Coating compositions, applications thereof, and methods of forming

摘要

Equipment having a protective coating layer for use in abrasive environments, e.g., sulfur-containing environments, is disclosed. The coating is formed from a single-component feedstock, as a Fe-based alloy composition comprising at least two refractory elements selected from Cr, V, Nb, Mo and W in an amount of up to 30% each and a total concentration of up to 40%. In one embodiment, the coating is applied by thermal spraying, followed by heat treatment for at least a portion of the refractory elements in the coating to fuse into the substrate forming a metallurgically bonded coating. The coating has an adhesion strength of at least 7,000 psi measured according to ASTM D4541. The coating layer is further characterized as being impermeable to corrosive environments showing no pin holes in the ferroxyl test according to ASTM A967 Practice E.

主权项

1. A work piece for use in an abrasive environment, the work piece comprising:
a metal substrate having a melting point of Ts; a carrier sheet having a first side and a second side opposite the first side, the second side having a coating layer deposited thereon, wherein the carrier sheet is applied to the work piece such that the second side is in contact with the work piece and the first side is facing away from the work piece; the coating layer from a single-component feedstock consisting of a composition in weight % of: Fe (55-65%), Cr (0-30%), R (4-30%), Si (0-10%), B (0-3%), and Al (0-20%), wherein R is two or more refractory elements V and Nb, wherein the coating layer comprises a matrix component and at least one additional phase component, the matrix component comprising a total refractory content, excluding Cr, of approximately 13.5%, and the coating having a melting point of Tm; wherein at least a portion of the refractory elements in the coating layer diffuse into the metal substrate for the metal substrate to have a gradient composition, in which the metal substrate is alloyed with at least a portion of the refractory elements for the metal substrate at a depth at least 25 μm from an interface between the coating layer and the substrate to have a concentration of refractory elements of at least 25% of a concentration of refractory elements in the coating layer.