Table 5 Leak rates, permeability, diffusivity and sample behaviour for autoclaves and ATP laminates following cryogenic cycling. Laminate No of Leak rate Permeability Diffusivity Behaviour cycles x̅ Cv(%) x̅ Cv(%) x̅ (m2/s) Cv(%) (Scc/sm2) 1 8.8×10-5 4 4.5×10-17 4 1.9×10-11 3 Near-Fickian C4AC 10 9.2×10-5 3 4.6×10-17 4 1.9×10-11 7 Near-Fickian 30 1.0×10-4 11 5.0×10-17 11 2.1×10-11 4 Near-Fickian 1 4.6×10-5 5 2.3×10-17 6 8.9×10-12 9 Near-Fickian C7AC 10 4.9×10-5 6 2.4×10-17 7 8.6×10-12 6 Near-Fickian 30 6.6×10-5 19 3.2×10-17 19 9.8×10-12 4 Near-Fickian 1 9.9×10-5 7 4.9×10-17 7 1.6×10-11 6 Near-Fickian T4AC 10 1.0×10-4 6 5.2×10-17 6 1.7×10-11 7 Near-Fickian 30 1.0×10-4 6 4.9×10-17 6 1.6×10-11 11 Near-Fickian 1 2.6×10-1 98 NA NA NA NA Non-Fickian S7AC1 10 7.6×10-1 69 NA NA NA NA Non-Fickian 30 8.6×10-1 70 NA NA NA NA Non-Fickian 1 1.9×10-1 52 NA NA NA NA Non-Fickian Fig. 1 Schematic of test setup used for leakage testing of laminates showing the helium gas supply, test chamber, cryogenic dewar, leak detector and the data acquisition system. Fig. 2 Micrographs of laminates S7AC, T4AC, C4AC, and C7AC showing the layup and microstructure of each CF-PEEK material.
Table 5 Leak rates, permeability, diffusivity and sample behaviour for autoclaves and ATP laminates following cryogenic cycling. Laminate No of Leak rate Permeability Diffusivity Behaviour cycles x̅ (Scc/sm2) Cv(%) x̅ Cv(%) x̅ (m2/s) Cv(%) C4AC 1 10 30 8.8×10-5 9.2×10-5 1.0×10-4 4 3 11 4.5×10-17 4.6×10-17 5.0×10-17 4 4 11 1.9×10-11 1.9×10-11 2.1×10-11 3 7 4 Near-Fickian Near-Fickian Near-Fickian C7AC 1 10 30 4.6×10-5 4.9×10-5 6.6×10-5 5 6 19 2.3×10-17 2.4×10-17 3.2×10-17 6 7 19 8.9×10-12 8.6×10-12 9.8×10-12 9 6 4 Near-Fickian Near-Fickian Near-Fickian T4AC 1 10 30 9.9×10-5 1.0×10-4 1.0×10-4 7 6 6 4.9×10-17 5.2×10-17 4.9×10-17 7 6 6 1.6×10-11 1.7×10-11 1.6×10-11 6 7 11 Near-Fickian Near-Fickian Near-Fickian S7AC1 1 10 30 2.6×10-1 7.6×10-1 8.6×10-1 98 69 70 NA NA NA NA NA NA NA NA NA NA NA NA Non-Fickian Non-Fickian Non-Fickian 1 1.9×10-1 52 NA NA NA NA Non-Fickian Fig. 1 Schematic of test setup used for leakage testing of laminates showing the helium gas supply, test chamber, cryogenic dewar, leak detector and the data acquisition system. Fig. 2 Micrographs of laminates S7AC, T4AC, C4AC, and C7AC showing the layup and microstructure of each CF-PEEK material.
Permeability_of_Carbon_Fibre_PEEK_Composites_all_.docx