# US 11,029,273 B2 · Corrosion monitoring device

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- Number: US 11,029,273 B2
- Document ID: US11029273B2
- Status: Granted
- Kind: B2
- Application number: 16/461,662
- Filed: 2017-10-23
- Published: 2019-11-21
- Granted: 2021-06-08
- Earliest claimed: 2016-11-18
- Assignees: Hitachi, Ltd.
- Applicants: Hitachi, Ltd.
- Inventors: Rintarou Minamitani
- Web page: https://patentgrep.com/patent/US11029273B2

## CPC

- G01N 17/02: Electrochemical measuring systems for weathering, corrosion or corrosion-protection measurement
- G01N 27/20: Investigating the presence of flaws
- G01N 33/2045: Defects
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A corrosion monitoring device includes: a sensor unit that includes an insulating substrate, a stainless steel plate disposed on the insulating substrate and is configured of stainless steel, an aluminum piece joined to the stainless steel plate and configured of aluminum having a lower corrosion potential than the stainless steel and smaller electrical resistivity than the stainless steel, and extraction electrodes coupled to the stainless steel plate; and an ohm meter that measures an electrical resistance of the sensor unit when a current flows in the sensor unit.

## Claims

### Claim 1

A corrosion monitoring device comprising:
at least one sensor unit that includes:
an insulating substrate;
a first metal layer disposed on the insulating substrate, the first metal layer being configured of a first metal;
a second metal layer joined to the first metal layer, the second metal layer being configured of a second metal having a lower corrosion potential than the first metal and smaller electrical resistivity than the first metal layer; and
a pair of electrodes coupled to the first metal layer; and
a resistance measurement device that measures an electrical resistance of the at least one sensor unit when a current flows between the pair of electrodes.

### Claim 2 (depends on 1)

The corrosion monitoring device according to claim 1, wherein the insulating substrate, the first metal layer, and the second metal layer are joined in this order.

### Claim 3 (depends on 1)

The corrosion monitoring device according to claim 1,
wherein the first metal layer is in a flat plate shape, and
the second metal layer is in a circular shape in a top view, the second metal layer being sparsely joined to the first metal layer on a surface of the first metal layer.

### Claim 4 (depends on 3)

The corrosion monitoring device according to claim 3, wherein a plurality of the second metal layers are joined so as to be positioned at respective apexes configuring a regular hexagon on a surface of the first metal layer.

### Claim 5 (depends on 1)

The corrosion monitoring device according to claim 1,
wherein two of each of the at least one sensor units and the resistance measurement devices are provided,
one sensor unit of the at least one sensor units has a film formed in order to reduce corrosion of the first metal layer and the plurality of second metal layers so as to cover the first metal layer and the plurality of second metal layers.

### Claim 6 (depends on 1)

The corrosion monitoring device according to claim 1,
wherein the first metal is at least one of stainless steel, nickel, and chrome, and
the second metal is at least one of iron, aluminum, copper, zinc, and magnesium.

### Claim 7 (depends on 1)

The corrosion monitoring device according to claim 1, wherein the insulating substrate, the second metal layer, and the first metal layer are joined in this order.