Abstract This work reports a quantitative evaluation of the aging behavior of adhesively bonded joints manufactured using a toughened epoxy adhesive applied on CFRP substrates. Low-pressure plasma (LPP) treatment was employed, adopting air and pure oxygen as process gases and varying working parameters such as power and exposure time. A preliminary testing campaign was performed under standard laboratory conditions to evaluate shear strength of single-lap joints (SLJ), comparing effectiveness of LPP treatments to a traditional mechanical abrasion of the adherends. Even at this early stage, experimental findings highlighted how this physical method provides for competitive performance over abrasion, resulting in a remarkable enhancement of the shear resistance. Four sets of LPP-treatment conditions were selected and then subjected to accelerated aging (consisting of 56 cycles of 5 h at T = 70 °C, RH>90% and 5 h at T = −40 °C each). Their behavior was compared to that of abraded joints, employed as a reference. To assess the durability of the CFRP-epoxy adhesive system under accelerated aging conditions, tensile shear strength (TSS) testing and wedge cleavage test (WT) were performed in parallel. The experimental results showed that low-pressure plasma treatment of the CFRP substrates results in increased short-term quality of the adhesive joint as well as in enhancement of its durability even under severe aging conditions.

中文翻译：

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用于粘合剂粘合的 CFRP 基材的低压等离子体处理：在严酷的温度-湿度条件下对接头耐久性的研究

摘要 这项工作报告了对使用涂在 CFRP 基材上的增韧环氧树脂粘合剂制造的粘合接头老化行为的定量评估。采用低压等离子体 (LPP) 处理，采用空气和纯氧作为工艺气体，并改变功率和暴露时间等工作参数。在标准实验室条件下进行了初步测试活动，以评估单搭接接头 (SLJ) 的剪切强度，将 LPP 处理的有效性与被粘物的传统机械磨损进行比较。即使在这个早期阶段，实验结果也强调了这种物理方法如何提供比磨损更具竞争力的性能，从而显着提高抗剪强度。选择了四组 LPP 处理条件，然后进行加速老化（由 56 个循环组成，每个循环在 T = 70 °C、RH> 90% 和 5 h 在 T = -40 °C）。将它们的行为与磨损接头的行为进行比较，用作参考。为了评估 CFRP-环氧树脂胶粘剂系统在加速老化条件下的耐久性，同时进行拉伸剪切强度 (TSS) 测试和楔形劈裂测试 (WT)。实验结果表明，CFRP 基材的低压等离子体处理可提高粘合接头的短期质量，并增强其即使在严重老化条件下的耐久性。为了评估 CFRP-环氧树脂胶粘剂系统在加速老化条件下的耐久性，同时进行拉伸剪切强度 (TSS) 测试和楔形劈裂测试 (WT)。实验结果表明，CFRP 基材的低压等离子体处理可提高粘合接头的短期质量，并增强其即使在严重老化条件下的耐久性。为了评估 CFRP-环氧树脂胶粘剂系统在加速老化条件下的耐久性，同时进行拉伸剪切强度 (TSS) 测试和楔形劈裂测试 (WT)。实验结果表明，CFRP 基材的低压等离子体处理可提高粘合接头的短期质量，并增强其即使在严重老化条件下的耐久性。