Materials Chemistry and Physics, Vol.137, No.3, 723-733, 2013
Development of nickel-phosphorus coatings containing micro particles of talc phyllosilicates
The present work aims to characterized nickel phosphorus coatings co-deposited with talc particles on steel. The NiP-talc composite deposits were developed to serve as hard coatings with a lubricating effect at 600 degrees C. This process, which is free of hexavalent chromium, could provide a reliable substitute for the electrodeposition of hard chromium coating used in industrial applications. Local responses to static and dynamic mechanical loading have been obtained by nano- and microhardness, microtensile and nano-scratch testing. The hardness and stiffness values slightly decrease when the amount of talc increases for untreated coatings. In contrast, a 420 degrees C heat treatment leads to high hardness and Young's modulus values due to crystallization. Moreover, a 600 degrees C heat treatment lowers these values through overageing. A 420 degrees C heat treatment greatly improves the adherence and the cohesion of the coatings containing talc. (C) 2012 Elsevier B.V. All rights reserved.