| Optimum effectiveness of high performance protective coatings is highly dependent on the preparation of the surface prior to application of the coating formulation. Superior results are achieved when the items to be coated are first degreased (using, preferably, conventional alkaline degreasing - although solvent based processes can also be used) and then blasted with an abrasive such as silica, steel grit, or alumina to achieve a surface profile that provides optimum performance and adhesion. In general, the best performance is achieved when the surface preparation is a white metal blast. |
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| Automatic Spray Application Plant For Wind Mill Bolts |
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Oil Cleaning-Degreasing |
| Environmental friendly Alkaline or Solvent base oil cleaning is recommended to use, It is applicable to all metal parts. Good oil cleaning is also enough as a pre-treatment for some parts. No acid cleaning for parts having 32 HRC or higher hardness and spring steel to avoid hydrogen embrittlement. |
Phosphate |
| Phosphate (as for example, zinc phosphate or iron phosphate) is often used as a surface preparation for coatings; it is inexpensive and relatively foolproof. The primary disadvantage of phosphate coatings is that they are non-conductive. Nearly all high performance protective coatings rely on sacrificial action to achieve a high level of protection; the traditional view is that having a non-conductive intermediate coating interferes with the efficacy of the coating; this view has disappeared somewhat over the past decade or so. |
Shot Blasting |
For high strength steels (10.9 grade and above or hardness >32 HRC), Shot blasting is preferred, since Phosphate treatment may lead to Hydrogen Embrittlement, so it is not recommended for spring steel and high strength steel.
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