Coatings and Diamond Technologies

Thomas Schuelke | |


The Fraunhofer group on campus works on advanced technology solutions in the area of thin film coatings and diamond technologies. Activities range from basic research in diamond technologies to solution deployment of in-house developed coatings for the machine tool industry.

Improving powertrain efficiency with low-friction wear resistant Diamor® coatings

Friction is a major cause of powertrain inefficiencies, reducing vehicle gas mileage and increasing total carbon dioxide emissions. Traditional oil lubrication may prove insufficient under high loads where the lubricious protective film can disappear, leading to substantial friction and potentially critical wear. An example is the oscillating motion between piston rings and cylinder liners in combustion engines. Emerging fuel saving technologies such as start-stop automatics may aggravate friction and wear-increasing circumstances even more. Low friction and wear resistant coatings aim to lastingly address some of the deficiencies of traditional liquid lubricants. Fraunhofer’s Diamor® coatings offer excellent friction reduction and wear protection for powertrain components that experience highly loaded contact situations.

In collaboration with an industrial partner, Fraunhofer engineers performed experiments comparing the performance of actual engines with and without coated components. The engines were first tested as delivered using standard oil lubrication. Then the engines were disassembled and parts relevant to friction reduction were coated with Diamor®. Finally the reassembled engines were tested again under conditions identical to the first test. The results proved reduced friction, which led to more than 3% increase in peak horsepower and more than 2% power increase across the usable speed range of the engine with Diamor® coated parts. These results demonstrate the tremendous potential to conserve fuel and reduce carbon dioxide emissions for Diamor® coated powertrains.

Boron-doped diamond electrodes – tailored to customer requirements

Boron-doped diamond is a new electrode material for electrochemical applications. Due to the fabrication from methane and hydrogen gases, boron-doped diamond electrodes are less expensive than platinum electrodes. Yet boron-doped diamond by far exceeds the electrochemical performance of metal-based electrodes. Especially the wide electrochemical potential window, the low background current and the low adsorption tendency make boron-doped diamond electrodes particularly interesting for electrochemical trace analysis and neurochemistry. Fraunhofer researchers developed fabrication processes to reliably fabricate custom-tailored boron-doped diamond electrodes. The material can be applied to a variety of substrates and shapes made from silicon, quartz, metals and diamond.

Manufacturing cost savings through 300% tool life increase of spindle punches with ceramic coating

Meritor Inc., a global leader in providing advanced drivetrain, mobility, and braking and aftermarket solutions for commercial vehicle and industrial markets, collaborated with Fraunhofer engineers to test new high performance ceramic coatings for high temperature forming processes. Several spindle punches were coated using a physical vapor deposition process developed in collaboration with the Fraunhofer Institute for Materials and Beam Technology (IWS) in Dresden, Germany.

The coated tools were tested in manufacturing using a hydraulic press at a Meritor plant in Morristown, Tennessee. The punches are used for hot forging of steel parts at an operating temperature of 1950 °F (1065 °C). The results are very encouraging. Compared to uncoated spindle punches, the best-performing coated tools lasted three times as long while enabling tool changes once a day rather than every shift.