scholarly journals Modeling of protective plasma spray ceramic coating made of clad powder mixture

2021 ◽  
Vol 2131 (2) ◽  
pp. 022032
Author(s):  
I Tsareva ◽  
L Krivina ◽  
O Berdnik
Keyword(s):  
Phase Composition ◽  
Powder Material ◽  
Powder Mixture ◽  
Mechanical Engineering ◽  
Ceramic Coating ◽  
High Hardness ◽  
Plasma Coating ◽  
High Energy ◽  
Columnar Structure ◽  
Cohesive Strength

Abstract To solve the problem of increasing the adhesive-cohesive strength of plasma multifunctional coatings used to protect parts of power and mechanical engineering equipment components from wear and corrosion, a ceramic coating of the “Al2O3 - Ni” system, obtained from a powder mixture based on corundum clad with nickel, is proposed for use and studied. The coating was applied by high-energy plasma powder deposition (on the “Thermoplasma-50” installation) to the intermetallic sublayer of the “Ni-Co-Cr-Al-Y” system. The aim of this work was to study the micro structure and phase composition of the powder mixture of oxide ceramics clad with a refractory metal component (nickel), as well as the plasma coating formed from this powder material. According to the results of the research, it was found that the powder mixture clad with nickel has a multiphase composition (Ni+l-Al2O3+r-Al2O3), a spherical morphology of particles. From this powder material, a coating with a phase composition (Ni+L -Al2O3+J ’-L J u Ll) is formed, characterized by a layered microstructure with a columnar structure of oxide grains and nickel interlayers. The coating has high hardness and adhesive-cohesive strength, low coefficient of friction and is recommended for protection against wear of energy and mechanical engineering parts.

Characterization of thermal barrier coatings formed by electon-beam physical vapor deposition (EB-PVD)

1989 ◽  
Vol 47 ◽  
pp. 426-427
Author(s):  
Ozer Unal
Keyword(s):  
Thermal Barrier Coatings ◽  
Physical Vapor Deposition ◽  
Ceramic Coating ◽  
High Vacuum ◽  
Ceramic Coatings ◽  
High Energy ◽  
Thermal Barrier ◽  
Protective Oxide ◽  
Barrier Coatings ◽  
Energy Beam

Interest in ceramics as thermal barrier coatings for hot components of turbine engines has increased rapidly over the last decade. The primary reason for this is the significant reduction in heat load and increased chemical inertness against corrosive species with the ceramic coating materials. Among other candidates, partially-stabilized zirconia is the focus of attention mainly because ot its low thermal conductivity and high thermal expansion coefficient.The coatings were made by Garrett Turbine Engine Company. Ni-base super-alloy was used as the substrate and later a bond-coating with high Al activity was formed over it. The ceramic coatings, with a thickness of about 50 μm, were formed by EB-PVD in a high-vacuum chamber by heating the target material (ZrO2-20 w/0 Y2O3) above its evaporation temperaturef >3500 °C) with a high-energy beam and condensing the resulting vapor onto a rotating heated substrate. A heat treatment in an oxidizing environment was performed later on to form a protective oxide layer to improve the adhesion between the ceramic coating and substrate. Bulk samples were studied by utilizing a Scintag diffractometer and a JEOL JXA-840 SEM; examinations of cross-sectional thin-films of the interface region were performed in a Philips CM 30 TEM operating at 300 kV and for chemical analysis a KEVEX X-ray spectrometer (EDS) was used.

Phase composition depth profiles using spatially resolved energy dispersive X-ray diffraction

2004 ◽  
Vol 37 (6) ◽  
pp. 967-976 ◽  
Author(s):  
Andrew C. Jupe ◽  
Stuart R. Stock ◽  
Peter L. Lee ◽  
Nikhila N. Naik ◽  
Kimberly E. Kurtis ◽  
...  
Keyword(s):  
Phase Composition ◽  
Spatial Resolution ◽  
Zinc Coating ◽  
High Energy ◽  
Sulfate Attack ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spatially Resolved ◽  
Composition Profiles

Spatially resolved energy dispersive X-ray diffraction, using high-energy synchrotron radiation (∼35–80 keV), was used nondestructively to obtain phase composition profiles along the radii of cylindrical cement paste samples to characterize the progress of the chemical changes associated with sulfate attack on the cement. Phase distributions were acquired to depths of ∼4 mm below the specimen surface with sufficient spatial resolution to discern features less than 200 µm thick. The experimental and data analysis methods employed to obtain quantitative composition profiles are described. The spatial resolution that could be achieved is illustrated using data obtained from copper cylinders with a thin zinc coating. The measurements demonstrate that this approach is useful for nondestructively visualizing the sometimes complex transformations that take place during sulfate attack on cement-based materials. These transformations can be spatially related to microstructure as seen by computed microtomography.

Effects of High-Energy Ball Milling Time on the Sintering Process of FeSe Superconductors

2016 ◽  
Vol 848 ◽  
pp. 657-663 ◽  
Author(s):  
Sheng Nan Zhang ◽  
Xiao Bo Ma ◽  
Ji Xing Liu ◽  
Jian Qing Feng ◽  
Cheng Shan Li ◽  
...  
Keyword(s):  
Phase Composition ◽  
Ball Milling ◽  
Optimal Parameter ◽  
High Energy ◽  
Superconducting Phase ◽  
High Energy Ball Milling ◽  
Superconducting Transition ◽  
Sintering Process ◽  
Energy Ball ◽  
Precursor Powders

FeSe superconducting bulks were prepared with high energy ball milling (HEBM) aided sintering process, within which process, tetragonal β-FeSe superconducting phase could be formed directly with one step sintering process, and the formation of hexagonal δ-FeSe non-superconducting phase was effectively avoided. The influences of HEBM time on the sintering process of FeSe bulks were systematically investigated. With different HEBM time, the phase composition and morphology of precursor powders changed correspondingly, which thus influenced the final phase composition and superconducting properties of FeSe superconducting bulks. Due to the formation of FeSe bulks with larger tetragonal phase content and higher superconducting transition temperature, HEBM time of 6.0 h was recognized as the optimal parameter. Shorter HEBM time could lead to the insufficient decrease of particle size and low density. While longer HEBM time caused the formation of amorphous hexagonal δ-FeSe, which crystallized during sintering process. Thus no more tetragonal FeSe could be obtained. The FeSe superconducting bulk with the critical temperature Tc(onset) of 8.0 K was obtained with the HEBM time of 6 h, and sintering temperature of 700 oC for 12 h.

scholarly journals COMPETITIVENESS OF DOMESTIC PRODUCTS IN THE INTERNATIONAL MACHINE BUILDING MARKET: REALITIES AND PROSPECTS

2021 ◽  
pp. 80-91
Author(s):  
V.H. Gerasymchuk ◽  
O.O. Zrobok
Keyword(s):  
Mechanical Engineering ◽  
International Competitiveness ◽  
Legal Regulation ◽  
High Energy ◽  
Machine Building ◽  
Capital Investments ◽  
Job Seekers ◽  
Step Method ◽  
Machine Building Complex ◽  
Building Enterprises

The essence of the concept of "product competitiveness" is considered. The factors of competitiveness of products of machine-building enterprises on the international market are systematized. Based on the systematization of quantitative and qualitative methods of assessing the level of competitiveness, a step-by-step method for mechanical engineering enterprises is proposed. The state of the machine-building complex of Ukraine is considered. The dynamics of factors of international competitiveness of machine-building enterprises is analyzed: number of enterprises by machine-building branches; volume of sales and production of machine-building products; shares of mechanical engineering products in domestic exports; capital investments of enterprises in the fields of mechanical engineering. As a result of diagnosing the factors, a PEST-analysis of the domestic machine-building complex with the division of factors into political, economic, social and technological was carried out. It is established that machine-building enterprises of Ukraine have a low level of competitiveness in international markets due to a number of negative factors, the key of which are: insufficient demand in foreign markets, high dependence on fluctuations in resource prices (economic); imperfect legislation, the war in eastern Ukraine (political); technological and moral obsolescence of products and fixed assets, high energy consumption and low productivity, low costs of R&D (technological); lack or outflow of qualified manufacturers abroad, low wages, low motivation of job seekers to employment in the field of mechanical engineering (social). Measures to increase international competitiveness which are proposed include following: preferential lending; revival of basic and applied science; reforming the legal regulation of intellectual property; ensuring compliance of products with European technical regulations. Prospects for the development of domestic engineering: digitalization, development of robotics, technology of Industry 4.0, infrastructure of technology parks.

Laser Cladding of Alumina Material Coating: Effects on Deposition Quality

2016 ◽  
Author(s):  
Yuzhou Li ◽  
Weilong Cong ◽  
Fuda Ning ◽  
Rongxia Huang
Keyword(s):  
Laser Cladding ◽  
High Performance ◽  
Ceramic Coating ◽  
High Hardness ◽  
Alumina Ceramic ◽  
Properties Of Coatings ◽  
Surface Protection ◽  
Laser Head ◽  
Coating Methods ◽  
Input Variables

Alumina ceramic is a high performance engineering material with excellent properties, including high melting point, high hardness and brittle nature make the alumina ceramic difficult to machine and needing high cost by using conventional manufacturing methods. Coating is an important method for alumina fabrication. The excellent properties of coatings can be used for special surface protection and ceramic parts repairing. Comparing with other coating methods, laser cladding method has many good properties to overcome the drawbacks. The reported investigations on laser cladding provide little information about alumina materials for ceramic coating. In this paper, effects of different input variables of laser cladding of alumina materials for ceramic coating were studied. And this paper for the first time reported the relationship between the properties (including surface roughness, flatness and powder efficiency) and input variables such as laser power, powder feeding rate and laser head moving rate. The obtained results will be helpful to establish efficient and effective processes for ceramics coating.

Study of corrosion resistance of doped surface layer with CuSn—CrxCy composition after plasma hardening

2021 ◽  
pp. 215-220
Author(s):  
Nguyen Van Trieu ◽  
N.A. Astafeva ◽  
A.E. Balanovsky ◽  
A.N. Baranov
Keyword(s):  
Corrosion Resistance ◽  
Surface Layer ◽  
Chromium Content ◽  
High Hardness ◽  
Plasma Coating ◽  
Corrosion Current ◽  
Ph Values ◽  
Alloyed Surface ◽  
Welding Electrode ◽  
Acidity Parameter

In the process of plasma surface hardening, coatings based on a mixture of CuSn alloy and 10/20 % OK 84.78 additive with high hardness were obtained. The study of the microstructures of the coatings showed that the content of the austenite phase decreases with an increase in the content of chromium carbide in the composition. The influence of the acidity parameter on the corrosion resistance of the alloyed surface layer with the composition of the mixture of alloys CuSn and the coating of the welding electrode OK 84.78 was evaluated. Corrosion control in 3% NaCl solutions with different pH values showed that the plasma coating has high corrosion resistance at pH = 7 and decreases by 2 times at pH = 3. An increase in the chromium content leads to an increase in the corrosion potential, and the presence of cracks leads to an increase in the corrosion current density.

Investigation of the Structure and Distribution of Chemical Elements between the Phases of Hard Alloys of the Cr3C2-Ti System, Obtained at Various Modes of Explosive Compaction

2020 ◽  
Vol 992 ◽  
pp. 487-492
Author(s):  
V.O. Kharlamov ◽  
Aleksandr Vasilevich Krokhalev ◽  
S.V. Kuz’min ◽  
V.I. Lysak
Keyword(s):  
Phase Composition ◽  
Powder Mixture ◽  
Chemical Interaction ◽  
Chemical Elements ◽  
Equilibrium Phase ◽  
Hard Alloys ◽  
Explosive Compaction ◽  
Thermo Calc Software ◽  
Equilibrium Phases ◽  
Explosive Pressing

The Article presents the findings of the studies of the microstructure, chemical and phase composition of the Cr3C2-Ti system alloys obtained by the explosion. Scanning electron microscopy, energy dispersive and x-ray diffraction analyses were used. The program Thermo-Calc software was used to calculate the equilibrium phases. The phase composition of the compact was shown to fully correspond to that of the initial powder mixture during explosive pressing in the modes of heating from 300 ̊С to 600 ̊С. When heated above 600 ̊С, the chemical interaction of the initial components begins with the formation of new boundary phases. Meanwhile, there is a change in the sample destruction nature and a significant increase in hardness, which points to the hard alloy consolidation. The increase in the powder mixture heating in shock waves to 1000 ̊С leads to intensive macrochemical interaction of the powder mixture components and to formation of an equilibrium phase composition. The established temperature limits determine the most appropriate parameters of shock-wave loading when producing hard alloys by explosive pressing.

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