Four years ago, researchers at the Department of Chemistry got a proposal to study powder metals. There wasn’t much interest at first – after all, powder metals had already long been developed in different parts of the world. However, then came the idea to study functional metal surfaces.
Metal injection moulding, MIM, combines the long-established plastic injection moulding technique with powder metallurgy. MIM, together with the space holder technique, allows for controlled manufacture of pores in a metal object during moulding, where diverse chemical agents can then be introduced.
“This type of space holder research addressing the use of pores to store functional chemistry is quite unique,” says Professor Mika Suvanto.
“We’ve conducted two projects in this field in collaboration with industrial partners and Karelia University of Applied Sciences. In four years, this resulted in ten scientific articles, seven Master’s theses and two doctoral dissertations.”
Matti Kultamaa is one of the people defending their dissertation on the topic late last year. He studied porous metals already for his Master’s thesis, so continuing with the topic seemed like a natural choice.
“By using metal injection moulding and the space holder technique, it is possible to reserve space for desired chemical agents in a controlled manner. In practice, tiny pores, less than 1 millimetre in size, are manufactured in a metal object and then filled with the desired agent,” he says.
“Using this technique, strong metal objects, such as bearings, can be moulded from powder metal.”
The best thing about this technique is that there is no need for after-treatment, such as heat treatment, after injection moulding.
“In other words, this is a convenient, fast, efficient and affordable mass technique that does not produce waste.”