Original title: Special high-temperature adhesive can firmly adhere to ceramics and alloys.
The reporter learned from the Civil Aviation University of China on December 18 that the undergraduate team of the school has developed a special high-temperature adhesive suitable for zirconia and titanium alloys. The adhesive has a maximum temperature resistance of up to 1200 meters, and the bonding strength is higher than 5 megapascals in the range of room temperature to 1100 meters, which well solves the technical problems of high-temperature bonding between ceramics and alloys, and has a wide range of application prospects in the aerospace field. The results were recently published in the international journal "Materials Today's Newsletter" and obtained the national invention patent authorization.
With the development of aerospace technology, many hypersonic vehicles have come into being. Among them, the thermal protection of hypersonic aircraft on the leading edge of the fuselage and the bulkhead around the engine has always been an important factor restricting the speed and safety of the aircraft.
Ceramic matrix composites can be used to prepare important parts for thermal protection, and when combined with metal parts, they have a better protection effect on aircraft. However, conventional methods such as mechanical connection, welding, brazing, and traditional gluing are difficult to ensure the effective connection of large ceramic and alloy components in extremely high temperature environments, and there is a gap in the connection between ceramics and alloys with great potential high-temperature bonding technology.
Chen Zhaoli, the leader of the undergraduate team of Civil Aviation University of China and a student majoring in materials physics, introduced that high-temperature adhesive bonding is an important way to realize the preparation of high-temperature components, the installation and repair of thermal protection systems, and the current high-temperature adhesive is mostly suitable for ceramics and cannot be applied to alloys. In view of the technical bottleneck that it is difficult to achieve high-temperature connection due to the inability to bond between ceramics and alloys, the large difference in physical and chemical properties, especially the thermal expansion, Chen Zhaoli led the team to improve the preparation process of silicone resin-based adhesive by using the prefabrication technology of high-activity polymetallic powder coated with sol gel, and realized the controllable regulation of alloying on the ceramic process of high-temperature resistant adhesives. By allowing the covalent bonds of the adhesive layer to coexist with the metal bonds, the team solved the bottleneck that ceramics and alloys are not chemically compatible. At the same time, through the controllable adjustment of the coefficient of thermal expansion, the research team finally broke through the barrier of large difference in the coefficient of thermal expansion between ceramics and alloys, and achieved effective alleviation of thermal stress.
In the end, the team successfully developed a new high-temperature adhesive product that can provide 5 megapascal and above bonding strength for zirconia ceramics and titanium-nickel alloys at room temperature to 1100. The product shows good high-temperature mechanical properties, with good thermal stability and oxidation resistance. The product is also suitable for the connection between titanium-nickel alloy and alumina fiber felt, aerogel and high-temperature glass.
It is understood that the current research and development products have been applied to the pre-research projects of the Institute of Aerospace Materials and Technology, the School of Materials of Tianjin University and other units, including the construction of flexible sensors and the installation of thermal insulation felt. Chen Zhaoli said that in the future, the product is expected to be applied in many fields such as aerospace aircraft, hypersonic civil aircraft, thermal protection of nuclear power plants, and thermal runaway protection of lithium batteries. (Reporter Chen Xi).
*:Technology**].