Effect of Heat Treatment on the Microstructure and Mechanical Properties of Stainless Steel 316L Coatings Produced by Cold Spray for Biomedical Applications

Abstract In this study, the effects of heat treatment on the microstructure and mechanical properties of cold sprayed stainless steel 316L coatings using N2 and He as propellant gases were investigated. Powder and coating characterizations, including coating microhardness, coating porosity, and XRD phase analysis were performed. It was found that heat treatment reduced porosity, improved inter-particle bonding, and increased ductility. XRD results confirmed that no phase transformation occurred during deposition. Significant increase in UTS and ductility was observed for the annealed specimens obtained with nitrogen propellant, whereas little changes were observed for the helium propellant produced specimen

Laser-Assisted Cold Spray (LACS)

International audienceRésumé du livre : Discovered almost fifty years ago at Bell Labs (1964), the Nd:YAG laser has undergone an enormous evolution in the years, being now widely used in both basic research and technological applications. Nd:YAG Laser covers a wide range of topics, from new systems (diode pumping, short pulse generation) and components (a new semiorganic nonlinear crystal) to applications in material processing (coating, welding, polishing, drilling, processing of metallic thin films), medicine (treatment, drug administration) and other various fields (semiconductor nanotechnology, plasma spectroscopy, laser induced breakdown spectroscopy)

Structural Transformation and Mechanical Properties of Cold Sprayed Nickel Coatings after Annealing

NRC publication: Ye

Influence of helium and nitrogen gases on the properties of cold gas dynamic sprayed pure titanium coatings

This study investigated the effect of the type of gas used, nitrogen and helium, during cold spraying of titanium coatings. In all conditions, the propelling gases\u2019 temperature and pressure were attuned to attain three similar particle velocities for each gas. Coatings were characterized by SEM and XPS. Deposition efficiency, coating microhardness, and porosity were evaluated for all conditions. Results show that for the same particle impact velocity, the deposition efficiency and coating density were mostly the function of the surface temperature, which in turn was influenced by spray parameters. It is shown that loosely-bonded particles at the surface can be detached by the passage of high pressure supersonic gas stream. In addition, a thick and fully dense cold sprayed titanium coating was achieved with optimized spray parameters with He and the corresponding average particle velocity was measured at 1173 m/s.Peer reviewed: YesNRC publication: Ye

The influence of Al2O3 particle morphology on the coating formation and dry sliding wear behavior of cold sprayed Al–Al2O3 composites

International audienceFive Al–Al2O3 coatings were deposited by gas dynamic cold spray, using feedstocks containing 0, 10, and 50 wt.% of Al2O3 particles admixed into commercially pure Al powders. Two feedstocks were made using Al2O3 powders with an angular, blocky Al2O3 morphology, two feedstocks used Al2O3 powders with a spherical morphology, and the fifth consisted of 100% Al. The influence of Al2O3 concentration and morphology in the feedstock powders on the cold spray coating formation was measured in terms of Al2O3 recovery in the coatings, deposition efficiency, and microstructural analysis. The Al–Al2O3 coatings were then subjected to dry sliding wear experiments from which the friction, wear, and microevolution of third body structures in the wear track and transfer film were observed. The spherical Al2O3 morphology was associated with improved tribological behavior compared to the angular morphology when comparing similar coating concentrations of Al2O3

Dynamic recrystallization in the particle/particle interfacial region of cold-sprayed nickel coating: Electron backscatter diffraction characterization

Electron Backscatter diffraction was used to investigate the microstructural evolution of nickel powder particles during the high-velocity impact in the cold spray process. Ultrafine grains in the scale of 100–200 nm were observed in the particle bonding region. The formation of these nanometer-sized grains is interpreted in terms of dynamic recrystallization by lattice and subgrain rotation.This research was supported by CFI Project NO. 8246, McGill University, Canada

Application of copper coatings onto used fuel canisters for the Canadian nuclear industry

The Nuclear Waste Management Organization (NWMO) was established in 2002 under the Nuclear Fuel Waste Act (NFWA) to investigate approaches for managing Canada's used nuclear fuel. Currently, nuclear power plants are operating or undergoing decommissioning in Ontario, Quebec, and New Brunswick. Canada's CANDU reactors generate used fuel with small amounts of fissile nuclides compared to other types of nuclear reactors, owing to the use of unenriched uranium as a fuel source; used nuclear fuel is currently planned for disposal without reuse/reprocessing. The present approach, shown in Figure 1, envisions the conceptual long term storage of radioactive fuel bundles in specially designed canisters. The canisters would be emplaced in the rock of a suitable geological formation at a minimum of 500 m of depth, for an intended lifespan of more than 100,000 years (i.e., indefinite storage). The Canadian spent fuel canister consists of an inner container of steel strong enough to withstand geological pressures, including glaciations scenarios, and an outer shell of copper for corrosion resistance.Peer reviewed: YesNRC publication: Ye

Characterization and performance evaluation of a helium recovery system designed for cold spraying

This paper describes and evaluates the performance of a Helium Recovery System (HRS) designed for cold spraying. A flexible, automated, full scale Helium Recovery System has been designed and installed in the McGill Aerospace Materials & Alloy Development Center Cold Spray Facility, located at and in collaboration with the National Research Council of Canada. The fully automated Helium Recovery System has been designed to recover helium from the cold spray chamber with sufficient purity (>99%) and flow capacity (5 to 220 Nm\ub3/h), allowing for a cost-effective operation by insuring a recovery rate of above 85%. In addition, a comparison of titanium coating properties obtained by using both He and N\u2082 as propellant gas is presented.Peer reviewed: YesNRC publication: Ye