scholarly journals Theoretical and technological aspects of production mechani‑cally alloyed powders for the production of coatings and products by additive methods

2021 ◽  
pp. 90-105
Author(s):  
F. G. Lovshenko ◽  
A. S. Fedosenko ◽  
E. I. Marukovich
Keyword(s):  
Phase Composition ◽  
Thermal Spraying ◽  
Thermal Spray Coatings ◽  
Layer By Layer ◽  
Properties Of Coatings ◽  
Spray Coatings ◽  
Structure Phase ◽  
316L Steel ◽  
Properties Of Materials ◽  
Additive Methods

The established regularities of the formation of powders based on iron and nickel, obtained by the method of mechanical alloying and intended for the deposition of thermal spraying coatings, as well as the manufacture of products by layer‑by‑layer synthesis. The structure, phase composition and properties of materials are investigated. Powders consist of particles with a size of 20–70 microns, differ in the submicrocrystalline type structures, and nonequilibrium phase composition. Thermal spray coatings made of them have a set of properties that significantly exceed the properties of coatings made of commercially available materials. The diameter of the grains of the material obtained by the SLМ method from the synthesized powder is 1.5–2.0 times smaller than that produced from the powder of 316L steel, and the heat resistance is higher.

Comprehensive Methods for Studying Microinhomogeneity in Thermal Spray Coatings with Amorphous-Crystalline Structure

1998 ◽  
Author(s):  
G. Grigorenko ◽  
A. Borisova
Keyword(s):  
Thermal Spray ◽  
Crystalline Structure ◽  
Structural Phase ◽  
Thermal Spraying ◽  
Integrated Approach ◽  
Thermal Spray Coatings ◽  
Chemical Heterogeneity ◽  
New Approach ◽  
X Ray ◽  
Spray Coatings

Abstract An integrated approach was developed for investigation of thermal spray coatings with the amorphous-crystalline structure. The new approach combines methods of metallography, differential thermal and X-ray phase analysis, scanning electron microscopy and X-ray microanalysis. This makes it possible to reveal structural, phase and chemical heterogeneity, determine the degree of amorphization of coatings, temperature and heat of crystallization of the amorphous phase during heating. The new integrated approach was used to study amorphous-crystalline coatings of the Ni-P, Fe-Ni-B and Fe-B systems produced by thermal spraying.

Image-Based Modeling for Assessing Thermal Conductivity of Thermal Spray Coatings at Ambient and High Temperature

2006 ◽  
Author(s):  
Y. Tan ◽  
A. Sharma ◽  
J. P. Longtin ◽  
S. Sampath ◽  
H. Wang
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Thermal Spray ◽  
Process Parameters ◽  
Thermal Spraying ◽  
Thermal Spray Coatings ◽  
Analysis Model ◽  
Element Analysis ◽  
Spray Coatings ◽  
Coating Microstructure

Thermal spray coatings are used extensively for protection of engineering components and structures in a variety of applications. Due to the nature of thermal spraying process, the coating thermal, mechanical, and electrical properties depend strongly on the coating microstructure, which consists of many individual splats, interfaces between the splats, defects and voids. The coating microstructure, in turn, is determined by the thermal spray process parameters. In order to relate coating process parameters to the final coating performance, then, it is desirable to relate coating microstructure to coating properties. In this work, thermal conductivity is used as the physical parameter of interest. Thermal conductivity of thermal spray coatings is studied by using an image analysis-based approach of typical coating cross sections. Three coating systems, yttria stabilized zirconia (YSZ), molybdenum, and Ni-5wt.%Al are explored in this work. For each material, thermal conductivity is simulated by using a microstructure image-based finite element analysis model. The model is then applied to high temperature conditions (up to 1200 °C) with a hot stage-equipped scanning electron microscope imaging technique to assess thermal conductivity at high temperatures. The coating thermal conductivity of metallic coatings is also experimentally measured by using a high-temperature laser flash technique.

Methods of Determination and Control of Residual Stresses in Plasma Spray Coatings

1997 ◽  
Author(s):  
L. Dekhtyar ◽  
A. Kleyman ◽  
V. Andreychuk ◽  
S. Berman
Keyword(s):  
Residual Stresses ◽  
Thermal Spray ◽  
Plasma Spray ◽  
Thermal Spraying ◽  
Thermal Spray Coatings ◽  
Coating Deposition ◽  
Spray Coatings ◽  
Plasma Spray Coatings ◽  
And Control ◽  
Elastic Characteristics

Abstract Residual stresses exert profound influence on the longevity of parts with thermal spray coatings. The distribution and value of the residual stresses depend on method of coating deposition, composition of the applied material, parameters of thermal spraying and methods of post-treatment. Therefore, the study of the influence of the various technological factors on the residual stresses in the plasma spray coatings is very important. Due to heterogeneity of the coating, residual stresses can be determined only by the experimentation by using new methods which take into consideration real values of elastic characteristics and density of elementary layers. Methods and formulas for the calculations of the residual stresses in coatings deposited on bars, rings, discs, cylinders are presented. Experimental results for the various thermal spray coatings are also shown. These results can be used for the optimization of coating deposition and would supplement the existing database.

Structure and phase composition of gas thermal spray coatings of low-alloy chromium

1987 ◽  
Vol 26 (11) ◽  
pp. 909-913 ◽  
Author(s):  
A. N. Rakitskii ◽  
E. V. Turtsevich ◽  
T. G. Rogul' ◽  
V. F. Gorban' ◽  
N. I. Zakharenko ◽  
...  
Keyword(s):  
Phase Composition ◽  
Thermal Spray ◽  
Thermal Spray Coatings ◽  
Spray Coatings

scholarly journals Structure, phase composition, mechanical properties and wear resistance of steel after microarc boriding and vanadation

2019 ◽  
Vol 62 (6) ◽  
pp. 446-451 ◽  
Author(s):  
M. S. Stepanov ◽  
Yu. M. Dombrovskii ◽  
L. V. Davidyan
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Surface Layer ◽  
Phase Composition ◽  
Alloying Elements ◽  
Base Layer ◽  
Discharge Zone ◽  
Initial State ◽  
Properties Of Coatings ◽  
Structure Phase

Boriding is a common method of thermo-chemical treatment of steel products. It increases their hardness and wear resistance, but also increases the surface fragility, has a long duration and high labor intensity. The combined coating with boron and vanadium is used to improve the properties, and it is possible to apply microarc surface alloying to reduce the duration of the diffusion saturation process. This makes it possible to intensify the diffusion of alloying elements by forming a gas discharge zone at the surface of the steel product. The aim of this work was to study the structure, phase composition, mechanical properties and wear resistance of steel after boriding and vanadation. During the experiments, a lubricant containing boron carbide powders B4C and ferrovanadium FeV80 were used, which was applied to the surface of the steel sample. During boriding and vanadation of steel a surface layer with a thickness of 150 – 190 μm is formed. It has a base with microhardness of 7.8 – 8.3 GPa and light grey granular inclusions and eutectic areas with microhardness of 13.5 – 14.0 GPa. Further there is a carbonized layer of eutectoid concentration, passing into the original ferrite-perlite structure. The content of alloying elements in the characteristic points of the surface layer was determined, which confirmed the increased content of carbon, vanadium and boron in the base layer, areas of eutectic and carbide phase. X-ray phase analysis revealed the presence of iron borides FeB and Fe2B, vanadium borides VB2 and V2B3 and vanadium carbide VC0.88 in the surface layer. Mechanical properties of coatings were studied by microindentation of its cross-section with registration and analysis of deformation diagram under loading and subsequent unloading of the indenter. Hardness at indentation in the base layer increased to 7.95 GPa, in dispersed inclusions – to 13.90 GPa. The modulus of elasticity for indentation in the base and inclusions is 238 MPa and 340 MPa, respectively. Creep and proportion of the plastic component in microindentation is naturally reduced with increase in hardness. Fine inclusions of iron borides, vanadium borides and carbides significantly increase the steel wear resistance. It has increased in 4 times during friction against the fixed abrasive particles in comparison with the initial state. 

scholarly journals The phase composition, structure and properties of high-temperature-based powders of the system iron-aluminum obtained by the technology of the reaction-mechanical alloying. Foundry production and metallurgy

2019 ◽  
pp. 133-141 ◽  
Author(s):  
F. G. Lovshenko ◽  
A. S. Fedosenko
Keyword(s):  
Phase Composition ◽  
Mechanical Alloying ◽  
Average Particle Size ◽  
Thermal Spraying ◽  
Average Particle ◽  
Structure And Properties ◽  
Prolonged Heating ◽  
Iron Aluminum ◽  
Properties Of Materials ◽  
Composition Structure

The regularities of the formation of powders based on the Fe-Al system, obtained by the method of mechanical alloying and intended for the deposition of thermal spraying coatings were established. The morphology, structure, phase composition and properties of materials are investigated. After mechanical synthesis, the powders have an average particle size of 30–100 µm, submicrocrystalline structures, and nonequilibrium phase composition. Annealing of powders causes to an increase in the hardness of particles up to 80%, the value of which is largely preserved after prolonged heating to 1170 K, which indicates the presence of heat-resistant materials.

The Ultimate Spray Booth

1997 ◽  
Author(s):  
L. Pejryd ◽  
J. Wigren ◽  
N. Hanner
Keyword(s):  
Thermal Spray ◽  
Thermal Spraying ◽  
Thermal Spray Coatings ◽  
Design Element ◽  
Production Flow ◽  
Statistical Process ◽  
Spray Coatings ◽  
Spray Process ◽  
Spray Booth ◽  
On Line

Abstract Reproducibility is a current challenge for the thermal spray industry. Reproducibility associated problems represent a large cost every year not only in terms of rejections and rework, but also in costs for destructive testing and decreased production flow. Thermal spray coatings are moving in the direction of being considered only as a "band aid" to becoming a design element. One of the prerequisites for such a development is an increase in reproducibility for thermal spray coatings. The purpose of this paper is to outline a vision aiming in the direction of a future "ultimate spray booth", where thermal spraying is as reproducible and reliable as machining, grinding or other production processes. A way to increase reproducibility and reliability in the future spray shop involves utilising major parts of IT - technology. This also includes active co-operation design-production in the pre-spray process. This paper will deal with areas such as: operation drawings and lists through multimedia techniques, education programs for operators and designers through multimedia techniques, CAD/CAM, Off-line programming and simulation, On-line diagnostics of flame (particle diagnostics) and coating (temperature & Acoustic emission measurements), on-line Statistical Process Control and Knowledge Based System techniques.

Principles and Applications of Thermal Spray Coatings

2021 ◽  
pp. 31-70
Author(s):  
John Henao ◽  
Carlos A. Poblano-Salas ◽  
Fabio Vargas ◽  
Astrid L. Giraldo-Betancur ◽  
Jorge Corona-Castuera ◽  
...  
Keyword(s):  
Thermal Spray ◽  
Thermal Spraying ◽  
Industrial Applications ◽  
Thermal Spray Coatings ◽  
Flame Spray ◽  
Spray Coatings ◽  
Thermal Barriers ◽  
Energy Conversion Devices ◽  
Thermally Sprayed ◽  
Sprayed Coatings

The goal of the chapter is to address the fundamental theory of thermal spraying and its modern industrial applications, in particular, those involving flame spray, HVOF, plasma spray, and cold spray processes. During the last 30 years, thousands of manuscripts and various book chapters have been published in the field of thermal spray, displaying the evolution of thermally sprayed coatings in many industrial applications. Thermal spray coatings are currently interesting for different modern applications including prosthesis, thermal barriers, electrochemical catalysis, electrochemical energy conversion devices, biofouling, and self-repairing surfaces. The chapter will explain the fundamental principles of the aforementioned thermal spraying processes and discuss the effect of different controlling parameters on the final properties of the produced coatings. This chapter will also explore current and future industrial applications of thermal spray coatings.

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