scholarly journals Analysis of the Quality of Sulfomolybdenum Coatings Obtained by Electrospark Alloying Methods

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6332
Author(s):  
Oksana P. Gaponova ◽  
Bogdan Antoszewski ◽  
Viacheslav B. Tarelnyk ◽  
Piotr Kurp ◽  
Oleksandr M. Myslyvchenko ◽  
...  
Keyword(s):  
Quality Parameters ◽  
Substrate Material ◽  
Metallographic Analysis ◽  
Electrospark Alloying ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
Molybdenum Electrode ◽  
Tribological Coatings ◽  
Machine Parts

The authors of this paper have attempted to improve the quality of surface layers applied to steel elements of machine parts constituting friction couples. The main goal of the research was to investigate an electrospark alloying method process for obtaining abrasion-resistant tribological coatings containing molybdenum disulfide on a steel surface. A substance in the form of sulfur ointment with a sulfur content of 33.3% was applied on the surfaces of C22 and C40 steel specimens. In order to determine the influence of the energy parameters of ESA equipment on the quality parameters of coatings, the ESA process was carried out using a molybdenum electrode with discharge energies Wp = 0.13; Wp = 0.55; Wp = 3.4 J. The following tests were carried out on specimens with such coatings: metallographic analysis, microhardness tests, surface roughness, and local X-ray diffraction microanalysis. The experiments revealed that sulfomolybdenum coatings consist of four zones with different mechanical properties. Depending on the discharge energy and the substrate material, the hardness of these zones varies from approx. 1100 to over 10,000 MPa. Differences in the distribution of, among others, sulfur and molybdenum in the obtained coatings, as well as differences in the microstructure of the observed coatings, were observed.

GaN On 6H-SiC – Structural And Optical Properties

1994 ◽  
Vol 339 ◽  
Author(s):  
C. Wetzel ◽  
D. Volm ◽  
B. K. Meyer ◽  
K. Pressel ◽  
S. Nilsson ◽  
...  
Keyword(s):  
Optical Properties ◽  
Transition Metal Ions ◽  
Substrate Material ◽  
X Ray Diffraction ◽  
High Quality ◽  
Paramagnetic Resonance ◽  
Lattice Constants ◽  
Donor Acceptor ◽  
Related Donor

ABSTRACTRecent progress in the growth of high quality 6H-SiC single crystals has led to an ideal substrate material for GaN epitaxial films. Nearly matching lattice constants of wurzite GaN to 6H-SiC in the hexagonal plane can reduce strain effects at the interface. We employed the sublimation sandwich method to grow single crystal layers at reasonable growth rates with free carrier concentrations of 2×1017 cm-3. Very sharp x-ray diffraction peaks of the GaN (0002) plane are obtained indicating the high quality of this system (Δ(2θ) < 0.1 degrees). These findings are directly reflected in the optical properties. The photoluminescence is dominated by a single sharp exciton line, impurity related donor acceptor transitions are seen with very weak intensities. However, at lower energies the internal luminescence transitions of the 3d transition metal ions Fe and V are observable. The incorporation of Fe is confirmed by electron paramagnetic resonance.

Application of Metallographic Analysis Techniques for Detection and Identification of Spray Paint Defects

2017 ◽  
Vol 270 ◽  
pp. 118-123
Author(s):  
Michaela Remešová ◽  
Lenka Klakurková ◽  
Ivana Ročňáková ◽  
Ladislav Čelko ◽  
Lucie Páleníková ◽  
...  
Keyword(s):  
Substrate Material ◽  
Consumer Electronics ◽  
Metallographic Analysis ◽  
Surface Appearance ◽  
X Ray ◽  
Detection And Identification ◽  
Digital Microscope ◽  
Negative Effect ◽  
Paint Films

The paper is focused on the metallographic analysis of spray paint films with defects. The painting has two important roles. Firstly, it protects the substrate material (ferrous, nonferrous and plastic) and secondly, it improves the appearance of the surface. Appearance and quality of painting film play an important role in the industry (automotive, aerospace, consumer electronics, etc.). Defects of spray painting film, which have a negative effect on the appearance of the product, can be detected and further analysed by common methods used in metallography. Such methods are very effective tool for revealing the cause of defects and their elimination within the technological process (degreasing, cleaning, pickling, drying, technological discipline, etc.). In this paper, defects were characterized by high-resolution digital microscope (LM) and scanning electron microscope (SEM) equipped with energy dispersive X-ray analyser (EDX).

scholarly journals Effect of Mo Addition on the Chemical Corrosion Process of SiMo Cast Iron

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1745
Author(s):  
Marcin Stawarz ◽  
Paweł M. Nuckowski
Keyword(s):  
Cast Iron ◽  
Substrate Material ◽  
Metallographic Analysis ◽  
X Ray Diffraction ◽  
Oxide Layers ◽  
Chemical Corrosion ◽  
High Adhesion ◽  
Cyclic Operation ◽  
Mo Content ◽  
Si Content

The study was carried out to evaluate five SiMo cast iron grades and their resistance to chemical corrosion at elevated temperature. Corrosion tests were carried out under conditions of an actual cyclic operation of a retort coal-fired boiler. The duration of the study was 3840 h. The range of temperature changes during one cycle was in the range of 300–650 °C. Samples of SiMo cast iron with Si content at the level of 5% and variable Mo content in the range 0%–2.5% were used as the material for the study. The examined material was subjected to preliminary metallographic analysis using scanning microscopy and an Energy dispersive spectroscopy (EDS) system. The chemical composition was determined on the basis of a Leco spectrometer and a Leco carbon and sulfur analyzer. The examination of the oxide layer was carried out with the use of Scanning electron microscope (SEM), EDS, and X-ray diffraction (XRD) methods. It was discovered that, in the analyzed alloys, oxide layers consisting of Fe2O3, Fe3O4, SO2, and Fe2SiO4 were formed. The analyzed oxide layers were characterized by high adhesion to the substrate material, and their total thickness was about 20 μm.

scholarly journals Quality assessment of AL-C-B coatings on steel surfaces obtained by electro spark alloying

2021 ◽  
pp. 13
Author(s):  
Oksana Gaponova ◽  
Oleksandr Myslyvchenko ◽  
Vitalina Dudchenko
Keyword(s):  
Aluminum Powder ◽  
Graphite Electrode ◽  
Diffusion Coating ◽  
Substrate Material ◽  
Original Method ◽  
Alternative Methods ◽  
Metallographic Analysis ◽  
Amorphous Boron ◽  
Surface Layers ◽  
Boron Powder

Problem. As a rule, during the operation of the product, the surface layers of materials are most affected. These can be parts that work in aggressive environments, at high temperatures, various force actions, the presence of abrasive particles, etc. Under such conditions, different types of steels and alloys are used, and, most commonly, it is high-alloy, which significantly complicates the manufacturing process and increases the cost of the finished product. Diffusion coating methods are the most widespread in the industry, which is due to the best study and ease of these processes. However, there are alternative methods of surface treatment, which are devoid of the disadvantages of diffusion methods. The goal is to develop a method of obtaining boron-containing coatings of the Al-C-B system by the electro spark alloying (ESA), applying STS to the treated surface, to study the processes of structural and phase formation of surface layers depending on the energy processes of ESA and substrate material. Methology. Samples made of steel 20 and 40 were used for the study, on which a coating consisting of their sulfur ointment, aluminum powder, amorphous boron powder was applied. Without waiting for drying, the ESA surfaces of the samples were carried out with a graphite electrode on an installation with a discharge energy of 0.13, 0.55 and 4.9 J. The surface roughness after treatment was determined on a profilograph-profilometer by removing and processing profilograms. Metallographic analysis of coatings was performed using an MIM-7optical microscope, and durometric studies were made on the PMT-3 device according to standard methods. Results: the article presents the original method for obtaining boron-containing coatings of the Al-C-B system by the ESA method, which involves applying a coating consisting of sulfur ointment, aluminum powder, amorphous boron powder on the treated surface, followed by electric spark doping with a graphite electrode.

METHODOLOGICAL FOUNDATIONS OF DIAGNOSTICS OF METALWORKING TECHNOLOGICAL SYSTEMS ACCORDING TO PARAMETRIC RELIABILITY OF ENSURING A GIVEN QUALITY OF THE TREATED SURFACES

2021 ◽  
Vol 2021 (11) ◽  
pp. 36-50
Author(s):  
Vladimir Fedorov ◽  
Maksim Nagorkin ◽  
Leonid Vayner
Keyword(s):  
Theoretical Models ◽  
World Market ◽  
Quality Parameters ◽  
Technological Systems ◽  
Software Analysis ◽  
Parametric Reliability ◽  
Machined Parts ◽  
Machine Parts ◽  
Further Development

The paper presents the results of research justifying the need for diagnostics of metalworking technological systems on the reliability of ensuring the quality parameters of the surfaces of machine parts during machining. The fundamentals of the methodology of its implementation have been developed. Theoretical models of forming the quality parameters of parts surfaces during machining are considered and refined. This characterizes the scientific novelty of the results obtained. Circuitries for the construction of experimental control systems when conducting bench tests of machined surfaces of parts in conditions close to operational are of practical value. Circuitries are developed and computerized systems based on them for measuring the quality parameters of machined parts surfaces, including the working area of the technological system, are implemented. Recommendations on the rational choice of technological systems and the use of simulation methods in the study of parametric reliability of technological systems are presented. Mathematical and software analysis and processing of experimental results are developed and tested. These results will serve as a foundation for further development of research in the field of parametric reliability of technological systems, improving the quality of domestic engineering products and increasing their competitiveness at the world market.

Electrospark Alloying of Carbon Steel with WC-Co-Al2O3: Deposition Technique and Coating Properties

2014 ◽  
Vol 874 ◽  
pp. 101-106 ◽  
Author(s):  
Norbert Radek ◽  
Augustín Sladek ◽  
Jozef Broncek ◽  
Izabela Bilska ◽  
Agnieszka Szczotok
Keyword(s):  
Carbon Steel ◽  
Abrasive Wear Resistance ◽  
Electrospark Alloying ◽  
Deposition Technique ◽  
Coating Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coating Microstructure ◽  
Machine Parts ◽  
Wear Coatings

The paper is concerned with the performance properties of electrospark deposited coatings. The properties were assessed by analyzing the coating microstructure, X-ray diffraction, microhardness, roughness and bonding strength.The studies were conducted using WC-Co-Al2O3electrodes produced by sintering nanostructural powders. The anti-wear coatings were electro-spark deposited over C45 carbon steel by means of an EIL-8A. These coatings are likely to be applied to increase the abrasive wear resistance of tools and machine parts.

Lithography below 100 nm

1983 ◽  
Vol 41 ◽  
pp. 96-99
Author(s):  
L. D. Jackel
Keyword(s):  
Spatial Distribution ◽  
Electron Beam ◽  
Electron Scattering ◽  
Electron Beam Lithography ◽  
Substrate Material ◽  
Local Electron ◽  
Electron Dose ◽  
Positive Resist ◽  
Exposure Process

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.

Modification of tundish design to improve quality of slabs, casted at CCM No. 4 of EVRAZ NTMK

2020 ◽  
Vol 76 (6) ◽  
pp. 559-563
Author(s):  
I. M. Zakharov ◽  
V. A. Smirnov ◽  
D. V. Sushnikov ◽  
A. G. Lyzhin ◽  
E. A. Lavrova ◽  
...  
Keyword(s):  
Basic Number ◽  
Metal Level ◽  
Surface Layers ◽  
Secondary Oxidation ◽  
Strip Rolling ◽  
Actual Distribution ◽  
Ultrasonic Control ◽  
Analysis Of Results ◽  
Water Simulation

A technology of continuous casting of steel has a large effect on its contamination. In particular, proper organization of metal flows in tundish and mold is very important. After completion a series of casting through a tundish and drop of metal level in it, it possible, that the slag flows from the surface layers of the tundish to capture the metal. An analysis of results of ultrasonic control of finished strip showed, that the basic number of the revealed defects was obtained during strip rolling out of the last slabs of the last heat in a series for a tundish. Metallographic studies determined, that the defects were located in the slab axis zone and filled by macro-inclusions of complex composition. To determine the actual distribution of metal flows, a water simulation of them was accomplished for the existing design of the EVRAZ NTMK tundish. It was determined, that at the drop of metal level in a tundish, a capture of slag from the metal reservoir and its transfer into the main bath of the tundish takes place due to whirligig flows. Following the weight metal consumption, the zone of slag inclusions distribution enlarges. Besides, denudation of the metal mirror in the metal reservoir takes place, resulted in metal secondary oxidation. Based on the results of the simulation, it was proposed to modify the design of the “turbostop”, which is installed in the metal reservoir of the tundish. Besides, it was proposed to remove the dividers installation in the tundish. It was noted, that the proposed steps enable to ensure a minimal level of rejections.

Quality of ram spermatozoa separated with modified swim up method

2018 ◽  
Vol 33 (2) ◽  
pp. 62-70 ◽  
Author(s):  
A Hossain ◽  
MM Islam ◽  
F Naznin ◽  
RN Ferdousi ◽  
FY Bari ◽  
...  
Keyword(s):  
Semen Quality ◽  
Membrane Integrity ◽  
Quality Parameters ◽  
Fluid Medium ◽  
Normal Morphology ◽  
The Mean ◽  
Mass Activity ◽  
Fresh Semen ◽  
Artificial Vagina

Semen was collected from four rams, using artificial vagina and viability%, motility% and plasma membrane integrity% were measured. Fresh ejaculates (n = 32) were separated by modified swim-up separation using modified human tubal fluid medium. Four fractions of supernatant were collected at 15-minute intervals. The mean volume, mass activity, concentration, motility%, viability%, normal morphology and membrane integrity% (HOST +ve) of fresh semen were 1.0 ± 0.14, 4.1 ± 0.1 × 109 spermatozoa/ml, 85.0 ± 1.3, 89.4 ± 1.0, 85.5 ± 0.7, 84.7 ± 0.5 respectively. There was no significant (P>0.05) difference in fresh semen quality parameters between rams. The motility%, viability% and HOST +ve % of first, second, third and fourth fractions were 53.4 ± 0.5, 68.2 ± 0.3, 74.8 ± 0.3 and 65.5 ± 0.4; 55.5 ± 0.4, 66.2 ± 0.4, 74.5 ± 0.3 and 73.6 ± 0.3 and 66.7 ± 0.5, 66.8 ± 0.5, 65.2 ± 0.4 and 74.7 ± 0.5 respectively. The motility%, viability% and membrane integrity% of separated semen samples differed significantly (P<0.05) between four fractions. The mean motility% and viability% were significantly higher (P<0.05) in third fraction (74.8 ± 0.3%), whereas the mean HOST +ve% was significantly higher (P<0.05) in fourth fraction (74.7 ± 0.5). All quality parameters of separated spermatozoa were significantly (P<0.05) lower than that of fresh semen. The pregnancy rates were higher with fresh semen (71%) in comparison to that of separated sample (57%).Bangl. vet. 2016. Vol. 33, No. 2, 62-70

Yield and Seed quality of barley (Hordeum vulgare L.) as affected by variety, nitrogen level and harvesting time

2014 ◽  
Vol 2 (2) ◽  
pp. 93-100
Author(s):  
Shahnaj Yesmina ◽  
Moushumi Akhtarb ◽  
Belal Hossain
Keyword(s):  
Grain Yield ◽  
Seed Weight ◽  
Seed Quality ◽  
Quality Parameters ◽  
Nitrogen Level ◽  
Yield Attributes ◽  
Harvesting Time ◽  
Nitrogen Levels ◽  
Vigour Index

The experiment was conducted to find out the effect of variety, nitrogen level and harvesting time on yield and seed quality of barley. The treatments used in the experiment consisted of two varieties viz. BARI Barley 4 and BARI Barley 5, three harvesting time viz. 35, 40 and 45 Days after Anthesis (DAA) and nitrogen levels viz. 0, 70, 85 and 100 kg N ha-1 . The experiment was laid out in a spilt- spilt-plot design with three replications assigning the variety to the main plot, harvesting time to the sub-plots and nitrogen level to the sub-sub plots. Variety had significant effects on the all yield attributes except fertile seeds spike-1 . Seed quality parameters viz. normal seeds spike-1 , deformed seeds spike-1 , germination (%) and vigour index were statistically significant. The variety BARI Barley 5 produced higher grain yield and seed quality than BARI Barley 4. Grain yield from BARI Barley 5 and BARI Barley 4 were 4.59 t ha-1 and 4.24 t ha-1 , respectively. Significantly, the highest 1000-seed weight (46.90 g) was produced by BARI Barley 5 than (37.90 g) BARI Barley 4. The result revealed that harvesting time had significant effect on yield and yield attributes and seed quality parameters. Seed yield was highest (4.65 t ha-1 ) when the crop harvested at 40 DAA and it was increased linearly from 35 DAA. Maximum quality seed and 1000-seed weight (43.20 g) was obtained when the crop harvested at 40 DAA. All the yields, yield attributes and seed quality parameters were significantly influenced by nitrogen levels. The highest grain yield (5.14 t ha-1 ) was obtained when BARI Barley 5 variety was fertilized by 100 kg N ha-1 and the lowest (3.14 t ha-1 ) was obtained from control treatments. Normal seeds spike-1 , vigour index, germination (%) were better at 85 kg N ha-1 in variety of BARI Barley 5 than BARI Barley 4. So it can be concluded that BARI Barley 5 showed better result when fertilized with 100 kg N ha-1 and harvested at 40 DAA for getting maximum yield and 85 kg N ha-1 and harvested at 40 DAA for getting better quality seed.

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