摘要 |
PROBLEM TO BE SOLVED: To provide a method for blackening a hot dip zinc plated steel product to about N3 and a hot dip zinc plated steel product obtained by the same. SOLUTION: Blacking to exhibit satisfactory appearance uniform over the entire part free from uneven color tones can be applied to the hot dip zinc plated steel product by first applying zinc phosphate treatment to the steel product, and then treating the product with blackening agents (a molybdenum system, a nickel system, etc.,). If activation treatment is applied prior to the blackening, beautiful spangles can be reproduced on the blacked surface. As a countermeasure for zinc white rust, a surface adjustment, zinc phosphate retreatment, chromate treatment, resin coating treatment, etc., are preferably executed. COPYRIGHT: (C)2007,JPO&INPIT |