A New Combined Method to Enhance Adhesive Bonding of Al2O3 Ceramic/Aluminum by Chemical Pretreatment and Ultrasonic

To effectively improve the interfacial adhesion between aluminum alloy 2024 and aluminum oxide ceramic substrates, a combined surface pretreatment and ultrasonic-assisted method was applied. Firstly, the surface of the aluminum alloy 2024 plate was roughened through hydrochloric acid etching under different concentrations and durations. The trend between joint strength and surface roughness of aluminum alloy 2024 remained largely consistent. The maximum bonding strength 27.82 MPa was achieved at a hydrochloric acid concentration of 15% and an etching time of 100 seconds. Subsequently, ultrasonic vibration was introduced during the adhesive bonding process. By integrating chemical etching with ultrasonic-assisted adhesive pretreatment, the strength of the adhesive-bonded joint was remarkably improved by 73.47%, from 18.13 MPa to 31.45 MPa. Without ultrasonic assistance, there were many flaws and defects along the adhesive-to-plates interface. However, ultrasonic assistance resulted in a void-free and uniformly distributed adhesive layer.