| 摘要 |
PURPOSE:To form colored rust preventive films having high surface hardness and high decorative value on iron and steel products by immersing said products which are cleaned of surfaces into a treating soln. contg. caustic alkali, sodium phosphate, sodium nitrate, iron powder and salts of tin and lead and heating the same. CONSTITUTION:After iron and steel products are degreased and washed, the products are immersed in a treating soln. having the following compsn. A soln. contg. 0.5-10wt% (in terms of phosphorous pentoxide) phosphorus pentoxide or sodium phosphate, 5-15wt% sodium nitrite, 3-8wt% sodium nitrate, metallic iron powder and sodium stannate, lead peroxide, etc. in a caustic alkali soln. contg. 40-55wt% caustic soda, etc. is used as a treating soln. and is heated to temp. near the boiling point of the caustic alkali soln. The colored rust preventive films having high hardness and beautiful decorative value are formed on the surfaces of the iron and steel products. |
