TWI Industrial Member Report Summary 759/2003
S Shrestha
Background
Thermal spraying processes are well established for the deposition of coatings for prevention of wear, corrosion and other functional coatings. First, corrosion protection of steel structures by the application of anodic coatings such as aluminium and zinc has been widely used in the offshore sectors. However, their durability is limited due to the coating quality that can be achieved using the traditional spraying systems such as conventional wire arc and wire flame spraying.
Stringent requirements, particularly in deep seawater applications, eg risers have necessitated new and reliable spraying systems that can deposit coatings of better quality. Secondly, thermal spraying in particular high velocity oxy-fuel (HVOF) spraying of corrosion resistant alloys onto low alloy steel has received much attention in recent years as a method to protect against corrosion in corrosive solutions.
Objectives
- To evaluate coating characteristics ( eg micro-structure, porosity, oxide content, surface roughness, adhesion) and the corrosion performance of coatings prepared using the HV wire flame spray system
- To compare characteristics and preliminary corrosion performance of the coatings produced using the HV wire flame spray process with a more conventional electrical wire arc and HVOF processes