scholarly journals Toprak İşleme Makinalarının Aktif Elemanlarında Yüzey Kaplama Uygulamaları

2020 ◽  
Vol 8 (sp1) ◽  
pp. 92-99
Author(s):  
Yaşar Serhat Saygılı ◽  
Bülent Çakmak
Keyword(s):  
Wear Resistance ◽  
Agricultural Sector ◽  
Thermal Spraying ◽  
Film Coating ◽  
Soil Tillage ◽  
Material Loss ◽  
Coating Materials ◽  
Coating Methods ◽  
Phase Coating ◽  
Phase Liquid

Tillage machines such as plow, cultivator, rotavator, and rototiller are widely used for this purpose. However, one of the major problems in working with tillage machines is the wear of active parts over time. Abrasion occurs differently in active parts of tillage machines and can cause the machines used to lose the functionality expected of them. It is preferred to cover the active parts with wear-resistant coating materials to reduce the level of wear to meet both agro technical demands and high tillage efficiency. The way of wear the active parts of the machines; it is abrasive wear caused by friction against solid materials in the soil (clods, stones, harder materials, etc.) and/or adhesive wear caused by soil moisture. Reducing the wear on the active parts with the coating process to be made will both prevent material loss caused by abrasion in the active part and increase the efficiency/effectiveness of the machine. Because of the limited number of studies on this subject in the agricultural sector shows that the subject is open to improvement. In this study, the use of new coating methods used in other production sectors (especially in mold manufacturing) for the last decade in coating the active parts of soil tillage machines and their effects on product performance and life by increasing wear resistance are compiled. Coating methods that can be adapted to the agricultural sector can be listed as; Gas Phase, Liquid Phase and Melted/Semi-Melted Phase. Among these, studies on Plasma Thermal Spraying (Molten / Semi-Molten Phase Coating Methods) and thin film coating (Vapor Phase Coating Methods) are prominent. On the other hand, it is predicted that the desired wear resistance can be further improved by applying different coating methods and combinations.

scholarly journals On Coating Techniques for Surface Protection: A Review

2019 ◽  
Vol 3 (1) ◽  
pp. 28 ◽  
Author(s):  
Behzad Fotovvati ◽  
Navid Namdari ◽  
Amir Dehghanghadikolaei
Keyword(s):  
Sol Gel ◽  
Thermal Spraying ◽  
Chemical Vapor ◽  
Manufacturing Cost ◽  
Coating Materials ◽  
Protective Function ◽  
Surface Protection ◽  
Common Purpose ◽  
Coating Methods ◽  
Micro Arc Oxidation

A wide variety of coating methods and materials are available for different coating applications with a common purpose of protecting a part or structure exposed to mechanical or chemical damage. A benefit of this protective function is to decrease manufacturing cost since fabrication of new parts is not needed. Available coating materials include hard and stiff metallic alloys, ceramics, bio-glasses, polymers, and engineered plastic materials, giving designers a variety freedom of choices for durable protection. To date, numerous processes such as physical/chemical vapor deposition, micro-arc oxidation, sol–gel, thermal spraying, and electrodeposition processes have been introduced and investigated. Although each of these processes provides advantages, there are always drawbacks limiting their application. However, there are many solutions to overcome deficiencies of coating techniques by using the benefits of each process in a multi-method coating. In this article, these coating methods are categorized, and compared. By developing more advanced coating techniques and materials it is possible to enhance the qualities of protection in the future.

Study of Cavitation Erosion-Corrosion Resistance of Thermally Sprayed Ni-Based Coatings Prepared by HVAF Process

2020 ◽  
Vol 299 ◽  
pp. 893-901
Author(s):  
Hussam L. Alwan ◽  
Yury S. Korobov ◽  
N.N. Soboleva ◽  
N.V. Lezhnin ◽  
A.V. Makarov ◽  
...  
Keyword(s):  
Cavitation Erosion ◽  
Thermal Spraying ◽  
Superior Performance ◽  
Material Loss ◽  
Coating Materials ◽  
Sem Micrographs ◽  
Coating Surface ◽  
Erosion Corrosion ◽  
Before And After ◽  
Nicrbsi Coating

In this study, two Ni-based coating materials, namely NiCrMoNb and NiCrBSi, have been applied using High Velocity Air Fuel (HVAF) thermal spraying process. The performance of the coated surface in resistance to cavitation erosion-corrosion of both coating materials, has been evaluated using an ultrasonic vibratory method. The cumulative material loss and erosion rate curves of the two coatings have been discussed. Surface topography, microhardness, macroscopic images, and scanning electron microscope (SEM) micrographs were used to characterize the coatings before and after the cavitation test. The cavitation results showed that the NiCrMoNb coating surface has exhibited better performance than the NiCrBSi coating surface under the same test conditions. The total cumulative weight loss of the NiCrMoNb coating was about 1/3 that of the NiCrBSi coating. SEM micrographs of the eroded surfaces showed that the surface layer of the NiCrBSi coating was more damaged, compared to layer of the NiCrMoNb coating. Overall, the NiCrMoNb coating can be effectively used against the cavitation wear, due to its superior performance.

Wear resistance of coating materials under the frictional heating conditions

2017 ◽  
Vol 38 (4) ◽  
pp. 265-271 ◽  
Author(s):  
V. B. Zelentsov ◽  
B. I. Mitrin ◽  
I. A. Lubyagin
Keyword(s):  
Wear Resistance ◽  
Frictional Heating ◽  
Coating Materials

scholarly journals Effects of Ambient Conditions on the Dielectric Properties of Thermally Sprayed Ceramic Coating

2018 ◽  
Author(s):  
M Niittymäki ◽  
B. Rotthier ◽  
K. Lahti ◽  
T. Suhonen ◽  
J Metsäjoki
Keyword(s):  
Dielectric Properties ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Thermal Spraying ◽  
Ceramic Coatings ◽  
Alumina Coating ◽  
Ambient Conditions ◽  
Coating Materials ◽  
Sprayed Coating ◽  
Thermally Sprayed

<p>Thermal spraying techniques are used to manufacture insulating coatings especially for demanding applications like fuel cells where normal insulating materials cannot be used. In electrical insulation applications, the mostly used coating materials are aluminum oxide (Al2O3), magnesium oxide (MgO) and magnesium aluminate (MgAl2O4). Dielectric properties of thermally sprayed ceramic coatings are strongly affected by ambient conditions, and in addition to this they are not well documented in the literature. In this paper the effects of environmental conditions on certain dielectric properties of a thermally sprayed coating are studied. DC resistivity as well as permittivity and losses at different frequencies at relative humidities of 20 % and 45 % at temperature of 20 °C, 40 °C and 60 °C will be reported in the paper for Al2O3 samples sprayed using HVOF (High Velocity Oxygen Fuel) technique. DC dielectric breakdown strength is also studied for the HVOF alumina coating at temperature of 20 °C and relative humidity of 20 %. Effects of ambient conditions and coating material composition are also analyzed.</p>

scholarly journals Cavitation Erosion and Sliding Wear of MCrAlY and NiCrMo Coatings Deposited by HVOF Thermal Spraying

2020 ◽  
Vol 20 (2) ◽  
pp. 26-38 ◽  
Author(s):  
M. Szala ◽  
M. Walczak ◽  
L. Łatka ◽  
K. Gancarczyk ◽  
D. Özkan
Keyword(s):  
Wear Resistance ◽  
Sliding Wear ◽  
Cavitation Erosion ◽  
Erosion Resistance ◽  
Nickel Content ◽  
Thermal Spraying ◽  
Point Of View ◽  
Engineering Practice ◽  
Hvof Thermal Spraying ◽  
Cavitation Erosion Resistance

AbstractThe investigation into wear resistance is an up-to-date problem from the point of view of both scientific and engineering practice. In this study, HVOF coatings such as MCrAlY (CoNiCrAlY and NiCoCrAlY) and NiCrMo were deposited on AISI 310 (X15CrNi25-20) stainless steel substrates. The microstructural properties and surface morphology of the as-sprayed coatings were examined. Cavitation erosion tests were conducted using the vibratory method in accordance with the ASTM G32 standard. Sliding wear was examined with the use of a ball-on-disc tribometer, and friction coefficients were measured. The sliding and cavitation wear mechanisms were identified with the SEM-EDS method. In comparison to the NiCrMo coating, the MCrAlY coatings have lower wear resistance. The cavitation erosion resistance of the as-sprayed M(Co,Ni)CrAlY coatings is almost two times lower than that of the as-sprayed NiCrMoFeCo deposit. Moreover, the sliding wear resistance increases with increasing the nickel content as follows: CoNiCrAlY < NiCoCrAlY < NiCrMoFeCo. The mean friction coefficient of CoNiCrAlY coating equals of 0.873, which almost 50% exceed those reported for coating NiCrMoFeCo of 0.573. The as-sprayed NiCrMoFeCo coating presents superior sliding wear and cavitation erosion resistance to the as-sprayed MCrAlY (CoNiCrAlY and NiCoCrAlY) coatings.

HVOF- and VPS-Coatings Using Nanostructured Iron-Based Alloys

1997 ◽  
Author(s):  
O.C. Brandt ◽  
S. Siegmann ◽  
H.-P. Isch
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Thermal Spraying ◽  
High Ductility ◽  
High Toughness ◽  
Iron Based

Abstract In thermal spraying, Fe-based alloys are often applied for relatively thick and inexpensive coatings. The main advantage of the Fe-based alloy coatings is their high ductility as compared to ceramic and hardmetal coatings. Other advantages such as high toughness, easy machineability and satisfactory corrosion resistance are characteristic of Fe-based alloys. The wear resistance is not outstanding, but nevertheless acceptable for a large number of applications. A further improvement of the wear resistance can be achieved by reinforcing the Fe-based alloy coatings, e.g. by addition of nitrogen to the spraying powder.

scholarly journals A Comparative Study on the Tribological Properties of a Cobalt-Free Superaustenitic Stainless Steel at Elevated Temperature

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1123
Author(s):  
Frederic van gen Hassend ◽  
Sebastian Weber
Keyword(s):  
Stainless Steel ◽  
Wear Resistance ◽  
Elevated Temperature ◽  
Superaustenitic Stainless Steel ◽  
Material Loss ◽  
Hardness Tests ◽  
Alternative Material ◽  
Wear Tests ◽  
Hot Hardness

The properties of a cobalt-free cast superaustenitic stainless steel (SASS) is investigated comparatively to the commercial high-cobalt alloyed GX15CrNiCo21-20-20 (1.4957, N-155) steel regarding its global hardness and wear resistance at elevated temperature by means of in situ hot hardness tests and cyclic abrasive sliding wear tests against an Al2O3 (corundum) counter-body at 600 °C. In the aged condition, results show that the 1.4957 steel suffers a higher material loss due to brittle failure initiated by coarse eutectic Cr-rich carbides which are incorporated into a mechanically mixed layer during abrasive loading. In contrast, within the Co-free steel eutectic M6(C,N) carbonitrides are distributed more homogeneously showing less tendency to form network structures. Due to the combination of primary Nb-rich globular-blocky MX-type carbonitrides and eutectic M6(C,N) carbonitrides dispersed within an Laves phase strengthened austenitic matrix, this steel provides comparable hardness and significantly improved wear resistance at elevated temperature. Thus, it may be an adequate alternative material to commercial SASS and offers the possibility to save cobalt for future applications.

scholarly journals Pharmaceutical Application of Tablet Film Coating

Pharmaceutics ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 853
Author(s):  
Ki-Soo Seo ◽  
Rajiv Bajracharya ◽  
Sang Hoon Lee ◽  
Hyo-Kyung Han
Keyword(s):  
Computational Modeling ◽  
Analytical Techniques ◽  
Film Coating ◽  
Dosage Forms ◽  
Coating Process ◽  
Coating Materials ◽  
Coating Technology ◽  
Advantages And Disadvantages ◽  
Pharmaceutical Application

Tablet film coating is a common but critical process providing various functionalities to tablets, thereby meeting diverse clinical needs and increasing the value of oral solid dosage forms. Tablet film coating is a technology-driven process and the evolution of coated dosage forms relies on advancements in coating technology, equipment, analytical techniques, and coating materials. Although multiple coating techniques are developed for solvent-based or solvent-free coating processes, each method has advantages and disadvantages that may require continuous technical refinement. In the film coating process, intra- and inter-batch coating uniformity of tablets is critical to ensure the quality of the final product, especially for active film coating containing active pharmaceutical ingredients in the coating layer. In addition to experimental evaluation, computational modeling is also actively pursued to predict the influence of operation parameters on the quality of the final product and optimize process variables of tablet film coating. The concerted efforts of experiments and computational modeling can save time and cost in optimizing the tablet coating process. This review provides a brief overview of tablet film coating technology and modeling approaches with a focus on recent advancements in pharmaceutical applications.

Climate variability, vulnerability and effectiveness of farm-level adaptation options: the challenges and implications for food security in Southwestern Cameroon

2002 ◽  
Vol 7 (3) ◽  
pp. 529-545 ◽  
Author(s):  
Ernest L. Molua
Keyword(s):  
Food Security ◽  
Climate Variability ◽  
Food Availability ◽  
Agricultural Production ◽  
Agricultural Sector ◽  
Soil Tillage ◽  
Farm Income ◽  
Steady Increase ◽  
Farm Level ◽  
The Impact

The risks associated with increasing climate variability pose technological and economic challenges to societies which are dependent on agriculture for their livelihood. In Southwestern Cameroon the natural variability of rainfall and temperatures contribute to variability in agricultural production and food insecurity. This paper explores the impact of climate variability in Southwestern Cameroon on food availability. It examines farm household's vulnerability to food availability relating to climate, and reviews the interplay of climate, agriculture, and prospects for food security in the region. An econometric function directly relates farm income and precipitation, in order to statistically estimate the significance of farm-level adaptation methods. The results reveal that precipitation during growing and adaptation methods through changes in soil tillage and crop rotation practices have significant effects on farm returns. An essential precondition for food security and overall agricultural development in Southwestern Cameroon is a dynamic agricultural sector brought about both by steady increase in agricultural production and by greater efforts in farmer support, to enable farm households to take advantage of the opportunities and to minimize the negative impacts of climate variation on agriculture.

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