Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
  • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
  • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
  • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
  • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
  • G01D5/35383—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using multiple sensor devices using multiplexing techniques
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
  • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
  • G01M11/08—Testing mechanical properties
  • G01M11/083—Testing mechanical properties by using an optical fiber in contact with the device under test [DUT]
  • G01M11/085—Testing mechanical properties by using an optical fiber in contact with the device under test [DUT] the optical fiber being on or near the surface of the DUT
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N17/00—Investigating resistance of materials to the weather, to corrosion, or to light
  • G01N17/02—Electrochemical measuring systems for weathering, corrosion or corrosion-protection measurement

Definitions

• the present invention is directed to a detection system.
• a detection system for monitoring an engineered structure includes an array of sensors disposable in a predetermined pattern on the engineered structure and disposable between a surface of the engineered structure and a protective coating substantially covering the surface.
• the detection system also includes a controller in communication with the array of sensors for retrieving data from the sensors.
• the controller communicates with the sensor array via an optical fiber backbone.
• the array of sensors can provide data corresponding to at least one of a degree of cure of the protective coating, a health of the cured protective coating, and a corrosion rate of the engineered structure at each of the sensors.
• Fig. IA is an exemplary detection system according to an embodiment of the present invention.
• Fig. IB is an exemplary detection system according to an alternative embodiment of the present invention.
• Fig. 2 is a cross-section view of a sensor embedded between a coating and an engineered structure according to an exemplary embodiment of the present invention.
• Fig. 3 A is an exemplary sensor according to an embodiment of the present invention.
• Fig. 3B is a schematic diagram of a portion of an exemplary sensor according to another alternative embodiment of the present invention.
• Fig. 3C is a schematic view of the electro-chromic switch of Fig. 3B.
• Fig. 4 is an exemplary display output from an example spectrum analyzer.
• Figs. 5 A and 5B show alternative implementations of an exemplary sensor disposed on non-flat surfaces.
• Figs. 6A and 6B show a method of making an alternative electrochromic switch assembly for use in the sensor system of the current invention. While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.
• the present invention is directed to a detection system.
• the detection system of the exemplary embodiments is embeddable and can be utilized to detect several key characteristics of a coated surface on an engineered structure.
• the detection system utilizes an optical fiber backbone or network to link one or more arrays of detectors with a central control system.
• the optical fiber backbone provides for long distance connections and a substantial reduction or elimination of electromagnetic interference (EMI) signal degradation.
• EMI electromagnetic interference
• the detection system can be utilized to detect the degree of cure of a coating that is applied to the surface of an engineered structure.
• the detection system can be utilized to detect the health of the coating after cure, e.g., by detecting the deterioration of the coating (e.g., moisture ingress) when exposed to natural elements.
• the detection system can be utilized to detect the integrity of the surface of the engineered structure, e.g., by detecting physical conditions that promotes corrosion.
• the detection system can be configured to provide real-time, periodic (e.g. per hour, per day, per week) data related to one or more physical conditions of an engineered structure through a data acquisition system.
• This type of data acquisition system can provide for "condition-based" maintenance for engineered structures, as opposed to “preventive” maintenance, which is currently used.
• the detection system of the exemplary embodiments can help maximize the operational life of an engineered structure or object by providing real-time data to better manage the scheduling of repairs or replacements of such objects or structures.
• the use of an optical backbone allows for a controller system to be located at a far distance (e.g., 10 km or more, as measured by the length of the optical fiber transmission line) from the engineered structure being monitored.
• Fig. IA shows a detection system 100 in schematic view.
• the detection system 100 includes a central controller 150 linked to a sensor array 120a via a transmission optical fiber 105a.
• sensor array 120a includes a plurality of sensors (in this example, a group of six (6) sensors (130a - 13Of) are shown for simplicity) coupled to a data transmission fiber 105 a/ 106a.
• the sensor array 120a is disposed on a surface 112 of an engineered structure 110.
• the embodiments of the present invention can utilize different types of sensors.
• a corrosion sensor configuration having a cathode-anode structure can measure impedance, current, and/or voltage to monitor corrosion.
• Other types of sensors, such as chemical detectors, can also be utilized.
• a coating 140 is applied to the surface 112 of the engineered structure 110.
• the sensors 130a- 130f are configured to have a very thin design (e.g., having a sensing portion thickness of about 13 ⁇ m to about 75 ⁇ m) so that the sensors are easily disposed between the surface 112 and the coating 140. In this manner, the sensors can simultaneously provide data on the health of the coating 140 and the engineered structure 110.
• the engineered structure 110 can be any type of structure or object that is exposed to natural elements, such as water, rain, wind, etc.
• the physical composition of the structure 110 can be a metal, such as steel, a carbon fiber composite, a ceramic, or a fiberglass based material such as a fiberglass laminate.
• the detection system 100 can be utilized in a marine platform (e.g., boat, submarine) to detect the health of the coatings and/or structures within a ballast tank or other water-holding structures.
• ballast tanks are used in marine platforms to provide ballast for the vessel. These tanks can be continually filled and/or drained and can also collect debris and other materials.
• salt water is a very corrosive substance
• real-time, periodic coating and/or structure health assessments detected by exemplary detection system 100 can provide critical information related to maintenance planning.
• detection system 100 can be used with other types of engineered structures, such as tunnels, bridges, pipes, and aircraft, which are also susceptible to corrosion or other forms of physical deterioration.
• sensors can be distributed along the length of an underwater/underground oil pipeline that is difficult to visually inspect due to physical boundaries.
• the remote sensing attributes of embodiments of the present invention can provide a user the ability to query sensors from many kilometers away.
• coating 140 can comprise a coating, such as an epoxy- based coating or paint, such as polyamide epoxies (e.g., an epoxy meeting MIL-spec. 24441) and coating epoxies (e.g., product no. 2216 A/B, available from 3M Company, St. Paul, Minnesota).
• detection system 100 can be used to detect characteristics such as the cure condition and/or health of coating 140.
• central controller 150 can be remotely located from the particular engineered structure 110 being monitored.
• controller 150 includes a data acquisition system 151 coupled to a light source 152 and a spectrum analyzer 154.
• An optical signal generated by the light source 152 is communicated to the sensor array 120a via a transmission optical fiber 105a.
• the controller 150 sends and receives optical signals.
• the return optical signals can be distributed to the optical spectrum analyzer 154 via an optical circulator 156.
• an optical switch 158 controlled by the controller 150, can be utilized to distribute the optical signal to other engineered structures and/or other sensor arrays, such as sensor array 120c.
• the use of an optical signal to communicate with the one or more sensor arrays of the overall system provides for long distance connections and a substantial reduction or elimination of electromagnetic interference (EMI) signal degradation.
• EMI electromagnetic interference
• data acquisition system 151 can be configured as a server or other computer-based device that communicates with light source 152, optical spectrum analyzer 154, and (optionally) optical switch 158.
• Data acquisition system 151 can include an interface device and a computer for data storage and display. Also, the data acquisition system can be coupled to a separate display to provide graphical data, such as real-time coating condition data, to a user.
• the data acquisition system 151 can be a computer, server, or computer-based device, data collection, manipulation, analysis, and delivery can be provided via application- specific software programs loaded thereon. Similar data retrieval, decoding and storing processes can be utilized for all sensors or sensor groups used in the system.
• an alert can be provided to the user (e.g., in audible and/or visual format). Otherwise, data can be displayed upon user request.
• An automated process can be employed to activate data retrieval and analysis in a real-time, periodic manner.
• light source 152 comprises a continuous broadband source (e.g., a lamp), with a (relatively) low spectrum power density.
• a source such as an amplified spontaneous emission source can be used to provide an optical signal having a total optical power of about 200 mw over a bandwidth of about 30 nm (with a center wavelength at 1550 nm).
• light source 152 can include a set of narrower band sources, each having an output at a different wavelength, yielding an output signal of light having multiple separate wavelength channels X 1 - X n .
• the set of narrower band sources can comprise a set of diode sources, such as laser diodes, each having a different output wavelength X 1 - X n .
• diodes having different wavelength outputs of Xi - X n can be used separately.
• light source 152 can include a tunable laser that produces laser output at a wider wavelength range (e.g., with laser output spanning a 10- 20 ⁇ m range).
• light source 152 can be a modulated light source to help increase sensitivity of the signal acquisition.
• light source 152 can include a combination of broadband and fixed wavelength or tunable wavelength laser sources.
• the multi-wavelength optical signal is transmitted to a first sensor array 120a along optical fiber 105 a.
• Optical fiber 105 a can be a conventional telecommunications fiber, such as a SMF28TM Optical Fiber available from Corning, Inc. (Corning, NY) or a different optical fiber that is operational at a wavelength region outside the typical optical telecommunication wavelength regions 1300 nm or 1550 nm.
• the optical signal can be further distributed to an additional sensor array 120b via switch 159. As shown in the embodiment of Fig. IA, the optical signal (having wavelengths X 1
• tap-off device 161a can comprise a power tap, distributing a portion of the incoming signal (e.g., about 1% of the signal) to sensor 130a, while the remaining signal is distributed to the other sensors of the array, sensors 13 Ob- 13 Of.
• devices 161a-161f can each comprise a 1 by 2 fiber-based power splitter or a 1 by 2 optical coupler.
• sensor array 12Od can comprise a plurality of individual sensors (in this example, sensors 130a - 1301).
• each individual sensor is coupled directly to the controller 150 (e.g., through optical fibers 105a-1051).
• a sensor 130a can be disposed on surface 112 of structure 110, such as a ballast tank.
• Sensor 130a can be secured to surface 112 via an adhesive, such as a moisture resistant 2-part epoxy (e.g., a Tra-Con 2151 adhesive, available from Tra-Con Corp., Bedford, MA), or a double-sided tape or transfer adhesive, such as 3M VHB, available from 3M Company, St. Paul, Minnesota.
• Sensor 130a can communicate to the controller 150 via optical fiber 105 a/ 106a.
• Coating 140 is applied to the surface 112 to protect the structure 110 from the corrosive effects of an external substance or material, such as seawater 160.
• sensor 130a can detect the health of the coating 140 (e.g. monitoring the impedance by detecting the presence of chemical species, such as chloride), which indicates general coating health as coating 140 deteriorates and as structure 110 starts to corrode.
• chemical species such as chloride
• sensor array 120a can include several individual sensors 130a- 130f. Of course, a greater number of sensors or a fewer number of sensors can be utilized in sensor array 120a, depending on the size of the engineered structure or the particular application.
• each individual sensor can have the same basic structure.
• sensor 130a can be formed on a flexible polyimide substrate (described in more detail below) and can include an optoelectronic interface 134 disposed thereon.
• individual sensors can have different structures.
• the optoelectronic interface 134 can be disposed on a base material, such as a polymer-based material, e.g., a polyamide, polyester, liquid crystal polymer or an acrylic material.
• the base material can provide support for the optoelectronic interface 134 and/or part of a hermetic seal with a cap portion (not shown).
• the base material and/or other portions of the sensor may be adhered to the surface of the engineered structure 110 by an adhesive, such as VHB adhesive available from 3M Company (St. Paul, MN).
• a protective coating or encapsulant 133 can also be provided to protect the components and interconnects from exposure.
• a package cap material such as a hard plastic, can provide an outer protective shell.
• the overall package thickness can be kept to about 100 ⁇ m to about 1000 ⁇ m.
• the optoelectronic interface 134 can include an optical signal demultiplexer 137 (see Fig. 3B).
• the demulitplexer 137 can comprise a thin film-based channel selector that selects a single predefined channel (e.g., X 1 ).
• the optical signal demultiplexer of each sensor can be used to identify each individual sensor by its wavelength X n .
• the optical signal demultiplexer 137 can be used to split the optical signals in two paths, e.g. paths 139a and 139b, as is shown in Fig. 3B.
• demulitplexer 137 selects a signal X 1 and sends it along path 139a, while the remaining signal X 2 - X n is sent along path 139b.
• Sensor 130a can further include a PIN diode array 135 to receive and convert a portion the optical signal into electrical power.
• the signal X 2 - X n is sent along path 139b to the PIN diode array 135, which receives the optical signal and generates electrical power.
• the electrical power can be used as a power source for an electro-chromic switch 136, which receives another portion of the optical signal split by optical signal demultiplexer 137.
• the signal Xi is sent along path 139a to the electro-chromic switch 136.
• the amount of power available to the electro-chromic switch 136 can depend on the condition of the protective coating 140, as the sensing portion 132 is coupled to the power source for the electro-chromic switch 136.
• the electro-chromic switch 136 includes two optically transmissive materials 136c, 136d having a voltage-sensitive material 136a disposed therebetween.
• Voltage-sensitive material 136a can comprise, e.g., tungsten trioxide.
• An electrolyte, 136e is disposed between the voltage sensitive material and layer 136f, preferably a vanadium pentoxide layer.
• Electrolyte layer 136e provides a charge transfer mechanism for the applied voltage V, where the vanadium pentoxide layer 136f can enhance the contrast ratio during the turning on and off of the electro-chromic switch.
• at least one of the transmissive materials, such as transmissive material 136d can be coated with a highly reflective coating 136b. The operation of the electro-chromic switch 136 is described in further detail below.
• a micro-electro-chromic switch can be utilized in the optoelectronic interface 134 as an alternative to the structure 136 shown in Fig. 3C.
• Figs. 6A and 6B illustrate a process for manufacturing a fiber based electro- chromic switch 200, and the components thereof.
• switch 200 can be an extremely compact structure, formed on the terminal end of an optical fiber 210, such as the optical fiber comprising path 139a shown in Fig. 3B.
• step 301 the section of an optical fiber that will be used to fabricate the micro-electro-chromic switch 200 is prepared.
• optical fiber 210 can be prepared by cleaving the fiber to produce a terminal end 215.
• the terminal end of the optical fiber 210 can be stripped of its protective polymer coatings 212 using concentrated acid solution, such as a 95% sulfuric acid solution.
• the rate of optical fiber stripping can vary with temperature and is preferably about 60 seconds at 150 0 C.
• a second optical fiber 220 is also utilized, with its terminal end 225 a also prepared in a similar manner.
• a layer of indium tin oxide (ITO) 230, 232 can be deposited onto the sides and terminal ends 215, 225a of optical fiber 210 and fiber 220, respectively.
• the ITO layer is deposited using a standard vacuum sputtering technique.
• the thickness of the ITO layer may be from about 100 nm to about 200 nm.
• step 303 electrical contacts 235, 237 are formed.
• the voltage source supplied by the PIN diode array 135 can be connected to the electro-chromic switch 200 via contacts 235, 237.
• the contacts may be formed using a vacuum deposition process, electroplating process, an electroless platting process or a combination thereof to deposit at least one conductive layer.
• the conductive layer comprises a metal layer selected from gold, copper, nickel and/or silver.
• the conductive layer can be deposited using an electroless metallization process, such as the process described in U.S. Patent No. 6,355,301, incorporated herein by reference in its entirety.
• a nickel layer band is electrolessly plated onto the fiber surfaces 217, 227 such that it overlaps the ITO glass layer.
• the nickel layer may have a thickness of about 0.1 ⁇ m to about 0.2 ⁇ m.
• an additional thickness of nickel can be electro lyrically plated to provide a nickel band with a thickness of about 1 ⁇ m.
• a layer of gold can be electroplated on top of the nickel band to a thickness of about 0.1 ⁇ m to complete the contact structure.
• a tungsten oxide (WO3) material 240 can be applied onto the ITO layer 230 on the terminal end of optical fiber 210 by a conventional process, such as a vacuum sputter deposition process or dip coating process.
• a dip coating an aqueous solution of WO3 can be used.
• the tip of the fiber 210 can be placed into the solution, withdrawn and dried (e.g., at 17O 0 C for 20 minutes) to yield a tungsten oxide layer having a thickness of at least about 100 nm.
• the thickness of the tungsten oxide layer can be varied according to the electro-chromic switch contrast ratio desired by, for example, changing the concentration of the tungsten oxide solution or by applying multiple applications of the aqueous solution.
• a vanadium oxide (V 2 O5) material 245 can be applied onto the ITO layer 232 on the terminal end of optical fiber 220 by a conventional process, such as a vacuum sputter deposition process or dip coating process.
• a dip coating an aqueous solution OfV 2 Os can be used.
• the tip of the fiber 220 can be placed into the solution, withdrawn and dried (e.g., at 17O 0 C for 20 minutes) to yield a vanadium oxide layer having a thickness of at least about 100 nm.
• the thickness of the vanadium oxide layer can be varied according to the electro-chromic switch contrast ratio desired by, for example, changing the concentration of the vanadium oxide solution or by applying multiple applications of the aqueous solution.
• fiber 220 can be cut, such that only a small portion of fiber 220 is utilized.
• a reflective coating or mirror 250 can be coated on the second terminal end 225b of optical fiber segment 220.
• the mirror 250 can be formed by metallization.
• the mirror 350 may be formed using a conventional process, such as a vacuum deposition process, an electroplating process, an electroless plating process, a dip coating or a combination thereof to deposit at least one reflective layer.
• the reflective layer may comprise silver, aluminum or a series of coating layers having alternating refractive indices.
• the mirror can have a thickness of at least about 150 nm.
• a polymer electrolyte 260 can be placed between the WO3 layer 240 on optical fiber 210 and the V 2 O 5 layer 245 on fiber segment 220.
• the polymer electrolyte preferably comprises a UV-curable polymer electrolyte containing lithium such as a lithium trifluoromethanesulfonimide electrolyte.
• the electrolyte can be applied by dipping the WO 3 coated on optical fiber 210 into an uncured solution of the polymer electrolyte.
• the V2O5 coated fiber segment 220 can then be brought into contact with the electrolyte.
• the assembly can be inserted into a UV-transmissive ferrule such as a glass ferrule to protect the electrochromic switch.
• the ferrule may be bonded to optical fiber 210 and fiber segment 220 by an adhesive at either end of the ferrule.
• the packaged assembly can be exposed to UV light to cure the polymer electrolyte in step 308.
• the thickness of the cured polymer electrolyte layer can be from about 1 ⁇ m to about 100 ⁇ m.
• Electrical wires can be soldered to the metallized electrical contacts to connect the electrochromic switch to the pin diode array.
• a standard lead-tin or silver soldering process may be used.
• Sensor 130a further includes a sensor portion 132.
• array sensing portion 132 can include an electrode structure having interdigitated metal-based (e.g., gold, silver, copper) circuits, which can be used as anodes and cathodes for electrochemical/corrosion measurements, and can be formed on a flexible polyimide substrate.
• a portion of sensor 130a can be coated with its own protective overcoat 133 (e.g., covering the electrical/optical conversion portion of the sensor, but leaving sensing portion 132 exposed to the structure 110 and coating 140).
• sensing portion 132 is formed on a thin, flexible substrate material, such as 3M's flexible circuit material, available under the trade name 3MTM Flex, from 3M Company, St. Paul, MN.
• a thin, flexible substrate material such as 3M's flexible circuit material, available under the trade name 3MTM Flex, from 3M Company, St. Paul, MN.
• 3MTM Flex 3MTM Flex
• An exemplary article and process for making such a flexible circuit are described in U.S. Patent No. 6,320,137, incorporated by reference in its entirety.
• flexible it is meant that the sensor and (if applicable) substrate can be bent so that the sensing portion does not delaminate (e.g., the sensing portion can undergo 90 degree (or greater) bend at a very small radius of curvature, or even a sharp right angle or being creased, without losing its conductive qualities).
• the sensing portion 132 can include a substrate, such as a polyimide material.
• the sensor electrode structure can be formed as a patterned multilayer material upon substrate having, for example, a chrome tie layer, a copper (or other conductive) layer disposed thereon, and a silver (or gold or other metal) layer disposed on the copper layer.
• Other multi-layer structures can be utilized, as would be apparent given the present description.
• a sensing portion 132 with an exemplary cathode-anode structure can provide the ability to measure a voltage drop between the cathode and anode, a current level between the cathode and anode, and/or measure impedance between the cathode and anode, at previously difficult-to-monitor locations.
• the sensing portion 132 can be configured as an electrode formed of a chemical species that is sensitive to water, such as Al, Fe, or Zn. When the chemical species interacts with water, there will be a change in the measured impedance or resistance. Other corrosion sensitive species can also be utilized, as would be apparent to one of ordinary skill in the art given the present description.
• the electro-chromic switch 136 is powered by the output of PIN diodes 135.
• the sensing portion 132 which preferably has a physical construction of an electrode structure having interdigitated metal-based circuits formed on a flexible polyimide substrate, is represented as a resistor electrically coupled to the electro-chromic switch 136.
• the quality of coating 140 is good. Accordingly, the resistance/impedance due to sensing portion 132 is high. As a result, the voltage (V) across the electro-chromic switch 136 is high (e.g., 3V). When the voltage (V) across the electro-chromic switch 136 is high, the voltage-sensitive material 136a absorbs incoming signal (X 1 ) so that no X 1 signal is reflected back to the controller 150. At later stages, after exposure to corrosive elements, the quality of coating 140 deteriorates. Accordingly, the resistance/impedance due to sensing portion 132 is decreased. As a result, the voltage (V) across the electro-chromic switch 136 is reduced.
• V voltage across the electro-chromic switch 136
• the voltage-sensitive material 136a begins to transmit more of the incoming signal (Xi) so that some Xi signal is reflected off coating 136d and sent back to the controller 150. As the coating condition worsens, more Xi signal is reflected back to the controller 150. Thus, the operator can determine the relative health of the coating 140 at a remote location. Other variations of this operation can also be utilized, as would be apparent to one of ordinary skill in the art given the present description. In a preferred aspect, other signals ( ⁇ 2 - K) at other sensors locations (130b- 13On) are generated corresponding to the coating health at the other locations of the engineered structure.
• a spectrometer device such as an optical spectrum analyzer 154 can be used to analyze the reflected light signal.
• Fig. 4 shows an exemplary display output from an example spectrum analyzer 154, where signal strength at particular wavelengths (e.g., ⁇ i - ⁇ n ) can provide the operator with corresponding coating conditions at different locations of the engineered structure.
• signal strength at particular wavelengths e.g., ⁇ i - ⁇ n
• EMI electromagnetic interference
• the sensors can be constructed on flexible, bendable substrates that allow a user to place sensors at critical areas of an engineered structure, such as non-flat surfaces (e.g., around bends and corners and other sharp-angled locations). These locations can be more susceptible to corrosion or other types of deteriorating events because protective coatings may not be evenly applied at corners and other sharp-angled locations.
• an exemplary sensor 130a can be disposed on a single corner surface 111 (Fig. 5A) or a multiple corner surface 113 (Fig. 5B) as might occur around the edge of an I-beam.
• embeddable corrosion sensors can be provided to detect moisture ingress, the ingress of species such as chlorides and other anionic species, coating curing, coating health, and structural health.
• sensors can be formed on flexible substrates, more location-specific real-time measurements can be provided to the user.
• thin circuits e.g., -0.001" thick
• the data acquisition system can provide real time measurement of corrosion-related events.
• Such a corrosion sensor can help reduce the direct and indirect cost of corrosion related damage.

Landscapes

• Chemical & Material Sciences (AREA)
• General Physics & Mathematics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Physics & Mathematics (AREA)
• Analytical Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Biochemistry (AREA)
• Pathology (AREA)
• Immunology (AREA)
• General Health & Medical Sciences (AREA)
• Environmental Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• Ecology (AREA)
• Biodiversity & Conservation Biology (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Molecular Biology (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)
• Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=39541890

Family Applications (1)

Country Status (6)

Families Citing this family (23)

Citations (5)

Family Cites Families (50)

• 2006
  • 2006-12-20 US US11/613,670 patent/US7504834B2/en not_active Expired - Fee Related
• 2007
  • 2007-12-20 EP EP07869627.5A patent/EP2097740A4/en not_active Withdrawn
  • 2007-12-20 WO PCT/US2007/088318 patent/WO2008079946A1/en not_active Ceased
  • 2007-12-20 JP JP2009543213A patent/JP2010515022A/ja active Pending
  • 2007-12-20 KR KR1020097012539A patent/KR20090101182A/ko not_active Ceased
  • 2007-12-20 CN CN2007800454036A patent/CN101553724B/zh not_active Expired - Fee Related

Patent Citations (5)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events