When the organic coatings are exposed to hot water under thermal gradient condition, blisters will form on the organic coating resulting in corrosion of steel substrate in some cases over a short periods of time. Corrosion protective properties of four organic coating and sprayed aluminium coating are studied by the thermal gradient test.
Main results of the experiment are summarized as follow;
(1) The sprayed aluminium coating has the best corrosion protective properties of all the other coatings.
(2) If the sprayed aluminium coating is coated by the thin organic paint, it will give better corrosion protective nrouerties.
(3) Good adhesion strength of aluminium sprayed coating is obtained by grit-blast or sand-blast cleaning before aluminium spraying.