Wetting of Lubricants on Cemented Tungsten Carbide Surfaces with Surface Structures Produced with Ultrashort Laser Pulses

In the presented work, surface structures were generated on cemented tungsten carbide surfaces using ultrashort laser pulses. The type of surface structures was varied by varying the spatial overlap of the laser pulses by using different feed rates while keeping the maximum average power of 10.76 W and the constant repetition rate of 500 kHz. Larger surface structures with increasing roughness could be created by increasing the pulse overlap. The contact angle was measured 30 days after structuring to consider aging. Decreasing contact angles were measured on surfaces of increasing roughness for deionized water. A contact angle of 0° was measured for deionized water on the roughest structure. The same rough surface also resulted in a low contact angle of 8° for a lubricant based on a fatty alcohol and for a water-based lubricant. Therefore, superhydrophilic behavior as well as high wetting of the two lubricants could be demonstrated.