US 12,203,176 B2
Corrosion inhibitor for systems with mixed metallurgy
Bingzhi Chen, Naperville, IL (US); and Zhangzhang Yin, Aurora, IL (US)
Assigned to Ecolab USA Inc., St. Paul, MN (US)
Filed by ECOLAB USA INC., St. Paul, MN (US)
Filed on Jul. 27, 2020, as Appl. No. 16/939,897.
Claims priority of provisional application 62/883,749, filed on Aug. 7, 2019.
Prior Publication US 2021/0040622 A1, Feb. 11, 2021
Int. Cl. C23F 11/167 (2006.01); C23F 11/14 (2006.01); C23F 11/18 (2006.01)
CPC C23F 11/1676 (2013.01) [C23F 11/149 (2013.01); C23F 11/185 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method of inhibiting corrosion of a metal surface in contact with an aqueous medium, comprising:
contacting the metal surface with a corrosion inhibitor composition, the corrosion inhibitor composition consisting of:
water;
a copolymer of acrylic acid and 2-acrylamido-2-methyl propane sulfonate;
a phosphino succinic oligomer (PSO) consisting of a first, a second, and a third compound of formula I:

OG Complex Work Unit Chemistry
wherein n is 1 and m is 2 to 5 in the first compound;
n is 1 and m is 0 in the second compound; and
m is 1 and n is 1 in the third compound;
an azole that is tolytriazole (TT);
a molybdate; and
a buffering agent that is triethanolamine,
wherein the metal surface comprises aluminum,
wherein a ratio of the PSO to the azole in the corrosion inhibitor composition is about 2 to 1, and a ratio of the PSO to the molybdate in the corrosion inhibitor composition is about 2 to 1;
wherein the aqueous medium has a pH of from about 6 to about 8, and
wherein the corrosion inhibitor composition is added to the aqueous medium at a dosage rate from about 0.1% by volume to about 2% by volume.