Indentation and Fracture Behaviour of Electroless Ni-P-based Composite Coatings

Abstract

Ni-P coatings have been a popular option for many applications because of their autocatalytic nature and excellent resistance to wear and corrosion. These properties of Ni-P coating suggest a potential application as a pipeline inner coating in oil industries. However, the erosion and indentation behaviour of the coating have not been fully explored yet. The objective of this study, is to determine the suitability of using electroless Ni-P and Ni-P-Ti coatings in the oil industry. To achieve this objective, Hertzian-type indentation, three-point bending tests and solid particle erosion tests were performed to investigate the extent of the mechanical damage in the coating. Acoustic emission energy spikes were collected and used to monitor crack formation in the coating during indentation and bend tests. The present research also correlates the fracture responses of coating to its microstructure. The microstructure, mechanical properties, erosion and indentation behaviour are identified and discussed in details.