Electronics has lead-free future

AUTHOR: Inavate

In the future electronic items will not contain lead, thanks to research carried out by scientists at the Norwegian University of Science and Technology (NTNU). Lead is a toxic substance that is found in PTZ, a material that generates an electric charge when under pressure.

Lead is one of the most problematic substances used in electronics but making lead-free electronics has proved problematic. However, researchers at NTNU claim to have developed a method that enables the industrial production of a substance that can be used to replace lead in many electronic applications.

European regulators have decided that lead, or more precisely lead oxide, must be phased out as the substance can cause both acute and chronic health and environmental problems.

However, finding a replacement for a lead-containing material called PZT, which is found in almost all electronics, has so far proved difficult. Researchers have mostly failed to find a good enough alternative that provides the same functionality. As a result, the electronics industry has been exempt from the ban.

A material called KNN has long been considered a possible alternative, but finding a manufacturing method that provides both the right material properties and is industrially feasible has proved problematic. A group of researchers led by Tor Grande at NTNU’s Department of Materials Science claims to have solved both problems.

The most common leaded material in today's electronics (PZT) generates an electrical voltage when exposed to pressure. It is used in “gadgets” where mechanical movement has to be transformed into an electrical signal, or vice versa.

You’ll find PZT in pretty much everywhere where there are sensors and displays.

Over the past ten years, there has been tremendous growth in research on lead-free alternatives. A type of material called alkali niobate, also known as KNN, is considered a likely successor.

However, KNN poses two main problems that have been difficult to resolve: one is finding a KNN variant that has the exact properties needed for electronics. The second is to develop a method for industrial production of the material.

Now, NTNU researchers say they have developed an approach that is ready for patenting.

“I had a theory and some ideas, and I knew that there would be something exciting out of this, I just did not know exactly what,” said Grande, research project manager.

Grande explains that microscopic ingredients are baked, rolled out and cooked in thin ceramic sheets. However, the secret is the highly precise structure of the ceramic sheet, which has a texture that helps transform mechanical pressure into electrical signals, and vice versa. This is designed to give the sheet the exact same properties as PZT.

“The method we have developed kills two birds with one stone,” said 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.”

The team has submitted a patent application and is now working on verification and further development.

“If we succeed, it will be of great commercial interest,” Grande said. “I will be surprised if this product doesn’t take over a significant part of the market in ten years. Maybe this will help in the creation of green electronic products?”