Thermal Spray Wire- Excellent material for boilers

The nickel alloy coatings produced have high structural integrity, are dense and can tolerate elevated temperatures and oxidizing atmospheres. The addition of chromium enhances high-temperature corrosion resistance. These wires are used as bond coatings and for machine element restoration. Nickel-based alloy thermal spray wires are used for bond coatings under ceramic top coatings and exhibit particle erosion resistance at high temperatures. These thermal spray wires are suitable for oxidation and hot gas corrosion at elevated temperatures. These wires provide salvage and build-up of machinable carbon steel and corrosion-resistant steels. Nickel-based alloy thermal spray wires are used as salvage and restoration materials for nickel-based superalloy components. These wires are suitable for corrosion resistance in oxidizing and reducing environments such as for use in boilers. These thermal wires are used on digesters.

Coatings have high bond strength and ideal in bond coat applications. Coating properties vary significantly as these are dependent on the chosen equipment, coating parameters, gun hardware and coating thickness. These coatings have resistance to ionic corrosion and deposit efficiencies of 65% or higher can be achieved when correctly sprayed. These coatings are machined or ground when dimensional control or a smooth surface finish is needed. The SmartArc PPG gun is advised when electric arc wire coatings with the lowest possible oxides are needed due to its ability to use other types of atomizing gases such as nitrogen.

The investigation of corrosion behavior of high velocity combustion wire sprayed coatings was conducted. 

The investigations on thermally sprayed Hastelloy C276 and stainless steel 316L showed that the applications of cathodic coatings for corrosion protection was limited and needed an additional sealant to decrease the amount of pores and cracks. Differences could be revealed with respect to spraying conditions by comparing coatings processed with a variety of spray systems. Finer microstructures with less interconnecting pores or cracks were achieved using high velocity spray systems such as HVCW and HVOF, therefore these coatings showed a better corrosion resistance than coatings produced by conventional flame spraying or arc spraying. All coatings showed a significantly less noble corrosion potential compared to the respective bulk material which could be attributed to compositional changes during spraying. The oxygen contents notably differed (ranging from about 2 to 7 wt. %) with respect to spraying conditions and had minor influences on the corrosion potentials of detached or sealed coatings. Thermal sprayed cathodic coatings showed a smaller corrosion resistance and higher corrosion current than respective bulk materials. It was observed that the corrosion protection by passivation was less effective than for bulk material. On comparison of sealed coatings achieved by various spray methods, the results showed that a sealant in case of very high porosity couldn’t avoid under-corrosion. Therefore, dense coatings produced by high velocity processes such as HVOF and HVCW spraying were needed for improved corrosion protection.

Thermal Spray Wires are mainly used in the Electric Arc Spray Process and the Flame Wire Spray Process. Hastelloy C276 thermal spray wire has excellent high temperature oxidation and corrosion properties. It is good for repair and build-up of similar chemistry super alloy components.