M. Parco, INASMET TECNICALIA, IRUN, Spain; I. Fagoaga, G. Barykin, C. Vaquero, Inasmet, San Sebastian, Spain
Carbide based cermets have been extensively used due to their outstanding wear properties. The high carbide contents prevent erosive and also abrasive attack as they make coatings hard. However, cermet coatings with high carbide contents become very ineffective in preventing wear by impact and the high production costs associated to the low deposition efficiency and the finishing steps used to make this technology prohibitive for large components. On this regard, nanostructured/pseudo amorphous steels represent a revolution in material science because they have strengths up to four times that of current steel and outstanding corrosion resistances. This work deals with the development of novel cost effective wear and corrosion resistant coatings based on a nanostructured/ pseudo amorphous steel matrix reinforced with tungsten carbide. As spray process, the recently introduced oxy-fuel ionisation (OFI) technology was used. The developed coatings have been characterised in terms of their sliding wear, cavitation and corrosion performance.
Summary: Due to their outstanding wear properties, tungsten-carbide based cermets have been extensively used to protect components against harsch abrasive and erosive service conditions. The high carbide contents prevent erosive and also abrasive attack as they make coatings hard. In contrary, cermet coatings with high carbide contents become very ineffective in preventing wear by impact and the high production costs associated to the low deposition efficiency and finishing steps, when required, used to make this technology prohibitive for large components. On this regard, nanostructured/pseudo amorphous steels represent a revolution in material science because they are iron-based materials with strengths up to four times that of current steel and outstanding corrosion resistances. This work deals with the development of a new family of cost effective wear and corrosion resistant coatings based on a nanostructured/ pseudo amorphous steel matrix reinforced with tungsten caride. As spray process, the recently introduced oxy-fuel ionisation (OFI) technology was used. The system consists on a combustion process improved by the addition of ionised gases. The coatings have been developed using commertial amouphous steel and carbide based cermets powders as feedstock mateial. The spray parameters were optimised to obtain a dense and homogeneous microstructure, whith different contents of the reinforcing phase.The resulting coatings have been characterised in terms of their sliding wear, cavitation and corrosion performance.
