ANODIZING TREATMENT METHOD AND STRUCTURE OF INTERNAL COMBUSTION ENGINE

• US 20160138179A1
• Filed: 03/26/2015
• Published: 05/19/2016
• Est. Priority Date: 03/27/2014
• Status: Active Grant

• Current Assignee: Suzuki Motor Corporation
• Original Assignee: Suzuki Motor Corporation
• Inventors: MURAKAMI, Haruhiko, FUJITA, Masahiro
• Granted Patent: US 10,458,034 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C25D 11/024 Anodisation under pulsed or modulated current or potential
• CPC Class Codes: C25D 11/04 of aluminium or alloys based thereon
• CPC Class Codes: C25D 11/06 characterised by the electrolytes used
• CPC Class Codes: C25D 11/08 containing inorganic acids
• CPC Class Codes: C25D 11/12 Anodising more than once, e.g. in different baths
• CPC Class Codes: C25D 11/246 for sealing layers
• CPC Class Codes: F02F 1/18 Other cylinders
• CPC Class Codes: F02F 1/24 Cylinder heads
• CPC Class Codes: F02F 3/0084 the pistons being constructed from specific materials
• CPC Class Codes: F02F 3/14 within combustion chambers

Abstract

Provided are a method for an anodizing treatment on an aluminum-based material and a structure of an internal combustion engine which are provided with both high heat insulation properties and a high corrosion resistance, a high durability and a high impact resistance, and high water-repellent and oil-repellent functions. This method comprises the steps of: forming a second anodic oxide coating 2b by application of AC-DC superimposition electrolysis to an aluminum-based material 1; and, after the step, forming a first anodic oxide coating 2a by application of direct-current electrolysis to the aluminum-based material 1, wherein the second anodic oxide coating 2b is formed on the first anodic oxide coating 2a.

Claims

1. An anodizing treatment method, comprising the steps of:

forming a second anodic oxide coating by application of AC-DC superimposition electrolysis to an aluminum-based material; and

after the step, forming a first anodic oxide coating by application of direct-current electrolysis to the aluminum-based material,

wherein the second anodic oxide coating is formed on the first anodic oxide coating.

2. The anodizing treatment method according to claim 1, wherein in the step of forming a second anodic oxide coating, a frequency of a high-frequency current is 5 kHz to 20 kHz, a voltage of a positive electrode is 12 V to 70 V, and a voltage of a negative electrode is −

10 V to 0 V.

3. The anodizing treatment method according to claim 1,

wherein a current density in the step of forming a first anodic oxide coating is 1 A/dm2 to 80 A/dm2.

4. The anodizing treatment method according to claim 1, wherein an anodizing treatment liquid used in the step of forming a first anodic oxide coating has an acid concentration of 10 g/L to 100 g/L.

5. The anodizing treatment method according to claim 1, wherein an anodizing treatment liquid used in the step of forming a second anodic oxide coating has an acid concentration of 100 g/L to 600 g/L.

6. The anodizing treatment method according to claim 1, further comprising, after the step of forming a second anodic oxide coating, a step of sealing pores of the first anodic oxide coating with a strongly basic solution.

7. A structure of an internal combustion engine, comprising at least:

a first anodic oxide coating on a surface of an aluminum-based material constituting a combustion chamber in an internal combustion engine; and

a second anodic oxide coating on a surface of the first anodic oxide coating,

wherein the first anodic oxide coating has more pores therein than the second anodic oxide coating.

8. The structure of an internal combustion engine according to claim 7,

wherein the first anodic oxide coating has a porosity of 25% to 75%.

9. The structure of an internal combustion engine according to claim 7, wherein the second anodic oxide coating has a film thickness of 10 μ

m to 100 μ

m.

10. The structure of an internal combustion engine according to claim 7, wherein a total film thickness of the first anodic oxide coating and the second anodic oxide coating is 50 μ

m to 500 μ

m.

11. The structure of an internal combustion engine according claim 7, wherein the first anodic oxide coating is obtained by application of direct-current electrolysis, and the second anodic oxide coating is obtained by application of AC-DC superimposition electrolysis.