Back to results
US 8,795,845 B2Granted
Low-temperature synthesis of integrated coatings for corrosion resistance
AssigneeWisconsin Alumni Research Foundation
InventorsJohn Harry Perepezko, Ridwan Sakidja
Life of this patent
Estimating the term…
Abstract
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.
Claims31
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.
5 more elements
An integrated coating structure comprising:
- (a) a substrate comprising a steel alloy;
- and
- (b) a corrosion resistant coating integrated with a surface of the substrate, the coating comprising:
- (i) a corrosion resistant layer comprising Al5Fe2 comprising constitutional vacancies for aluminum atoms;
- and
- (ii) a diffusion barrier layer underlying the corrosion resistant layer and integrated into the surface of the substrate, wherein the diffusion barrier layer hinders the diffusion of atoms that occurs via constitutional vacancies for aluminum atoms relative to their diffusion through the corrosion resistant layer that occurs via constitutional vacancies for aluminum atoms, the diffusion barrier layer comprising at least one intermetallic compound comprising at least one metal or metalloid selected from the group consisting of Group IB, Group VIII, Group IIIA, Group IVA, Group VA and Group VB of the periodic table in addition to at least one of aluminum or iron, wherein said intermetallic compound has a structure comprising fewer constitutional vacancies for aluminum atoms than Al5Fe2.
3 more elements
An integrated coating structure comprising:
- (a) a substrate alloy comprising metal elements, the alloy characterized in that it is susceptible to oxidation in a steam environment at temperatures in the range from about 500° C. to about 700° C.;
- and
- (b) a coating integrated with a surface of the substrate alloy, the coating comprising:
- a metal element of the substrate alloy, aluminum and a third element that is a metal or metalloid selected from the group consisting of Group IB, Group VIII, Group IIIA, Group IVA, Group VA and Group VB of the periodic table;
- wherein the coating has:
- (i) a corrosion resistant layer comprising a first intermetallic compound comprising the metal element of the substrate alloy and aluminum, the first intermetallic compound having a defect structure comprising constitutional vacancies that allow for the diffusion of aluminum atoms through the first intermetallic compound;
- and
- (ii) a 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 metal element of the substrate alloy and the metal or metalloid selected from the group consisting of Group IB, Group VIII, Group IIIA, Group IVA, Group VA and Group VB of the periodic table, the second intermetallic compound having a structure comprising fewer constitutional vacancies that allow for the diffusion of aluminum atoms than the defect structure of the first intermetallic compound, such that the diffusion barrier hinders the diffusion of aluminum atoms through the diffusion barrier relative to their diffusion through the corrosion resistant layer.
5 more elements
Dependencies are inferred from the claim text.