Each part of a mobile phone (i.e. keypad, battery, antenna…) is made of a material; choosing the best material at an acceptable cost is a complex process.

Using a mobile phone (also known as a cell phone) to make a call is a simple action that we all do many times a day. However, very few people understand that without materials to make the phone components, and without the developments of Materials Science, this would not be possible.

Phone (News - Alert) components

In every mobile phone there are many different parts, each one performing a specific function, and essential for the phone to work properly. For example, parts of a phone include:

• A circuit board containing the brains of the phone
• An antenna
• A liquid crystal display (LCD)
• A microphone
• A speaker
• A battery

Characteristics of each component

For each part of the phone very specific and different properties will be needed, depending on the function that the part will perform. If we consider the keypad and the case, they both need to be solid – to protect the internal parts of the phone – and not fragile – otherwise the phone will get broken very easily. At the same time however, the material has to be light, because we do not want to carry something very heavy.

All the internal parts of the phone (i.e. battery, antenna, microphone, speaker…) have to be small; on the other hand, they still have also to be very efficient. A battery, for instance, has to provide enough power, so the phone can work as long as possible. This is especially important with “smart phones” with high-definition screens, which consume a lot of power.

Different material for each part

Every component listed above is made of a material; therefore the chosen material will require appropriate characteristics for that part to work properly.

The case and keypad of the phone, for example, are usually made of metal, plastic or a combination of the two. As we need light but strong materials, two properties that are often conflicting, it is important to choose the right metal or plastic, or combination of the two.

For the batteries, the most common materials are lithium ion or nickel-metal hydride batteries. They both have high energy density, thus we can have a small battery supplying a reasonable amount of power.

Antennas, modems and filters are usually made of ceramics. Coltan, an ore based on niobium and tantalum elements, is used as a source to make many ceramics used in phones.

Political implications and Costs

Sometimes, to choose the right material, there are not just technical issues to consider but also wider implications; the use of coltan for ceramics is an example of this. Both niobium and tantalum were extracted from mines in the Democratic Republic of Congo.

Similar to the problem of “blood diamonds”, the commerce of these elements was exploiting the people working in the mines and funding one of the most notorious and bloodiest conflicts of our times. Today, alternative tantalum and niobium sources have been discovered (i.e. Australia, Brazil).

In the end, as always, it is a question of money. All mobile phone manufacturers want to make the maximum profit; this means they want a good material, with all the properties they need, but also at the lowest possible price. Again, these two issues – quality and cost – can conflict with each other, as normally the best quality materials are not the cheapest ones.

Complex topic, always evolving

There are many other parts in mobile phone (i.e. the screen, the SIM card or the electronic components); hence many more materials are used to make them. To choose each material is a complex process, as shown in the examples described above.

The mobile phones that we use today are completely different from the first ones that appeared decades ago – heavy, big, ugly, expensive, and useful just to make phone calls and nothing else! If things are so different now, it is partly because there was a lot of study and research in Materials Science. Things that were impossible 20 years ago are possible today, often because there is a new appropriate material, performing a particular function.

Therefore, it is important to continue to study and to develop new materials, or improve the ones we already have. In this way, it will be possible to respond to the requirements of the new technologies of the modern society.