Superior Rare Earth Simg Cored Wire with Low Price is a new type of high quality and durable cored wire. It replaces thoriated tungsten and has many advantages compared to it. The main benefits of this type of cored wire are as follows: 1. Superior electro-thermal performance. 2. Better loop stability. 3. Improved bonding property.
Due to the increasing demands of high power and highly integrated electronic packaging, the development of bonding wires with higher performance is becoming a priority. Currently, Au and Cu are the most popular bonding wires in electronic packaging, but both have disadvantages in terms of reliability.
For example, bare Au wire is easy to generate Kirkendall voids due to different atomic diffusion rates. These voids lead to ball lifting from chip metallization, resulting in catastrophic failure of the bonding wire.
To improve the performance of these wires, some scholars have proposed using Pd-coated Au wire. This type of coating has better oxidation and sulfidation resistance, and it also inhibits Ag+ migration.
In many welding applications, the ability to maximize productivity without sacrificing quality is critical. This is especially true in wire-fed processes such as submerged arc welding (SAW).
Cored wires offer several benefits for high-productivity fabrication, including lower cost and improved weld quality. They can also reduce rework costs and increase productivity by increasing travel speeds.
Because of their higher deposition rates and higher deposition efficiency compared to solid wires, metal-cored SAW wires can often be used at higher travel speeds than solid wires when the same amperage is applied. This allows for faster welding cycles and shorter cycle times, which can help reduce labor costs.
Solid wire is easy to use for novice and occasional welders who work on thinner applications. It produces less spatter and a more aesthetically pleasing weld bead. However, using a solid wire in a windy location may expose the welder to wind loss of the shielding gas. This can result in a lower penetration and require multiple welding passes.
Flux-cored wire has a higher current density and better metal transfer in the arc due to ionising elements. This enables the welder to reduce welding amperages and achieve faster metal deposition rates.
The high price of bare Cu wire limits its use in microelectronic packaging. The evaporation of Cu during bonding with Al causes Kirkendall voids and increases interface resistance by non-constant Fickian diffusion [41].
Due to high power and high-frequency communication ICs and electric automotive, the requirement for circuit reliability has increased. In order to meet the requirements, researchers have developed a variety of bonding wires with different material properties and processes. Cu bonding wire is the most popular, because it has good electrical and thermal conductivity, low cost, and simple bonding process.
However, Cu wire has poor loop formability and is easy to collapse during the wire bonding process, which leads to high-temperature storage life failures such as Kirkendall voids [28]. Therefore, it is necessary to modify the alloying element in the bonding wire to improve its performance.
Using the proper welding parameters on either solid or flux-cored wire is important to achieve good weld results. While both types of wire produce sound welds and good weld bead appearances, some variables may affect how each type performs. These variables include the thickness of the application, proper shielding gas combination and welding location.
Flux-cored wires can typically handle dirtier materials (such as rust, mill scale or oil) better than solid wire because they contain de-oxidizing elements that trap these contaminants in the slag layer and prevent their release into the weld bead. This allows for greater productivity and a more attractive weld bead appearance.
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