Foam phosphatizing method and composition
US4060433A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 5, 1976 |
| Grant date | Nov 29, 1977 |
| Priority date | — |
| Expiry date | Mar 5, 1996 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C22/44
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The disclosed foamable phosphatizing compositions comprise a phosphatizing agent combined with a high-foaming surfactant. When mixed with a gas such as air, the composition provides a relatively stable foam which adheres to overhead or inclined or vertical metal surfaces. When the foam has been in place on the metal surface for a certain minimum dwell time (and the coating weight has reached at least 10mg/ft.sup.2), the phosphatizing composition is rinsed off or is permitted to drain off. By procedures which involve reproducible laboratory tests, maximum and minimum dwell times or contact times can be determined even for use in the field under poorly controlled conditions. As a result, the control over the resulting phosphate coating weights is comparable to the control obtainable in immersion techniques or tunnel sprayer techniques. This high degree of control in a foam spraying technique makes possible an efficient, economical method for spray-phosphatizing bulky three-dimensional objects or inclined or overhead surfaces, regardless of whether or not reuse of the phosphatizing composition is a realistic possibility.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.