Skip Nav Destination
Close Modal
Update search
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
NARROW
Format
Topics
Subjects
Article Type
Volume Subject Area
Date
Availability
1-20 of 49
M. Jeandin
Close
Follow your search
Access your saved searches in your account
Would you like to receive an alert when new items match your search?
1
Sort by
Proceedings Papers
ITSC 2021, Thermal Spray 2021: Proceedings from the International Thermal Spray Conference, 561-568, May 24–28, 2021,
Abstract
View Paper
PDF
One of the main levers to reduce CO2 emissions in cars and trucks is mass and friction reduction, which is often achieved through the use of special coatings. The aim of the present work was to develop metal-ceramic-lubricant composite coatings with the best combination of wear, seizure, fatigue, and thermal resistance. Metal-based coatings incorporating hard particles and solid lubricants were cold sprayed onto steel substrates and the relationship between coating microstructure and tribology was studied. To meet the demanding tribological requirements of heavily loaded engines, the interfaces between the different components were optimized by selecting appropriate feedstock powders and assessing a wide range of process parameters. Alumina-reinforced bronze composite coatings were made from powders with different morphologies. Aggregated ceramic powders were found to be more beneficial in terms of wear than massive powders, and graphite was found to be effective for reducing seizure.
Proceedings Papers
ITSC 2017, Thermal Spray 2017: Proceedings from the International Thermal Spray Conference, 719-724, June 7–9, 2017,
Abstract
View Paper
PDF
Cold spray is continuously expanding for the repair of parts made of aluminum-based alloys. Beyond repair applications, the process is now expected to be exploited efficiently for the additive manufacturing of shaped parts. However, up to now, cold spray is limited to the achievement of rather simple shapes due to a lack of basic knowledge on coating build-up mechanisms to result in dimension-controlled deposition. The objective of this work is to fill that gap through an experimental and modeling study of the coating build-up in cold spray for this specific application. Experimentally, Al-based coatings were deposited for a large range of particle velocity due to the use of low-pressure, medium-pressure and high-pressure cold spray facilities. Particle velocity was monitored as a function of cold spray conditions. Two different types of Al 2024 (Aluminium 2024 Alloy) powders were tested. Coating porosity and microhardness were studied as a function of (both morphological and metallurgical) powder characteristics and spray conditions, primarily in the light of particle velocity. Various correlations could be exhibited. Finite element (FE) simulations of particle impacts were developed, including particle velocity from experimental measurements. These will be used as inputs in an in-house morphological model, the first stages of which could be established successfully.
Proceedings Papers
ITSC2016, Thermal Spray 2016: Proceedings from the International Thermal Spray Conference, 437-443, May 10–12, 2016,
Abstract
View Paper
PDF
In this work, copper and PEEK powder mixtures are cold sprayed onto carbon fiber-reinforced polymer (CFRP) substrates with the aim of producing a well-adhered conductive layer. The composite coatings were optimized through the study of the deposited mass and its dependence on process parameters and Cu powder morphology. A morphological model based on Cu phase data was developed to better understand coating microstructures. Coatings synthesized from irregular Cu particles were found to be electrically conductive, while those containing spherical Cu particles were insulating. These phenomena are explained using the developed simulation tools coupled with the investigation of coating build-up and microstructure.
Proceedings Papers
ITSC2016, Thermal Spray 2016: Proceedings from the International Thermal Spray Conference, 579-585, May 10–12, 2016,
Abstract
View Paper
PDF
This study assesses the influence of powder morphology on the microstructure and bond strength of cold-sprayed aluminum. Aluminum powders with spherical and irregular particle shapes were deposited on shot-peened steel. The feedstocks were mixed with alumina powders, either spherical or angular in shape, to improve coating properties. Coating samples and powder mixtures were examined by means of SEM and XRD analysis and pull-off tests were conducted to evaluate coating adhesion. It was found that alumina addition reduces porosity and increases hardness and that aluminum-alumina mixtures with the same particle shape are more suitable for producing dense coatings with high bond strength.
Proceedings Papers
ITSC2014, Thermal Spray 2014: Proceedings from the International Thermal Spray Conference, 69-74, May 21–23, 2014,
Abstract
View Paper
PDF
This study deals with the influence of spray angle on the deposition of cold-sprayed Al particles. Spray trails were conducted in parallel with finite element simulations of particle deformation and coating build-up as a function of spray angle, powder size, substrate roughness, and surface configuration. Coating cross-sections and splats were examined by SEM; bonding strength and particle adhesion were determined via laser shock adhesion testing. Experimental as well as modeling results show that splats deposited at spray angles less than 60° are highly deformed and poorly adhered. Based on the findings, several conclusions are drawn with regard to the potential use of cold spraying for the repair of aircraft components.
Proceedings Papers
ITSC2014, Thermal Spray 2014: Proceedings from the International Thermal Spray Conference, 221-226, May 21–23, 2014,
Abstract
View Paper
PDF
In this work, a numerical model of the cold spray process was developed to reproduce microstructures obtained in coatings by simulating the deformation of impinging particles and resulting coating build-up. The model employs a library of particle images generated by x-ray microtomography. To each image, a velocity is assigned and the deformation that would be produced by particle impact is estimated by means of finite element analysis and stored for later use. Based on the results, the ing approach has good potential for simulating coating microstructures that can be achieved through cold spraying.
Proceedings Papers
ITSC2014, Thermal Spray 2014: Proceedings from the International Thermal Spray Conference, 500-505, May 21–23, 2014,
Abstract
View Paper
PDF
The aim of this study is to measure residual stress profiles in conventional and continuously graded thermal barrier coatings (TBCs), including those with laser-drilled effusion holes added to improve heat protection. Three sets of TBCs with different bond coat-topcoat interfaces were produced on Haynes 188 substrates. Two sample sets were prepared by plasma spraying NiCrAlY and YSZ powders, in one case, at fixed feedrates, and in the other, at feedrates simultaneously changing in opposite directions. A third sample set was obtained by combining a cold-sprayed CoNiCrAlY bond coat with a plasma-sprayed YSZ topcoat. Residual stress profiles were measured by means of incremental-step hole drilling and speckle interferometry. An original test method was also developed and is used to determine residual stress gradients before and after effusion hole drilling. The results are presented and discussed along with best practices for controlling residual stresses.
Proceedings Papers
ITSC2014, Thermal Spray 2014: Proceedings from the International Thermal Spray Conference, 535-540, May 21–23, 2014,
Abstract
View Paper
PDF
This study assesses the strength and adherence of VPS titanium coatings on ultrahigh molecular weight polyethylene (UHMWPE) substrates. Four-point bend tests show the existence of a critical tensile strain of 1% corresponding to the onset of cracking. For strains up to 6%, crack density increases with no observed debonding. Fatigue tests over 106 cycles reveal that the coating remains uncracked at a strain of 1% and stays in a stable cracked state without debonding as strain is increased to approximately 6%. A laser shock test developed specifically for titanium-polymer interfaces revealed the existence of a debonding threshold corresponding to the adhesion strength. The results serve as a guide for the design of orthopedic implants on which VPS titanium coatings are used and, more generally, open the way for systematic measurement of adhesion between metallic coatings and polymer substrates.
Proceedings Papers
ITSC2014, Thermal Spray 2014: Proceedings from the International Thermal Spray Conference, 886-891, May 21–23, 2014,
Abstract
View Paper
PDF
In the present study, X-ray microtomography is used to examine cold-sprayed tantalum splats on copper substrates. To resolve tantalum splats intermeshed with other splats of the same chemical composition, a contrasting medium of some sort is required. For this purpose, the feedstock powder is coated with an iron layer by means of fluidized-bed chemical vapor deposition. Experimental tests were coupled with finite element simulations to determine how stresses generated during the impact of a spherical iron-coated particle affect the integrity of the added contrasting layer.
Proceedings Papers
ITSC2014, Thermal Spray 2014: Proceedings from the International Thermal Spray Conference, 923-928, May 21–23, 2014,
Abstract
View Paper
PDF
This study demonstrates the feasibility of an in-situ heat treatment for cold spray coatings. By controlling heat flow, temperature gradients are maintained in the coatings, leading to the development of graded mechanical properties. Initial experimental results validate both the starting idea and the first results of numerical simulations.
Proceedings Papers
ITSC 2013, Thermal Spray 2013: Proceedings from the International Thermal Spray Conference, 252-257, May 13–15, 2013,
Abstract
View Paper
PDF
The aim of this work is to characterize the performance and durability of Zn-based composite coatings produced by low-pressure cold spraying and evaluate their potential for use in repair and restoration applications. Mechanically blended Zn+Al+Al 2 O 3 , Zn+Cu+Al 2 O 3 , and Zn+Ni+Al 2 O 3 powder mixtures were deposited on grit-blasted carbon steel (Fe52), copper, aluminum, and nodular cast iron substrates using optimized feed rates. In addition, round samples were drilled and the holes were repaired by handheld spraying. Coated substrates are assessed based on microstructural analysis, laser shock adhesion testing (LASAT), and thickness and hardness measurements. Hole repairs are evaluated based on bond strength and gas permeability measurements. The procedures are described and the finding are presented and discussed.
Proceedings Papers
ITSC2012, Thermal Spray 2012: Proceedings from the International Thermal Spray Conference, 114-119, May 21–24, 2012,
Abstract
View Paper
PDF
The efficiency of aero-engines combustion chambers with thermal barrier coating (TBC) is improved when numerous cooling holes are laser drilled with inclined angles. However, during the laser drilling process, especially in the percussion mode, a detrimental crack can be generated at the TBC interface. Thus, each hole could be edged with a non-visible delaminated area underneath the ceramic top-coat. The present work is focused on the thorough study of the delamination induced by laser percussion drilling when interrupted drilling conditions are presented. Shallow angle drilling was applied on separated holes with 1 to 4 laser pulses respectively and various acute incident angles. Crack length was assessed by conventional metallographic preparation. A special experimental method was carried out in order to inspect the delaminated interface and the lateral edge of a semi-hole. This non-destructive assessment of the delamination of laser drilled TBC was complemented by a 3D imaging of a semi-hole using X-Ray microscopy. Results are presented with attention on both crack initiation and propagation during the laser percussion drilling of plasma-sprayed TBC.
Proceedings Papers
ITSC2012, Thermal Spray 2012: Proceedings from the International Thermal Spray Conference, 259-264, May 21–24, 2012,
Abstract
View Paper
PDF
Cold spray can substitute for several coating processes for various applications, due to a high efficiency coupled with high properties for the sprayed product. The use of a composite powder rather than a powder blend was shown to be beneficial, especially for the cold spray of electrical contacts. The objective of this work is to optimize a composite powder (Ag-14wt% SnO 2 ) using numerical simulation of the deformation of the particle at the impact onto the substrate (Cu). Every elementary composite particle was made of an agglomerate of Ag and SnO 2 smaller particles, which exhibited more or less porosity depending on the powder processing conditions. The first step was to study the distribution of these various constituting phases plus porosity. Three types of powders which showed different phases and porosity characteristics deliberately were developed. Three-dimensional images of the agglomerate were acquired using microtomography which exhibited the porosity network well in the dual-phased particle material. These actual 3D images were used to feed a simulation of the impingement of a particulate agglomerate to result in a splat onto the substrate. For this, a two dimensional deformation model was developed on the route to a three-dimensional model which is expected to be more powerful. The influence of agglomerate characteristics, primarily porosity, on the deformation behavior was studied. Consequences on splat-substrate adhesion and deposition efficiency could therefore be investigated in the light of direct observation of the cold-sprayed material.
Proceedings Papers
ITSC2012, Thermal Spray 2012: Proceedings from the International Thermal Spray Conference, 265-270, May 21–24, 2012,
Abstract
View Paper
PDF
Numerous automotive and aircraft/aerospace applications involve metallic coating of organic matrix composite materials, e.g. for aesthetic, electric, or engineering functions. In the thermal spray process family, cold spray is very attractive for the achievement of metallization of low-temperature resistant materials such as organic composites, due to its “cold” characteristic. However, despite the current (and justified) craze for cold spray, little is still known about the potential of this process for this type of application. The work demonstrated the feasibility of cold spray for satisfactory metallization of PA66-matrix composites with Al. This paves the way for using cold spray as an advantageous substitute process for the industrial protection of polymer-based composites.
Proceedings Papers
ITSC2012, Thermal Spray 2012: Proceedings from the International Thermal Spray Conference, 521-528, May 21–24, 2012,
Abstract
View Paper
PDF
Thermally sprayed ceramic coatings such as plasma-sprayed alumina exhibit a composite microstructure due to the presence of defects such as pores, interlamellar and intra-lamellar cracks. These second phase typed features influence the mechanical behaviour of the coating dramatically. In this study, an excimer laser surface treatment of plasma-sprayed alumina surface was developed for the optimization of component properties of a wireline tool used in the oil industry. In contrast to liquid phase treatment realized with CO 2 or YAG laser, an excimer laser processing presents short wavelength which means that for ceramic materials, the energy is absorbed in a region of the surface. This condition leads to surface treatment free of cracks. Effect of laser operating parameters, i.e. wavelength, pulse number and power density, on microstructure and the sealing quality of the coating are discussed. First, surfaces and cross sections of the microstructures were studied using image analysis of scanning electron microscope (SEM). Surface roughness and coating ablation were characterized according to laser treatment. Then, three dimensional (3D) microstructures were obtained using X-ray microtomography to evaluate the 3D porosity after laser treatment. Finally, nanoindentation and Electrochemical Impedance Spectroscopy (EIS) were carried out to characterize respectively the mechanical and electrical properties of the modified coating microstructure. The excimer laser surface processing was shown to be an innovative process to control the insulating characteristics of plasma-sprayed alumina.
Proceedings Papers
ITSC 2011, Thermal Spray 2011: Proceedings from the International Thermal Spray Conference, 60-65, September 27–29, 2011,
Abstract
View Paper
PDF
The adhesion mechanisms involved in the cold spray coatings are not still well elucidated. The quality of the deposit does depend mainly on particles and dynamic characteristics (which result from nozzle type, nozzle-substrate distance, etc.). The present work is based on the study of particle-substrate and particle-particle interfaces in the tantalum-copper coating-substrate system. The content focuses on the influence of the oxygen content in the starting powder on interface features, consequently on coating properties. Tantalum powders with different oxygen levels were studied using SEM (Scanning Electron Microscopy) and EPMA (Electron Probe Microanalysis). Laser shock spallation of cold-sprayed Ta coatings was developed as a reliable and flexible process to achieve Ta spalls to be deposited at a high-velocity onto Cu targets. The velocity due to the laser shock could be controlled to be similar to that of particles in conventional cold spray. This results in Ta-Cu interfaces, the study of which was carried out to go into interface phenomena involved in cold spray, using TEM (Transmission Electron Microscopy) in particular. Results were compared to those obtained from laser shock spallation of Ta bulk specimens (i.e. made of a conventional Ta sheet). The role of powder oxidation on interface soundness was exhibited. Adhesion was shown to be all the lower as powder oxygen content was higher, using LASAT (“ Laser Shock Adhesion Test”) in addition to direct observation of interfaces. Results were exploited to discuss properties of the corresponding Ta coatings onto Cu, i.e. which were cold sprayed using powders with different oxygen contents.
Proceedings Papers
ITSC 2011, Thermal Spray 2011: Proceedings from the International Thermal Spray Conference, 357-362, September 27–29, 2011,
Abstract
View Paper
PDF
In the oil industry, logging systems involving geological sensors are designed to operate under increasing severe service conditions of deep and horizontal boreholes. Under these conditions, metal matrix composites (MMCs) with ceramic reinforcement are applied on components to achieve wear and corrosion resistant systems. The ‘cold spray’ could be described as a cold and inert process to form coating layers through severe plastic deformation of a ductile metal. Ceramic/metal MMC coating could be achieved by co-deposition of a ceramic with a ductile material. In this work, it was it was investigated the use of MMC B 4 C-Ni coating from both mechanically milled blends or B 4 CNi CVD coated batches. Powder blends involving Ni powder with fine or coarse B 4 C powders were prepared by mechanical milling. Three CVD coated B 4 C-Ni powder batches were synthesized with 30, 40 and 50 Ni wt% respectively. Cold spray coatings were achieved with 1 pass and 5 passes to investigate the building-up mechanisms and interfaces with AISI316L. Powders and cold sprayed coatings microstructures were observed by optical and scanning electron microscopies and further quantitative image analysis were carried out to determine the content of B 4 C embedded in the Ni matrix of B 4 C-Ni cold spray coatings. The highest B 4 C vol.%, up to 45%, could be reached in the case of B 4 C-Ni coated powder. Micro-hardness values of such MMC coatings were also determined through Vickers micro-indentation. The beneficial role of the Ni surrounding layer on coating formation is discussed in relation to the unique features of the microstructures obtained by cold spray of B 4 C-Ni coated powders.
Proceedings Papers
ITSC 2009, Thermal Spray 2009: Proceedings from the International Thermal Spray Conference, 1151-1156, May 4–7, 2009,
Abstract
View Paper
PDF
In this study, fine aluminum powder was cold sprayed onto aluminum substrates, some of which were polished, some grit blasted, and some pretreated using a nano-pulsed Nd:YAG laser. In the latter case, the laser is coupled with the cold spray gun and the irradiation treatment occurs just prior to deposition. To better understand the interaction mechanisms involved with laser pretreating, coating-substrate interfaces were examined on thin-foil specimens and adhesion strength was determined by laser shock testing. The results show that substrate pretreatment with a nano-pulsed laser significantly improves the coating-substrate interface as well as coating adhesion.
Proceedings Papers
ITSC 2008, Thermal Spray 2008: Proceedings from the International Thermal Spray Conference, 41-45, June 2–4, 2008,
Abstract
View Paper
PDF
The aim of this study was to investigate the microstructure (including surface roughness, microstructure and microhardness) of cold sprayed copper coatings on 2017 Al alloy, before and after annealing at 350°C for 1h. It seemed that keeping constant the powder flow rate and increasing the gas pressure from 2.0 to 2.5 MPa, the surface roughness of the coating tended to decrease, while the thickness of the coating tended to increase. Also, it seemed that keeping constant the pressure and increasing the powder flow rate from 22 to 130 g/min, the surface roughness and the thickness of the coating tended to increase. The microstructural study of the coatings after etching revealed particle interfaces and in some cases grain boundaries. Twins were observed in some of the coatings. Negligible porosity, absence of cracks and good adhesion of the coatings to the substrate were observed. The microhardness of the coatings varied between 95 HV 0.3 and 150 HV 0.3 for the different employed cold sprayed conditions. After coatings’ annealing the microhardness of all the coatings (cold sprayed and HVOF sprayed) decreased. The aforementioned results were compared with those of HVOF coating.
Proceedings Papers
ITSC 2008, Thermal Spray 2008: Proceedings from the International Thermal Spray Conference, 271-275, June 2–4, 2008,
Abstract
View Paper
PDF
Thermal-sprayed MCrAlY coatings are widely used for land-based gas turbine applications. The cold spray may increase the coating density owing to the high-velocity particle impacts during spraying. Many researchers have considered critical velocity to be the most important factor of the deposition mechanism of cold-sprayed coatings. However, this dominant parameter of critical deposition condition has not been completely understood. In order to understand the mechanism, two approaches were used in this study. One is the transmission electron microscope (TEM) observation of the interface between the coating and the substrate, and the other is the cross-sectional observation of the deposited particle by using the focused ion beam (FIB) cutting technique. From the TEM observations, there are no evidences of melting at the interface, and it is found that the actual bonding occurred at the nascent surfaces. Generally, there is a native oxide on the surface of the particles and substrate. After the plastic deformation of the particles and substrate, the native oxide breaks down; subsequently, a nascent surface can be created and direct contact initiates deposition. From the results of these investigations, it is thought that the dominant factor for deposition is the plastic deformation of the particles and substrates.
1