Tribological behaviour of Si3N4 and Si3N4–%TiN based composites and multi-layer laminates

Si3N4–TiN based multi-layer laminates exhibit differences in residual stress between individual layers due to a variation of the thermal expansion coefficient between the layers. The residual stress distribution in these multi-layer laminates is known to improve the apparent macroscopic fracture toughness. In this work, the tribological behaviour of bulk, composites and multi-layers laminates are investigated. Si3N4 bulk, Si3N4 based composites with 10, 20 and 30 wt% TiN and different multi-layer laminates have been tested under dry conditions with reciprocal movement using a ball-on-block configuration. In particular, the influence of sliding directions with respect to the layer orientations has been investigated. The experimental results show that wear resistance increased with increasing TiN content in Si3N4–TiN composites. However, multi-layer laminates exhibit an up to three times higher apparent fracture toughness, but do not show an improvement of wear resistance compared to composites