scholarly journals Hard Alloys with High Content of WC and TiC—Deposited by Arc Spraying Process

2020 ◽  
Author(s):  
Stefan Lucian Toma ◽  
Radu Armand Haraga ◽  
Daniela Lucia Chicet ◽  
Viorel Paleu ◽  
Costica Bejinariu
Keyword(s):  
High Hardness ◽  
Industrial Applications ◽  
Atmospheric Plasma ◽  
Arc Spraying ◽  
Hard Alloys ◽  
X Ray Diffraction ◽  
Additional Material ◽  
Thermal Spray Process ◽  
Spray Process ◽  
Spraying Process

Obtained by different spraying technologies: in atmospheric plasma spray, High Velocity Oxygen Fuel (HVOF) or laser cladding, the layers of hard alloys with a high content of WC and TiC find their industrial applications due to their high hardness and resistance to wear. Recognized as being a process associated with welding, the arc spraying process is a method applied industrially both in obtaining new surfaces and for reconditioning worn ones. This chapter presents the technology for obtaining ultra-hard layers based on WC and TiC - by the arc spraying process, using a classic spray device equipped with a conical nozzle system and tubular wire additional material containing ultra-hard compounds (WC, TiC). To study both the quality of deposits and the influence of thermal spray process parameters on the properties of deposits with WC and TiC content, we approached various investigative techniques, such as optical scanning microscopy (SEM), X-ray diffraction, and determination of adhesion, porosity, Vickers micro-hardness and wear resistance.

THE EFFECT OF FUEL TO OXYGEN RATIOS ON THE PROPERTIES OF HIGH VELOCITY OXY-FUEL TiO2 NANO-PHOTOCATALYST COATINGS

2010 ◽  
Vol 24 (02) ◽  
pp. 247-255 ◽  
Author(s):  
MARYAMOSSADAT BOZORGTABAR ◽  
MEHDI SALEHI ◽  
MOHAMMADREZA RAHIMIPOUR ◽  
MOHAMMADREZA JAFARPOUR
Keyword(s):  
Electron Microscopy ◽  
Crystallite Size ◽  
High Velocity ◽  
X Ray Diffraction ◽  
Thermal Spray Process ◽  
Spray Process ◽  
Transmission Electron ◽  
Hvof Thermal Spray ◽  
Coating Morphology ◽  
Oxygen Ratio

A liquid fuel high velocity oxy-fuel (HVOF) thermal spray process has been used to deposit TiO 2 photocatalytic coatings utilizing a commercially available anatase/rutile nano-powder as the feedstock. The coatings were characterized in terms of the phases present, its crystallite size and coating morphology by means of X-ray diffraction analysis, scanning electron microscopy and transmission electron microscopy, respectively. The results indicate that the sprayed TiO 2 coatings were composed of both TiO 2 phases, namely anatase and rutile with different phase content and crystallite size. A high anatase content of 80% by volume was achieved at 0.00015 fuel to oxygen ratio with nanostructure coating by grain size smaller than feedstock powder. It is found that fuel to oxygen ratio strongly influenced on temperature and velocity of particles in stream jet consequently on phase transformation of anatase to rutile and their crystallite size and by optimizing the ratio which can promote structural transformation and grain coarsening in coating.

Grey modeling for thermal spray processing parameter analysis

2020 ◽  
Vol 10 (3) ◽  
pp. 265-279 ◽  
Author(s):  
Meimei Liu ◽  
Yicha Zhang ◽  
Wenjie Dong ◽  
Zexin Yu ◽  
Sifeng Liu ◽  
...  
Keyword(s):  
Thermal Spray ◽  
Processing Parameters ◽  
Industrial Applications ◽  
Parameter Analysis ◽  
Processing Parameter ◽  
Content Type ◽  
Thermal Spray Process ◽  
Spray Process ◽  
Non Linear ◽  
Spray Processing

PurposeThis paper presents the application of grey modeling for thermal spray processing parameter analysis in less data environment.Design/methodology/approachBased on processing knowledge, key processing parameters of thermal spray process are analyzed and preselected. Then, linear and non-linear grey modeling models are integrated to mine the relationships between different processing parameters.FindingsModel A reveals the linear correlation between the HVOF process parameters and the characterization of particle in-flight with average relative errors of 9.230 percent and 5.483 percent for velocity and temperature.Research limitations/implicationsThe prediction accuracies of coatings properties vary, which means that there exists more complex non-linear relationship between the identified input parameters and coating results, or more unexpected factors (e.g. factors from material side) should be further investigated.Practical implicationsAccording to the modeling case in this paper, method has potential to deal with other diverse modeling problems in different industrial applications where challenge to collecting large quantity of data sets exists.Originality/valueIt is the first time to apply grey modeling for thermal spray processing where complicated relationships among processing parameters exist. The modeling results show reasonable results to experiment and existing processing knowledge.

scholarly journals Evaluation of adhesion of epoxy resin sealant to improve the corrosion resistance of thermal sprayed coatings

2020 ◽  
Author(s):  
Mateus R. D. Carneiro ◽  
Bruno C. Freitas ◽  
Iuri B. de Barros ◽  
Jose Brant de Campos ◽  
Ivan N. Bastos ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Carbon Steel ◽  
Adhesion Strength ◽  
Salt Spray ◽  
Test Method ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Spray Process ◽  
Spray Process

Abstract The adhesion of coatings on a given substrate has fundamental importance on the functionality of a coating/substrate system. The current paper presents the adhesion strength results of FeCr and CoCr-based deposits produced by electric arc thermal spray process on carbon steel, with an intermediate layer of 95Ni5Al. Three chemical compositions were tested for coating deposition and was characterized using plate and tube specimens made of carbon steel UNS G10200 to result in a screening of performance. Microstructural evaluation by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed. Coating strength was measured using standard pull-off test method. The corrosion resistance was analyzed with salt spray exposure, electrochemical polarization and impedance spectroscopy (EIS) tests. The adhesion strength of FeCr and CoCr alloy coatings shows an overall average tensile strength of 27.2 MPa. All sealed conditions presented low corrosion and the samples with epoxy sealant exhibited a high resistance against corrosion. The X-ray diffraction results have revealed the presence of alpha and gamma FeCr alloys and chromite as deposited phases after the coating process.

Development of Corrosion and Wear Resistant Coatings by an Improved HVOF Spraying Process

2005 ◽  
Vol 475-479 ◽  
pp. 237-240
Author(s):  
Yasunari Ishikawa ◽  
Jin Kawakita ◽  
Seiji Kuroda
Keyword(s):  
Industrial Applications ◽  
Hvof Spraying ◽  
Wear Resistant Coatings ◽  
Spray Process ◽  
The Past ◽  
Property Evaluation ◽  
Hvof Spray ◽  
Near Future ◽  
Sprayed Coatings ◽  
Spraying Process

We have developed an improved HVOF spray process called “Gas-shrouded HVOF” (GS-HVOF) over the past several years. By using an extension nozzle at the exit of a commercial HVOF spray gun, GS-HVOF is capable of controlling the oxidation of sprayed materials during flight as well as achieving higher velocity of sprayed particles. These features result in extremely dense and clean microstructure of the sprayed coatings. The process has been successfully applied to corrosion resistant alloys such as SUS316L, Hastelloy C, and alloy 625 as well as cermets such as WC-Cr3C2-Ni. The spray process, coatings microstructure and property evaluation will be discussed with potential industrial applications in the near future.

scholarly journals Evaluation of adhesion of epoxy resin sealant to improve the corrosion resistance of thermal sprayed coatings

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Mateus R. D. Carneiro ◽  
Bruno C. Freitas ◽  
Iuri B. de Barros ◽  
José B. de Campos ◽  
Ivan N. Bastos ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Carbon Steel ◽  
Adhesion Strength ◽  
Salt Spray ◽  
Test Method ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Spray Process ◽  
Spray Process

Abstract The adhesion of coatings on a given substrate has fundamental importance on a coating/substrate system's functionality. The current paper presents the adhesion strength results of FeCr and CoCr-based deposits produced by the electric arc thermal spray process on carbon steel, with an intermediate layer of 95Ni5Al. Three chemical compositions were tested for coating deposition and were characterized using plate and tube specimens made of carbon steel UNS G10200 to result in a screening of performance. Microstructural evaluation by optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were performed. Coating strength was measured using the standard pull-off test method. The corrosion resistance was analyzed with salt spray exposure, electrochemical polarization, and impedance spectroscopy (EIS) tests. The adhesion strength of FeCr and CoCr alloy coatings shows an overall average tensile strength of 27.2 MPa. All sealed conditions presented low corrosion and the samples with epoxy sealant exhibited a high resistance against corrosion. The X-ray diffraction results have revealed alpha and gamma FeCr alloys and chromite as deposited phases after the coating process.

Performance of HVOF-Sprayed Carbide Coatings in Aqueous Corrosive Environments

2000 ◽  
Author(s):  
S. Simard ◽  
B. Arsenault ◽  
K. Laul ◽  
M.R. Dorfman
Keyword(s):  
Thermal Spray ◽  
Material Selection ◽  
Corrosive Wear ◽  
Industrial Applications ◽  
Process Technology ◽  
Aqueous Corrosion ◽  
Coating Materials ◽  
Thermal Spray Process ◽  
Spray Process ◽  
Corrosive Environments

Abstract The HVOF technology is well known to provide a wide variety of coating materials having excellent performance characteristics under different aggressive conditions such as wear, erosion by impact of particle and corrosion. Carbides, as a family, constitute a big segment of materials used by the thermal spray industry. Although their material properties may be well known since they are often used in wear or corrosive-wear industrial applications, aqueous corrosion of such coatings are not well characterized. Moreover, thermal spray process technology being in constant evolution, past literature on these coatings may not be directly applicable as newer produced coatings have higher adhesive and cohesive strength. Recent technology allows a better control on density and oxides content that are important parameters to consider for corrosion applications. The success of a coating is related to judicious material selection for various applications. However, the choice of the starting materials for producing a coating is often difficult since there is a lack of data on the corrosion performance of thermal spray coatings. The present paper addresses the performance of various carbide HVOF coatings in terms of corrosion rate and degradation mode in two corrosive environments — HCl and HNO3. Behavior of the coatings is compared using bulk SS316 and SS316 HVOF coating as a benchmark.

The properties of thermal sprayed aluminium coatings on non-alloy structural steel

2019 ◽  
Vol 2 (95) ◽  
pp. 64-73
Author(s):  
A. Czupryński
Keyword(s):  
Structural Steel ◽  
Erosive Wear ◽  
Industrial Applications ◽  
Flame Spraying ◽  
Arc Spraying ◽  
Pure Aluminium ◽  
Additional Material ◽  
Aluminium Powder ◽  
Wire Arc Spraying ◽  
Wear And Corrosion Resistance

Purpose: of this paper was comparison of the structure, hardness and erosive wear of aluminium coatings produced on non-alloy structural steel S355JR (EN 10025-2) using the powder flame spraying and wire arc spraying methods. Design/methodology/approach: The latest model of flame powder sprayer and wire arc sprayer was used in the experiments. This provided very reliable spraying conditions. The additional material for flame-spraying was of Metco 54NS-1 pure aluminium powder (EN AW 1100 series). In the arc spraying process the Metco Aluminium (EN AW 1100 series) 1.6 mm diameter pure aluminium thermal spray wire was used. In each spraying technology binding alloy, i.e. Ni-Al, was employed as a primer coating. The used spray processes produced dense, abrasion and erosion resistant coatings approximal 1.0 mm thick. Aluminium coatings were characterized in accordance with ASTM G 76-95 erosion resistance tests, ASTM C 633-01 adhesion strength, HV 0.1 hardness tests and metallographic analyses. The scope of research included: preparation material for spraying, selection of properly process parameters for each sprayed technique based on preliminary technological tests, coatings manufacturing, examining the structure and tribological properties of aluminium coatings, comparison of obtained samples. Findings: The obtained results have proven superior properties of arc sprayed aluminium material coatings and have shown to be promising in industrial applications. Research limitations/implications: The presented test results are a preliminary assessment of the properties of thermally sprayed aluminium coatings. Therefore, further research is required regarding the resistance of aluminium coatings to abrasion and corrosion. Practical implications: The study is focused on selecting the best and most economical technique for manufacturing of wear and corrosion resistance aluminium coatings with a thickness of approximately 1 mm. Originality/value: It has been demonstrated that the use of a Ni-Al primer coating improves the adhesion of flame and arc sprayed aluminium coatings to steel surfaces.

Modelling Sequential Impact of Molten Droplets on a Solid Surface in Plasma Spray Process

2011 ◽  
Vol 227 ◽  
pp. 111-115
Author(s):  
Ilhem R. Kriba ◽  
A. Djebaili
Keyword(s):  
Plasma Spray ◽  
High Performance ◽  
Spray Deposition ◽  
Thermal Spraying ◽  
Spray Coating ◽  
Atmospheric Plasma ◽  
Formation Mechanisms ◽  
Temperature Plasma ◽  
Spray Process ◽  
Spraying Process

Plasma spray deposition is one of the most important technologies available for producing the high-performance surfaces required by modern industry. In this process, powder of the coating material is fed into high-temperature plasma, which melts and accelerates the powder; the molten particles subsequently hit and solidify on the surface to be coated. To obtain good quality coating, the powder particle must be at least partially molten and hit the substrate with a high velocity. The flattening characteristics of the droplets impinging on a substrate are important determinants in governing the eventual quality of the plasma spray coating. Different codes have been developed in recent years to simulate the overall thermal spraying process, as well as the growth of the 3D coatings, in which entrained particles are modeled by stochastic particle models, fully coupled to the plasma flow. The present investigation was carried out to have an approach to systematize the atmospheric plasma spraying process in order to create a basis for numerically modeling the plasma dynamics, the coating formation mechanisms and to predict the particle thermo- kinetic state at impact.

Wear Behavior of Al/SiC Composite Coatings According to Sliding Speed and Applied Load

2012 ◽  
Vol 152-154 ◽  
pp. 216-219
Author(s):  
Jae Hong Lee ◽  
Kyun Tak Kim ◽  
Yeong Sik Kim
Keyword(s):  
Thermal Spray ◽  
Wear Behavior ◽  
Thermal Spray Technology ◽  
Composite Coatings ◽  
Dry Sliding Wear ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Spray Process ◽  
Spray Process ◽  
Thermally Sprayed

Thermal spray technology allows providing wear-resistant coating on the surface of mechanical components. In this study, wear characteristics of thermally sprayed Al/SiC composite coatings were evaluated. These Al/SiC composite coatings reinforced with SiC particles were fabricated on Al 6061 substrate by thermal spray process. Dry sliding wear tests were performed using the varied sliding speeds and applied loads. Wear behavior of these Al/SiC composite coatings were investigated using scanning electron microscope(SEM), energy dispersive X-ray spectroscopy(EDX) and X-ray diffraction(XRD).

Properties of WC-Co Components Produced Using the HVOF Thermal Spray Process

2000 ◽  
Author(s):  
J. Stokes ◽  
L. Looney
Keyword(s):  
Residual Stress ◽  
Thermal Spraying ◽  
Shape Distortion ◽  
Powder Feed Rate ◽  
Thermal Spray Process ◽  
Spray Process ◽  
Hvof Thermal Spray ◽  
Hvof Thermal Spraying ◽  
Hvof Thermal Spray Process ◽  
Spraying Process

Abstract This paper presents a study of the residual stress and microstructural properties of thick, spray-formed components, produced using the High Velocity Oxy-Fuel (HVOF) thermal spraying process. The forming material used is Tungsten carbide cobalt (WC-Co), a material which is more usually processed using expensive press and sinter technology. The aim of this study is to examine the effect of production parameters on the formation of thick components. In order to fabricate thick specimens, certain problems have to be overcome. More specifically these problems include the minimizing residual stresses, which cause shape distortion in the components and maining the integrity of the coating on a microstructural scale. The dependence of residual stress, and sprayed material characteristics on spraying distance, and powder feed rate conditions is presented. Results show that cylindrical WC-Co components up to a thickness of 9mm can successfully be produced, by careful control of these parameters. This represents a significant improvement on maximum thickness values previously reported for WC-Co [1,2].

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