| abstract |
A water-based composition for protective film formation, characterized by containing a water-compatible inorganic salt and a smectite clay mineral. By merely applying the composition to a surface of a metallic material and drying it, a coating film can be formed which is less apt to have spots and is even, and is equal or superior in processability and seizing resistance to coating films formed by a chemical treatment. In the case where the composition further contains a lubricating ingredient, the coating film can further have improved lubricity. |