Capability of cold spraying to obtain high deposition efficiency for the metallization of PEEK

The cold spray (CS) metallization of thermally sensitive materials such as thermoplastic has been investigated for developing new surface functions such as conduction performance. The copper metallization of PEEK is a typical exploratory case, successful but suffers from a weak deposition efficiency lower than 40% until date. This paper focuses on the possibilities to overcome this issue. A review of current achievements and limitations is addressed to appropriately place the suitability of cold spray working conditions we suggest, i.e. the high-pressure deposition. The formation of the first layer of copper powders onto the PEEK substrate is not difficult, but the deposition mainly fails during the coating build-up. No heating of propellant gas, which is a suitable working condition for thermally sensitive materials, there is no development of coating, even using the highest-pressure delivered by the CS system for a non-heated gas (25bar, 29°C). Increasing the prechamber pressure is necessary but implies to increase the gas temperature up to 400°C to reach high deposition efficiency up to 70%. However, the exposure to such working temperature causes delamination issues to overcome.