Zinc-based plated steel sheet having post-treated coating formed thereon

Patent metadata

Field	Value
Publication number	US-11255010-B2
Application number	US-202017014460-A
Country	US
Kind code	B2
Filing date	Sep 8, 2020
Priority date	Dec 22, 2015
Publication date	Feb 22, 2022
Grant date	Feb 22, 2022

Abstract

Provided is a zinc-based plated steel sheet having a post-treated coating filmed thereon including: a steel sheet; a zinc plated layer formed on the steel sheet; and a post-treated coating formed on the plated layer, wherein the atomic ratio (O/M) of oxygen (O) to metals (M) contained in the post-treated coating is greater than 2 and less than 20, and a method for post-treating a zinc-based plated steel sheet. According to this, the zinc-based plated steel sheet having the post-treated coating formed thereon has the effects excellent in lubricity, weldability, adhesiveness, film-removing property and paintability. As the method of post-treating a zinc-based plated steel sheet of the present invention employs a simple coating method irrespective of the kind of plating layer, the process is simple and economical and the process operation cost is low.

First claim

What is claimed are:

1. A zinc-based plated steel sheet having a post-treatment coating, the zinc-based plated steel sheet comprising:
a steel sheet;
a zinc-based plating layer formed on the steel sheet; and
a post-treatment coating formed on the zinc-based plating layer, wherein the post-treatment coating includes a coating upper portion and a coating lower portion, a thickness of the coating lower portion being ¼ to ¾ of a total thickness of the post-treatment coating,
wherein the post-treatment coating includes a metal oxide salt and an organic compound, the metal oxide salt including at least one metal selected from the group consisting of molybdenum (Mo), titanium (Ti), and zirconium (Zr), and
wherein an atomic ratio (O/M) of oxygen (O) to metal (M) derived from a metal oxide salt included in the post-treatment coating is greater than 2 and smaller than 20,
an atomic ratio (O/M) of oxygen and metal derived from a metal oxide salt of the coating upper portion is greater than 3.2, and
an atomic ratio (O/M) of oxygen and metal derived from a metal oxide salt of the coating lower portion is less than 5.

2. The zinc-based plated steel sheet of claim 1 , wherein
the atomic ratio (O/M) of oxygen and metal derived from the metal oxide salt of the coating upper portion is greater than 5, and
an atomic ratio (O/M) of oxygen and metal derived from the metal oxide salt of the coating lower portion is less than 3.2.

Assignees

• Posco

Inventors

• Kim Yeon-Ho
• Kim Yung-Keun
• Park Young-Jun
• Kim Yong-Woon

Classifications

• C23C18/00

  Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating · CPC title

• C23C22/48

  not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates · CPC title

• B32B15/18

  comprising iron or steel {(B32B15/011, B32B15/012 and B32B15/013 take precedence)} · CPC title

• Y10T428/12604

  Film [e.g., glaze, etc.] · CPC title

• C23C22/46

  containing oxalates · CPC title