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Title: Electrochemical analysis of the erosion-corrosion of HVOF aluminium bronze coatings
Author: Tan, KengSoong
ISNI:       0000 0001 3497 6026
Awarding Body: University of Southampton
Current Institution: University of Southampton
Date of Award: 2003
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Modern industries such as marine, oil and gas production, and power plants require cooling systems for their generators and reactors. Seawater is often used for this purpose due to the location of these industries and its abundance. The entrainment of sand particles in seawater can result in simultaneous erosion and corrosion attacks on metallic components such as pipes and valves, resulting in enhanced material removal (synergy). The present work is interested in quantifying die synergy that occurs when High Velocity Oxy-Fuel (HVOF) aluminium bronze (AB) and nickel aluminium bronze (NAB) coatings are subjected to erosion-corrosion conditions. Estimation of the synergy was based on mass loss and electrochemical measurements obtained from erosion, flow corrosion and erosion-corrosion experiments. Due to a porous microstructure, the erosion mechanism of the ductile HVOF coatings was shown to be different from bulk ductile materials. Cracking at the brittle splat boundary under normal impingement angle resulted in coating splat removal. Wear maps based on volume loss and kinetic energy and dimensional analysis were investigated. Surface filming occurred on the AB and NAB coatings under flowing conditions. Imperfections such as open pores on the coating surface resulted in flaws in the surface film which reduced its corrosion resistance. The contribution of a synergistic constant and the determination of an electrochemical transition between positive and negative synergy based on critical velocity and kinetic energy can provide guidance to engineers when specifying materials/coatings for use under erosion-corrosion conditions.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Seawater sand particle kinetic energy