echemi logo
  • Product
  • Supplier
  • Inquiry
    Home > Coatings News > Paints and Coatings Market > Experts talk about the phosphating process before applying primer

    Experts talk about the phosphating process before applying primer

    • Last Update: 2020-02-21
    • Source: Internet
    • Author: User
    Search more information of high quality chemicals, good prices and reliable suppliers, visit
    The phosphating treatment before the application of the primer will improve the adhesion between the paint film and the base metal, improve the corrosion resistance of the whole coating system, and provide inter process protection to avoid the formation of secondary rust Therefore, the primary problem of phosphating before painting is that the phosphating film must have excellent matching with the primer, while the rust resistance of the phosphating film itself is secondary, and the phosphating film is fine, dense and thin When the phosphating film is thick, it will have a negative effect on the overall performance of the film The selection of phosphating system and process is mainly determined by: workpiece material, oil rust degree, geometry; time interval between phosphating and painting; primer type and construction method as well as relevant site equipment conditions Generally speaking, the high carbon steel of low carbon steel is easy to carry out phosphating treatment, and the phosphating film forming performance is better For the rusty (oxide skin) workpiece, it must go through the pickling process, and the pickling workpiece will bring a lot of troubles to the phosphating, such as rust yellowing between processes, removal of residual acid, coarsening of phosphating film, etc After pickling, the surface of the workpiece should be adjusted before phosphating In the intermittent production situation, due to the limited conditions, the phosphating workpiece must be stored for a period of time before painting, so the phosphating film itself is required to have good rust resistance If the storage period is more than 10 days, medium temperature phosphating should be used generally, such as medium temperature zinc system, medium temperature zinc manganese system, medium temperature zinc calcium system, etc., and the thickness of phosphating film should preferably be between 2.0-4.5g/m2 After phosphating, the workpieces should be dried immediately, and should not be dried naturally, so as to avoid the formation of corrosion in the seam and welding If the storage period is only 3-5 days, low temperature zinc series and light iron series phosphating can be used, and the drying effect will be better than natural cool drying.
    This article is an English version of an article which is originally in the Chinese language on and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

    Related Articles

    Contact Us

    The source of this page with content of products and services is from Internet, which doesn't represent ECHEMI's opinion. If you have any queries, please write to It will be replied within 5 days.

    Moreover, if you find any instances of plagiarism from the page, please send email to with relevant evidence.