Scratch resistance of fibre laser surface textured TiN coatings

In this work, the scratch resistance of laser surface textured TiN coatings is studied to discriminate laser conditions in terms of coating adhesion and integrity in view of future wear tests. Laser surface texturing (LST) is performed on TiN coating ,3 mm thick using a pulsed active fibre laser working in nanosecond pulse regime. Laser process parameters are varied to obtain several patterns with different dimple diameter, depth and pitch, all of which are essential for controlling tribological behaviour. Scratch tests are applied to the obtained patterns to evaluate the friction coefficient, the critical loads for crack generation and adhesion. The most suitable LST pattern is identified as having shallow dimples without substrate contamination, showing no cracks even under harsh scratch conditions.