Study of barrier layer on moisture absorption of thin carbon fiber reinforced plastic substrates

2018 Fiscal Year Final Research Report

• Project/Area Number: 17K18782
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Particle-, Nuclear-, Astro-physics, and related fields
• Research Institution: Ehime University
• Principal Investigator: Awaki Hisamitsu 愛媛大学, 理工学研究科(理学系), 教授 (30252414)
• Research Collaborator: Matsumoto Hironori ; Kamiya Tomohiro
• Project Period (FY): 2017-06-30 – 2019-03-31
• Keywords: 炭素繊維強化プラスチック / 膨潤変形 / 反射鏡

Outline of Final Research Achievements

Carbon fiber reinforced plastic (CFRP) has a higher strength-to-weight ratio and forming flexibility than metals, making it suitable for fabricating lightweight X-ray mirrors. However, CFRP has the disadvantages of print-through and deformation due to moisture absorption, which have prevented its use in optical mirrors. To expand the application of CFRP, we studied the formation of a moisture barrier layer on CFRP substrates. We formed a flattening layer a few micrometers thick on a CFRP substrate, following which we coated the substrate with SiOx as a moisture barrier. The effect of moisture absorption was then evaluated using accelerated aging tests. We found that the diffusivity of the CFRP substrate at 60°C and a relative humidity of 100% was about 2 × 10－6 mm2 h－1, which is 1/500th that of the barrier-less substrate. We also demonstrate potential for a CFRP mirror.

Free Research Field

X線天文学

Academic Significance and Societal Importance of the Research Achievements

CFRPを長期に利用する際や宇宙または真空中で使用する際に、CFRP内の水分量が作成時と比べて変化し、それがもとで変形する。このためCFRPを光学素子や精密部品として使用する際の大きな課題となっている。吸湿対策はこの変形を大幅に軽減する有効な手段であり、CFRPの精密部品への応用を可能とする。また、反射鏡として使用可能なシリカ面が形成できれば、CFRPを容易に光学系に利用することが可能となり、その応用範囲は広い。本研究は、日本の主力技術であるCFRPの可能性を増やすことにつながるものである。