Corrosion monitoring
By using polymer layer encapsulation on corrosive metal films, the increase in resistance is solved by using gas diffusion, which is difficult to quickly respond to changes in ambient gases and detect chemical compositions of corrosive gases in the prior art, and online continuous monitoring of corrosive gases is achieved.
Patent Information
- Application Number
- CN202411486600.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-10-25
- Filing Date
- 2024-10-23
- Publication Date
- 2025-04-25
AI Technical Summary
The prior art is difficult to respond quickly to rapid changes in ambient gases, and offline measurements are not suitable for detecting chemical composition or relative concentrations of corrosive gases.
Corrosive metal films encapsulated with polymer layers penetrate the polymer layer through gas diffusion, resulting in an increase in resistance, thereby providing an indication of corrosion. The thickness, chemical composition and processing conditions of the polymer layer can adjust the sensitivity of the sensor.
The online continuous monitoring of corrosive gases is achieved, which can quickly respond to gas changes and provide information on the presence, absence or relative concentration of corrosive gases.
Smart Images
Figure CN119881018A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to corrosion monitoring and, more particularly, to corrosion sensors. Background Art
[0002] The following description of the background technology may include insights, discoveries, understandings or disclosures, or be associated with disclosures not known to the related art before the present invention but 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 with their 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 repair costs.
[0004] Corrosive gases can be detected at ppb levels by indirect measurements of corroded metal panels, such as corrosion coupons (e.g., Purafil's Corrosion Grading Coupons), where an offline analytical tool is used to detect the thickness of the layer of corrosion crust that forms on top of the corroded metal panel (such as silver, copper, or iron). The thickness of the corrosion layer can then be correlated to a certain amount of corrosive gas.
[0005] In the visual inspection of the silver corrosion sensor, the silver-white color of the silver film changes with respect to the corrosive sulfur-containing gas. Due to the different diffusion rates of gases in air, the silver corrosion sensor can be used to qualitatively distinguish H by the length of the black area of the corrosion sensor. 2 S gas and reduced sulfur gas (S 8 ), because H 2 S causes longer black areas due to its higher diffusion rate. The concentration of the gas is measured by silver sulfide (Ag 2 S) The length of the yellow area was qualitatively detected.
[0006] However, this slow and cumbersome offline measurement is not sufficient when it is necessary to respond to rapid changes in ambient gases. In addition, offline measurement is not suitable for detecting the chemical composition or relative concentration of corrosive gases.
[0007] For online continuous monitoring of corrosive gases, silver corrosion sensors can be used in electrical corrosion sensors, in which a thin film of silver is deposited on top of a non-corroding substrate metal. The corroded silver metal changes the resistance of the resistor network of the substrate metal and the silver film in parallel. Summary of the invention
[0008] The following briefly summarizes the features disclosed herein 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 / critical elements of the present invention, nor is it intended to describe the scope of the present invention. Its sole purpose is to present some concepts disclosed herein in a simplified form as a preface to a more detailed description.
[0009] According to an aspect, the subject matter of the independent claims is provided. Embodiments are defined in the dependent claims.
[0010] One or more embodiments will be described in more detail in the description that follows. Other features will be apparent from the description and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Hereinafter, the present invention will be described in more detail by way of preferred embodiments with reference to the accompanying drawings, in which
[0012] Figure 1 Test results on the sensitivity of corrosion sensors based on polymer-encapsulated metal films are shown. DETAILED DESCRIPTION
[0013] The following embodiments are exemplary. Although the specification may refer to "one", "an" or "some" embodiments in multiple places, this does not necessarily mean that each such reference refers to the same embodiment, 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", "include" and "comprising" should be understood as not limiting the embodiments to consist only of the features mentioned, and the embodiments may also include features / structures not specifically mentioned.
[0014] Although silver is a precious metal, it may corrode in the ambient atmosphere, for example, when it is exposed to sulfur-containing gases such as hydrogen sulfide (H2S). 2 S) and / or carbon sulfide. Copper is considered a precious metal; although some air pollutants (such as H 2 S) changes its surface properties even at ambient temperature, but it remains resistant to attack by oxygen. Sulfidation of copper is a rapid process occurring at the metal-vapor interface, compromising copper's corrosion resistance and causing electrical failures in electronic devices.
[0015] The permeation of gases through nonporous polymer membranes follows a solution and diffusion mechanism when there is a pressure differential across the membrane. The first step in gas permeation is a solution step where the gas is absorbed into the membrane from the interface on the high pressure side of the membrane. The gas then diffuses through the membrane by molecular diffusion (via random walks) and finally the gas desorbs at the interface on the low pressure side of the membrane. Molecular diffusion is a rate limiting step in the permeation process. The diffusion rate of molecules can be estimated using Fick's diffusion law. As a gas diffuses through a membrane, there is a delay between the initial exposure of the gas on one side of the membrane and its appearance at a constant rate on the other side of the membrane. This delay is given by the time lag (L), where L = h 2 / (6D 0 ), where h is the coating thickness in cm, D 0 is the diffusion coefficient, in cm 2 / s.
[0016] When assuming that Ag (or Cu) is a diffuse corrosive gas (such as H 2 S reacts with Ag to form Ag 2 S), it can be assumed that the delay between the onset of corrosion of the metal film under the gas permeable coating follows a similar time lag. Therefore, the sensitivity of the corrosion sensor can be varied by changing the thickness (h) of the gas permeable coating, the chemical composition (which affects D 0 ) and / or processing conditions (affecting D 0 ) without changing the size of the corroded metal. This can result in sensor components having different measurable lag times, similarly for corrosion sensors with steel resistors encapsulated under different thicknesses of epoxy.
[0017] As an additional feature, the gas permeable coating can exhibit a gas selectivity of a desired separation factor, as shown in Equation 1 below:
[0018]
[0019] in and are selective diffusion and solubility selectivity, respectively, A is gas A, B is gas B, α*(A / B) is the ideal separation factor (between gas A and B), D(A) is the average diffusion coefficient of gas A, D(B) is the average diffusion coefficient of gas B, S(A) is the solubility coefficient of gas A, and S(B) is the solubility coefficient of gas B. In this case, the corrosion sensor can provide additional information about the presence, absence or relative concentration of certain corrosive gases. By selecting a group of similar corrosive metal film patterns encapsulated under different gas selective coatings, the presence of certain corrosive gases can be detected. This additional information can be used to identify the source of the corrosive gas.
[0020] One aspect of the invention is a corrosion sensor comprising a corrosive metal film encapsulated with a polymer layer, wherein the polymer layer is permeable to corrosive gases by diffusion, wherein an increase in the electrical resistance of the corrosion sensor when exposed to the corrosive metal film provides an indication of corrosion when the corrosive gas permeates the polymer by diffusion. The polymer may be an electrically insulating polymer, or at least the electrical conductivity of the polymer layer is significantly lower than the electrical conductivity of the metal film.
[0021] In one embodiment, the corrosion sensor may be in the form of a metal strip coated with a polymer.
[0022] In an embodiment, the corroding metal may be silver, copper, zinc and / or iron and / or any other corroding metal.The corroding metal is electrically conductive.
[0023] In an embodiment, the polymer may be polyethyl methacrylate. In an embodiment, the polymer may be polydimethylsiloxane (PDMS), poly (1-trimethylsilyl-1-propyne) (PTMPS) or polycarbonate (PC). 2 They are permeable and resistant to CO 2 / H 2 In an embodiment, the polymer may be selective for H 2 S has high permeability cellulose acetate, ethyl cellulose, poly (vinyl butyral) or polyethylene. In an embodiment, the polymer can be polyethylene terephthalate (PET, Mylar A), regenerated cellulose, poly (vinyl alcohol), poly (vinyl butyral / vinyl alcohol) copolymer, polyamide (nylon-6), poly (vinylidene chloride), polypropylene or poly (vinyl chloride), for H 2 They are permeable. In embodiments, the polymer can be any combination of polymers. The polymers of adjacent sensors can be different if selectivity is desired.
[0024] In an embodiment, the sensitivity of the corrosion sensor to the corrosive gas may depend on the layer thickness of the polymer layer in the corrosion sensor. As the thickness of the polymer layer in the corrosion sensor decreases, the sensitivity of the corrosion sensor to the corrosive gas may increase. As the thickness of the polymer layer in the corrosion sensor increases, the sensitivity of the corrosion sensor to the corrosive gas may decrease.
[0025] In an embodiment, the sensitivity of the corrosion sensor to the corrosive gas may depend on the permeability of the polymer layer in the corrosion sensor. The sensitivity of the corrosion sensor to the corrosive gas may increase as the permeability of the polymer layer in the corrosion sensor increases. The sensitivity of the corrosion sensor to the corrosive gas may decrease as the permeability of the polymer layer in the corrosion sensor decreases.
[0026] In an embodiment, the corrosion sensor may be in the form of a vacuum deposited, patterned metal film encapsulated using a spin-coated poly(ethyl methacrylate) polymer.
[0027] In an embodiment, the corrosion sensor can be in the form of a patterned metal film obtained by slot extrusion coating, rod coating, blade coating and / or vacuum deposition (evaporation, sublimation, atomic layer deposition (ALD), molecular layer deposition (MLD), chemical vapor deposition (CVD)), where the pattern can be formed by etching, lift-off, laser ablation or using a physical mask layer during deposition.
[0028] In an embodiment, the metal film may be patterned using inkjet printing, flexographic printing, gravure printing, and / or screen printing.
[0029] In an embodiment, the polymer coating can be deposited on the metal film by slot die coating, rod coating, blade coating, printing (inkjet printing, flexographic printing, gravure printing and / or screen printing) and / or vacuum deposition (evaporation, sublimation and / or ALD, MLD, CVD).
[0030] In embodiments, the corrosion sensor may be fabricated directly on discrete electronic components (electronic components as substrate) or integrated into electronic circuits during fabrication of the corrosion sensor (by depositing metals and polymers onto pre-arranged contact pads on the electronic-electronic circuits).
[0031] In an embodiment, the corrosive gas may be SO 2 and H 2 At least one of S.
[0032] In an embodiment, the layer thickness of the encapsulating polymer layer in the corrosion sensor may be 10 nm to 10 μm. The time lag may depend on the square of the thickness, and if the coating is pinhole / defect free, different time lags (ie, sensitivities) may be achieved by scaling the thickness of the sensor.
[0033] In an embodiment, the initial thickness of the corrosion metal film in the corrosion sensor may be in the range of 5 nm to 500 nm, or in the range of 50 nm to 500 nm. During use, when the corrosion sensor / corrosion metal film is partially or completely corroded, the thickness may decrease.
[0034] In an embodiment, a corrosion sensor can be used to monitor the presence of corrosive gases, wherein the corrosion sensor is in the form of a corroded metal film encapsulated with an electrically insulating polymer layer. However, if the resistance of the polymer encapsulation is significantly higher than the resistance of the corroded metal, i.e., the conductivity of the polymer layer is significantly lower than the conductivity of the metal film, a conductive or semiconductive polymer layer may be used in addition / alternatively.
[0035] In an embodiment, a method for monitoring the presence of corrosive gases is provided, the method comprising depositing or attaching a corrosion sensor on a substrate, placing the corrosion sensor in an atmosphere to be monitored, and measuring an increase in resistance in the corrosion sensor. The substrate may be composed of prefabricated pads and electronic circuits for integrating the sensor elements. The substrate may be electrically connected to an external circuit via connectors, wire bonding, and / or conductive adhesives. The prefabricated pads and electronic circuits may be encapsulated with materials that are resistant to corrosive gases. Examples of materials that can be used to protect against the effects of corrosive gases include pinhole-free metal oxide material layers, such as Al 2 O 3 、TiO 2 、SiO 2 , HfO 2 and / or nanolaminates thereof, and / or metal nitride materials, such as TiN, TaN and / or WN, deposited using ALD.
[0036] In embodiments, the sensitivity of the corrosion sensor can be adjusted by using a polymer layer on one, two, three, or four sides of the thin metal. Thus, the sensitivity of the corrosion sensor can be adjusted by, for example, leaving one side of the sensor open for corrosion, i.e., one side of the metal conductor is not completely covered by the polymer. For example, a laser can be used to cut a piece of the polymer layer, leaving one side of the metal open.
[0037] In an embodiment, the corrosion sensor may be cut into a desired shape using laser technology.
[0038] Embodiments provide an electronic, low-cost corrosive gas sensor element that can provide in-situ information of corrosion phenomena. When the corrosive gas sensor element is exposed to a corrosive gas, its resistance increases, thereby enabling the detection of corrosion phenomena. A corrosive metal film, such as Ag or Cu, is encapsulated under a gas-permeable coating, such as a polymer, that allows certain corrosive gases to penetrate. As the corrosive gas diffuses through the gas-permeable (polymer) coating, the corrosion resistance of the corrosion sensor element begins to increase.
[0039] Embodiments provide a tunable corrosion sensor in which a corrosive metal is encapsulated as a thin film under a gas permeable coating (e.g., a polymer film). The resistance of the corrosion sensor increases with exposure to corrosive gases that permeate the encapsulation. The corrosion sensor can be used to monitor corrosion behavior in situ. By varying the thickness, chemical composition, and processing conditions of the polymer encapsulation, the corrosion of the thin film metal can be inhibited when exposed to certain corrosive gases.
[0040] Embodiments enable providing low cost, continuous monitoring of corrosive gases. Embodiments enable providing replaceable corrosion sensors that can be replaced when the sensor is completely corroded or changes occur in the gas atmosphere. In addition, embodiments enable selective detection of the presence of different corrosive gases by using polymer coatings with different permeabilities (ideal separation factors) or different polymer layer thicknesses, or by printing a polymer mask with an optimal design on top of the corroded metal layer.
[0041] Embodiments enable in-situ corrosion measurements, providing real-time information on corrosion behavior under operating conditions.
[0042] In an embodiment, an ER (resistance) probe can be used to measure the increase in resistance in a corrosion sensor. A current transformer probe can be used to measure the change in ohmic resistance of a corrosion sensor when exposed to a corrosive gas. The effect of corrosion on a corrosion sensor is to reduce its cross-sectional area and increase its resistance accordingly. The increase in resistance can be directly related to the metal loss, which as a function of time is the corrosion rate. With an ER probe, a direct corrosion rate can be obtained. They react quickly to corrosion anomalies and can be used to trigger an alarm. The (increase) in resistance can be measured / detected using Ohm's law and provide a constant current (voltage) and measure the voltage drop (current passing) across the corrosion sensor.
[0043] Example 1
[0044] The patterned Ag thin films (Ag layer thickness of 30 nm) vacuum deposited on PET substrates were encapsulated by spin-coating polyethylmethacrylate (PEMA) polymer, at least for H 2 Compared with the unencapsulated Ag film, the polymer has a high permeability. 2 S and 1005ppb SO 2 In an atmosphere of , the onset of corrosion was delayed by about 40 days.
[0045] Example 2
[0046] A 30nm thick Ag layer was vacuum thermally evaporated onto a PET substrate through a light shield to form a 1mm wide and 38mm long Ag strip, and the resistance of the Ag strip was monitored in an etching gas. The initial sheet resistance of the Ag strip was 1.1Ohm / sq.
[0047] For H 2S, polyethyl methacrylate (PEMA) polymer has permeability. PEMA with an average molecular weight of about 515kg / mol was dissolved in toluene with a concentration of 3wt% to form a spin-coated ink. The PEMA ink was spin-coated on the Ag sample at a speed of 2000rpm and dried on a hot plate at 110℃ for 1min to form a corrosion-inhibiting layer on top of the Ag strip. The initial sheet resistance of the PEMA-coated Ag strip was 1.3Ohm / sq.
[0048] Ag films (3 wt %) with or without PEMA coating were exposed to H 2 S (1005 ppb) and SO 2 (1005 ppb) corrosive gas. The resistance of the bare Ag strip increased immediately with a linear increase in resistance, while the onset of the linear increase in resistance of the PEMA coated sample was delayed by about 40 days. This indicates that an observable time lag is obtained using PEMA coating. The test results are shown in Figure 1 The results show that PEMA coating can inhibit the corrosion of easily corroded metal films under certain corrosive gases.
[0049] 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 corrosive metal film, encapsulated with a polymer layer or at least partially coated with a polymer layer, wherein the corrosive gas can penetrate the polymer layer by diffusion, wherein the electrical conductivity of the polymer layer is significantly lower than the electrical conductivity of the corrosive metal film, Wherein when the corrosive gas permeates the polymer layer by diffusion, an increase in the resistance of the corrosion sensor provides an indication of corrosion when exposed to the corrosive gas that corrodes the corrosive metal film. 2 . The corrosion sensor according to claim 1 , wherein the corrosion sensor is in the form of a metal strip, encapsulated with a polymer or at least partially coated with a polymer.
3. The corrosion sensor according to claim 1 or 2, wherein the corrosion metal is silver, copper, zinc and / or iron and / or any other conductive metal.
4. A corrosion sensor according to claim 1, 2 or 3, wherein the polymer is an electrically insulating polymer.
5. The corrosion sensor according to any of the preceding claims, wherein the polymer is poly(ethyl methacrylate), polydimethylsiloxane, poly(1-trimethylsilyl-1-propyne), polycarbonate, cellulose acetate, ethyl cellulose, poly(vinyl butyral), polyethylene, polyethylene terephthalate, regenerated cellulose, poly(vinyl alcohol), poly(vinyl butyral / vinyl alcohol) copolymer, polyamide, poly(vinylidene chloride), polypropylene, poly(vinyl chloride) or any combination thereof, preferably poly(ethyl methacrylate).
6. 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 layer thickness of the polymer layer in the corrosion sensor, wherein the sensitivity of the corrosion sensor to the corrosive gas increases as the layer thickness of the polymer layer in the corrosion sensor decreases, The sensitivity of the corrosion sensor to the corrosive gas decreases as the thickness of the polymer layer in the corrosion sensor increases.
7. 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 gas permeability of the polymer layer in the corrosion sensor, wherein the sensitivity of the corrosion sensor to the corrosive gas increases as the gas permeability of the polymer layer in the corrosion sensor increases, The sensitivity of the corrosion sensor to the corrosive gas decreases as the gas permeability of the polymer layer in the corrosion sensor decreases.
8. A corrosion sensor according to any one of the preceding claims, wherein the corrosion sensor is in the form of a vacuum deposited, patterned metal film, encapsulated with or at least partially coated with a spin-coated poly(ethyl methacrylate) polymer.
9. The corrosion sensor according to any one of the preceding claims, wherein the corrosive gas is at least one of SO2 and H2S. 10 . The corrosion sensor according to claim 1 , wherein the polymer layer has a layer thickness of 10 nm to 10 μm in the corrosion sensor.
11. The corrosion sensor according to any one of the preceding claims, wherein the corrosion metal thin film has a thickness of 5 nm to 500 nm in the corrosion sensor.
12. Use of a corrosion sensor according to any one of claims 1 to 11 for monitoring the presence of corrosive gases, wherein the corrosion sensor is in the form of a corrosive metal film, encapsulated with a polymer layer or at least partially coated with a polymer layer.
13. A method for monitoring the presence of corrosive gases, the method comprising depositing a corrosion sensor according to any one of claims 1 to 11 on a substrate, placing the corrosion sensor in an atmosphere to be monitored, and measuring an increase in resistance in the corrosion sensor.