Cold spray onto carbon fibre reinforced polymer for lightning strike protection
Notice bibliographique
Résumé
Carbon fibre reinforced polymer (CFRP) is a very competitive alternative to aluminum for aircraft structures for lightweighting purposes, but this leaves vulnerability against lightning strike. Cold spray is one coating approach to make the polymers lightning strike proof. The aim of this work is to use cold spray on aircraft quality CFRPs to produce a metal coating with sound mechanical properties and good electrical conductivity for lightning strike protection. Copper, aluminum and tin were used as the coating materials and cold sprayed with both a high-pressure and a low-pressure cold spray system. A number of different combinations of the gas pressure and gas preheating temperature were used for the cold spray process. Erosion was found to be the key obstacle to developing continuous coatings on the CFRP substrates with the high-pressure system. On the other hand, continuous tin coatings were successfully obtained on the CFRP with the low-pressure system, due to the very soft tin coating the substrate through a "crack filling" mechanism; a process map was generated to define appropriate cold spray conditions. The tin/CFRP adhesion, which was assessed by pull-off tests, revealed the bonding was mainly mechanical since the adhesion strength was at a low level. Copper, aluminum and zinc powders were mixed with tin with the aim of increasing conductivity, and the addition of copper and zinc led to much higher deposition efficiencies compared to the pure tin coating. To understand, more generally, the cold sprayability of metal powders on polymeric substrates, powders of various compositions and characteristics were sprayed on different polymer substrates. Thermoplastic polymers generally showed positive results; in particular, thick copper coatings were successfully deposited on two thermoplastics. The electrical conductivity of the cold sprayed coatings was measured by the four-point conductivity measurement method. The conductivity in the as-sprayed tin coating was approximately half of that of bulk tin, and increased to 73 per cent as conductive as bulk tin after annealed at 80°C for 72 hours. The addition of copper generally did not increase the overall conductivity due to the growth of the more resistive intermetallics. Last but not least, continuing current injection tests, which duplicated component C of a lightning waveform, were performed on the tin coatings. The results showed that the cold sprayed tin coatings can provide effective protection to the CFRP underneath when subjected to a 100A current.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,000 | 0,001 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».