Corrosion inhibitor composition:
A corrosion inhibitor for ferrous metals comprising four different components of:
(a) an inorganic acid component (such as molybdate or tungstate),
(b) an aliphatic hydroxycarboxylic or aliphatic dicarboxylic acid or its salt (such as citric acid, gluconic acid or succinic acid),
(c) An inorganic heavy metal compound, like zinc chloride or stannous chloride, is employed. A water-soluble polymer component with a molecular weight of NUM0, such as acrylic homo or copolymer, is particularly beneficial for water recycling systems.)