COOLANT HAVING RAPID METAL PASSIVATION PROPERTIES

摘要

It has been found that the chemical reactivity of the metal surface of heat exchangers with coolants in presence of nitrites can be reduced by the addition of additives such as phosphonates or phosphinates. Aluminum, other Group III metals, as well as other metals commonly used in cooling systems, such as those of automobile engines, may thus be effectively protected.

主权项

1. A heat transfer solution which provides passivation when placed in contact with metal surfaces, said solution comprising:
(a) water, an alcohol, or a mixture of both; (b) a nitrite; and (c) a phosphonate having the formula R-[CR2]m-PO3M2 wherein each R-group is selected from the group consisting of hydrogen, alkyl, alkenyl, hydroxyl, phosphono group, carbonyl group, amino, alkylamino and an aryl group wherein m is 1 or an integer greater than 1, and each M is hydrogen or an alkali metal ion, or phosphinate having the formula R-[CR2]m-P(O2M)H wherein each R-group is selected from the group consisting of hydrogen, alkyl, alkenyl, hydroxyl, phosphino group, carbonyl group, amino, alkylamino and an aryl group, wherein m is 1 or an integer greater than 1, and M is hydrogen or an alkali metal ion.