Search results for "Thermal spraying"
showing 9 items of 19 documents
Prediction and analysis of high velocity oxy fuel (HVOF) sprayed coating using artificial neural network
2019
Abstract Thermal spray comprises a group of coating processes for coating manufacturing in which metallic or nonmetallic materials are deposited in a molten or semi-molten condition. Most often, the coating properties are significantly influenced by the operating parameters. However, obtaining a comprehensive modeling or analytical analysis of the thermal spray process is too difficult to be practical due to the complex chemical and thermodynamic reactions. Accordingly, the present study aims at applying an artificial neural network (ANN) model to predict the HVOF sprayed Cr3C2−25NiCr coatings and analyze the influence of operating parameters regardless of the intermediate process. The proce…
Synthesis of bulk FeAl nanostructured materials by HVOF spray forming and Spark Plasma Sintering
2006
Abstract This paper examines the efficiency of two consolidation processing techniques: High Velocity Oxy-Fuel (HVOF) spray forming and Spark Plasma Sintering (SPS) to obtain bulk nanostructured materials from an Y 2 O 3 reinforced Fe–40Al (at.%) milled powder. The microstructures of the sintered end-products were characterized by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) in order to gain new insights in their microstructure formation mechanisms. HVOF spray forming is more effective to retain fine nanograins, in particular within retained unmelted powder particles. The drawbacks of this technique are that it inevitably leads to a high fraction of porosity…
Laser Ultrasonic Testing for Estimation of Adhesion of Al2O3Plasma Sprayed Coatings
2001
Abstract The aim of the present study was to investigate the possibility of using a laser ultrasonic technique for the estimation of the adhesion of ceramic coatings, deposited onto metallic substrates by thermal spraying techniques. For this purpose, a pulsed Nd : YAG laser (λ = 1064 nm, 14 ns) was used to irradiate Al2O3 coatings, of different thickness (30–350 µm), deposited onto stainless steel substrates by atmospheric plasma spraying. The laser generated ultrasonic waves were in situ recorded at the epicentre using a laser heterodyne interferometer. The acoustic waveforms were correlated with the interaction between the pulsed laser radiation and the coated metal, taking into account …
Influence of laminated architectures of heterostructured CeO2-ZnO and Fe2O3-ZnO films on photodegradation performances
2020
Abstract The development of photocatalytically active films has gained a great attention in recent years. Herein, new heterostructured films associating ZnO and CeO2 or Fe2O3 and exhibiting various architectures were prepared by the solution precursor thermal spray (SPPS) process. The paper examines the effect of the films laminated architectures on the photodegradation performance. For CeO2-ZnO and Fe2O3-ZnO films, the photodegradation efficiency of the Orange II dye is 100% and 95% after 240 min UV light irradiation and after 360 min visible light irradiation, respectively. The photocatalytic activity of the laminated structures was found to depend on the materials used to construct the h…
Bulk FeAl nanostructured materials obtained by spray forming and spark plasma sintering
2007
Abstract This paper examines the efficiency of two consolidation processing techniques high velocity oxy-fuel (HVOF) spray forming and spark plasma sintering (SPS) which allow to obtain bulk dense nanostructured materials. An oxide dispersion strengthened (ODS) Fe–40Al (at.%) based milled powder (with a nanostructure
Surface modifications induced by pulsed-laser texturing—Influence of laser impact on the surface properties
2014
Abstract Laser cleaning technology provides a safe, environmentally friendly and very cost effective way to improve cleaning and surface preparation of metallic materials. Compared with efficient cleaning processes, it can avoid the disadvantages of ductile materials prepared by conventional technologies (cracks induced by sand-blasting for example) and treat only some selected areas (due to the optical fibers). By this way, laser technology could have several advantages and expand the range of thermal spraying. Moreover, new generations of lasers (fiber laser, disc laser) allow the development of new methods. Besides a significant bulk reduction, no maintenance, low operating cost, laser f…
Yttria-stabilized zirconia in-flight particle characteristics under vacuum plasma spray conditions
2009
This paper deals with the diagnostic yttria-stabilized zirconia (YSZ) in-flight particles in Vacuum Plasma Spray (VPS) process using an optical measurement device. Particle velocity, temperature and diameter were correlated to spray distance under a fixed chamber pressure of about 14 kPa. Experiments were carried out with a two-color pyrometer. Results show that correlations can be satisfactory described with linear relationships. Particle velocity and temperature decrease when increasing spray distance whereas particle diameter exhibits a linear increase with the spray distance.
Exposure to nanoparticles in thermal spraying - Vigilance towards the operator and the outside environment
2021
International audience; The previous survey of the French CaRPE project has shown a lack of information and showed the interest to assess the residual exposure to these particles. This paper presents the results of various sampling operations and emission analyses of plasma spraying equipment. For this purpose, different areas have been targeted, such as at the level of the emissions channeled upstream and downstream of the filtration system, at the workstation level as well as fugitive emissions. Various measurements were carried out: real-time particle size distribution, mass concentration of total suspended dust, heavy metals, sampling characterization by EDX/ MET, etc. The metallic aero…
Elaboration et caractérisation mécanique et physico-chimique des revêtements déposés sur des substrats en laiton par les techniques de projection the…
2019
Brass alloys are used in many applications, especially in the sanitary industrial application. In this field, the brass is coated with an electroplated chromium layer. However, the electroplating technique is achieved by means of solutions in which the chromium is in the six oxidation state. At this degree of oxidation, chromium is toxic and has the reputation of being carcinogenic. In this context, the main objective of this work is to develop functional coatings on brass substrates using new techniques namely thermal and pneumatic spraying techniques. The mechanical and physical-chemical properties are studied in order to evaluate the performances of these coatings and the potency of thei…