Advanced alloy opens up new possibilities in electronics manufacturing

“Make or break” – a phrase that rings true to the bending performance of most contact spring alloys. The harder the alloy, the likelier it is to break when a specific bending radius is exceeded. To make flexibility achievable, hardness of the contact spring alloy needs to be modified.

Having this in mind, Vacuumschmelze (VAC), global leader in advanced magnetic materials has come up with the right material for high-performance alloys. VAC discovered that magnetic soft NiFe (nickel iron) and CoFe (cobalt iron) based materials can provide better flexibility, which is impossible with today’s standard alloys. VAC applied its expertise in Co, Ni and Fe phase diagrams that lead to the development of high-strength spring alloys that feature unique properties, suited to a wide range of applications. Its latest series of FeCoNi alloys – the Duracon – provides high strength, good conductivity and optimum bending performance. The Duracon 17A, for instance, is a hardened FeNiCo spring alloy which is subject to phase transition during cold temperature, resulting in good electrical and thermal conductivity. The contact spring alloy features ultra-high strength and outstanding bending performance, allowing extremely small bending radii to be achieved. These improvements are opening up new areas of potential savings in terms of material volume and design space.

The smaller, the better

An alloy’s low bending radii enables many electronic components, such as contacts, connectors, switchers and relays to be miniaturized. This results in significant reductions in weight, which follows the miniaturization trend common to all consumer applications, such as mobile phones, mp3 players and video cameras. Likewise, the automotive industry is also increasing its use of electronic components. Luxury cars such as the Mercedes S Class, for example, make use of compact multipole connectors that save space. Other applications such as industrial, home entertainment and telecoms are expected to follow suit.

Following the green rule

In addition to the technological benefits of Duracon, a number of ‘green arguments’ in favor of VAC’s contact spring alloy are significant in today’s environmental and climate issues. Technically, the closest comparison to Duracon is copper-beryllium (CuBe). CuBe is primarily used as a hardening agent in alloys. Commercial use of beryllium metal presents technical challenges due to the toxicity (especially by inhalation) of beryllium-containing dust. Although the use of beryllium in alloys is not yet prohibited, it’s assumed that as environmental compliances become rigid, prohibition of beryllium will soon follow. Complying with the RoHS standards, Duracon is already beryllium and lead free.

Temperature behavior

Duracon comes in two different delivery conditions, suited to customer requirements. In cold worked condition, additional hardening of the spring elements is recommended to achieve maximum strength and optimal thermal stability at temperatures of up to 250ºC. The latest Duracon 17A is supplied in specially heat-treated strips in a delivery condition comparable to mill-hardened grades. It can withstand temperatures up to 200ºC, without age-hardening of the components and loss of positive properties of the materials. Moreover, Duracon may also be hardened to achieve higher application temperatures of up to 250ºC and further increase yield strength of over 1500MPa.

Currently, VAC supplies Duracon 17A strips in the heat-treated condition in thickness of 0.05 to 0.3mm. The material is suited to low-voltage contact interfaces found in telecoms and automotive applications, which have rigid requirements on form factor and thermal behavior.

Conclusion

Many vital developments and modern technologies would be impossible without the correct selection of materials. VAC’s latest contract spring alloy – Duracon – is a perfect demonstration of this philosophy. Opening new possibilities in the electronics manufacturing segment, the Duracon satisfies the ever increasing demands of new applications; complies with environmental regulations; and withstands high ambient temperatures.

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