Journal Article

Numerical and Experimental Investigation of Cold Spray Gas Dynamic Effects for Polymer Coating

Alhulaifi, Abdulaziz S., Buck, Gregory A., Arbegast, William J.

2012

Overview

Low melting temperature materials such as polymers are known to be difficult to deposit using traditional cold spray techniques. Computational fluid dynamics (CFD) models were created for various nozzle geometries and flow conditions. A schlieren optical system was used to visualize the density gradients and flow characteristics in the free jet impingement region. Based on the CFD models, it was determined that a diffuser placed into the carrier gas flow near the nozzle exit not only leads to lower particle impact velocity required for polymer deposition, but also provides for appropriate application of compression heating of the particles to produce the conditions necessary at impact for successful coating adhesion of these materials. Experiments subsequently confirmed the successful deposition of polyethylene powder onto a 7075-T6 aluminum substrate. Using air as the carrier gas, polyethylene particles of 53-75 μm diameter and 0.94 g/cm 3 density , were cold spray deposited onto the aluminum substrate, with a critical impact velocity of 191 m/s. No apparent melting of the polymer particles was observed. Refinements to these concepts are currently under investigation and a patent disclosure for the idea is pending.

• Publisher: Springer US,Springer
• Subject: Analytical Chemistry / Applied sciences / Characterization and Evaluation of Materials / Chemistry and Materials Science / Corrosion and Coatings / Exact sciences and technology / Machines / Manufacturing / Materials Science / Metals. Metallurgy / Nonmetallic coatings / Peer-Reviewed / Processes / Production techniques / Surface treatment / Surfaces and Interfaces / Thin Films / Tribology