Shi Chengyu,Li Nan,Yuan Qisong,Liu Tao,Cao Qingyuan,Qian Hanqi,Jiang Bo,Wang Jiazhi,Yu Xiangtao
Developing epoxy structural adhesives with excellent high-temperature adhesion remains a great challenge. The incorporation of fillers can enhance the performance of epoxy adhesives, albeit at the expense of reduced high-temperature adhesion properties. Polyhedral oligomeric silsesquioxanes (POSS) is considered a promising filler for enhancing high-temperature adhesion properties due to its excellent compatibility and nano cage-structured. Herein, the rigid cage-structured was covalently introduced epoxy adhesives to improve the high-temperature adhesion properties. The introduction of 1 wt% POSS significantly increased the high-temperature (120°C) adhesion strength by 197% and toughness by 283%. The POSS-reinforced adhesive also featured excellent wide temperature adaptability, indicating that it maintained high adhesion strength at various temperatures. Furthermore, POSS drastically enhanced the transparency of epoxy adhesive by three times. It is highly anticipated that this work will open a new avenue of designing epoxy adhesives with the excellent high-temperature adhesion properties and transparency.
To meet the high demand for ceramic/superalloy composite structural components in various fields, an advanced high-temperature adhesion technique was firstly developed by preparing a novel inorganic/organic hybrid adhesive suitable for ZrO 2 and TC4 . Chemical bonding started to work at ∼600°C, and became the crucial bonding mechanism at elevated temperatures. The formation of ZrSiO 4 and Ti 5 Si 3 at the interfaces of two substrates not only increased the interfacial connection strength , but also formed two gradient layers with a size of ∼2 μm to effectively alleviate the difference of composition and performance between the adhesive and substrates. In the temperature range of 500–900°C, the matching degree of CTE among ZrO 2 , adhesive and TC4 is higher, and the maximum difference does not exceed 3×10 -6 K -1 . Meanwhile, the formation of a composite structure containing various ceramics (ZrO 2 , SiC and ZrB 2 ) and intermetallics (Ni–Si, Al–Ni), and the improvement of structural compactness of adhesive from 500 to 900°C greatly improved the bonding strength to the maximum value of 31.4 MPa at 900°C. Also, the adhesive pretreated at 900°C showed good thermal cycling resistance, and the strength was still higher than 15 MPa after 50 cycles. For cured adhesive, when used directly in an extreme environment, it can provide bonding strength not less than 5 MPa in the whole temperature range, indicating that the adhesive possessed potential emergency repair convenience. This work significantly broadened the application of high-temperature-resistant adhesion technology in the connection of dissimilar ceramics and alloys.
危险品化学品经营许可证（带存储）