8 AUGUST - 2023By Leo Antony, Vice President, Advanced Technology, Kymera International METALLURGICALLY FORMED NIOBIUM CARBIDE COMPOSITES FOR CORROSION, EROSION AND WEAR PROTECTIONNew cored wire materials have been developed, bringing a new dimension to the thermal spray coatings of Niobium Carbide Composites. Niobium Carbide (NbC) Composites can now be metallurgically formed and deposited using this cored wire material during the wire arc spray process. The resultant coating has already proved to be an excellent candidate for corrosion, erosion, wear, and anti-slip protection.Recognition of the potential of NbC Composites has brought with it new approaches and the development of novel feedstock materials. Increased demand for coated and non-coated component longevity, more cost-effective coating solutions, and health and safety considerations during coating processes and post-coating machining operations proved a strong motivation to produce a new cored wire for wire arc processing. Using HSC 10 Chemistry software package, thermodynamic models were generated as a first step in the coating design process, to determine the optimum cored wire feedstock composition. HSC 10 utilized the Gibbs Free energy minimization method to determine the ideal stoichiometries of the cored wire to achieve the desired metal matrix NbC composite coating. An example of a thermodynamic model is shown below in Figure 1. In this case, a Nickel-Chromium metal matrix with an NbC composite was generated.With the option of changing the metal matrix between Iron, Nickel, and Aluminum, this NbC composite coating system is versatile, cost-efficient and high performing in various lab/field validation test conditions. In the case of Fe-based NbC composite coating, the resultant material is offered.1) 6X better than uncoated carbon steel under a severe sulfidizing environment.2) 20% better in erosion testing (ASTM-G76) than other competing products3) Less fume generation because of the metallurgical reaction during spraying4) Less toxicity considering the coating contains less Chromium, Nickel, and no Tungsten Leo AntonyIN MYOPINIONFigure 1. Gibbs free energy minimization plot for the Nickel base NbC Composite coating systems.
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