摘要
Carbon fiber-reinforced carbon aerogel(C/CA)composites are one of the most promising candidates for applications requiring both thermal insulation and load bearing capabilities.The preparation of anti-oxidation coatings on C/CA to address its susceptibility to oxidation is a feasible approach to promote its application in oxidative environments.However,the currently reported coatings on C/CA mainly focus on improving the ablation performance and coating preparation process typically necessitating high-temperature heat treatment.This procedure can increase its thermal conductivity and reduce its thermal insulation ability.In this study,a series of ceramic-resin coatings were fabricated on C/CA through a simple slurry brushing-drying approach at room temperature.The effects of phenolic resin content on the coating structure,residual stress,thermal shock,and oxidation behaviors were investigated.Due to the adhesive properties and curing-induced shrinkage,the PR-7.5 coating(containing 7.5%(in mass)phenolic resin in the slurry)exhibits bonding strength close to fracture strength of the substrate and residual compressive stress of 0.853 GPa,which is beneficial for resisting thermal shock cracking.However,excessive resin content(PR-10.0 containing 10.0%(in mass)phenolic resin in the slurry)induces tensile stress due to uneven curing shrinkage,thereby leading to thermal shock cracking.Meanwhile,oxidation tests reveal significantly reduced weight losses for PR-7.5(17.46%at 800℃/100 min,8.15%at 1000℃/120 min,3.15%at 1200℃/120 min)versus uncoated C/CA’s 44.60%loss at 800℃/20 min.This work provides a brand-new and simple approach to improving the anti-oxidation performance of C/CA and expands its application in mild oxidative environments.
碳纤维增强碳气凝胶(C/CA)复合材料是同时满足隔热和承载应用需求的最具潜力的候选材料之一。在C/CA上制备抗氧化涂层用于解决其易氧化问题,是促进其在氧化环境中应用的重要方法。然而,目前已报道的C/CA抗氧化涂层主要用于提升材料的烧蚀性能,且涂层制备工艺常涉及高温热处理过程,这会导致C/CA热导率增加,进而降低隔热效果。本研究在室温下采用简单的浆料刷涂-干燥方法,在C/CA上制备了一系列陶瓷-树脂涂层,并研究了酚醛树脂含量对涂层结构、残余应力、热冲击以及氧化行为的影响。结果表明,得益于树脂的黏接作用和固化收缩作用,PR-7.5涂层(料浆中酚醛树脂质量分数为7.5%)结合强度与基底本征断裂强度相近,且具有0.853 GPa的残余压应力,显著提升了其热震性能;而进一步提高树脂含量(PR-10.0,料浆中酚醛树脂质量分数为10.0%),涂层因树脂不均匀固化导致收缩不一致而产生了残余拉应力,热震时易开裂。实验结果显示,PR-7.5在800℃下氧化100 min、1000℃下氧化120 min以及1200℃下氧化120 min后失重率分别为17.46%、8.15%和3.15%;而没有涂层的C/CA复合材料在800℃下氧化20 min后失重率高达44.60%。本工作为提高C/CA的抗氧化性能提供了一种全新且简单的途径,拓展了其在温和氧化环境中的应用。
出处
《无机材料学报》
2026年第3期401-408,I0008-I0011,共12页
Journal of Inorganic Materials
基金
National Natural Science Foundation of China(52272075,52472053)
Research Fund of Youth Innovation Promotion Association of CAS,China(2021190)
Defense Industrial Technology Development Program(JCKY2021130B007)。
