Low-temperature synthesis of integrated coatings for corrosion resistance

摘要

Methods for the low-temperature synthesis of an integrated, corrosion-resistant coating structure for metal substrates by means of multi-component pack cementation are provided. The synthesis of the integrated coating structures at low temperatures can avoid or minimize degradation of the mechanical properties of the substrates. The integrated coating structures can increase the lifetime of high temperature steels under severe steam environments and, therefore, provide a technological enabler for the high-temperature operation of steam power generation plants.

主权项

1. An integrated coating structure comprising:
(a) a substrate alloy comprising metal elements; and (b) a coating integrated with a surface of the substrate alloy, the coating comprising: a first element that is a metal element of the substrate alloy, a second element characterized in that it is capable of reacting with the first element to form an intermetallic compound and a third element that is a metal or metalloid; wherein the coating has: (i) a corrosion resistant layer comprising a first intermetallic compound comprising the first and second elements, the first intermetallic compound having a defect structure comprising constitutional vacancies for atoms of the second element, wherein the constitutional vacancies allow for the enhanced diffusion of the atoms of the second element through the first intermetallic compound relative to their diffusion through a diffusion barrier layer; and (ii) the diffusion barrier underlying the corrosion resistant layer and integrated into the surface of the substrate alloy, the diffusion barrier comprising a second intermetallic compound comprising the first element and the third element, the second intermetallic compound having a structure comprising fewer constitutional vacancies for atoms of the second element than the defect structure of the first intermetallic compound, such that the diffusion barrier hinders the diffusion of the atoms of the second element through the diffusion barrier relative to their diffusion through the corrosion resistant layer.