Ultrasonic Vibration Assisted Brazing Glass Process

Ultrasonic Vibration Assisted Brazing Glass Process – Sonic4Lab

Using sound waves to “bond” glass and metal: ultrasonic brazing technology for cross-border connection

In the manufacturing field, firmly combining glass and metal, two materials with vastly different properties, has always been a huge challenge. Traditional adhesives are not resistant to high temperatures, and high-temperature welding can easily cause glass cracking or performance damage. However, a technology called ultrasonic vibration assisted brazing has recently successfully achieved this seemingly impossible “cross-border” connection in the laboratory, opening up new possibilities for us.

The key to successful experiments: precise craftsmanship and appropriate “bridges”

The researchers designed a precise experimental plan: under strict temperature control conditions, two common low melting point metals – pure zinc (Zn) and pure tin (Sn) – were selected as filling materials (i.e. brazing materials) to act as “bridges” connecting glass and aluminum.

The experimental results show that both materials can successfully achieve connection. Through microscopic observation, it was found that regardless of the type of brazing material used, the interface of the glass remained flat and smooth, without any traces of metal erosion or dissolution. This indicates that the connection process has minimal impact on the glass itself, protecting its integrity. Inside the brazed joint, a complex microstructure composed of solid solution, eutectic structure, etc. is formed, which provides the necessary strength for the joint.

Where does the magical power of connection come from?

The core secret to the success of this technology lies entirely in the series of physical and chemical effects induced by ultrasonic vibration.

1. The “cleaning” and “boosting” effects of ultrasound: When high-frequency ultrasound is transmitted in liquid zinc or tin, it produces strong “cavitation” and “jet” effects. This is like countless tiny ‘high-pressure water guns’ fiercely impacting the surfaces of aluminum and glass. For aluminum, it can instantly remove the oxide film on its surface; For glass, this force ensures that the liquid metal spreads tightly and adheres to its surface, greatly improving its “wettability”.

2. The three major “treasures” of interface bonding: Research has found that the reason why glass and metal can firmly bond is the result of the combined action of three mechanisms:

• Electronic level “handshake”: There are unsaturated chemical bonds (broken bonds) on the surface of glass, which can interact with metal atoms at the electronic level, forming the most basic electronic bonding.
• Localized ‘chemical reaction’: The extreme high temperature and pressure environment generated by ultrasound at the interface is sufficient to excite weak interfacial reactions between glass and aluminum, zinc, forming stronger reaction bonds.
• Microscopic “mechanical bite”: The impact force of ultrasound can also make the glass surface slightly rough at the nanoscale, allowing liquid metal to infiltrate and form interlocking structures after cooling, resulting in mechanical bite effect.

Overall, the connection process can be understood as: electronic bonding is the “main force”, while local chemical reactions and mechanical interlocks play a role in “strengthening and reinforcing”.

The Road to Optimization: Exploring Better Alloy Bridges

Researchers also attempted to use tin zinc alloys as brazing materials. It was found that at the connection interface, it was mainly the tin based alloy that interacted with the glass. Zinc, on the other hand, tends to react strongly with aluminum and instead “neglects” the glass interface, failing to effectively enhance the bonding strength between glass and metal.

This discovery points to a key direction: the core of improving connection quality lies in optimizing the condition of the interface between glass and metal. The focus of future research will be on finding or designing brazing alloys that are more compatible with glass, and obtaining stronger and more reliable connection joints by precisely controlling interface reactions.

Conclusion

This study confirms that ultrasonic vibration assisted brazing technology is a highly promising method for achieving reliable connections between glass and metal in low-temperature, open environments. It not only breaks through the limitations of traditional craftsmanship, but also reveals complex interface bonding mechanisms, providing valuable scientific basis and new ideas for connecting more incompatible “cross-border” materials in the future.

 

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