Anti-coking iron spinel surface
AssigneeNOVA Chemicals (International) S.A.
InventorsEvan Mah, Vasily Simanzhenkov, Leslie Benum, Hany Farag, Bolaji Olayiwola
Life of this patent
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Abstract
An anti-coking surface having a thickness up to 15 microns comprising from 15 to 50 wt. % of MnCr2O4 (for example manganochromite); from 15 to 25 wt. % of Cr0.23Mn0.08Ni0.69 (for example chromium manganese nickel); from 10 to 30 wt. % of Cr1.3Fe0.7O3 (for example chromium iron oxide); from 12 to 20 wt. % of Cr2O3 (for example eskolaite); from 4 to 20 wt. % of CuFe5O8 (for example copper iron oxide); and less than 5 wt. % of one or more compounds chosen from FeO(OH), CrO(OH), CrMn, Si and SiO2 (either as silicon oxide or quartz) and less than 0.5 wt. % of aluminum in any form provided that the sum of the components is 100 wt. % is provided on steel.
Claims16
A process to produce a surface coating on a substrate comprising from 20 to 50 wt. % of Ni and less than 0.05 wt. % of one or more elements chosen from Cu and Al comprising:
- applying to not less than 75% of the surface of the substrate a uniform coating comprising not less than 80 wt. % of one or more of copper, and copper oxides, provided elemental copper is present in an amount of less than 10 wt. %, and comprising less than 2 wt. % trace elements including Si, and
- heating the surface to a temperature from 500° to 1000° C. for at least 3 cycles under alternating oxidizing atmospheres for a time of at least 15 hours and reducing atmospheres for a time of at least 1 hour;
- wherein the uniform coating comprises a copper iron oxide and has a thickness less than 12 microns.
A process to produce a surface coating on a substrate comprising from 20 to 50 wt. % of Ni and less than 0.05 wt. % of one or more elements chosen from Cu and Al comprising:
- applying to not less than 75% of the surface of the substrate a uniform coating, and
- heating the surface to a temperature from 500° to 1000° C. for at least 3 cycles under alternating oxidizing atmospheres for a time of at least 15 hours and reducing atmospheres for a time of at least 1 hour;
- wherein the uniform coating has a thickness less than 12 microns and comprises 15 to 50 wt. % of manganochromite, from 15 to 25 wt. % of chromium manganese nickel;
- from 10 to 30 wt. % of chromium iron oxide;
- from 12 to 20 wt. % of eskolaite;
- from 4 to 12 wt. % of copper iron oxide;
- less than 5 wt. % of one or more compounds chosen from FeO(OH), CrO(OH), CrMn, Si and SiO2;
- and less than 0.5 wt. % of aluminum in any form.
Dependencies are inferred from the claim text.