Corrosion monitoring

Abstract

The invention relates to corrosion monitoring. A corrosion sensor is disclosed that includes a mixture of a corrosive material and a non-corrosive material, where the corrosive material and the non-corrosive material are electrically conductive, the corrosive material having a higher electrical conductivity than the non-corrosive material. An increase in resistance of the corrosion sensor provides an indication of corrosion upon exposure to a corrosive gas that corrodes the corrosive material.

Description

Technical Field

[0001] The present invention relates to corrosion monitoring and, more particularly, to corrosion sensors. Background Art

[0002] The following description of background technology may include insights, discoveries, understandings or disclosures, or associations with disclosures that were unknown to the relevant art before the present invention but are provided by the present invention. Some such contributions of the present invention may be specifically pointed out below, while other such contributions of the present invention will be apparent from their context.

[0003] Corrosion is the deterioration of metals due to chemical reactions between the metal and its environment. Corrosion of electronic components occurs in environmental conditions containing corrosive gases, which can lead to electronic component failure or electronic system failure, operational downtime and expensive repairs.

[0004] The presence of corrosive gases at ppb concentrations can be detected using indirect measurements performed on corroding metal plates, such as corrosion coupons (e.g., corrosion classification coupons by Purafil), where an offline analysis tool is used to detect the layer thickness of the corrosion crust formed on top of the corroding metal plate (such as Ag, Cu, or Fe). The thickness of the corrosion layer can then be correlated to a specific level of corrosive gas.

[0005] When visually inspecting the Ag corrosion sensor, the silver color of the Ag film changes relative to the corrosive sulfur-containing gas. Due to the different diffusivities of the gases in air, the Ag corrosion sensor can be used to qualitatively distinguish between H2S and reduced sulfur gas (S8) by the length of the black area of ​​the corrosion sensor, as H2S causes a longer black area due to its higher diffusivity. The gas concentration is qualitatively detected by the length of the yellow area of ​​silver sulfide (Ag2S).

[0006] However, when it is necessary to respond to rapid changes in the surrounding gas, such slow and cumbersome offline measurements are insufficient. In addition, offline measurements cannot be used to detect the chemical composition or relative concentration of corrosive gases.

[0007] For online continuous monitoring of corrosive gases, Ag corrosion sensors can be used in electrical corrosion sensors, where Ag thin films are deposited on top of non-corroding base metals. The corroded Ag metal changes the resistance of the resistor network of the base metal and Ag thin film connected in parallel. Summary of the invention

[0008] A simplified overview of the features disclosed herein is presented below to provide a basic understanding of some exemplary aspects of the present invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key / important elements of the present invention or to indicate the scope of the present invention. Its sole purpose is to present some of the concepts disclosed herein in a simplified form as a prelude to a more detailed description.

[0009] According to one aspect, the subject matter of the independent claims is provided. Embodiments are defined in the dependent claims.

[0010] One or more of the embodiments are set forth in greater detail in the description which follows. Other features will be apparent from the description and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention will be described in more detail below with reference to the accompanying drawings by means of preferred embodiments, in which

[0012] Figure 1 illustrates a printed Ag / C corrosion sensor layer on top of a metal electrode;

[0013] Figure 2a and Figure 2b Test results of measuring resistance changes for a corrosion sensor based on flexographically printed ink are shown. DETAILED DESCRIPTION

[0014] The following embodiments are exemplary. Although the specification may refer to "one", "an" or "some" embodiments (one or more) in several locations, this does not necessarily mean that each such reference refers to the same embodiment (one or more), or that the feature applies only to a single embodiment. Individual features of different embodiments may also be combined to provide other embodiments. In addition, the words "comprise", "contain" and "include" should be understood as not limiting the described embodiments to consist only of those features already mentioned, and such embodiments may also include features / structures not specifically mentioned.

[0015] Although silver is a noble metal, it can corrode in the ambient atmosphere, for example by reacting with sulfur-containing gases such as hydrogen sulfide (H2S) and / or carbonyl sulfide. Copper is considered a noble metal; although some air pollutants, such as H2S, can alter the surface properties of copper, copper is resistant to attack by oxygen even at ambient temperatures. Copper sulfidation is a rapid process occurring at the metal-gas interface, impairing the corrosion resistance of copper and causing electrical failures in electronic equipment.

[0016] One aspect of the present invention is a corrosion sensor comprising a mixture of a corrosive material and a corrosion-resistant material, wherein the corrosive material and the corrosion-resistant material are electrically conductive, the corrosive material having a higher electrical conductivity than the corrosion-resistant material, wherein an increase in the electrical resistance of the corrosion sensor when exposed to a corrosive gas that corrodes the corrosive material provides an indication of corrosion. The corrosion-resistant material herein may also be referred to as a non-corrosive material.

[0017] In an embodiment, the corrosive material is a metal, such as Ag, Cu, Zn and / or Fe and / or any other corrosive metal.

[0018] In an embodiment, the corrosion-resistant material is carbon. "Corrosion-resistant" or "non-corroding material" herein refers to a material that is less susceptible to corrosion than a corrosive material. In an embodiment, the corrosion-resistant material is carbon in the form of graphite.

[0019] In an embodiment, the corrosion sensor may be in the form of a composite printing ink or a composite printing paste.

[0020] In an embodiment, the sensitivity of the corrosion sensor to the corrosive gas depends on the weight ratio of the corrosive material to the non-corrosive material in the corrosion sensor. The sensitivity of the corrosion sensor to the corrosive gas may increase as the weight ratio of the corrosive material to the non-corrosive material in the corrosion sensor increases. The sensitivity of the corrosion sensor to the corrosive gas may decrease as the weight ratio of the corrosive material to the non-corrosive material in the corrosion sensor decreases.

[0021] In an embodiment, the corrosive gas is at least one of SO2, H2S, NO2, Cl2, Cl, NH3, CH3NH and any derivatives thereof.

[0022] In an embodiment, the weight ratio of the corrosive material to the non-corrosive material in the corrosion sensor is 90 / 10 to 10 / 90, such as 80 / 20. This refers to the initial weight ratio. During the use of the corrosion sensor, as the corrosive material corrodes under exposure to the corrosive gas(es), the weight ratio may change, resulting in a decrease in the proportion of the corrosive material in the corrosion sensor.

[0023] In an embodiment, the corrosion sensor may be used to monitor the presence of corrosive gases.The corrosion sensor may be in the form of a composite printing ink printed on a substrate.

[0024] In an embodiment, the substrate is an electronic component.

[0025] In an embodiment, the corrosion sensor in the form of a composite printing ink is printed on the substrate with a composite printing ink layer thickness of 0.1 to 50 μm, preferably 0.1 to 20 μm, more preferably 0.1 to 10 μm.

[0026] In an embodiment, a method for monitoring the presence of a corrosive gas includes depositing or attaching a corrosion sensor to a substrate, subjecting the corrosion sensor to the atmosphere to be monitored, and measuring an increase in resistance in the corrosion sensor.

[0027] An embodiment discloses a corrosion sensor comprising a mixture of a corrosive material and a non-corrosive material. The corrosion sensor may comprise a printable mixture of a corrosive material and a non-corrosive material. In an embodiment, both the corrosive material and the non-corrosive material are electrically conductive. Typically, the corrosive material has a higher conductivity than the non-corrosive material. The difference in conductivity can be used in a corrosion sensor to monitor the presence of corrosive gases in the atmosphere. As the corrosive material corrodes, the conductivity of the corrosion sensor changes, and thereby the resistance of the corrosion sensor also changes. The change in resistance, i.e., the increase in the resistance of the corrosion sensor, can be measured using a resistance probe. The sensitivity of the corrosion sensor can be selected by selecting a specific mixing ratio and / or the total thickness of the resistor, and / or by selecting a specific combination of non-corrosive material and corrosive material.

[0028] The corrosive material and the non-corrosive material can be mixed in different proportions as a printable paste or a printable ink. The ink or paste can be applied as a thin layer to a suitable substrate, such as an electronic component, by using flexographic printing and / or another printing method, such as inkjet printing, gravure printing, laser printing and / or screen printing. The higher the percentage of corrosive material in the mixture, the more sensitive the printed layer is to corrosion, even if the layer thickness remains unchanged.

[0029] Embodiments can continuously monitor corrosive gases at low cost. Embodiments can use the corrosive gas sensor as a replaceable corrosion sensor that can be changed when the corrosion sensor is completely corroded or when a change occurs in the corrosive gas environment to be monitored. In addition, it is possible to adjust the sensitivity of the corrosion sensor by adjusting the proportion of corrosive material in the corrosion sensor.

[0030] Silver (Ag) and carbon (C) inks can be printed, for example, on metal electrodes. Figure 1 Illustration of silver and carbon inks printed on metal electrodes.

[0031] In an embodiment, for example, when preparing the ink or selecting the appropriate ink for a specific corrosive gas environment, the corrosion sensor layer thickness can be fixed, but the sensitivity can vary with the Ag / C concentration because Ag is more sensitive to corrosive gases. Other material combinations such as Cu / C, Zn / C, or Fe / C can also be used.

[0032] The adjustable corrosion sensor properties enable the scalability of the preparation method and the availability of corrosive and non-corrosive materials. The impedance level and sensitivity of the corrosion sensor can be changed by changing the mixing ratio of the corrosive material and the corrosion-resistant material. The impedance level and sensitivity of the corrosion sensor can also be changed by changing the total thickness of the resistor and by selecting the combination of non-corrosive and corrosive materials. For example, the corrosion sensor layer thickness can remain unchanged when the Ag concentration is changed.

[0033] Embodiments enable in-situ corrosion measurements that provide real-time information on corrosion behavior under operating conditions. The present invention enables printable, low-cost, mass-producible and manufacturable corrosion sensors.

[0034] Embodiments enable low-cost, continuous corrosion monitoring, particularly in the presence of corrosive gases. Embodiments enable a corrosion resistor sensor in which the resistor thickness can be constant even when the sensitivity of the corrosion sensor to corrosive gases changes.

[0035] In an embodiment, an ER (resistance) probe may be used to measure the increase in resistance in a corrosion sensor. An ER probe may be used to measure the change in ohmic resistance of a corrosion sensor exposed to corrosive gas(es). The effect of corrosion on a corrosion sensor is to reduce its cross-sectional area and to correspondingly increase resistance. The increase in resistance may be directly related to metal loss, which as a function of time is the corrosion rate. With an ER probe, a direct corrosion rate may be obtained. They react quickly to corrosion disturbances and may be used to trigger an alarm. The resistance (increase) may be measured / detected using Ohm's law and providing a constant current (voltage) and measuring the voltage drop across (current passing through) the corrosion sensor.

[0036] Example 1

[0037] Flexographic printing inks were prepared in which silver (Ag) as a corrosive material and carbon (C) as a non-corrosive material were mixed in different weight ratios. Ag and C can be used as nanoparticles or microparticles. The inks with different Ag / C weight ratios were printed on a PET substrate. Figure 2a and Figure 2b It is shown in the first ( Figure 2a ) test condition and the second ( Figure 2b) The resistance change of the corrosion sensor layer printed with different flexographic printing conditions. Figure 2a and Figure 2b As shown in Figure 2, different Ag / C concentrations are very sensitive to corrosive gases. Figure 2a and Figure 2b In the figure, the ratios 80 / 20 and 10 / 90 in the sample labels indicate the Ag / C mass ratio in the ink, and the number (5) or (1) in the brackets indicates the number of layers printed by flexographic printing. By varying the Ag / C ratio in the ink, corrosion changes in the printed material were observed by electrical resistance measurement in the presence of corrosive gases.

[0038] The sensitivity to corrosive gases was increased by increasing the Ag concentration in the printed ink. The impedance level was also varied by varying the layer thickness, i.e. by varying the number of printed ink layers (thicker layers resulted in lower impedance. The corrosion sensitivity (resistance change) can be adjusted by the weight ratio of the corrosive materials and / or the layer thickness. It was observed that the flexographically printed Ag / C layer could be used as a corrosion sensor.

[0039] It is obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways.The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

1. A corrosion sensor comprising a mixture of a corrosive material and a non-corrosive material, wherein the corrosive material and the non-corrosive material are electrically conductive, the corrosive material having a higher electrical conductivity than the non-corrosive material, Wherein an increase in the resistance of the corrosion sensor when exposed to a corrosive gas that corrodes the corrosive material provides an indication of corrosion.

2. The corrosion sensor according to claim 1, wherein the corrosion sensor is in the form of a composite printing ink or a composite printing paste.

3. The corrosion sensor according to claim 1 or 2, wherein the corrosion material is a metal such as Ag, Cu, Zn and / or Fe.

4. A corrosion sensor according to claim 1, 2 or 3, wherein the non-corrosive material is carbon.

5. The corrosion sensor according to any one of the preceding claims, wherein the sensitivity of the corrosion sensor to the corrosive gas depends on the weight ratio of the corrosive material to the non-corrosive material in the corrosion sensor, wherein the sensitivity of the corrosion sensor to the corrosive gas increases as the weight ratio of the corrosive material to the non-corrosive material in the corrosion sensor increases, The sensitivity of the corrosion sensor to the corrosive gas decreases as the weight ratio of the corrosive material to the non-corrosive material in the corrosion sensor decreases.

6. The corrosion sensor according to any one of the preceding claims, wherein the corrosive gas is at least one of SO2 and H2S.

7. The corrosion sensor according to any one of the preceding claims, wherein the weight ratio of the corrosive material to the non-corrosive material in the corrosion sensor is 90 / 10 to 10 / 90.

8. Use of a corrosion sensor according to any one of claims 1 to 7 for monitoring the presence of corrosive gases, wherein the corrosion sensor in the form of a composite printing ink is printed on a substrate.

9. The use according to claim 8, wherein the substrate is an electronic component.

10. The use according to claim 8 or 9, wherein the corrosion sensor in the form of the composite printing ink is printed on the substrate with a composite printing ink layer thickness of 0.1 to 50 μm, preferably 0.1 to 20 μm, more preferably 0.1 to 10 μm.

11. A method for monitoring the presence of a corrosive gas, the method comprising depositing a corrosion sensor according to any one of claims 1 to 7 onto a substrate, subjecting the corrosion sensor to an atmosphere to be monitored, and measuring an increase in resistance in the corrosion sensor.

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