Improved tribological properties of carbon coatings by pulsed laser hardening

For many applications in cutting tools or watchmaking industries, the need to develop new solutions in order to improve the lifetime and performances of the components requires new approaches and solutions. In a joint project between the (Berner Fachhochschule) BFH and the (Haute Ecole ARC) HE-ARC, promising results have been obtained with nanotextured graphite layers produced using a two step hybrid production technology. First, a graphite coating is deposited using magnetron sputtering technology. Second, the coating is treated at with high power pulsed laser at high repetition rate.
As pin-on-disc measurements show, laser nanotexturing not only lowers the friction coefficient of the graphite coating, but also eliminates the run-in phase and significantly reduces wear in dry conditions. In addition, the topography induced by the laser treatment generates an optical effect of iridescence which adds a decorative function.
These first result open possibilities to develop a new type of graphite coating modified by laser pulses for application on 2D or 3D products with sizes in the order of mm2 to a few cm2.
These are first results, further improvement are expected via appropriate texture patterns and doping of the carbon target. Under wet condition, microchannel with heights in the nanometer range between are expected to be beneficial for storing lubricant.