First, a preliminary feasibility was performed enabling to identify a functional and industrial transferable coating solution suitable for the metallization of thermoplastic polymers, thermoset composite, and thermoplastic composite. Three development axis were investigated: i) the metallic material to be sprayed, through the use of appropriate feedstock, ( granulometry, shape, oxidation rate) as well as alternative to pure copper such as aluminium, polymer powder mix; ii) the use of three different spraying technologies: LPCS (Low Pressure Cold Spray), HPCS (High Pressure Cold Spray) and SND (Supercritical Nitrogen Deposition) as well as their coupling; iii) the development of a surface interlayer, called polymeric protective layer (PPL). Promising results were obtained on the LPCS of Aluminium/polymers powder mix, as well as with pure copper powder combined with a polymeric protective layer (PPL). The coupling of SND and HPCS was investigated and results demonstrate an interesting way for improve the mechanical adhesion with the substrate.
Then, the most promising solutions were further developed, enabling the increase of the deposition efficiency, as well as the understanding of the coating morphology. HPCS of pure metallic powder was widely studied, on functionalized thermoset composite mainly. The influence of the powder distribution, powder type, PPL thickness were widely studied. Outstanding results were obtained, combining high electrical conductivity with high adhesion level. The deposition efficiency was measurement and show a deposition rate closed to 90%. LPCS was further developed to try to reach the electrical conductivity vs adhesion properties combination. The role of the polymer type, polymer vs metal ratio, as weld as gradient of composition were analysed enabling to reach satisfying properties combination.
Based on the selected coating technology, a test plan was performed enabling the direct comparison of CO3 solutions with reference. The test plan was focus on mechanical, electrical, morphological, ageing, post treatment and finally lightning strike test according to SAE ARP5412 & SAE ARP5416 standards. Both HPCS and LPCS were able to reach the same level of performances compared to references, but also to overpass them especially by lightning strike, where no composite substrate damage was found after lightning strike, unlike the reference.
To demonstrate to CO3 approach at the demonstrator scale, a 3D demonstrator model, digital twin of the physical installation, was created. This 3D model can calculate the trajectories by using the normal of the points of the part to be impacted using an offline robotic programming software.
Finally, CO3 project has demonstrated at the demonstrator scale the cold spray coating process on a composite material by using industry representative composite manufacturing and coating process. The use of this two pilot line for Cold coating and composite manufacturing have allowed the development and evaluation of the CO3 approach in repeatable and transferable conditions as the process parameters control as well as the automation level guaranty reliable evaluation on 3D complex part geometry. Several wind edge demonstrators were metalized, demonstrating the ability of those technologies to be upscale on real part scale.
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