Corrosion Resistant Coatings Suitable For Elevated Temperature Application
AssigneeSouthwest Research Institute
InventorsKwai S. CHAN, Narayana Sastry CHERUVU, Wuwei LIANG
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Abstract
The present invention relates to corrosion resistance coatings suitable for elevated temperature applications, which employ compositions of iron (Fe), chromium (Cr), nickel (Ni) and/or aluminum (Al). The compositions may be configured to regulate the diffusion of metals between a coating and a substrate, which may then influence coating performance, via the formation of an inter-diffusion barrier layer. The inter-diffusion barrier layer may comprise a face-centered cubic phase.
Claims15
A method of forming an inter-diffusion resistant matrix in an alloy coating positioned on a substrate comprising:
- supplying a coating composition having the formula:
- Fe—XCr—YNi-ZAl
- wherein X has a value of 20-30 weight percent, Y has a value of 30-50 weight percent, Z has a value of 0-10 weight percent and Fe accounts for the remainder of the alloy composition, where the total X, Y, Z and the amount of Fe is 100 weight percent;
- applying said coating composition to a substrate and forming a face-centered-cubic (fcc) phase identified by the presence of a cubic unit cell in Space Group 225, wherein the value of a1 and a2 is about 0.36 nm and the value of a3 is also about 0.36 nm wherein the fcc phase comprises 20-25 weight percent Cr, 30-50 weight percent Ni, and the remainders are Fe and Al.
A method of forming an inter-diffusion barrier layer between an alloy coating positioned on a substrate comprising:
- supplying a coating composition having the formula
- Fe—XCr—YNi-ZAl
- wherein X has a value of 20-30 weight percent, Y has a value of 30-50 weight percent, Z has a value of 0-10 weight percent and Fe accounts for the remainder of the alloy composition, where the total X, Y, Z and the amount of Fe is 100 weight percent;
- applying said coating composition to a substrate and forming a face-centered-cubic (fcc) phase identified by the presence of a cubic unit cell in Space Group 225 wherein the values of a1 and a2 are about 0.36 nm and the value of a3 is also about 0.36 nm wherein the fcc phase comprises 20-25 weight percent Cr, 30-50 weight percent Ni, and the remainders are Fe and Al;
- wherein said coating contains 90 mole percent or more of said fcc phase;
- and
- wherein said coating includes up to 10 mole percent of a body-centered cubic (bcc) phase identified by the presence of a body-centered cubic unit cell in Space Group 229 wherein the values of a1, a2, and a3 are about 0.29 nm.
A coating composition of a metallic alloy which forms a face-centered cubic (fcc) phase at the interface of said coating with a selected substrate, comprising:
- Fe—XCr—YNi-ZAl
- wherein X has a value of 20-30 weight percent, Y has a value of 30-50 weight percent, Z has a value of 0-10 weight percent and Fe accounts for the remainder of the alloy composition, where the total X, Y, Z and the amount of Fe is 100 weight percent;
- said face-centered-cubic (fcc) phase identified by the presence of a cubic unit cell, wherein the values of a1 and a2 are about 0.36 nm and the value of a3 is about 0.36 nm and wherein the fcc phase comprises 20-25 weight percent Cr, 30-50 weight percent Ni, and the remainders are Fe and Al.
A fossil fired power generating boiler, having a surface that is exposed to the burning of a fossil fuel wherein said surface includes a coating composition of a metallic alloy which forms a face-centered cubic (fcc) phase at the interface of said coating with a selected substrate, comprising:
- Fe—XCr—YNi-ZAl
- wherein X has a value of 20-30 weight percent, Y has a value of 30-50 weight percent, Z has a value of 0-10 weight percent and Fe accounts for the remainder of the alloy composition, where the total X, Y, Z and the amount of Fe is 100 weight percent;
- said face-centered-cubic (fcc) phase identified by the presence of a cubic unit cell, wherein the values of a1 and a2 are about 0.36 nm and the value of a3 is about 0.36 nm and wherein the fcc phase comprises 20-25 weight percent Cr, 30-50 weight percent Ni, and the remainders are Fe and Al.
Dependencies are inferred from the claim text.