is due to the fact that the correctness of the formulation and solution of the problem provided adequate results. In contrast to the existing methods, the proposed one makes it possible to significantly influence the amount of harmful oxygen involved in the formation of a sprayed coating, which makes it possible to obtain a sprayed layer with the required performance characteristics. And also allows to improve its quality without significant capital costs. In addition, the issues of resource and energy saving are being addressed, since the burnout of chemical elements decreases and the air consumption during arc metallization decreases. To solve this problem, a simple design of the pulsator is proposed, which provides the ability to control the spray flow by adjusting the level of overlapping of the holes.

Characterization of Cr2O3 Adhesion Properties by Destructive Testing in Accordance with the APS Metal Spraying Process Parameters

2017 ◽  
Vol 750 ◽  
pp. 91-96
Author(s):  
Roxana Alexandra Gheța ◽  
Mariana Goran ◽  
Alina Elena Bușaru ◽  
Laurenția Bichir ◽  
Gabriel Marius Dumitru
Keyword(s):  
Base Material ◽  
Basic Material ◽  
Destructive Testing ◽  
Adhesion Properties ◽  
Quality Of Products ◽  
Sprayed Coating ◽  
Metal Spraying ◽  
Spraying Process

This paper aims to study the correlation between some parameters of the metalspraying by APS process and the level of chromium oxide (Cr2O3) adhesion to the base material. Among the properties of the layers deposited by APS are those of wear resistance. In the context of evaluating the coatings properties and understanding aspects related to the coat structure phenomena, the purpose of the experiment presented here is to characterize the adherence of thermal sprayed coating Cr2O3. Because, the main problem of metalspraying layers is adhesion to the base material, there were subjected to tensile testing 2 samples made by 1C45 steel, which were previously bonded with an epoxy glue. The adhesion of the deposited layer on the basic material is important for ensuring the quality of products. The results show that the quality of surfaces and the existence of accidental defects at the interface lead to a decrease of adherence.

scholarly journals Contaminant Emissions As Indicators of Chemical Elements in The Snow Along a Latitudinal Gradient in Southern Andes

2020 ◽  
Author(s):  
Jaime Pizarro ◽  
Pablo Vergara ◽  
Sergio Cerda ◽  
Raul Cordero ◽  
Ximena Castillo ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Atmospheric Transport ◽  
Chemical Elements ◽  
Spatial Scales ◽  
Anthropogenic Pollution ◽  
Air Contaminants ◽  
Latitudinal Transect ◽  
Volatile Organic ◽  
Particulate Contaminants

Abstract The chemical composition of snow provides insights on atmospheric transport of anthropogenic contaminants at different spatial scales. In this study, we assess how human activities influence the concentration of elements in the Andean mountain snow along a latitudinal transect throughout Chile. The concentration of seven elements (Al, Cu, Fe, Li, Mg, Mn and Zn) was associated to gaseous and particulate contaminants emitted at different spatial scales. Our results indicate carbon monoxide (CO) averaged at 20 km and nitrogen oxide (NOx) at 40 km as the main indicators of the chemical elements analyzed. CO was found to be a significant predictor of most element concentrations while concentrations of Cu, Mn, Mg and Zn were positively associated to emissions of NOx. Emission of 2.5 mm and 10 mm particulate matter averaged at different spatial scales was positively associated to concentration of Li. Finally, the concentration of Zn was positively associated to volatile organic compounds (VOC) averaged at 40 km around sampling sites. The association between air contaminants and chemical composition of snow suggests that regions with intensive anthropogenic pollution face reduced quality of freshwater originated from glacier and snow melting.

scholarly journals Phase Structure Evolution of the Fe-Al Arc-Sprayed Coating Stimulated by Annealing

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3210
Author(s):  
Tomasz Chmielewski ◽  
Marcin Chmielewski ◽  
Anna Piątkowska ◽  
Agnieszka Grabias ◽  
Beata Skowrońska ◽  
...  
Keyword(s):  
Phase Structure ◽  
Protective Coatings ◽  
Structural Evolution ◽  
Intermetallic Phases ◽  
Structure Evolution ◽  
Arc Spraying ◽  
Sem Images ◽  
Sprayed Coating ◽  
Spraying Process

The article presents the results of research on the structural evolution of the composite Fe-Al-based coating deposited by arc spray with initial low participation of in situ intermetallic phases. The arc spraying process was carried out by simultaneously melting two different electrode wires, aluminum and low alloy steel (98.6 wt.% of Fe). The aim of the research was to reach protective coatings with a composite structure consisting of a significant participation of FexAly as intermetallic phases reinforcement. Initially, synthesis of intermetallic phases took place in situ during the spraying process. In the next step, participation of FexAly fraction was increased through the annealing process, with three temperature values, 700 °C, 800 °C, and 900 °C. Phase structure evolution of the Fe-Al arc-sprayed coating, stimulated by annealing, has been described by means of SEM images taken with a QBSD backscattered electron detector and by XRD and conversion electron Mössbauer spectroscopy (CEMS) investigations. Microhardness distribution of the investigated annealed coatings has been presented.

scholarly journals Determination of adhesion of the coating deposited by arc spraying with pulsation of atomizing air flow

2021 ◽  
Vol 3 (12 (111)) ◽  
pp. 39-47
Author(s):  
Iryna Zakharova
Keyword(s):  
Adhesion Strength ◽  
Air Flow ◽  
Complex Loading ◽  
Test Methods ◽  
Aluminum Coating ◽  
Alloying Elements ◽  
Arc Spraying ◽  
Optimal Size ◽  
Pulsation Frequency ◽  
Conservation Of Energy

During electric arc spraying, during the transfer of molten metal by air flow, there is a significant burnout of alloying elements with the formation of a large amount of oxides, which negatively affects the adhesion of the coating to the base. A solution to the problem of increasing the adhesion strength by using pulsation of the atomizing air flow is proposed. At the optimal frequency of the pulsed flow shut-off, the time of formation of liquid metal droplets at the ends of the electrodes coincides with the frequency of pulses of the spraying flow. As a result, the droplets acquire an optimal size, they are transported by an air flow with conservation of energy, a lower mass of oxygen and, as a consequence, a significant decrease in the oxidation of alloying elements in the sprayed material. The existing test methods of sprayed coatings for adhesion strength to the base are analyzed. The design of a modernized device for determining the adhesion strength is developed and described, which provides complex loading of the coating with a combination of tear-off and shear. The tests revealed a significant (up to two times) increase in the adhesion strength of aluminum, zinc-aluminum and steel (Sv08A) coatings applied with air pulsation. This is achieved by increasing the number of fusion zones of the coating particles between themselves and with the base. It is shown that the effect of the pulsation frequency on the adhesion strength changes along a curve with a maximum corresponding to a frequency of 70–80 Hz, regardless of the coating material. It has been established that the aluminum coating has an increased tendency to oxidation, as a result of which it is 15–20 % inferior to the zinc-aluminum coating in adhesion strength. The data obtained substantiate the use of the proposed spraying technology in production

scholarly journals Irrigation-Induced Changes in Chemical Composition and Quality of Seeds of Yellow Lupine (Lupinus luteus L.)

2019 ◽  
Vol 20 (22) ◽  
pp. 5521 ◽  
Author(s):  
Justyna Polit ◽  
Iwona Ciereszko ◽  
Alina Dubis ◽  
Joanna Leśniewska ◽  
Anna Basa ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Chemical Elements ◽  
Irrigation System ◽  
Calcium Content ◽  
Poor Quality ◽  
Cellular Level ◽  
Lupinus Luteus ◽  
Yellow Lupine ◽  
Semi Solid

The quality and amount of yellow lupine yield depend on water availability. Water scarcity negatively affects germination, flowering, and pod formation, and thus introduction of an artificial irrigation system is needed. The aim of this study was to evaluate the influence of irrigation on the quality of yellow lupine seeds. Raining was applied with a semi-solid device with sprinklers during periods of greatest water demand. It was shown that watered plants produced seeds of lesser quality, having smaller size and weight. To find out why seeds of irrigated plants were of poor quality, interdisciplinary research at the cellular level was carried out. DNA cytophotometry evidenced the presence of nuclei with lower polyploidy in the apical zone of mature seeds. This may lead to formation of smaller cells and reduce depositing of storage materials. The electrophoretic and Fourier transform infrared spectroscopic analyses revealed differences in protein and cuticular wax profiles, while scanning electron microscopy and energy dispersive spectroscopy revealed, among various chemical elements, decreased calcium content in one of seed zones (near plumule). Seeds from irrigated plants showed slightly higher germination dynamics but growth rate of seedlings was slightly lower. The studies showed that irrigation of lupine affected seed features and their chemical composition, an ability to germination and seedlings growth.

scholarly journals ASSESSMENT OF THE QUALITY OF LUNAR SAMPLES

ASJ. ◽  
2021 ◽  
Vol 1 (45) ◽  
pp. 25-29
Author(s):  
A. Gavrishin ◽  
A. Coradini
Keyword(s):  
United States ◽  
Chemical Composition ◽  
Quality Assessment ◽  
Chemical Elements ◽  
Lunar Regolith ◽  
Lunar Soil ◽  
The United States ◽  
Lunar Samples ◽  
First Time

The aim of the research is to assess the reproducibility of analyses of the chemical composition of lunar samples and to study the quality of lunar regolith. As a result of the space expeditions "Moon" and "Apollo" performed by the USSR and the United States, numerous lunar samples were delivered to Earth. This paper explores two aspects of assessing the quality of lunar samples. 1) Reproducibility of analyses. Assessment of errors of determining the concentrations of chemical elements in lunar samples. 2) Assessment of the quality of the lunar regolith by the magnitude of the differences with the composition of the earth's soil (geoecological quality assessment). Geoecological assessment of the quality of the composition of the lunar regolith was made for the first time. Comparison of the chemical composition of the regolith delivered by the Luna-16 space expedition with the composition of terrestrial soils at concentrations of 30 elements has been made. It is determined that the lunar soil in the concentrations of many elements is significantly different from the earths. The geoecological situation is rated as a "crisis". 

The Influence of Spraying Distance on the Chemical Composition of Arc Sprayed Layers

2015 ◽  
Vol 754-755 ◽  
pp. 865-868
Author(s):  
Iuliana Silvia Georgescu ◽  
Silviu Ionuţ Ursache ◽  
Elena Raluca Baciu ◽  
Daniel Hriţcu ◽  
Andrei Victor Sandu ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Chemical Elements ◽  
Thermal Spraying ◽  
Electric Arc ◽  
Filler Material ◽  
Arc Spraying ◽  
Technological Parameters ◽  
Edax Analysis ◽  
Initial Chemical Composition ◽  
Spraying Method

Arc spraying (AS) is a thermal spraying method. The spraying distance represents one of the main technological parameters. EDAX analysis, performed on the sprayed layers (SDA and SDS), have shown differences between the initial chemical composition of the filler material and of the obtained layers. The quantitative variations determined for Ni, Fe and Cr can be explained by: the volatilization process of the chemical elements from the electric arc area; losses increase with increasing the length of the spraying jet.

Chemical Composition of Alloys as Primary Material Property Influencing the Accuracy of Measurements Obtained in Energy-Dispersive X-Ray Spectroscopy (EDS), Wavelength-Dispersive X-Ray Spectroscopy (WDX) and X-Ray Fluorescence (XRF)

2021 ◽  
Vol 326 ◽  
pp. 185-190
Author(s):  
Dawid Szyba
Keyword(s):  
Phase Composition ◽  
Chemical Composition ◽  
Material Properties ◽  
Chemical Elements ◽  
X Rays ◽  
Materials Properties ◽  
X Ray ◽  
Accuracy Of Measurements ◽  
Material Tests

The properties of the material affect the quality of the manufactured product. Before transferring the finished product to the production phase and sending it to the customer, material tests should be carried out. Examined material properties such as chemical composition, phase composition, grain boundaries influence results obtained after measurements of the chemical composition. The spectrometers used in SEM or as separate XRFs can be compared due to the principle of operation. The main difference in EDS/WDX or XRF is the types of a beam that excite the characteristic X-rays radiation peaks. Unfortunately, both types of spectroscopy have limitations due to materials properties such as the application light chemical elements in alloys an example of B. As well as small quantities of chemical elements in used alloys that affect the obtained results.

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