Phosphate solution for zinc or zinc-based alloy plated steel sheet, and zinc or zinc-based alloy plated steel sheet using the same

Patent metadata

Field	Value
Publication number	US-9957619-B2
Application number	US-201214758170-A
Country	US
Kind code	B2
Filing date	Dec 28, 2012
Priority date	Dec 27, 2012
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

A phosphate solution for a zinc or zinc-based alloy plated steel sheet, and a zinc or zinc-based alloy plated steel sheet using the same are provided. The phosphate solution for a zinc or zinc-based alloy plated steel sheet contains a molybdenum (Mo) ion, a calcium (Ca) ion and a phosphate ion. A zinc or zinc-based alloy plated steel sheet includes a base steel sheet, a zinc-based or zinc alloy-based plating layer formed on the base steel sheet, and a phosphate film formed on the zinc-based or zinc alloy-based plating layer. The phosphate film contains a molybdenum compound, Ca and a phosphate. A pitting phenomenon occurring at the time of treating a steel sheet with a phosphate is prevented, and excellent corrosion resistance is exhibited on a phosphate film.

First claim

The invention claimed is:

1. A zinc or zinc-based alloy plated steel sheet comprising:
a base steel sheet;
a zinc-based or zinc alloy-based plating layer formed on the base steel sheet; and
a phosphate film formed on the zinc-based or zinc alloy-based plating layer,
wherein the phosphate film contains a molybdenum compound, calcium (Ca) and a phosphate, and
wherein the Ca and the phosphate are present as a scholzite film.

2. The zinc or zinc-based alloy plated steel sheet of claim 1 , wherein the zinc-based or zinc alloy-based plating layer is a Zn—Mg-based plating layer.

3. The zinc or zinc-based alloy plated steel sheet of claim 2 , wherein the Mg is contained in an amount of 3 to 30 wt %.

4. The zinc or zinc-based alloy plated steel sheet of claim 1 , wherein the zinc-based or zinc alloy-based plating layer is formed using a dry plating process.

5. The zinc or zinc-based alloy plated steel sheet of claim 1 , wherein the molybdenum compound is MoO3.

6. The zinc or zinc-based alloy plated steel sheet of claim 1 , wherein the scholzite film contains magnesium (Mg).

7. The zinc or zinc-based alloy plated steel sheet of claim 1 , wherein the phosphate film is adhered in a range of 1 to 5 g/m2, and an average size of crystalline grains is in a range of 1 to 10 μm.

8. The zinc or zinc-based alloy plated steel sheet of claim 1 , wherein the phosphate film additionally contains Zn and Mn.

9. The zinc or zinc-based alloy plated steel sheet of claim 1 , wherein the phosphate film additionally contains Ni.

Assignees

• Posco

Inventors

• Kwak Young-Jin
• Nam Kyung-Hoon
• Jung Yong-Hwa
• Kim Tae-Yeob
• Lee Dong-Yoeul
• Cho Seok-Won
• Lee Young-Ra
• Eom Mun-Jong
• Jung Woo-Sung
• Hong Seok-Jun
• Min Jae-Kyu
• Sohn Hong-Kyun

Classifications

• C23C28/321

  with at least one metal alloy layer · CPC title

• C23C28/34

  including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates · CPC title

• Y10T428/12667

  Oxide of transition metal or Al · CPC title

• C23C18/1637 Primary

  metallic substrate · CPC title

• C23C18/48

  Coating with alloys · CPC title