Flame Thermal Spray Research Articles

Study of Behaviour and Morphology of Corrosion Region of Copper Layer Coated on Polymer Substrates by Flame Thermal Spraying

Study of Behaviour and Morphology of Corrosion Region of Copper Layer Coated on Polymer Substrates by Flame Thermal Spraying

Exploration of Structural and Physical Characteristics of a Ceramic-Based System via Flame Thermal Spraying

Exploration of Structural and Physical Characteristics of a Ceramic-Based System via Flame Thermal Spraying

Study on the Corrosion Resistance Of Thermal Sprayed Aerospace Coatings Under The Action Of High Current Pulsed Electron Beam

Aluminum-based amorphous alloys have excellent mechanical properties and corrosion resistance and are currently used in the form of coating materials for the protection of aircraft surfaces. In this study, AlCoCe alloy and powder are prepared, and then AlCoCe alloy coating is prepared on Q235 substrate by supersonic flame thermal spraying technology, and finally, the surface remelting modification treatment is carried out on the coating by current pulsed electron beam, and the transformation behavior of microstructure of the coating and the change of the corrosion resistance in this process are analyzed by structural characterization and corrosion experiment, to make clear the relationship between the structure of the coating and its corrosion resistance performance. After 15 current pulsed electron beam pulses, the coating surface formed a layer of dense and homogeneous composition of the amorphous structure of the treatment layer, when the number of pulses is higher, due to the heat of the substrate leads to a decrease in the cooling rate, which in turn will lead to the emergence of a crystalline structure of the surface treatment layer.

Effect of Heat Treatment on the Electrochemical and Tribological Properties of Aluminum-Bronze Coatings Deposited Used the Thermal Spraying Process

The corrosion and wear resistance of aluminum-bronze coatings deposited by thermal flame spraying were investigated after a 10 h heat treatment at 500 °C in a nitrogen atmosphere. The coatings were characterized by SEM, EDS, XRD, and XRF. Corrosion resistance was evaluated by Tafel and EIS tests, while wear resistance was assessed using a ball-on-disc test. Results showed the heat treatment compacted the coating microstructure, increased oxide content, and improved splat bonding through diffusion mechanisms. This led to enhanced corrosion resistance, evidenced by reduced corrosion current density in electrochemical tests, resulting from densification impeding electrolyte penetration. Heat treatment also increased wear resistance, as indicated by lower wear rates in ball-on-disc tests, attributable to increased hardness, reduced friction coefficients, and annealing-induced microstructural changes. Overall, the heat treatment optimizes the anticorrosive and tribological properties of thermally sprayed aluminum-bronze coatings via favorable alterations in composition, morphology, and physical characteristics. The research provides a new understanding of how thermal spray parameters and post-deposition heat treatment can be utilized to enhance the corrosion and wear resistance of aluminum-bronze coatings for marine applications.

Modeling Temperature of Contact Generated in Coatings of Pure Alumina Ceramic onto Low Carbon Steel Type 1.0060 Obtained by the Thermal Spraying Process

In previous research problem statement occur in hardness to reach the thermal flux between surfaces during movement. The aim of the present investigation has been conducted to study the thermal behavior of ceramic Al2O3 (AL-99) coated on a low carbon steel type 1.0060 by using a thermal flame spray technique. The key methods used is microstructural characterization and comparing between experimental data record and numerical program.SEM showed that the Al2O3 coatings have a dense microstructure, lamellar morphology and complex of several phases. The XRD analysis of the coating after the spray showed a majority phase of α -Al2O3 rhombohedral structure and secondary phase of γ-Al2O3 orthorhombic structure. The experimental data recorded From wear indicate two step, first one corresponds to the phase of accommodation between surfaces (samples/ disc), the contact temperature gradually increases to a value Of 75 °C for both pairs, the second step , we could remark from experimental and numerical simulation, it reach 95°C for experimental test and 85 for numerical model.The important findings in tribological results showed that the temperature at the contact is related to the shear stress that will result from the increase of the heat flux. From these results it can be said that the measured temperature increases with the increase of the charge and converges with the contact time. The gap of temperature between experimental and numerical results is probably due to the parameter of microstructure, where in experimental porosities improve convection in the area, in contrast the numerical materials don't add this phenomena.

Manufacturing of composite (Ni-Al +Al2O3-ZrO2) by using Flame Thermal Spray Technique.

Flame Thermal Spray technique was used to produce matrix composite of ZrO2 (25%) reinforced with Alumina (25%) with (Al-Ni) (50)% have been spray into base substrate of stainless steel type (316L). All samples were grit blasted as initial preparation state and all spraying done at different distances from substrate (12, 14, 16,17, 18, 20) cmtest of stiffness, porosity and adhesion has been experienced on the compound layer which produced to study the effect of changing the spraying distance on the layer characteristic. All samples were heated at (950, 1050) ºC for(1/2hr). The results before and after heat treatment show that the optimum condition for spraying distance at (16 cm) and heat treatment at (1050 ºC) which are most effective to give best results especially hardness, porosity and adherence bond.

Investigation of the Diffusion Depth of Ni-Cu Thermal Spray Coating for the Low Carbon Steel

The effect of some parameters on the diffusion depth of the Ni-Cu coating layer on 52 low carbon steel samples using flame thermal spraying was investigated. In this research, coating-powder particle (1926.6 nm) was used, spraying gases pressure (0.5, 1bar) for oxygen and acetylene was implemented, and the temperature of the sprayed coating layer on the substrate was in the range (500- 750 C°). Diffusion cross-section was observed by using an optical microscope. The microstructure and phase analysis of the coating layer was observed by using X-ray diffraction (XRD), and SEM respectively. At standoff distance was 125 mm, powder feeding rate 30g/ min, substrate surface roughness N10 µm, and the gun carrier transverse velocity 50 mm/m, the results showed high and homogeneous diffusion zone between the coating layer and the substrate (image 1f and 3f), however, image 2f exhibit the porosity in the boundary between the coating layer and the substrate.

Aluminum and copper deposition through the process of thermal flame spray on polypropylene-pine wood fiber composite filaments and their applications

This paper presents a study about polypropylene-pine wood composites, both as filaments and products, coated with aluminum (Al) or copper (Cu), obtained through flame thermal spray process after subjecting the composites to thermal treatments in the second and third step of the study. Results revealed that a previous aluminum layer was needed in order to obtain copper coatings on the composites. The physical and mechanical properties of both metal coated composite filaments were also evaluated and compared with the uncoated composite filaments with and without heat treating these. Consequently, it was observed that the nature of the coating adhesion on the substrates was mechanical, and therefore abrasion blasting of filaments or the use of a higher wood fiber content in the composite improved the Al or Cu adhesion. Also, it was observed that extruded wood fiber/PP filaments should not be cooled in water because pieces might be molded directly once the moisture affects the metal coatings adhesion onto the substrates.

Study Effect Treatment Thermal for Cermet Composite Prepared by Flame Thermal Spray Method.

Flame thermal spraying technology was used in the production of 25% zirconia composite material with 25% alumina particle with binder material of 50% Al-Ni alloy base on 316L alloy steel base, after preparation the base surface with a method of roughing the granular. Spraying was carried out using a spray distance (12,14,16,18,20) cm. Hardness tests were carried out on the composite material to study the effect of changing spray distance on the properties of the resulting layer. The thermal treatment was performed on the samples at (850,950,1050,1150) for an hour. The results of the tests confirmed that the best spraying distance (16 cm) and the thermal treatment (1050 ) have a significant effect on improving the hardness of the layers of the composite material.

Studying the Erosion Corrosion Behavior of NiCrAlY Coating Layer Applied on AISI 446 Stainless Steel Using Thermal Spray Technique

Erosion-Corrosion behavior of NiCrAlY coatings deposited on 446 stainless steel samples by flame thermal spraying was performed in this research. The hardness of uncoated and coated sample is measured, using HVS-1000 Digital Micro hardness Tester. The results of hardness show that the coated samples have higher hardness than uncoated samples. Microstructure and phase analysis of the coating layer was observed by using optical microscope, X-ray diffraction (XRD), and SEM respectively. Erosion –Corrosion test was performed in different period of time (6, 12, and 18 hr.) using the erosion-corrosion system. The result shows that because of uniform distribution and homogeneous of coating layer, weight loss was very low and approximately equal in all period of testing time.

The Effect of Adding Nickel Content to Turbine Blades Coating Using Thermal Flame Spraying

The Effect of Adding Nickel Content to Turbine Blades Coating Using Thermal Flame Spraying

Effect of oxygen pressure on the microstructure and mechanical properties of Mo coating deposited on steel 42CD4 by thermal flame spraying

Surface treatments and coatings are a practical approach used to extend the life of components and structures, especially the most stressed surfaces of the technical component under consideration. The objective of this work is to study the effect of oxygen pressure on the microstructure and the mechanical properties of the Mo coating deposited on 42CD4 steel by flame thermal spraying. The effect of the oxygen flow is controlled by the oxygen pressure. The coatings were characterized by scanning electron microscopy (SEM), energy dispersion spectrometry, X-ray diffraction, Vickers hardness measurement and four-point bending tests. The results show that oxygen pressure in the oxidant is a critical parameter, as our results revealed that increasing oxygen pressure has a positive effect on microstructure and on mechanical properties of the coating. The increase in oxygen pressure generates a better microstructure, with a denser, more compact coating and a low porosity.

Obtaining and characterizing of WC-Co coatings obtained from thermal spray by flame

Tungsten carbide is used in the production of cutting tools for steel and as protection against wear due to its extremely high hardness. High speed oxygen fuel spraying process has been widely used to deposit WC-Co coatings. However, the decomposition and oxidation of WC-Co has been reported during the process, where carbon and tungsten are released, resulting in the formation of an amorphous matrix with the cobalt of the compound. This is attributed to the high heating and cooling rates suffered by the raw material. An alternative method is the thermal spray by flame, which allows controlling the working temperature and the residence time of the particles in the hot flame, avoiding the decomposition of tungsten carbide, on the other hand, it is a versatile and a low cost method. In this study projection parameters of a WC-18Co coating sprayed with a thermal flame spraying process from a commercial feedstock powder were determined to decide the conditions under which compact coatings are obtained with low porosity, avoiding dissociation of the tungsten carbide. The composition of the powders and substrates was determined by X-ray fluorescence microscopy and optical emission, respectively, X-ray diffraction studies were performed to characterize compositions and microstructures the coatings sprayed; the morphology was by scanning electron microscope. It was found that the best condition for this type of coatings is a neutral flame at a projection distance of 12 cm.

Microstructure and Wear Behavior of MMC Coatings Deposited by Plasma Transferred Arc Welding and Thermal Flame Spraying Processes

In this study, two erosion protection MMC coatings with WC particles were deposited by the plasma transferred arc (PTA) welding. One of the coatings with tungsten carbide WC in the NiBSi matrix (WC/NiBSi), and the second coating WC in NiCrBSi matrix (WC/NiCrBSi) was deposited by the flame spray process on the same substrate material S235JR steel. Experiments were performed using a gas blast sand erosion test facility with high-velocity erodent particles impact (approximately 100 m/s) at different particle impact angles (20°–45°), with an objective to study erosion wear characteristics and mass loss of two MMC coatings. Microstructural characterization of MMC coatings was done by scanning electron microscope equipped with energy-dispersive X-ray spectroscopy, whereas X-ray diffraction analysis was used for identification of present phases. The hardness of coatings was determined by Vickers hardness measurements. WC/NiBSi obtained by the PTA process shows superior hardness and erosion properties.

MULTICOMPONENT Al-BRONZE COATINGS THERMALLY SPRAYED ONTO TIN BRONZE SUBSTRATE: MICROSTRUCTURAL, MECHANICAL AND CORROSION CHARACTERIZATION IN A 3.5% NaCl SOLUTION

In this work, multicomponent Al-bronze alloys coated Tin-Bronze substrates, fabricated by thermal flame spraying, are characterized by X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy. Mechanical characterizations are also presented: microhardness measurement and friction coefficient. The electrochemical behavior of tin-bronze samples uncoated and coated with multicomponent Al-Bronze coatings is studied in NaCl 3.5% solutions using potentiodynamic polarization curves and polarization resistance measurements. The microstructure of the coatings has a lamellar morphology. Each lamella is constituted of a mixture of Cu3Al globular micro precipitates ([Formula: see text]-phase) uniformly distributed over the solid solution matrix ([Formula: see text]-Cu). An oxide based on Cu, Al and Fe is also present in very low concentration. [Formula: see text]-phase is unexpected because it is present only above 570∘C in the Cu-Al phase diagram. Compared with the tin-bronze substrate, multicomponent Al-bronze coatings show a friction coefficient three times lower and have a better electrochemical behavior in 3.5% NaCl solution.

Desarrollo de recubrimientos a partir de silicato de zirconio de origen mineral mediante proyección térmica por llama oxiacetilénica para aplicación sobre ladrillos refractarios

En el presente trabajo se documenta el desarrollo experimental empleado para obtener mediante proyección térmica por llama oxiacetilénica, recubrimientos a partir de arena de circonio (ZrSiO4) de origen mineral y de una mezcla de ZrSiO4 con 50 % en peso de alúmina comercial referencia Oerlikon-Metco 105 SFP. La arena de ZrSiO4 fue molida y tamizada, con el fin de seleccionar las fracciones de tamaño de partícula -37 +25 μm y -25 μm. Diferentes parámetros de proyección térmica fueron simulados con la herramienta computacional Jets et Poudres SPCTS versión 2002-2009 y las condiciones con mayor potencial para obtener recubrimientos fueron verificadas experimentalmente. Los recubrimientos elaborados sobre sustratos refractarios silico-aluminosos fueron caracterizados mediante MEB y DRX, encontrando que aquellos depositados a partir de la fracción de tamaño más fina, utilizando una llama producida con 22 y 70 L/min de acetileno y oxígeno respectivamente, a una distancia de proyección de 10 cm y con una velocidad de desplazamiento de la antorcha de 0,275 cm/s y con una rotación de los sustratos de 34,57 rpm fueron los que presentaron las mejores características estructurales. La porosidad de los recubrimientos fabricados a partir de la arena de circonio y de la mezcla ZrSiO4 con alúmina fueron de 30,5 ± 6,6% y 20,3 ± 9,2% en área y su dureza fue de 3.06±0.70 GPa y 6.0±0.30 GPa, respectivamente. A partir de los resultados obtenidos se concluye que es posible la utilización de este mineral como materia prima en el proceso de proyección térmica oxiacetilénica.

Preparation and Properties of a New Cost-effective Amorphous Composite Coating

A NiFeBSiNb amorphous/nanocrystalline composite coating was prepared through flame thermal spraying, where a gas atomized alloy powder substituted an amorphous powder. The microstructure and thermal behavior of the laboratory-produced powders and the produced as-sprayed coating were characterized. The results demonstrate that the powder, which is spherical or ellipsoidal, is mainly composed of Nb2Ni21B6 and (Ni,Fe)23B6 crystalline phases, whereas the as-sprayed coating consists of a glassy structure and certain nanocrystalline phases. It is obtained through calculations that the Rc (critical cooling rate) of the powder and the as-sprayed coating for the amorphous phase formations is 6.01×105 and 4.56×103 K/s, respectively. The explanation for the amorphous structure, as it occurred in the as-sprayed coating, is the rapid quenching from the melt at the cooling rates which exceeds the critical cooling rate Rc. The as-sprayed amorphous coatings displays a low friction coefficient of 0.17 and excellent wear resistance.

Effect of preheating and of single and multiple passes on the porosity, oxidation and microhardness of a duplex stainless steel coating deposited by wire flame thermal spraying

The wire flame thermal spraying process involves continuous combustion between the gases C2H2 + O2, released from the torch nozzle and accelerated by the stream of compressed air. The wire is fed a...

Investigation of WC decarburization effect on the microstructure and wear behavior of WC-Ni hardfacing under dry and alkaline wet conditions

The performance of drilling tools hardfacing in different conditions is strongly related to microstructural aspect of the coating and to the adhesion with the substrate. In the present investigation, the manual oxy-acetylene brazing process was employed for AISI 1020 steel hardfacing using WC-Ni. The substrate/hard facing interface was particularly studied which was a Ni-Cr-Al-Mo interlayer prepared by flame thermal spray method. The microstructural results exhibit a good embedding of WC particles into the Ni matrix, where the inter-diffusion of Ni, Cr, and Fe elements at the interface is enhanced using the interlayer. The dissolution and decarburization phenomena of WC particles with the formation of W2C eutectic phase and their effect on the decohesion and pull out of the particles during the wear test were studied. The hardness (HIT) and Young's modulus (EIT) of different parts of the hardfacing were investigated by instrumented nanoindentation. The wear resistance of the surface coatings under alkaline condition using sodium hydroxide (NaOH) basic solution of pH = 12 is two times higher than under dry condition. Furthermore, the formation of SiO2 third body stripes along the wear track promotes the decrease of the friction coefficient and the volume loss. On the other side, the wear mechanism is adhesive with severe plastic deformation of the Ni matrix in dry condition and oxidative/abrasive wear in alkaline wet condition.

Influence of the Process Parameters on the Properties of Diamax Deposits Obtained by Flame Thermal Spray

The paper aims to determine the influence of the process parameters, namely: C2H2 gas flow rate and inclination angle of the spraying gun on physico and mechanical properties of the hardalloyed layers of Diamax 10999 Eutalloy, on steel support - obtained by flame thermal spray process. For this purpose, the two technological parameters varied on three levels and in each case were evaluated the deposits properties. Investigations conducted by electronical microscopy SEM, X-ray, micro-hardness and by adherence evaluation and of the deposits porosity allowed the establishment of the performant deposit. Thus it was found that at the decreasing of the spraying distance,the deposit porosity decreases; in layer appear the phenomena of overheating, issue that determine the adherence reducing in average of 22%, and also the modification of chemical composition. The results recorded have afforded the obtaining of an optimum domain of variation of the process parameters.