Sealing of Sapphire Infrared Windows by Ultrasonic Interfacial Deposition Soldering
Sapphire/metal soldering joints are widely needed in various optical instruments. Traditional soldering methods are expensive and time consuming, because they usually involve a sapphire surface metallization procedure and a vacuum soldering procedure. In this study, we sealed infrared sapphire windows using a novel ultrasonic soldering method in the ambient atmosphere, with Sn-Zn-Al alloy as the solder. The wetting and bonding at the sapphire/solder and solder/metal-tube interfaces were realized by ultrasound. The microstructure of the joints was revealed by means of scanning electron microscope (SEM). The gas impermeability of the samples was investigated. This new method is very simple and cost-saving. The reliability of the samples made by this new method is equal to that made by traditional method. This is the first application of the ultrasonic interfacial deposition brazing and soldering (UIDBS) method to a practical device. We hope this method to be applied to other optical devices.