J. G. Legoux, National Research Council Canada, Boucherville, QC, Canada; E. Irissou, Industrial Materials Institute / -National Research Council Canada, Boucherville, QC, Canada; C. Moreau, National Research Council Canada (CNRC-NRC), Boucherville,, QC, Canada
Cold Spray coating properties are known to be influenced by both process parameters and starting powder characteristics. However their relative effects on different cold systems have never been reported.
In this work, the effect of spray parameters and powder morphology on in-flight particle velocity and coating characteristics is evaluated for two Cu powders: one spherical, the other exhibiting a flake-shape morphology, sprayed using three commercial cold-spray systems, namely CGT Kinetiks 3000, Inovati KM-CDS 2.2 and Centerline SST.
For both types of Cu powder feedstock, the operational range for each system was defined by varying the process parameters, namely, gas pressure varied from 40 to 600 psi (2.8-41 bar) and gas temperature from room temperature to 600 °C. It is found that the velocity is influenced by the particle shape and the inlet gas pressure and temperature values. Varying those input parameters impart particle velocities ranging from 350 to 850 m/s. For coating evaluation, spray conditions were selected to produce a similar average velocity of 480 m/s to the two types of powder feedstock particles with the three guns. Coatings were also produced at higher velocities for each gun. Stand-off distance, gun traverse speed and feed rate were optimised for each gun in term of deposition efficiency prior to spray test coupons.
Coatings were deposited on grit-blasted mild steel substrates. The coating microstructures were evaluated and coating properties such as bond strength, microhardness, electrical resistivity and thermal diffusivity were measured. In addition, the anisotropy of electrical resistivity and thermal diffusivity values, parallel and perpendicular to the substrate surface, were evaluated on selected samples. Coating properties obtained from the different spray systems are compared and the observed differences are discussed in terms of particle morphology and velocity as well as cold spray gun characteristics and operational parameter range.
Summary: Cold Spray coating properties are known to be influenced by both process parameters and starting powder characteristics. However their relative effects on different cold systems have never been reported.
In this work, the effect of spray parameters and powder morphology on in-flight particle velocity and coating characteristics is evaluated for two Cu powders: one spherical, the other exhibiting a flake-shape morphology, sprayed using three commercial cold-spray systems, namely CGT Kinetiks 3000, Inovati KM-CDS 2.2 and Centerline SST.
For both types of Cu powder feedstock, the operational range for each system was defined by varying the process parameters, namely, gas pressure varied from 40 to 600 psi (2.8-41 bar) and gas temperature from room temperature to 600 °C. It is found that the velocity is influenced by the particle shape and the inlet gas pressure and temperature values. Varying those input parameters impart particle velocities ranging from 350 to 850 m/s. For coating evaluation, spray conditions were selected to produce a similar average velocity of 480 m/s to the two types of powder feedstock particles with the three guns. Coatings were also produced at higher velocities for each gun. Stand-off distance, gun traverse speed and feed rate were optimised for each gun in term of deposition efficiency prior to spray test coupons.
Coatings were deposited on grit-blasted mild steel substrates. The coating microstructures were evaluated and coating properties such as bond strength, microhardness, electrical resistivity and thermal diffusivity were measured. In addition, the anisotropy of electrical resistivity and thermal diffusivity values, parallel and perpendicular to the substrate surface, were evaluated on selected samples. Coating properties obtained from the different spray systems are compared and the observed differences are discussed in terms of particle morphology and velocity as well as cold spray gun characteristics and operational parameter range.
