Materials Used for EMI Shielding
There are many different types of RFI shields available in a variety of materials. Each has different properties and is therefore suitable for different uses.
When choosing the material for your EMI shielding, it’s important to look at the long-term costs of each option.
For example, more durable materials will require less frequent replacement. On the other hand, a heavy material could affect overall design and functionality.
This has led to the recent trend of using paints with shielding properties, as this is a lightweight solution, but the thinness of the resulting shield makes it less effective against higher frequencies (known as skin effect).
What to Consider When Selecting a Material for EMI/RFI Shields
The important factors when choosing a material for RFI shielding are:
Conductivity
Different devices need protection from different frequencies of electromagnetic waves, so the material must match the device’s intended use.
Solderability
This is important both in terms of the usefulness of the shield itself, and the cost of attaching it to the component or device.
Weight
Weight is an important factor in mobile devices which must be as lightweight as possible but can be an issue in any industry.
Corrosiveness
This is less important for shields being used in short-term products such as mobile phones but is critical in things like medical devices, where durability is essential.
Cost
Cost is most often a factor for mass-manufactured items but needs to be taken into account even in the development stage.
Material Options for EMI/RFI Shields
RFI/EMI shields must be conductive, so they are made from a variety of metals and alloys.
Copper is often included in the alloy because of its high conductivity as well as its natural resistance to corrosion which is an important factor in almost all RFI shield uses.
Gold and platinum are useful as RFI shield materials as they are non-reactive, as well as non-corrosive, making them perfect for use in medical devices such as pacemakers, where durability and safety are more important than cost.
Aluminum can be useful as a material for EMI shielding in certain situations and is popular due to its efficient strength-to-weight ratio, but it poses some serious challenges.
It is susceptible to corrosion and is difficult to solder, making it expensive to use.
Best Choice: Tin-Steel and Nickel Silver RF Shields
The most popular materials for RFI/EMI shields are tin-steel and nickel silver, because they offer the optimal cost-benefit balance.
Tin-steel (also known as tin-plated steel) is a popular material for RFI shielding because of its low cost.
Steel offers good protection again lower frequency interference making it useful as a material for shielding communication devices.
The tin plating ensures a high level of corrosion protection, giving the shields a satisfactory lifespan at a budget cost.
Tin-steel RFI shields are used for mobile phones and other mobile tech, as well as IoT devices, and are also used for smart cities and other “smart” technology.
One of the benefits of tin-steel is its high level of solderability, making it easy and cheap to work with.
Nickel silver alloy is used when a hard-wearing shield is needed, for example in life-and-death scenarios or to protect expensive equipment. It is the material of choice for MRI rooms and other medical devices, as well as aircraft and other vehicles.
Nickel silver blocks both electrical and magnetic waves and is anti-corrosive, making it suitable for use in a variety of conditions where durability is imperative.
EMI Shields to Suit Your Requirements
The drawn shields come in many different sizes. This exclusive production method creates seamless RFI/EMI shields which offer optimal protection for all types of devices and equipment.
All sizes can be manufactured in both tin-steel and nickel silver options, and all shields can be manufactured either in a single piece or as two pieces, a frame, and a cover.
The shields are also all suitable for use with SMT (surface mount technology) making them ideal for use in mass production.