Zinc Phosphate and Manganese Phosphate Coating
The phosphate conversion process is one of the most commonly used processes in the industry. Most phosphate coatings serve as a surface preparation for further coating and/or painting in every automobile industry in the world. The phosphate process creates a layer of crystals which gives the material a dark shade.
The phosphate conversion process is in fact a chemical conversion coating of three types: thin Zinc Phosphate coating, thick Zinc Phosphate coating and Manganese Phosphate coating.
Thin Zinc Phosphate Coating
- Serve as a surface preparation for painting
- Can only be applied on steels
- Characterized by a thin layer of salt chemical conversion of zinc phosphate implemented by dip on coatings such as: cadmium, electrolytic zinc, hot galvanizing etc.
- Provides high corrosion resistance
Thick Zinc/Manganese Phosphate Coating
Thick Zinc phosphate Coating is not used as preparatory layer before painting, but for other application preparations such as lubrication for abrasion resistance. The coating has similar qualities as manganese phosphate (see Blackening).
Phosphate Conversion Use:
- Paint adhesion improvement
- Improve corrosion-resistance even in the event of the outbreak of the color layer
- Improve abrasion resistance
Zinc Phosphate MIL-DTL-16232 TYPE Z
Classification according to Class- final procedure
| Class | Description |
|---|---|
| Class 1 | Additional layer on top of the zinc phosphate- a type of coating or a preservative as determined by the drawing |
| Class 2 | Additional oil treatment by one of the oils that are compliant with standard MIL- PRF- 16173 or MIL- PRF- 3150 |
| Class 3 | No additional treatment |
| Class 4 | A chemical passivation without additional treatment, or additional treatment according to the drawing or customer demand |
Manganese phosphate coating MIL- DTL-16232 TYPE M
Classification according to Class
| Class | Description |
|---|---|
| Class 1 | Additional layer on top of the zinc phosphate- a type of coating or a preservative as determined by the drawing |
| Class 2 | Additional oil treatment by one of the oils that are compliant with standard MIL- PRF- 16173 or MIL- PRF- 3150 |
| Class 3 | No additional treatment |
| Class 4 | A chemical passivation without additional treatment, or additional treatment according to the drawing or customer demand |
TT-C-490 (Zinc Phosphate)
| Type | Description |
|---|---|
| Type 1 | Zinc phosphate coating weight of 1.5-5 grams per square meter. Serve as a surface preparation for painting |
| Type 5 | Zinc phosphate coating weight of 1.5-5 grams per square meter. Serve as a surface preparation for painting |
