AL alloy member having excellent corrosion resistance

• US 6,686,053 B2
• Filed: 07/17/2002
• Issued: 02/03/2004
• Est. Priority Date: 07/25/2001
• Status: Active Grant

• Current Assignee: Klaus Schmidt
• Original Assignee: Klaus Schmidt
• Inventors: Hisamoto, Jun, Wada, Koji
• Primary Examiner(s): Koehler, Robert R.
• Application Number:
  US10/196,198
• Publication Number:
  US 20030035970A1
• Time in Patent Office: 566 Days
• Field of Search: 428/472.2, 428/613, 428/701
• US Class Current: 428/472.2
• CPC Class Codes: C22C 21/02 with silicon as the next major constituent
• CPC Class Codes: C22C 21/08 with silicon
• CPC Class Codes: C25D 11/06 characterised by the electrolytes used
• CPC Class Codes: C25D 11/18 After-treatment, e.g. pore-sealing
• CPC Class Codes: Y10T 428/12479 Porous [e.g., foamed, spongy, cracked, etc.]

Abstract

An Al alloy member having excellent corrosion resistance comprises an Al or Al alloy substrate having an anodic oxide film including a porous layer and a pore-free barrier layer. At least a part of a structure of the barrier layer is altered into boehmite and/or pseudo-boehmite, a dissolution rate of the film is at 100 mg/dm²/15 minutes or below when determined by an immersion test in phosphoric acid/chromic acid (JIS H 8683-2), and a corroded area percent is at 10% or below after allowing the film to stand in an atmosphere of 5% Cl₂—Ar gas at 400° C. for 4 hours.

Claims

1. An Al alloy member having excellent corrosion resistance, which comprises an Al or Al alloy substrate having an anodic oxide film including a porous layer and a pore-free barrier layer, wherein at least a part of a structure of said barrier layer is altered into boehmite and/or pseudo-boehmite, a dissolution rate of said film is at 100 mg/dm²/15 minutes or below when determined by an immersion test in phosphoric acid/chromic acid defined in JIS H 8683-2, and a corroded area percent is at 10% or below after allowing said film to stand in an atmosphere of 5% Cl₂—

Ar gas at 400°

C. for 4 hours.

2. An Al alloy member according to claim 1, wherein said Al alloy comprises 0.1 to 2.0 wt % of Si, 0.1 to 3.5 wt % of Mg, 0.1 to 1.5 wt % of Cu, or 1.0 to 1.5 wt % of Mn, 1.0 to 1.5 wt % of Cu, 0.7 to 1.0 wt % of Fe, with the balance being Al and inevitable impurities.

3. The use of the Al alloy member defined in claim 1 as a vacuum chamber member.

4. The use of the Al alloy member defined in claim 2 as a vacuum chamber member.