Advanced high-temperature (RT-1100°C) resistant adhesion technique for joining dissimilar ZrO2 ceramic and TC4 superalloys based on an inorganic/organic hybrid adhesive

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 ZrO2 and TC4. Chemical bonding started to work at ∼600°C, and became the crucial bonding mechanism at elevated temperatures. The formation of ZrSiO4 and Ti5Si3 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 ZrO2, 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 (ZrO2, SiC and ZrB2) 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.