Lead is a toxic substance, and it’s in your mobile phone. It’s also probably in your TV, your computer, and just about any other electronic appliance where mechanical movement is transformed into an electrical signal. All those devices utilize PZT, a substance which contains lead, and that generates an electrical charge when subjected to pressure. While lead has been phased out of most consumer goods, a suitable alternative has never been found for use in electronics... until now, perhaps. Researchers have developed an innocuous material with PZT-like qualities, and it’s made in a fashion somewhat like cookies.
One PZT-replacement candidate that’s been around for a few years is called alkali niobate, or KNN. Unfortunately, it has proven difficult to find a type of KNN that is exactly right for electronics, or that could be easily mass-produced. A new material developed at the Norwegian University of Science and Technology (NTNU) addresses both of these shortcomings.
The researchers start by baking “microscopic ingredients" (no, they don’t say what), then roll them out and cook them into thin ceramic sheets. The structure of these sheets results in a texture that transforms mechanical pressure into electrical signals, just like PZT.
“The method we have developed kills two birds with one stone,” said project leader Tor Grande. “Not only can we adjust the process to create properties in the ceramic sheet that are precisely suited to different electronics - we can also scale up the process so that we can produce almost unlimited amounts of it.”
Grande and his team have applied for a patent, and are currently developing the material further.
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