High strength-to-weight ratio, corrosion resistance, and various alloy properties have made aluminum one of the most useful engineering materials. Aluminum alloys can be found in industries ranging from electronics and automotive to aerospace. Despite being a high surface energy (HSE) material, the characteristics and applications of aluminum make it more challenging to adhere than other materials.
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Weaknesses of traditional aluminum bonding methods
Common aluminum bonding methods such as screws, rivets, and bolts exhibit the following drawbacks:
- Create stress concentration that can lead to material failure in high-load situations.
- Create a hole in the material, reducing bond strength over time and weakening the material surface, allowing moisture ingress.
- In many applications, aesthetics are a primary concern, and the presence of screw heads affects design. In the case of aluminum welding, skilled workers are required to achieve a good weld.
In many applications, aluminum is attached to various materials, which can be challenging if the materials have different thermal expansion rates (Coefficient of Thermal Expansion – CTE). The thermal expansion coefficient of aluminum is twice that of glass, while some plastics are five times that of aluminum. This can lead to warping or cracking depending on the stiffness of the materials involved.
Advantages of Technical Tape
An effective solution to address these concerns is bonding with double-sided adhesive tape. The adhesive in the tape spreads evenly over a larger area, reducing stress concentration. Reinforced tape can also be designed to transfer or isolate loads depending on the choice of adhesive, allowing for easy design with the differing thermal expansion coefficients of substrates while maintaining flexible and secure bonding..
Tape does not require drilling holes in the material surface, meaning there are no weaknesses in terms of force, bonding, or susceptibility to water ingress.
Tape is insulating, so there are no concerns about galvanic corrosion due to dissimilar metals (between screws, bolts, and the material being connected). This means the joint will not rust and remains strong over time.
The most significant advantage of tape for aluminum lies in its speed and ease of application. Even with low-skilled labor, a durable bond can be quickly and easily formed with tape.
Key advantages of tape:
- Spreads force over a wider, more even surface area compared to concentrated force at one point.
- Tape can be used to transfer or isolate loads.
- Minimizes issues arising from different thermal expansion coefficients.
- Easy to use.
- Quick application.
- Does not require highly skilled labor.
- Does not create holes in the surface.
- Insulates, eliminates galvanic corrosion.
- High aesthetics, virtually invisible bonding.
- Cost-effective.
Things to Consider When Bonding Aluminum
Aluminum has excellent compatibility with most adhesives, as it has a very high surface energy (HSE) that allows the adhesive to flow onto its surface, and aluminum surfaces can accept many types of bonds. That’s why aluminum is rarely found as a pure metal; it’s almost always found in alloy form with other materials. This reactive ability creates a protective oxide layer on aluminum alloys. Aluminum forms this ultra-fine oxide layer very quickly upon contact with air.
Oxygen in the air reacts with the active surface of aluminum to create a passive aluminum oxide layer that prevents additional corrosion (a process called passivation). This is similar to rust on steel, but unlike rust, aluminum oxide is retained to protect the surface.
Therefore, surface preparation is necessary before bonding aluminum. This process involves cleaning with acetone to remove dirt and oil from the top layer, then using sandpaper to clean the aluminum oxide layer, and finally cleaning with acetone again.
Hitta offers a range of specialized products for bonding different metals and bonding aluminum. Please contact us for advice.
Contac us
Hitta specializes in providing various specialized tapes for both industrial and commercial sectors. Contact us for the most cost-effective and efficient solution advice.
- ☎️ Hotline: 090.8611.011 (Mr. Dương).
- ✉️ Email: hittajsc@hitta.vn
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