Despite the rigors of scientific inquiry and the methodical approaches of the world's most talented researchers, sometimes science has a surprise in store. Such was the case when a group of researchers from the U.S. Department of Energy's (DOE) Argonne National Laboratory and the University of Akron discovered that a particular form of carbon coating not necessarily designed for wind turbines may indeed prove a boon to the wind industry--a serendipitous finding that was recently highlighted in the journal Tribology International. 

Due to the strenuous environment inherent in wind turbine drivetrains, key components such as actuators, bearings and gears are prone to failure, meaning turbines require regular maintenance that helps drive up the price of wind energy. Prolonging the life of these components could greatly reduce the cost of wind power, the fastest growing source of energy in the world, thereby making it an even more attractive energy source.

These failures are often due to a phenomenon known as micropitting in which the repeated rolling and sliding cycles in the gears and bearings of turbines lead to cracks on the surface of drivetrain components. Further contact only exacerbates the cracking once it begins, chipping away at the metal and increasing the severity of the existing cracks until costly maintenance is necessary or, even worse, the drivetrain fails.

Enter Argonne's Tribology and Thermal-Mechanics Section and its Surface and Lubrication Interaction, Discovery and Engineering (SLIDE) initiative, which investigates how lubricants and materials interact and develops novel lubrication and coating concepts that reduce friction, and therefore micropitting, prolonging component life across a range of energy technologies. 

And sometimes they get a little lucky. Such was the case when SLIDE researchers applied this "diamond-like" (some of the carbon-to-carbon bonding in the coating is similar to that of diamonds) coating to wind turbine components, which was not the intended use.

"We felt that if it was working under other sliding conditions, it might work in wind turbine drivetrains as well," said SLIDE's Ali Erdemir, an Argonne Distinguished Fellow. "Initially, our expectations were low, as we thought the coating would wear out due to the high stresses inherent in wind turbines, but that didn't happen."