Speaker
Description
Erosion-corrosion performance of nickel
aluminium bronze alloys in marine environments: recent developments
Robert JK Wood and Julian A Wharton
National Centre for Advanced Tribology at Southampton (nCATS), Department of Mechanical Engineering, School of Engineering, Faculty of Engineering and Physical Sciences, University of Southampton, SO17 1BJ, UK.
Abstract
Nickel Aluminium Bronze (NAB) is a common alloy used in seawater cooling of power stations and onboard vessels as well as seawater handling and marine propulsion systems and is now being considered for offshore tidal and wave energy capture systems. However, although standards for casting NAB are used to minimise selective phase attack the performance under erosion-corrosion is often sub-optimal reducing service lifetimes and efficiency of pumps and propulsors. These lead to expensive maintenance of systems and reduced fuel efficiency. As the marine industry moves to net zero and decarbonisation; the improvement of asset lifetimes and reducing fuel usage are key to achieving national and global targets. Therefore, this paper reviews recent research into erosion-corrosion of nickel aluminium bronze with attention to surface state and surface - environment interactions, for example [1-9]. Both solid particle and cavitation erosion-corrosion are reviewed with a focus on the surface condition of NAB prior to testing including the effects of shot peening, compressive surface stresses, pre-exposure by long term seawater immersions, influence of oxide films. The influence of deposition techniques such as surface welding, stir welding, electroplating and the effects of adding Cr into friction stir welded NAB as well as Ce, Sm and Yb additions into as-cast NAB.
Techniques such electrochemical noise looking a selective phase attack and the influence of sulphide concentration on performance are discussed. Recent work by the authors on cavitation erosion-corrosion mimicking the switching from static-dynamic seawater environments seen by marine propulsion systems will be detailed and the consequence for long term service will be addressed. The importance of understanding the mechano-electrochemical-microstructural interactions are highlighted. Data from recent literature are used to rank the performance of surfaces produced by different manufacturing/deposition processes and to update synergy values mapped against the ratio of mechanical to electrochemical contributions to surface loss. The role of corrosion of anodic phases/microstructure in tribocorrosion are also discussed and the state-of-the-art of current understanding will be outlined along with future research needs.
[1] Corrosion and Cavitation Erosion Behaviours of Cast Nickel Aluminium Bronze in 3.5% NaCl Solution with Different Sulphide Concentrations
[2] Effects of Ce, Sm and Yb on cavitation erosion of NAB alloy in 3.5% NaCl solution - PMC
[3] Effect of Oxide Film on the Cavitation Erosion-Corrosion Behavior of Nickel-Aluminum Bronze Alloy - ProQuest
[4] Effect of compressive stress on cavitation erosion-corrosion behavior of nickel-aluminum bronze alloy - PMC
[5] Biofouling and corrosion rate of welded Nickel Aluminium Bronze in natural and simulated seawater
[6] A Study of Erosion–Corrosion Behaviour of Friction Stir-Processed Chromium-Reinforced NiAl Bronze Composite - PMC
[7] Synergistic improvement of erosion-corrosion resistance and mechanical properties of nickel aluminium bronze alloy by the addition of Cr | Rare Metals
[8] Understanding the Corrosion Behavior of Nickel–Aluminum Bronze Induced by Cavitation Corrosion Using Electrochemical Noise: Selective Phase Corrosion and Uniform Corrosion - PMC
[9] Erosion-corrosion behavior of Ni-Al-Cu coating on nickel-aluminium bronze alloy in 3.5 wt% NaCl solution - ScienceDirect