Birmingham scientists create antibacterial stainless steel
Using an active screen plasma process to introduce silver, nitrogen and carbon into the steel
Scientists at the University of Birmingham in the UK have developed a new type of stainless steel that is more durable and resistant to bacteria.
In a project funded by the UK’s Engineering and Physical Sciences Research Council, the team, led by Hanshan Dong, professor of surface engineering at the University of Birmingham, have introduced silver or copper into the surface of the steel (rather than coating it on to the surface).
To do so, the team has developed a novel surface alloying technology using Active Screen Plasma (ASP) with a purpose-designed composite or hybrid metal screen.
The ASP process introduces silver, along with nitrogen and carbon, into the steel. Silver is an antibacterial agent and the nitrogen and carbon increase the steel’s hardness and durability.
The researchers cleaned treated stainless steel medical instruments 120 times, replicating the cleaning process in hospitals. They found that the antibacterial properties of the stainless steel were still intact and the surface still resistant to wear.
Dong said: “Previous attempts to make stainless steel resistant to bacteria have not been successful as these have involved coatings which are too soft and not hard-wearing.
“Thin antibacterial coatings can be easily worn down when interacting with other surfaces, which leads to a low durability of the antibacterial surface.
“Our technique means that we avoid coating the surface, instead we modify the top layers of the surface.”
The Birmingham scientists are already able to surface engineer items of up to 2m x 2m in the laboratory and are confident that their technique could be used in the manufacturing of stainless steel products for use in hospitals and cleanrooms.
