Corrosion detection sensor device

• US 9,297,741 B2
• Filed: 01/14/2015
• Issued: 03/29/2016
• Est. Priority Date: 03/22/2011
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kato, Juri, Miyazawa, Takao
• Primary Examiner(s): NGUYEN, VINH P
• Application Number:
  US14/596,850
• Publication Number:
  US 20150123683A1
• Time in Patent Office: 440 Days
• US Class Current: 1/1
• CPC Class Codes: G01N 17/02 Electrochemical measuring systems for weathering, corrosion or corrosion-protection measurement
• CPC Class Codes: G01N 27/125 Composition of the body, e.g. the composition of its sensitive layer
• CPC Class Codes: G01N 27/4167 pH electrodes therefor G01N27/302, G01N27/36
• CPC Class Codes: G01N 31/221 for investigating pH value
• CPC Class Codes: G01N 33/20 Metals
• CPC Class Codes: G01N 33/383 Concrete, cement

Abstract

A sensor device includes first and second electrodes, a coating film and a functional element. The first electrode includes a first metallic material in which either a first passivation film forms on a surface thereof or the first passivation film present on the surface thereof is lost, in association with changes in the pH of a measurement site. The second electrode includes a second metallic material different from the first metallic material, and is spaced apart from the first electrode. The coating film includes a third metallic material different from the first and second metallic materials. The coating film covers at least the first or second electrode. The functional element is configured to measure a difference in electric potential between the first and second electrodes that changes depending on presence or absence of each of the first passivation film and the coating film in association with the changes in pH.

Claims

1. A sensor device comprising:

a first electrode including a first metallic material, the first metallic material being a metallic material in which either a first passivation film forms on a surface thereof or the first passivation film present on the surface thereof is lost, in association with changes in the pH of a measurement site;

a second electrode including a second metallic material different from the first metallic material, the second electrode being spaced apart from the first electrode, the first electrode and the second electrode being provided on the same plane;

a coating film including a third metallic material different from the first metallic material and from the second metallic material, the coating film covering at least one of the first electrode and the second electrode; and

a functional element configured to measure a difference in electric potential between the first electrode and the second electrode that changes depending on presence or absence of each of the first passivation film and the coating film in association with the changes in pH.

2. The sensor device according to claim 1, wherein

the functional element is configured to detect whether or not the pH of a site to be measured of an object to be measured is at or below a set value, based on the difference in electric potential between the first electrode and the second electrode.

3. The sensor device according to claim 1, wherein

the second metallic material is a metallic material in which either a second passivation film is formed on a surface thereof or the second passivation film present on the surface thereof is lost, in association with changes in the pH of the measurement site,

the first metallic material forms the first passivation film when the pH becomes greater than a first pH, and

the second metallic material forms the second passivation film when the pH becomes greater than a second pH, the second pH being different from the first pH.

4. The sensor device according to claim 3, wherein

the third metallic material dissolves when the pH becomes greater than a third pH, the third pH being different from the first pH and from the second pH.

5. The sensor device according to claim 3, wherein

the first pH is 3 to 5, and

the second pH is 8 to 10.

6. The sensor device according to claim 1, wherein

the third metallic material dissolves when the pH becomes greater than a lower limit of a pH range in which the first metallic material forms the first passivation film.

7. The sensor device according to claim 1, wherein

the first metallic material is iron or an iron-based alloy.

8. The sensor device according to claim 1, wherein

the second metallic material is iron or an iron-based alloy.

9. The sensor device according to claim 1, wherein

the second metallic material does not form a passivation film.

10. The sensor device according to claim 9, wherein

the first metallic material forms the first passivation film when the pH becomes greater than a pH of 3 to 5.

11. The sensor device according to claim 9, wherein

the first metallic material forms the first passivation film when the pH becomes greater than a pH of 8 to 10.

12. The sensor device according to claim 1, wherein

the coating film has a first coating film covering the first electrode, and a second coating film covering the second electrode, the second coating film being spaced apart from the first coating film and including a material different from that of the first coating film.

13. The sensor device according to claim 1, wherein

the coating film covers only one of the first electrode and the second electrode.

14. The sensor device according to claim 1, wherein

an object to be measured by the sensor device is concrete.

15. The sensor device according to claim 1, further comprising

a sealing part defining an opening part, a part of the first electrode and a part of the second electrode being disposed in the opening part.

16. The sensor device according to claim 15, wherein

the sealing part seals in the functional element, the first electrode and the second electrode such that the part of the first electrode and the part of the second electrode are exposed through the opening part.

17. The sensor device according to claim 1, wherein

the first electrode is formed of a plurality of first sub electrodes, with the plurality of first sub electrodes being arranged in a first direction,

the second electrode is formed of a plurality of second sub electrodes, with the plurality of second sub electrodes being arranged in a second direction, and

the first direction and the second direction are parallel to each other.

18. The sensor device according to claim 1, wherein

the sensor device is disposed inside a structure,

the first electrode is formed of a plurality of first sub electrodes, with the plurality of first sub electrodes being arranged in a first direction,

the second electrode is formed of a plurality of second sub electrodes, with the plurality of second sub electrodes being arranged in a second direction, and

the first direction and the second direction are perpendicular to a surface of the structure.

19. The sensor device according to claim 18, wherein

a distance from the surface of the structure to a first sub electrode, which is closest to the surface of the structure among the plurality of first sub electrodes, and a distance from the surface of the structure to a second sub electrode, which is closest to the surface of the structure among the plurality of second sub electrodes, are equal.

20. The sensor device according to claim 1, further comprising

an antenna configured to transmit measurement results measured by the functional element.

21. The sensor device according to claim 1, wherein

the first electrode and the second electrode are comb-shaped.