In this study, Mo-14Si-10B Headphones and Mo-57Si-10B (at%) elemental powders were separately milled using an attritor mill.Mechanically alloyed powders were agglomerated and annealed.Then, powders of Mo-Si-B as alloyed (with composites) and agglomerated (without composites) were plasma sprayed onto plain carbon steels.The samples, both coated and non-coated, were subjected to isothermal oxidation tests.Metallurgical characteristics of powders and coatings were evaluated by SEM and XRD.
Plasma-sprayed Mo-Si-B coveralls coatings (with phases of MoSi2, Mo5Si3, MoB and Mo5SiB2) greatly improved the oxidation resistance of the plain steel substrates, but plasma-sprayed Mo-Si-B coatings (without any phases) did not significantly improve the oxidation rate of substrates.Also, the kinetics and composition of the oxide-scale have been found to depend on the alloy composition.