SAMBIX specializes in plating metal parts used in general industry. We do plating treatments in zinc, nickel, tin as well as chemical conversion treatments.

surface treatment technnologysurface treatment technnology

Anti-rust treatment that doesn’t harm people or the environment　Zero Chromium

As hexavalent chromium, which is contained in chromate filming agents used in zinc plating, has a harmful effect on the environment, we have been asked passionately for a chromium free anti-rust treatment agent. Responding to this need, our company, as a result of much diligent research in techniques, found that tannic acid and a specific metallic compound combined to form an anti-corrosive film. From this, a highly corrosive resistant rust proofing technique (patent no. 3337134), which is not harmful to people or the environment, was established.


Strong points

  1. It is completely chromium free.
  2. Zero Chromium S has tones close to those of colored chromate, and Zero Chromium SB has similar tones to black chromate.
    3. Zero Chromium S｜Colored Chromate Zero Chromium SB｜Black Chromate
    Zero Chromium S Colored Chromate Zero Chromium SB Black Chromate
  3. For rack-and-pinion plated items, S was superior to SB in corrosion resistance.
    4. For ___Rack??? plated rack items, S was superior to SB in corrosion resistance.
  4. Even in unplated areas the corrosion resistance is excellent.

    5. The example shows a pipe interior, one treated with Zero Chromium S and one treated with trivalent chromium.

    untreated area tannic acid film forms untreated area trivalent chromium film unformed
    untreated area tannic acid film forms untreated area trivalent chromium film unformed
    ※Tannic acid unites not only with zinc,but also with iron. ※Trivalent chromium does not unite with iron, leaving it exposed.

    After 4 days of outdoor exposure

    No red rust development Red rust development
    No red rust development Red rust development

    8 hours after saline atomizing testing

    Slight red rust development Red rust development
    Slight red rust development Red rust development
  5. Example with a housing configuration

    6. After 9 days of outdoor exposure

    Zero Chromium S treated item Trivalent chromium treated item
    Zero Chromium S treated item｜No rust formation Trivalent chromium treated item｜The thinly plated area results at the time of trivalent chromium treatment when zinc in dissolved with a strong acid exposing the underlying iron, so rust forms.
    No rust formation The thinly plated area results at the time of trivalent chromium treatment when zinc is dissolved with a strong acid exposing the underlying iron, so rust forms.
  6. Comparative merits of various rust-resistant coatings
    7. Comparative merits of various rust-resistant coatings

    ★1.Since it contains miniscule quantities of hexavalent chromium, there is the danger of natural oxidization into hexavalent chromium after disposal.
    ★2.The PH control range is narrow, making PH control apparatus indispensable.
    ★3.Blending with miniscule quantities of copper or iron etc, causes treatment liquid to age.
    ★4.It is prone to have by a product of hexavalent chromium in waste water treatment.