Enlargement of Anti-corrosion of Zinc Plating by the Trivalent Chromium Sulfate Conversion Coating

3가 크롬황산염의 크로메이트에 의한 아연도금내식성 증대

  • Lee, Chul-Tae (Department of Chemical Engineering, Dankook University)
  • 이철태 (단국대학교 공학부 화학공학전공)
  • Received : 2007.05.02
  • Accepted : 2007.05.16
  • Published : 2007.06.10

Abstract

A trivalent chromate conversion coating solution which is composed with $KCr_2(SO_4)$ as main component was investigated to test a feasibility of use as an alternative six-valent chromate conversion coating for improvement of anti-corrosion of zinc plating. The proposed trivalent convesion coating was consisted of $KCr(SO_4)$ 35~45 g/L as trivalent chromium source, $NaH_2PO_4$ 20~30 g/L as phosphate, $CoSO_4$, 10~20 g/L, $ZnSO_4$ 10~20 g/L as metallic sulfates. This trivalent chromate films which are coated by this chromate conversion coating solution under pH 2.0~2.2, immersion time of 20~25 s at room temperature are able to achieve over 120 h in neutral salt spray test to 5% white rust.

Keywords

trivlaent chromate;coating;corrosion;surface treatment

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