Abstract
Most commercial high velocity oxy-fuel (HVOF) flame spraying systems are primarily designed for mechanised use in thermal spraying booths and are limited to powder-based consumables that are often much more expensive than wire materials. However, a smaller wire fed HVOF system has recently become available with simpler, portable control units. This system is of particular interest for depositing a wide range of wire-based consumables, e.g. aluminium, zinc and their alloys for sacrificial corrosion protection of offshore platforms, risers and piping, crude oil vessels and bridges. Other applications include corrosion resistant coating materials such as stainless steels and nickel alloys. The objective of this work were to compare the corrosion performance of the HVOF wire flame spray system with the twin wire arc-spray and HVOF powder processes for the preparation of coatings of pure aluminium, 316L stainless steel and nickel alloy 625. Coating characteristics such as porosity, oxide content and adhesion were evaluated. The corrosion properties of the coatings were compared using an accelerated potentiodynamic electrochemical corrosion test.
