Optimisation of HVOF thermal spray coatings for their implementation as MSWI superheater protectors

Abstract

The aim of this paper is to the study high velocity oxygen fuel thermal spray coatings as superheater tubes protectors against degradation problems in municipal solid waste incinerators. Ni based and Fe based high velocity oxygen fuel coatings have been sprayed through optimised spray parameters with the help of online monitoring technology. All these coatings have been tested under laboratory conditions simulating the boiler erosion and corrosion mechanisms. The influence of the spray parameters on the porosity and oxidation has been studied in order to optimise the coatings structure. Interconnected porosity and spray oxidation must be avoided to attain the best coating resistance under corrosion and erosion mechanisms identified on the municipal solid waste incinerators. Tribological and electrochemical coating properties have been determined under standardised tests. Different erosion tests have been carried out in order to determine coatings resistance. X-ray diffraction studies show the main formed phases under corrosion mechanisms for the different studied alloys. The Ni based Inconel 625 coatings have been reported as a good superheater tubes protector for its industrial application.

Keywords

HVOF CORROSION COATINGS OXIDATION INCINERATION NI-BASED

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