Patent Description:
In many fields, components on large structures, including those found on vehicles, including aircraft, etc., are typically coated with paints, primers, coatings, etc. that can provide a number of important functions to a substrate surface, including, for example, protection from corrosion and other forms of environmental degradation, overcoat or sealant adhesion, abrasion resistance, appearance, etc. Coating and sealants are often applied to areas of assembled components or sub-assemblies that are difficult to access through traditional coating and sealant application processes. In addition, a significant number, sometimes numbering in the thousands and tens of thousands, of small parts requiring coatings and/or sealants (e.g., fasteners, etc.) can occur in assemblies in a large structure (. , fuel tanks on aircraft, etc.). Such coatings and sealants require lengthy curing protocols of several days or more, or require applying heat or other added triggering mechanism (e.g. ultraviolet radiation, etc.) to obtain an appropriate degree of curing. Further, some coatings (e.g. paints and primers, etc.) and sealants are often electrically insulative and can result in an impediment to the dissipation of static and other electrical charges. However, certain structures require the need to dissipate electrical charges that build up on a structure's interior and/or exterior surfaces, including static electrical charges, and charges resulting from, for example lightning strikes, etc. The need for electrical charge dissipation is increasingly important in the aircraft industry, as aircraft manufacture continues to incorporate non-metallic materials. Further, in certain aircraft assemblies, non-metallic materials, such as composites, plastics, etc., that do not dissipate electrical charges predictably across their surfaces may be joined with, or otherwise contact, assemblies and sub-assemblies that comprise metallic materials that do conduct electrical charges. That is, components, assemblies and sub-assemblies that include both composite and metallic materials may be used in the manufacture of, or otherwise incorporated into, larger structures (e.g. aircraft).

Such structures may encounter electromagnetic effects (EMEs) including, for example, and without limitation, lightning strikes. When a structure encounters an EME, the charge delivered to the structure travels throughout any conductive path, and can cause damage to exposed dielectric materials including, for example, composite materials. The electrical damage to composite materials from EMEs can be exacerbated if the edges of the composite material comprise exposed carbon fibers. If the path of charges resulting from an EME encounters varying materials having varying conductivities, damage at or near the material interface can occur. Such interfaces include, without limitation, fasteners/substrate interfaces; and can further include joint interfaces where, for example, seals occur.

Carbon fiber reinforced plastic materials (CFRPs) have utility in structures including, without limitation, vehicles including, without limitation, aircraft. CFRPs comprise a fiber material (e.g. carbon fibers, etc.) impregnated with a resin material (e.g. epoxy resin, acrylic resin, etc.) to make so-called prepregs. Prepregs are partially cured layers that can be manufactured into rolls that can yield unrolled sheets for use in composite material manufacture. Prepreg material, or "prepregs" can then be "laid-up" or "stacked" into multi-layered "stacks" that can be shaped on forming mandrels or other tooling, followed by curing or partially curing the shaped material to produce a composite material that, if desired, adopts desired and predetermined shapes and dimensions imparted by the tool, with the composite material having desired weight and strength. Alternately, prepregs may be oriented into a stack that is trimmed and cured to form a solid stack for use as a composite material structure or other type of composite component.

In aircraft manufacture, CFRP parts are often joined to metallic parts. Problems can occur with respect to predictably dissipating electrical charges when materials, such as CFRPs and various metals (e.g. aluminum, titanium, etc.) that have differing conductivities are joined, fastened, or are otherwise in close proximity to one another.

Coatings, especially coatings used in aircraft manufacture, also must be robust enough to possess a plurality of characteristics, but may not adequately provide all of the required functions to an equivalent or acceptable degree. For example, conductive coatings for dissipating electrical charges across metallic and non-metallic coatings alike have been tried with varying success. However, the known conductive coatings must be loaded with conductive particles to such an extent (sometimes as much as <NUM>-<NUM> weight percent), that other required coating characteristics suffer.

In addition, surface coatings that may be designed to alleviate electrical imbalances across various metallic and/or non-metallic surfaces must often, at least in part, address additional concerns and functions including appearance, adhesion, abrasion resistance, environmental degradation, etc..

Further, inherent coating characteristics (viscosity, etc.,) may make it difficult to apply such coatings to parts (e.g., including without limitation, fasteners located in or on restrictive locations and surfaces) using efficient application techniques. For example, an otherwise desirable coating may be too viscous to apply to a surface using sprayers, when an application mode such as spraying could otherwise offer improvements to coating processing in terms of, efficiency, cost savings, etc..

In addition, specialized coatings having a useful range of varying properties may be expensive to prepare, maintain, store, or deploy. Otherwise useful coatings may further have long curing times, for example taking days to cure with or without the presence of elevated curing temperatures or the use of additional triggering processes. Such extended or complex curing regimens further add to the manufacturing time required, as well as increasing cost. In addition, specialized coatings may lack an adequate shelf life or pot life to be useful for very long on-site. It may further be economically impractical for a particular manufacturing facility (in terms of equipment or space requirements) to store and/or inventory coatings that require, for example, maintenance at particular temperatures.

<CIT> in accordance with its Abstract states "The invention discloses an antistatic high-temperature-resistant polyether-ether-ketone coating and a preparation method of the antistatic high-temperature-resistant coating, and belongs to the technical field of paint. The mass ratio of the polyether-ether-ketone resin to a carbon nano tube in the coating disclosed by the invention is (<NUM>-<NUM>) to (<NUM>-<NUM>). The preparation method of the coating comprises the steps of grinding and drying the polyether-ether-ketone resin; mixing with the carbon nano tube to obtain mixed paint, and spraying the mixed paint on a sanded metal plate by an electrostatic spraying technology; and curing at room temperature after melting at high temperature to obtain the antistatic high-temperature-resistant coating. The alternating current conductivity of the antistatic high-temperature-resistant coating disclosed by the invention under the frequency of <NUM><NUM>Hz is <NUM>*<NUM>-<NUM>s/m to <NUM>*<NUM>-<NUM>s/m, and has the antistatic function. The preparation method of the antistatic high-temperature-resistant coating disclosed by the invention is simple and convenient; the conductive padding is evenly dispersed in resin; the conductivity of the coating is improved; and the antistatic high-temperature-resistant coating can be applied to the industries such as electronics, electric appliances, aviation and petrochemical engineering".

<CIT> in accordance with its Abstract states "The invention belongs to the technical field of paint, and particularly relates to high-antistatic polyether ketone ketone electrostatic spraying powder paint as well as a preparation method and application thereof. The high-antistatic polyether ketone ketone electrostatic spraying powder paint is prepared from polyether ketone ketone resin and conductive fillers coated with acrylic resin at the surface according to the mass ratio of (<NUM> to <NUM>):(<NUM> to <NUM>); the melt index of the polyether ketone ketone resin is <NUM> to <NUM>/<NUM>; the test conditions are as follows: the temperature is <NUM> DEG C, and the load is <NUM>. <NUM>; the powder grain diameter D50 of the polyether ketone ketone resin is <NUM> to 120mu m. The high-antistatic powder paint provided by the invention has better flowability; during the antistatic spray coating, the construction is simple; the conductive fillers in a formed coating are uniformly dispersed in the resin; the electric conductivity of the prepared electrostatic spraying coating is improved. The invention also provides the preparation method and application of the high-antistatic polyether ketone ketone electrostatic spraying powder paint".

<CIT> in accordance with its Abstract states "A polymer/carbon monometre tube composite powder is prepared from granular polymer (average grain size <NUM> microns-<NUM>), carbon nanometre tube (<NUM>-<NUM>) and disperser through proportionally mixing in a highspeed stirrer for <NUM>-<NUM>, and shear-dispersing in a solid-phase shear pulverizing for shear dispersing <NUM>-<NUM> times. It can be used to prepare the plastic, rubber and fibre product with electrically conducting, antistatic, thermally conducting, electromagnetic shielding and microwave absorbing performances".

<CIT> in accordance with its Abstract states "A method for molding amorphous polyether ether ketone including steps of preparing a molten mass including polyether ether ketone, cooling a mold assembly to a temperature of at most about <NUM>° F. , and injecting the molten mass into the cooled mold assembly".

<CIT> in accordance with its Abstract states "Provided is an aircraft assembly equipped with a lightning protection structure that is not easily destroyed by lightning current and that is highly reliable. In an aircraft assembly including a skin (<NUM>) in which a CFRP layer (<NUM>) serves as a main structure; a shear-tie (<NUM>) that support the skin (<NUM>) from the inside; and a fastener (<NUM>) that couples the skin (<NUM>) and the shear-tie (<NUM>), a copper foil (<NUM>) and an outside GRFP layer (<NUM>) are provided on an outer surface side of the skin (<NUM>), in this order towards the outside, and a copper paint layer (<NUM>), which contains copper powder, is provided on the outside GFRP layer (<NUM>)".

<CIT> in accordance with its Abstract states "Surface films, paints, or primers can be used in preparing aircraft structural composites that may be exposed to lightning strikes. Methods for making and using these films, paints or primers are also disclosed. The surface film can include a thermoset resin or polymer, e.g., an epoxy resin and/or a thermoplastic polymer, which can be cured, bonded, or painted on the composite structure. Low-density electrically conductive materials are disclosed, such as carbon nanofiber, copper powder, metal coated microspheres, metal-coated carbon nanotubes, single wall carbon nanotubes, graphite nanoplatelets and the like, that can be uniformly dispersed throughout or on the film. Low density conductive materials can include metal screens, optionally in combination with carbon nanofibers".

In an aspect there is provided an assembly as defined in claim <NUM>.

In another aspect there is provided an object as defined in claim <NUM>.

A present aspect as defined in claim <NUM> discloses an assembly including a first substrate and a second substrate, a fastener configured to join the first substrate and the second substrate, and a spray-deposited thermoplastic polymer coating material configured to coat the installed fastener. The spray-deposited thermoplastic polymer coating material is made from a powdered feedstock material, said powdered feedstock material comprising: a thermoplastic polymer powder feedstock comprising at least one of: nylon, polyetheretherketone, polyetherketoneketone, polyamide, polyphenylsulfide, polyphenylsulfone, polysulfone, and polyetheramide.

In another aspect, the assembly includes a thermoplastic polymer coating material that further includes a conductive material comprising at least one of: titanium, nickel alloy, copper, carbon black, graphene powder, and carbon nanotubes.

Also disclosed is a fastener coating system including a high-velocity sprayer and at least one thermoplastic polymer powder as a feedstock, with the thermoplastic polymer powder including at least one of: nylon, polyetheretherketone, polyetherketoneketone, polyamide, polyphenylsulfide, polyphenylsulfone, polysulfone, and polyetheramide. The spray-deposited thermoplastic polymer coating further includes at least one thermoplastic polymer comprising at least one of: copolymers including Hytrel® TPC-ET (DuPont®), thermoplastic elastomers, and thermoplastic fluoroelastomers including DAI-EL® T-<NUM> (Daikin®).

In another aspect, the thermoplastic polymer powder further includes a conductive material powder including at least one of: titanium, nickel alloy, copper, carbon black, graphene powder, or carbon nanotubes.

In another aspect, the feedstock includes a feedstock mixture of at least one thermoplastic polymer powder feedstock.

In a further aspect, the feedstock mixture includes a mixture of at least one thermoplastic polymer powder feedstock combined with a conductive powder feedstock material.

Still further aspects are directed to fasteners including the disclosed thermoplastic polymer coatings and the disclosed conductive thermoplastic polymer coatings, as well as assemblies that include the coated fasteners, and larger objects that include the assemblies that further include the coated fasteners.

Also disclosed is a method for coating an installed fastener including delivering a thermoplastic polymer powder feedstock to a high-velocity sprayer, with the thermoplastic polymer powder feedstock comprising at least one of: nylon, polyetheretherketone, polyetherketoneketone, polyamide, polyphenylsulfide, polyphenylsulfone, polysulfone, and polyetheramide. Further thermoplastic polymer powder feedstocks include at least one thermoplastic polymer powder comprising at least one of: copolymers including Hytrel® TPC-ET (DuPont®), thermoplastic elastomers, and thermoplastic fluoroelastomers including DAI-EL® T-<NUM> (Daikin®). A thermoplastic polymer coating material is formed, followed by directing the thermoplastic polymer coating material from the high-velocity sprayer to the installed fastener and depositing an amount of the thermoplastic polymer coating material on the installed fastener, and coating the installed fastener with the thermoplastic polymer coating material.

Also disclosed is a method for coating an installed fastener including delivering a thermoplastic polymer powder feedstock to a high-velocity sprayer, with the thermoplastic polymer powder feedstock comprising at least one of: nylon, polyetheretherketone, polyetherketoneketone, polyamide, polyphenylsulfide, polyphenylsulfone, polysulfone, and polyetheramide; and a conductive powder feedstock comprising at least one of: titanium, nickel alloy, copper, carbon black, graphene powder, or carbon nanotubes. Further thermoplastic polymer powder feedstocks further include at least one thermoplastic polymer powder comprising at least one of: copolymers including Hytrel® TPC-ET (DuPont®), thermoplastic elastomers, and thermoplastic fluoroelastomers including DAI-EL® T-<NUM> (Daikin®). A conductive thermoplastic polymer coating material is formed, followed by directing the conductive thermoplastic polymer coating material from the sprayer to the installed fastener and depositing an amount of the conductive thermoplastic polymer coating material on the installed fastener, and coating the installed fastener with the conductive thermoplastic polymer coating material.

In another aspect, the high-velocity sprayer is a thermal sprayer or a cool sprayer.

Also disclosed is a method for coating an installed fastener further including directing the movement of the high-velocity sprayer by associating a robot in communication with the high-velocity sprayer and a controller for controlling and regulating the amount of thermoplastic polymer coating material or conductive thermoplastic polymer coating material deposited onto a fastener installed in a substrate.

In further aspects, one or more thermoplastic polymer powder feedstocks are combined into a thermoplastic polymer powder feedstock mixture, with the feedstock mixture then supplied as the feedstock material to the high-velocity sprayer.

In another aspect, more than one thermoplastic polymer powder feedstock is supplied directly to the high-velocity sprayer as separate feedstock materials via one or more feedstock feedlines.

In further aspects, one or more thermoplastic polymer powder feedstocks and a conductive powder feedstock are combined to form a conductive thermoplastic polymer powder feedstock mixture that is supplied to a high-velocity sprayer as the feedstock material.

In another aspect, more than one thermoplastic polymer powder and a conductive powder are supplied directly to the sprayer as separate feedstock materials via one or more feedstock feedlines.

According to further aspects, when a thermoplastic spray formulation includes a conductive component delivered by the conductive powder feedstock, the resulting conductive thermoplastic coating delivered from the high-velocity sprayer to a substrate surface has a resistivity ranging from about <NUM>×10e<NUM> to about <NUM>×<NUM><NUM> ohm-meter (ohm-m). More preferably, the resulting conductive thermoplastic coating delivered from the high-velocity sprayer to a substrate surface has a resistivity ranging from about <NUM>×10e<NUM> to about <NUM>×<NUM><NUM> ohm-m.

Aspects of the present disclosure further contemplate, without limitation, objects, components, sub-assemblies, assemblies having substrate surfaces that include the thermoplastic coatings and conductive thermoplastic coating delivered to a substrate surface according to the methods disclosed. The objects include, for example, and without limitation, a manned aircraft, an unmanned aircraft, a manned spacecraft, an unmanned spacecraft, a manned rotorcraft, an unmanned rotorcraft, a satellite, a rocket, a manned terrestrial vehicle, an unmanned terrestrial vehicle, a manned and unmanned hovercraft, a manned surface water borne vehicle, an unmanned surface water borne vehicle, a manned sub-surface water borne vehicle, an unmanned sub-surface water borne vehicle, and combinations thereof.

Aspects of the present disclosure are directed to powdered thermoplastic feedstock formulations that can be tunable, or otherwise have their characteristics changed in real time during deposition and that can include conductive materials and that can be conductively tunable. The powdered thermoplastic polymers powder feedstocks include powdered polymers that include at least one conductive powdered material that can be deposited onto a substrate surface via a high-velocity sprayer to form a thermoplastic coating on a substrate surface, with the coating having predetermined characteristics.

Aspects of disclosed powdered conductive thermoplastic coating formulations that contain a conductive powder and that can be tuned or tailored, including in real time, provide a wide range of required characteristics for electrically conductive thermoplastic coatings offering a particular, and wide-ranging amount of resistivity or conductivity, while also providing robust protective qualities to the substrates being coated with the presently disclosed conductive thermoplastic coatings.

Additionally, aspects of the present disclosure are directed to thermoplastic coating formulations that can be tailored to deliver a thermoplastic coating using high-velocity spraying techniques to metallic and non-metallic substrates and components, with the thermoplastic coatings having predetermined characteristics,. When a conductive powdered feedstock material is present in the thermoplastic polymer powder feedstock, various characteristics of the resulting applied conductive thermoplastic coatings can be predictably tailored, even in substantially real-time, by changing the proportions of powdered feedstock constituents (e.g. the at least one thermoplastic polymer powder feedstock and the conductive powder feedstock) that are provided to the high-velocity sprayer.

`Young's (elastic) modulus' is a well known term in the art in relation to thermoplastic polymer sealants. Young's modulus may be measured, for example, according to ASTM D638-<NUM> - Standard Test Method for Tensile Properties of Plastics.

'Resistivity value' is a well known term in the art in relation to thermoplastic polymer sealants. The resistivity value may be measured, for example, according to ASTM D257-<NUM> - Standard Test Methods for DC Resistance or Conductance of Insulation Materials.

Without being limiting, the average particle size of the thermoplastic polymer powders used according to aspects of the present disclosure range from about <NUM> to about <NUM>. In addition, without being limiting, the average particle size of the conductive powders used according to aspects of the present disclosure range from about <NUM> to about <NUM>.

The high-velocity sprayers used in connection with aspects of the present disclosure include sprayers able to disperse a feedstock at velocities ranging from about <NUM>/s to about <NUM>/s. Such sprayers include thermal (e.g., flame sprayers, etc.) and cold sprayers.

`Average particle size' is a well known term in the art. Average particle size may, for example, be determined using standard methods including the use of particle sizing analyzers that employ laser diffraction (Beckman Coulter Life Sciences, Indianapolis, IN. Accordingly, average particle size may refer to Dv50 (the median for a volume distribution). Average particle size may be measured, for example, according to ASTM E2651 - Standard Guide for Powder Particle Size Analysis.

Aspects of the present disclosure are directed to powdered thermoplastic formulations that can be tunable, or otherwise have their characteristics changed in real time during deposition and that can include conductive materials and that can also be conductively tunable. The powdered thermoplastic polymer feedstocks can include at least one conductive powdered material to form a conductive thermoplastic powder feedstock mixture that can be deposited onto a substrate surface via a high-velocity sprayer to form a tunable conductive thermoplastic coating on a substrate surface, with the conductive thermoplastic coating having predetermined characteristics.

Aspects of disclosed thermoplastic polymer powder powdered conductive coating formulations can be tuned or tailored, including in real time, to provide a wide range of required coating characteristics, while also providing robust protective coating qualities to the substrates being coated with the presently disclosed thermoplastic coatings.

According to further aspects, powdered conductive thermoplastic polymer coating formulations (that contain a conductive powder) can be tuned or tailored, including in real time, and provide a wide range of required characteristics for electrically conductive thermoplastic coatings offering a particular, and wide-ranging amount of resistivity or conductivity, while also providing robust protective qualities to the substrates being coated with the presently disclosed conductive thermoplastic coatings.

Additionally, aspects of the present disclosure are directed to thermoplastic polymer powder coating formulations that can be tailored as precursor feedstock mixtures, or that can be delivered substantially concurrently or in predetermined sequence to a sprayer (e.g., a predetermined programmed sequence) from separate feedstock sources or supplies to a high velocity sprayer. The sprayer then delivers the thermoplastic polymer powder coating formulations to form a thermoplastic coating, using high-velocity spraying techniques, to metallic and/or non-metallic substrates and components, with the thermoplastic coatings having predetermined characteristics that can be tuned in real time (e.g., in real time during application to a substrate surface, etc.). When a conductive powdered feedstock material is present in the thermoplastic polymer powder feedstock, various characteristics of the resulting applied conductive thermoplastic coatings can be predictably tailored, even in substantially real-time, by changing the proportions of powdered feedstock constituents (e.g., the proportion(s) of the at least one thermoplastic polymer powder feedstock and the conductive powder feedstock) that are provided to the sprayer.

Without being limiting, the average particle size of the thermoplastic polymer powder feedstock(s) used according to aspects of the present disclosure range from about <NUM> to about <NUM>. In addition, without being limiting, the average particle size of the conductive powder feedstock(s) used according to aspects of the present disclosure range from about <NUM> to about <NUM>. The high-velocity sprayers used in connection with aspects of the present disclosure include sprayers able to disperse a feedstock at velocities ranging from about <NUM>/s to about <NUM>/s. Such sprayers include thermal (e.g., flame sprayers, etc.) and cold sprayers. According to one aspect, the thermoplastic polymer powder comprises at least one of a nylon, polyetheretherketone (equivalently referred to as PEEK), polyetherketoneketone (equivalently referred to as PEKK), polyamide, polyphenylsulfide, polyphenylsulfone, polysulfone, and polyetheramide.

In further aspects, the thermoplastic polymer powder feedstock comprises at least one of a thermoplastic polyester elastomer powder or a thermoplastic fluoroelastomer powder. Contemplated thermoplastic elastomer powders include those that can be obtained as PEEK, PEKK, Hytrel® <NUM> (DuPont); Dai-El™, (Daikin®); Hipex®, (Kraiburg), etc. The thermoplastic polymer powder feedstocks preferably have an average particle size ranging from about <NUM> to about <NUM>.

Polyether ether ketone (PEEK) is an organic thermoplastic in the polyaryletherketone (PAEK) family, with PEEK having the general formula:
<CHM>.

PEEK has a coefficient of thermal expansion value (depending upon grade) ranging from of about <NUM> to about <NUM> ppm/°F (about <NUM> to about <NUM> ppm/°C), (i.e. about <NUM> to about <NUM> ×<NUM>-<NUM> in. /in/°F (about <NUM> to about <NUM> × <NUM>-<NUM> cm/cm/°C)), a Young's modulus value of about <NUM> GPa and a tensile strength ranging from about <NUM> MPa to about <NUM> MPa. PEEK is highly resistant to thermal degradation as well as attack by both organic and aqueous environments (e.g. environments including, without limitation, those environments coming into contact with fuels and fuel systems, etc.) , and has a high resistance to biodegradation.

According to another, and as also presented in the Examples below, ret polymer powder. Polyetherketoneketone (PEKK) is a semi-crystalline thermoplastic in the PAEK family, with PEKK having the general formula:
<CHM>.

PEKK has a coefficient of thermal expansion value (depending upon grade) of about <NUM> to about <NUM> ppm/°F (about <NUM> to about <NUM> ppm/°C), (i.e. about <NUM> to about <NUM> × <NUM>-<NUM> in. /in/°F (about <NUM> to about <NUM> × <NUM>-<NUM> cm/cm/°C)), a Young's modulus value of about <NUM> GPa and a tensile strength of about <NUM> MPa. PEKK is also highly resistant to thermal degradation as well as attack by both organic and aqueous environments (e.g. environments including, without limitation, those environments coming into contact with fuels and fuel systems, etc.), and has a high resistance to biodegradation.

The density of the contemplated thermoplastic polymer coating deposited onto a substrate surface can be of any desired thickness, but is particularly deposited at a thickness ranging from about <NUM> to about <NUM>, with the contemplated thermoplastic coatings having a material density ranging from about <NUM>/cc to about <NUM>/cc). Being able to deposit a thermoplastic coating having such tailorable and predetermined densities and deposited to such desired thicknesses at reduced densities realizes substantial weight reduction compared with material coatings presently used in, for example, aircraft production where overall weight impacts vehicle range, fuel consumption, available cargo capacity, manufacturing time, etc., all of which can impact total production cost.

If desired, according to further contemplated aspects, the thermoplastic coatings (and when conductive components are present to form conductive thermoplastic coatings, such resulting conductive thermoplastic coatings) can be tailored or "tuned", for example, in real time during the coating deposition process, such that the deposited coatings possess various desired and predetermined characteristics, e.g., physical, chemical, thermal, etc. Such aforementioned tailorable characteristics are. in addition to the desired and tailorable conductivity or resistivity values achievable with the presently disclosed conductive thermoplastic coatings. This can be achieved by providing differing powdered thermoplastic polymer feedstock(s), differing amounts (e.g., differing comparative ratios, etc.) of differing powdered thermoplastic polymer feedstock(s), additional numbers of differing powdered thermoplastic polymer feedstock(s), or by providing additives to the powdered thermoplastic polymer feedstock(s).

According to other aspects, contemplated conductive powder feedstock materials include, without limitation, various metallic powders including titanium, nickel alloy, copper, carbon black, graphene powder, or carbon nanotubes. The contemplated conductive powder feedstock materials preferably have an average particle size ranging from about <NUM> to about <NUM>. The powdered thermoplastic polymer feedstock formulations disclosed, according to aspects of the present disclosure, when combined or otherwise mixed with one or more conductive powder feedstock(s) produce a resulting conductive thermoplastic polymer feedstock mixture that yields a conductive thermoplastic polymer coating on a substrate surface, with the resulting conductive coating having a desired and predetermined resistivity ranging from about <NUM>×10e<NUM> to about <NUM>×<NUM><NUM> ohm-m, and more preferably from about <NUM>×10e<NUM> to about 10e<NUM> ohm-m.

To provide a conductive thermoplastic coating on a substrate surface having a resistivity ranging from about <NUM>×10e<NUM> to about <NUM>×<NUM><NUM> ohm-m, the conductive thermoplastic polymer powder feedstock(s) have a relative percentage by volume of the conductive component (e.g. the conductive powder) ranging from about <NUM>% to about <NUM>% by volume of the total volume of conductive thermoplastic polymer powder provided to the sprayer.

It is further understood that the thermoplastic polymer powder (e.g., provided as a feedstock to the sprayer) can be a mixture that is formed prior to the introduction of the multi-component feedstock to the sprayer. In one aspect, when the powdered feedstock comprises more than one type of powder component (e.g. more than one thermoplastic polymer powder feedstock; one thermoplastic polymer powder feedstock and at least one type of conductive powder feedstock; more than one thermoplastic polymer powder feedstock and at least one type of conductive powder feedstock, etc.), the multiple component powder feedstock materials can be mixed together to form a thermoplastic (or conductive thermoplastic) polymer powder mixture, or "feedstock mixture". The feedstock mixture is then introduced as the feedstock to the sprayer. For the purpose of the present disclosure, the term "feedstock" refers to a precursor material that is supplied from a supply of a material to a mixture, or is supplied directly to a sprayer via a feed line from a supply of a material.

In an alternate aspect, when the powdered feedstock comprises more than one type of powder component (e.g., more than one thermoplastic polymer powder feedstock; one thermoplastic polymer powder feedstock and at least one conductive powder feedstock; more than one thermoplastic polymer powder feedstock and at least one conductive powder feedstock, etc.), the multiple powdered feedstock components can be directed via separate feed lines to the sprayer, such that no multiple component powdered feedstock mixture is pre-formed as a single feedstock that is then provided to the sprayer. According to this aspect, on or more controllers can be used to monitor and control the rate at which a single powdered feedstock is released from a supply and directed to the sprayer. In this way, the individual flow rate of a particular powdered feedstock component is controlled, monitored and maintained to insure that a particular ratio of feedstock components that arrive at (e.g., are delivered to) the sprayer is achieved and, if desired, maintained for the duration of the material (e.g. coating) spray deposition onto a substrate surface. For example, in this aspect, to produce a conductive thermoplastic coating having a resistivity ranging from about <NUM>×10e<NUM> to 10e<NUM> ohm/m, the presence of an amount of conductive powder feedstock delivered to the sprayer ranges from about <NUM>% to about <NUM>% by volume of the combined powdered material feedstock delivered to the sprayer (e.g., the combined powdered material volume equaling the volume of thermoplastic polymer powder feedstock combined with the conductive powder feedstock volume, and, for example, controlled, monitored and maintained by regulating the comparative flow rates of the individual component feedstocks fed via one or more feed lines to the sprayer, etc.).

According to present aspects, a formed conductive thermoplastic polymer powder feedstock mixture becomes the thermal sprayer feedstock material that is converted by the thermal sprayer into a conductive coating or conductive sealant that is desirably applied (via the thermal sprayer) to a metal, non-metal, or metal/non-metal interface at, for example, a fastener, or a joint, or to a component edge as an edge seal. The comparative amount of conductive powder that is selected and added to the thermoplastic powder to form the conductive thermoplastic powder mixture, is selected to achieve a particular conductive effect in the eventual conductive thermoplastic coating and/or conductive thermoplastic sealant that is deposited onto a substrate in the form of a conductive coating or conductive sealant. That is, by tailoring the amount of conductive powder added to form the form the thermoplastic powder mixture used as the thermal sprayer feedstock material, the resulting material exiting the thermal sprayer and deposited onto a substrate surface will become a coating or sealant having a particularly preselected resistivity on the substrate surface.

The tailorable conductive thermoplastic coatings that are obtained according to aspects of the present disclosure provide conductive flexibility with respect to dissipating static charges that build up with and along a particular material, or are caused by significant electrical events including, for example, lightning strikes. In addition, the conductive thermoplastic coatings disclosed herein have significant advantages commensurate with thermoplastic coatings in terms of ease of handling, ease of application, retention and adhesion characteristics, safety due to lower toxicity (e.g., as compared with polysulfides and chromates, etc.), etc..

Still further, since the presently disclosed conductive coatings are thermoplastic in nature, the conductive thermoplastic coatings or sealants do not require a separate curing step after application. In other words, the thermoplastic coatings/sealants will "set" upon cooling and require no subsequent curing protocol or regimen to "set up". The disclosed thermoplastic polymer coatings and conductive thermoplastic polymer coatings can be fabricated to further comprise a particular color to, for example, facilitate inspection with respect to both initial application quality as well as repair and maintenance inspections that will be conducted at various quality control and servicing intervals. Still further, if repair or replacement of a thermoplastic polymer coated part or surface (or a conductive thermoplastic polymer coated part or surface) is required, such coated parts or the coatings on such coated parts can be more easily removed using various solvent or mechanical removal as compared to, for example, epoxy- or acrylamide-based coatings and/or sealants that require curing regimens.

With respect to adhesion, the conductive coatings/sealants of the present disclosure have adhesion values ranging from about <NUM> lbs/in (<NUM> N/m) to about <NUM> lbs/in (<NUM> N/m) wide area on both metals and non-metals when performing adhesion testing set forth in ASTM D6862-<NUM>(<NUM>) Standard Test Method for <NUM>° Peel Resistance.

In this way, the thermoplastic coating and sealant systems disclosed herein combine the benefits of thermoplastic material characteristics with high-velocity spray techniques and systems (e.g., thermal flame spraying and cold spraying), and the deposited thermoplastic coating and sealant characteristics are further tailorable to a desired end use as coatings and/or sealants on a substrate surface. When a conductive powder feedstock component is added to the thermoplastic powder feedstock, the conductive coatings deposited to a substrate surface have electrical characteristics (e.g., conductivity, resistivity, etc.) that can also be tailored as required for their intended use as conductive coatings, particularly as coatings and/or sealants on homogeneous or hybrid surfaces comprising metallic and/or non-metallic components.

According to a further aspect, the presently known thermal and cold spray equipment and systems can be retrofitted to deposit coatings made from the presently disclosed thermoplastic formulations that can also include conductive materials to form conductive thermoplastic coatings. Particularly preferred thermal sprayers include flame sprayers.

Thermal spraying techniques are coating processes where melted or heated materials are sprayed onto (e.g., deposited onto) a surface. Feedstock material is supplied to the sprayer as a coating precursor. The feedstock is heated by electrical (e.g., plasma or arc) or chemical means (e.g., combustion flame). Thermal spraying can achieve coatings having a coating thickness ranging from about <NUM> to about <NUM> over a large area and at a high deposition rate as compared to other known coating processes, with the presently contemplated deposition rate ranging, for example, from about <NUM> on <NUM> ft<NUM> (<NUM><NUM>) in <NUM> seconds, or greater, etc., or coatings deposited at a rate ranging from about <NUM> to about <NUM> grams/second, (g/s), etc..

Flame spray coating refers to a type of thermal spraying where melted or heated feedstock materials are sprayed onto a substrate surface. The feedstock (e.g., the coating precursor material) is heated by electrical (e.g., plasma or arc) or chemical means (e.g., combustion flame). During coating processes the substrate preferably undergoes no distortion, as the substrate temperature remains below about <NUM>°F (<NUM>) during the spray operation. When the substrate is metallic, the substrate is not metallurgically altered. Coating thickness ranging from about <NUM> to <NUM> can be achieved, with deposition (e.g., coating application) rates for such thicknesses ranging from at least about <NUM> on <NUM> ft<NUM> (<NUM><NUM>) in <NUM> seconds, or greater; or coatings deposited at a deposition rate ranging from about <NUM> to about <NUM> grams/second (g/s), etc. Without limitation, thermal (e.g., flame, etc.) sprayers useful according to present aspects include, for example, TAFA Models <NUM> HP/HVOF®, <NUM> HP/HVOF®, <NUM> JPid HP/HVOF® (ID), <NUM> (UPCC), JP-<NUM> HP/HVOF®, JP-<NUM>® HP/HVOF® (Praxair, Inc. , Danbury, CT); Powderjet® <NUM>, Powderjet®<NUM> (Metallizing Equipment Co. (Jodhpur, India)Plasma Technology Inc. , Torrence, CA): and systems available from Plasma Technology Inc. (Torrence CA), etc. Universal Flame Spray System PG-<NUM> (Alamo Supply Co. , (Houston, TX), etc. Various controllers can be used in conjunction with the TAFA systems described including, for example, TAFA Model 7700GF HVOF System (Praxair, Inc. , Danbury, CT).

In contrast with the flame sprayer systems mentioned above, in "cold spray" systems powder particles (e.g., feedstock particles) typically having an average particle size ranging from about <NUM> to about <NUM>, and are accelerated to very high velocities (<NUM> to <NUM>/s) by a supersonic compressed gas jet at temperatures below their melting point. Upon impact with the substrate, the particles experience extreme and rapid plastic deformation that disrupts the thin surface oxide films that are present on all metals and alloys. This allows intimate conformal contact between the exposed substrate surfaces under high local pressure, permitting bonding to occur with the layers of deposited material. The layers of deposited material can be built up rapidly, with very high deposition efficiency (e.g., above <NUM>% in some cases). Using cold spray systems, materials can be deposited without high thermal loads, producing coatings with low porosity and oxygen content. Without limitation, cold sprayers useful according to present aspects include, for example, Impact Spray System <NUM>/<NUM>; Impact Spray System <NUM>/<NUM> (Impact Innovations Waldkraiburg, Germany), etc..

Cold spray processes refer to the thermal spray processes and collectively refers to processes known as cold gas dynamic spraying, kinetic spraying, high velocity particle consolidation (HPVC), high velocity powder deposition, supersonic particle/powder deposition (SPD), and the like. In cold spraying, a high velocity gas jet, for example, a deLaval converging/diverging nozzle can be used to accelerate powder particles generally having an average particle size ranging from about <NUM> to about <NUM>. The particles are accelerated by the gas jet at a temperature that is below the melting point of the feedstock material particles. The particles are then sprayed onto a substrate that can be located about <NUM> from the nozzle. The particles impact the substrate and form a coating. Without being bound by a particular theory, it is believed that the kinetic energy of the particles, rather than an elevated temperature causes the particles to plastically deform on impact with the substrate surface to form "splats" that bond together to produce the coating. The coatings formed from the cold sprayed particles are formed in the solid state, and not via the melting followed by solidification as occurs in thermal spray processes (e.g., flame spraying, etc.) using elevated temperature. Such a cold spray process avoids deleterious effects that can be caused by high temperature deposition, including, for example, high-temperature oxidation, evaporation, melting, crystallization, residual stress, gas release, etc. As a result, according to present aspects, cold spraying can be advantageously used for temperature sensitive (e.g., heat sensitive) substrates. The resulting coatings according to present aspects, possess characteristics including high strength, low porosity and minimal residual stress.

As mentioned above, characteristics of the thermoplastic coatings contemplated according to present aspects can be altered in a predetermined fashion by providing a predetermined combination of materials to form a tailored thermoplastic polymer powder feedstock material, and by further incorporating additives, including, without limitation, additives such as pigments, dyes, or coloring agents, etc. Such coloring agents can facilitate the inspection of the condition of coatings during, for example, inspections, etc..

As mentioned previously, the sprayers used in the systems and methods disclosed herein can be operated manually, but can also be automated by incorporating or otherwise attaching the sprayer to a robot, or robotic arm that includes or is in communication with sensors, controllers, software and hardware, etc. for the purpose of controlling the operation and movement of the sprayer and the operation of the sprayer during, for example a material deposition (e.g., coating, etc.) cycle. The robot and equipment associated with the robot and sprayer can be operated and powered directly, and further can be operated remotely in response to, for example, wireless signals, etc. Where coating characteristics have included robustness in terms of adhesion and/or resistance to environmental factors such as those encountered, for example, in vehicle fuel tanks, etc., coating materials have been classified with various toxicities, making their handling and application hazardous to personnel. In addition, various application sites have been difficult to access. In addition, maintaining and/or replacing the coatings presently in use has resulted in significant repair and replacement time, as the removal of cured coatings. The coatings made possible according to aspects of the present disclosure, being thermoplastic materials, have significantly reduced toxicity during application, and can be more easily removed and replaced (e.g., at scheduled routine inspection and/or replacement).

In addition, the presently disclosed coatings made from the disclosed thermoplastic polymer powder formulations maintain adhesion characteristics over a required service period that is at least equivalent to or exceeds that, which is achievable using the previously available coatings and sealants (e.g., epoxy and acrylamide based options, etc.). The adhesion of the thermoplastic polymer coating made from the disclosed thermoplastic polymer powder formulations have an adhesion ranging from about <NUM> to about <NUM> lbs. /in<NUM> (about <NUM> mPa to about <NUM> mPa)wide area when performing adhesion testing set forth in ASTM D6862-<NUM>(<NUM>) Standard Test Method for <NUM>° Peel Resistance.

When a conductive film or coating is desired, the contemplated thermoplastic polymer coatings, sealants, films, etc. can be tailored to achieve a desired surface resistivity, for example, ranging from about <NUM>×<NUM><NUM> to <NUM>×<NUM><NUM> ohm-m when the conductive component composition of the thermoplastic polymer powder feedstock ranges from about <NUM>% to about <NUM>% by volume of the conductive thermoplastic polymer powder feedstock. The desired characteristics of the coating produced, including, for example, the desired resistivity, setting time, thickness, etc., determines the concentration of the conductive powder feedstock component that is incorporated into the thermoplastic polymer powder feedstock, or that is supplied to the sprayer substantially concurrently with the thermoplastic polymer powder feedstock (e.g., in the situation where feedstocks are supplied to the sprayer separately and a feedstock mixture is not prepared and then delivered to the sprayer.

Coatings and sealants typically applied to spatially restrictive and other difficult-to-access areas in various assemblies and sub-assemblies found, for example, in vehicles including aircraft have required coatings and sealants (e.g., epoxies and acrylamides, etc.) that require significant curing times in excess of many days. Components for use in such assemblies and sub-assemblies comprising the presently disclosed coatings find particular utility in the manufacture of vehicles, including aircraft, as well as structural components used in the manufacture of fuel tanks on such vehicles.

Further, long curing times delay manufacturing and increase manufacturing cost. In contrast to epoxy-based and other materials requiring curing time of several days or longer, the presently disclosed thermoplastic polymer coatings and sealants applied according to the presently disclosed methods do not require curing, and only require the time necessary for the thermoplastic material to cool and "set" (e.g. thermoplastic material "set" times understood to range from about less than a few mins. to about several mins. , or the amount of time a thermoplastic material takes to cool from an applied temperature to about room (ambient) temperature, assuming coating thicknesses ranging from about <NUM> to about <NUM>). According to present aspects, such "set" times for the deposited thermoplastic polymer coatings and sealants disclosed herein (including the deposited conductive thermoplastic polymer coatings and sealants) are in strong contrast to the curing times of several hours or even several days that are required to cure sealants and coatings previously used for the purposes intended herein on the substrates and substrate surfaces intended and disclosed herein.

While many of the characteristics of thermoplastic polymers may have been desirable for use in coatings and sealants in hard to access locations in assemblies and sub-assemblies, use of such thermoplastic polymeric coatings had been particularly hampered where the coatings or sealants required conductivity (or needed to have certain resistivities), or where it had not been previously possible to deposit a thermoplastic coating having variable or tailored characteristics. According to aspects of the present disclosure, the fabrication and use of electrically conductive coatings and sealants that have multiple physical and chemical characteristics tailored that are made from presently disclosed thermoplastic polymer powder formulations, and applied according to presently disclosed methods has now been achieved.

<FIG> shows a block diagram outlining an aspect showing a thermoplastic polymer powder feedstock and a system <NUM> including directing the thermoplastic polymer powder feedstock to a high-velocity sprayer for depositing a thermoplastic polymer coating onto a substrate surface. As shown in <FIG>, a thermoplastic polymer powder feedstock <NUM> is directed from a thermoplastic polymer powder feedstock supply via a thermoplastic polymer powder feedstock feedline <NUM> in communication with the thermoplastic polymer powder feedstock <NUM> and also in communication with a high-velocity sprayer <NUM>. Predetermined amounts of the thermoplastic polymer powder feedstock <NUM> can be directed by any desirable means that will direct the thermoplastic polymer powder feedstock <NUM> to the high-velocity sprayer <NUM>, including automated means regulated by a controller (not shown) and subject to, for example, software and hardware known to control, for example, feedstock flow rates, etc. The high-velocity sprayer can be a thermal sprayer or a cold sprayer. As shown in <FIG>, the thermoplastic polymer powder feedstock <NUM> is converted by the high-velocity sprayer <NUM> into a thermoplastic polymer coating 16a onto substrate <NUM>. While the high-velocity sprayer <NUM> can be operated manually, <FIG> shows an optional robotic arm <NUM> (or "robot") that can be in communication with a controller <NUM>. Controller <NUM> can further optionally be in communication with remote or integrated software or hardware, as desired, to control robotic arm movement as well as control flow rates and amounts of material deposited as a thermoplastic coating 16a onto a substrate <NUM>. Optionally, additional controllers (not shown) can be integrated into system <NUM> to control one or more aspects of system <NUM>.

<FIG> shows a block diagram outlining an aspect showing a thermoplastic polymer powder feedstock mixture and system <NUM> including mixing multiple thermoplastic polymer powder feedstocks to form a thermoplastic powder mixture, and then directing an amount of the thermoplastic powder mixture to a high-velocity sprayer and depositing a thermoplastic polymer coating onto a substrate surface. As shown in <FIG>, in system <NUM>, predetermined amounts of a first thermoplastic polymer feedstock 22a, and a second thermoplastic polymer feedstock 22b are directed to a mixing vessel (not shown). The predetermined amounts of the first and second thermoplastic polymer feedstocks 22a, 22b are delivered via first and second thermoplastic polymer powder feedstock feedlines 21a and 21b, respectively, and mixed together to form a thermoplastic polymer powder feedstock mixture <NUM>. The thermoplastic polymer powder feedstock mixture <NUM> is directed via feedstock mixture feedline <NUM> to high-velocity sprayer <NUM>. Feedstock mixture Feedline <NUM>, as shown in <FIG>, is in communication with thermoplastic polymer powder feedstock mixture <NUM> and the high-velocity sprayer <NUM>. Predetermined amounts of the first thermoplastic powder feedstock 22a and the second thermoplastic polymer powder feedstock 22b can be directed from respective feedstock supplies (not shown) by any desirable means, including automated means regulated by a controller (not shown) and subject to, for example, software and hardware known to control, for example, feedstock flow rates from a supply to a sprayer, etc. The high-velocity sprayer <NUM> can be a thermal sprayer or a cold sprayer. As shown in <FIG>, the thermoplastic polymer powder feedstock mixture <NUM> is converted by the high-velocity sprayer <NUM> into a thermoplastic polymer coating 26a deposited onto substrate <NUM>. While the high-velocity sprayer <NUM> can be operated manually, <FIG> shows an optional robotic arm <NUM> (or "robot") that can be in communication with a controller <NUM>. Controller <NUM> can further optionally be in communication with remote or integrated software or hardware, as desired, to control robotic arm movement as well as control flow rates and amounts of material deposited as a thermoplastic polymer coating 26a onto a substrate <NUM>. Optionally, additional controllers (not shown) can be integrated into system <NUM> to control one or more aspects of system <NUM>.

<FIG> shows a block diagram outlining an aspect showing two thermoplastic polymer powder feedstocks and system <NUM> similar to system <NUM> shown in <FIG>, except that, as shown in <FIG>, system <NUM> comprises first and second thermoplastic polymer powder feedstock feedlines 31a and 31b in communication with the high-velocity sprayer <NUM> and the first and second thermoplastic polymer powder feedstocks 22a and 22b, respectively. That is, as shown in <FIG>, amounts of the first and second thermoplastic polymer powder feedstocks 22a, 22b are not mixed together to form a feedstock mixture. Instead, according to the aspect shown in <FIG> as system <NUM>, a predetermined amount of the first thermoplastic polymer powder feedstock 22a is directed to high-velocity sprayer <NUM> via first thermoplastic polymer powder feedstock feedline 31a. Similarly, a predetermined amount of the second thermoplastic polymer powder feedstock 22b is directed to the high-velocity sprayer <NUM> via second thermoplastic polymer powder feedstock feedline 31b. While the high-velocity sprayer <NUM> can be operated manually, <FIG> shows an optional robotic arm <NUM> (or "robot") that can be in communication with a controller <NUM>. Controller <NUM> can further optionally be in communication with remote or integrated software or hardware, as desired, to control robotic arm movement as well as control flow rates and amounts of material deposited as a thermoplastic polymer coating 26a onto a substrate <NUM>. Optionally, additional controllers (not shown) can be integrated into system <NUM> to control one or more aspects of system <NUM>.

<FIG> shows a block diagram outlining an aspect showing a thermoplastic polymer powder feedstock and a conductive powder feedstock and a system <NUM>. As shown in <FIG>, in system <NUM>, a thermoplastic polymer powder feedstock 42a, and a conductive powder feedstock 42b are directed to a mixing vessel (not shown). The predetermined amounts of the first and second thermoplastic polymer feedstocks 42a, 42b are delivered via first and second thermoplastic polymer powder feedstock feedlines 41a and 41b, respectively, and mixed together to form a conductive thermoplastic polymer powder feedstock mixture <NUM>. An amount of the conductive thermoplastic polymer powder feedstock mixture <NUM> is directed via conductive thermoplastic polymer powder feedstock mixture feedline <NUM> to high-velocity sprayer <NUM>. Feedline <NUM> as shown in <FIG> is in communication with conductive thermoplastic feedstock mixture <NUM> and the high-velocity sprayer <NUM>. Predetermined amounts of conductive thermoplastic polymer feedstock mixture <NUM> can be directed to the high-velocity sprayer <NUM> by any desirable means, including automated means regulated by a controller (not shown) and subject to, for example, software and hardware known to control, for example, feedstock flow rates from a supply to a sprayer, etc. The high-velocity sprayer <NUM> can be a thermal sprayer or a cold sprayer. As shown in <FIG>, the conductive thermoplastic polymer powder feedstock is converted by the high-velocity sprayer <NUM> into a conductive thermoplastic polymer coating 46a deposited onto substrate <NUM>. While the high-velocity sprayer <NUM> can be operated manually, <FIG> shows an optional robotic arm <NUM> (or "robot") that can be in communication with a controller <NUM>. Controller <NUM> can further optionally be in communication with remote or integrated software or hardware, as desired, to control movement of the robotic arm <NUM> as well as control flow rates and amounts of deposited conductive thermoplastic polymer coating 46a onto a substrate <NUM>. Optionally, additional controllers (not shown) can be integrated into system <NUM> to control one or more aspects of system <NUM>.

<FIG> shows a block diagram outlining an aspect showing a conductive thermoplastic polymer powder and a system <NUM> similar to system <NUM> shown in <FIG>, except that as shown in <FIG>, system <NUM> comprises a thermoplastic polymer powder feedstock feedline 51a in communication with a thermoplastic polymer powder feedstock 42a and a high-velocity sprayer <NUM>. Conductive powder feedstock feedline 51b is shown in communication with the conductive powder feedstock 42b and the high-velocity sprayer <NUM>. That is, as shown in <FIG>, an amount of the thermoplastic polymer powder feedstock 42a is not mixed with an amount of the conductive powder feedstock 42b to form a conductive thermoplastic polymer feedstock mixture. Instead, according to an aspect shown in <FIG> as system <NUM>, a predetermined amount of the thermoplastic polymer powder feedstock 42a is directed to high-velocity sprayer <NUM> via thermoplastic polymer powder feedstock feedline 51a. Similarly, a predetermined amount of the conductive powder feedstock 42b is directed to the high-velocity sprayer <NUM> via conductive powder feedstock feedline 51b. While the high-velocity sprayer <NUM> can be operated manually,.

<FIG> shows an optional robotic arm <NUM> (or "robot") that can be in communication with a controller <NUM>. Controller <NUM> can further optionally be in communication with remote or integrated software or hardware, as desired, to control movement of the robotic arm <NUM> as well as control flow rates and amounts of deposited conductive thermoplastic polymer coating 46a onto a substrate <NUM>. Optionally, additional controllers (not shown) can be integrated into system <NUM> to control one or more aspects of system <NUM>.

<FIG> shows a block diagram outlining an aspect showing a conductive thermoplastic polymer powder feedstock and a system <NUM> including mixing first and second thermoplastic polymer powder feedstocks with a conductive powder feedstock to form a conductive thermoplastic powder feedstock mixture, and then directing an amount of the conductive thermoplastic powder feedstock mixture to a high-velocity sprayer and depositing a conductive thermoplastic polymer coating onto a substrate surface. As shown in <FIG>, in system <NUM>, an amount of a first thermoplastic polymer powder feedstock 62a, an amount of a second thermoplastic polymer powder feedstock 62b, and an amount of a conductive powder feedstock 62c are directed to a mixing vessel (not shown) and are mixed together to form a conductive thermoplastic polymer powder feedstock mixture <NUM>. A desired amount of the conductive thermoplastic polymer powder feedstock mixture <NUM> is directed via feedstock mixture feedline <NUM> to high-velocity sprayer <NUM>. Feedstock mixture feedline <NUM>, as shown in <FIG>, is in communication with conductive thermoplastic polymer powder feedstock mixture <NUM> and the high-velocity sprayer <NUM>. Predetermined amounts of: <NUM>) the first thermoplastic polymer powder feedstock 62a; <NUM>) the second thermoplastic polymer powder feedstock 62b; and <NUM>) the conductive powder feedstock 62c are directed to the conductive thermoplastic polymer powder feedstock mixture <NUM> via first thermoplastic polymer powder feedstock feedline 61a, second thermoplastic polymer powder feedstock feedline 61b and conductive polymer powder feedstock feedline 61c, respectively, by any desirable means. Predetermined amounts of conductive thermoplastic polymer feedstock mixture <NUM> are directed to the high-velocity sprayer <NUM> by any desirable means, including, for example, an automated means regulated by a controller (not shown) and subject to, for example, software and hardware known to control, for example, feedstock flow rates to a sprayer, etc. The high-velocity sprayer <NUM> can be a thermal sprayer or a cold sprayer. As shown in <FIG>, the conductive thermoplastic polymer powder feedstock mixture <NUM> is converted by the high-velocity sprayer <NUM> into a conductive thermoplastic polymer coating 66a deposited onto substrate <NUM>. While the high-velocity sprayer <NUM> can be operated manually, <FIG> shows an optional robotic arm <NUM> (or "robot") that can be in communication with a controller <NUM>. Controller <NUM> can further optionally be in communication with remote or integrated software or hardware, as desired, to control movement of the robotic arm <NUM> as well as control flow rates and amounts of deposited conductive thermoplastic polymer coating 66a onto a substrate <NUM>. Optionally, additional controllers (not shown) can be integrated into system <NUM> to control one or more aspects of system <NUM>.

<FIG> shows a block diagram outlining an aspect showing a conductive thermoplastic polymer powder and a system <NUM> similar to system <NUM> shown in <FIG>, except that as shown in <FIG>, system <NUM> comprises: <NUM>) a first thermoplastic polymer powder feedstock feedline 71a in communication with the first thermoplastic polymer powder feedstock 62a and the high-velocity sprayer <NUM>; <NUM>) a second thermoplastic polymer powder feedstock feedline 71b in communication with the first thermoplastic polymer powder feedstock 62b and the high-velocity sprayer <NUM>; and <NUM>) a conductive powder feedstock feedline 71c in communication with the conductive powder feedstock 62c and the high-velocity sprayer <NUM>. That is, as shown in <FIG>, an amount of the first thermoplastic polymer powder feedstock 62a, and an amount of the second thermoplastic polymer powder feedstock 62b are not mixed with an amount of the conductive powder feedstock to form a conductive thermoplastic polymer feedstock mixture. Instead, according to system <NUM> shown in <FIG>, a predetermined amount of the first thermoplastic polymer powder feedstock 62a is directed to high-velocity sprayer <NUM> via first thermoplastic polymer powder feedstock feedline 71a. Similarly, a predetermined amount of the second thermoplastic polymer powder feedstock 62b is directed to high-velocity sprayer <NUM> via second thermoplastic polymer powder feedstock feedline 71b. Further, a predetermined amount of the conductive powder feedstock 62c is directed to the high-velocity sprayer <NUM> via conductive powder feedstock feedline 71c. While the high-velocity sprayer <NUM> can be operated manually, <FIG> shows an optional robotic arm <NUM> that can be in communication with a controller <NUM>. Controller <NUM> can further optionally be in communication with remote or integrated software or hardware, as desired, to control movement of a robotic arm <NUM> (or "robot") as well as control flow rates and amounts of deposited conductive thermoplastic polymer coating 66a onto a substrate <NUM>. Optionally, additional controllers (not shown) can be integrated into system <NUM> to control one or more aspects of system <NUM>.

The robotic arm disclosed above is equivalently referred to herein as a "robot", such that any feature of the robot (in addition to the "arm") can control the relative movement of the high-velocity sprayer, and/or the robot can control the direction of spray emitted from the high-velocity sprayer (e.g., the robot controls the direction and change the direction of spray from the high-velocity sprayer while the sprayer itself remains in a substantially stationary position, etc.).

<FIG> is an illustration of an aircraft <NUM> comprising assemblies and sub-assemblies and components that further comprise fasteners, with the fasteners having coatings according to aspects of the present disclosure, with the fasteners coated using systems and coated via methods according to aspects of the present disclosure. It is further understood that, the coatings described herein can be advantageously coated onto substrates occurring on components, assemblies and sub-assemblies incorporated in further types of manned and unmanned aircraft, terrestrial vehicles, sub-surface and surface marine (e.g., water borne) vehicles, manned and unmanned satellites, etc..

<FIG>, <FIG> and-<NUM> are flowcharts outlining aspects of the present disclosure. <FIG> outlines a method <NUM> comprising directing <NUM> at least one thermoplastic polymer powder to a high-velocity sprayer, followed by forming <NUM> a thermoplastic polymer spray formulation at or near the high-velocity sprayer. The method outlined in <FIG> further comprises directing <NUM> the thermoplastic spray formulation from the high-velocity sprayer to a substrate having a substrate surface, and forming <NUM> a thermoplastic polymer coating on the substrate surface. The method outlined in <FIG> is understood to at least relate to the systems shown in <FIG>, <FIG> and <FIG>.

<FIG> outlines a method <NUM> comprising directing <NUM> an amount of at least one thermoplastic polymer powder to a high-velocity sprayer, followed by directing <NUM> an amount of conductive powder to the high-velocity sprayer concurrently with thermoplastic polymer powder and forming 104a a conductive thermoplastic polymer spray formulation at or near the high velocity sprayer. The method further comprises directing 106a the conductive thermoplastic polymer spray formulation from the sprayer to a substrate surface, and forming 108a a conductive thermoplastic coating on the substrate surface. The method outlined in <FIG> is understood to at least relate to the systems shown in <FIG>, <FIG>, <FIG> and <FIG>.

<FIG> outlines a method <NUM> comprising directing 102a an amount of a first thermoplastic polymer powder and an amount of a second thermoplastic polymer powder and an amount of a conductive powder to a high-velocity sprayer, followed by forming 104a a conductive thermoplastic polymer spray formulation. The method further comprises directing 106a the conductive thermoplastic polymer formulation from the sprayer to a substrate surface, and forming 108a a conductive thermoplastic coating on the substrate surface. The method outlined in <FIG> is understood to at least relate to the systems shown in <FIG> and <FIG>.

<FIG> shows a representative illustration of a thermal spray deposition system <NUM> according to aspects of the present disclosure. As shown in <FIG>, a feedstock <NUM> comprising individual feedstock particles <NUM> are heated, such as by directing the feedstock particles <NUM> to a flame <NUM> in a thermal sprayer (e.g., a flame sprayer, not shown in <FIG>) at a particular velocity and in a direction as indicated by large arrows. The feedstock particles <NUM> deform as they melt to a semi-solid or liquid state. The deformed particles <NUM> then impact a substrate surface <NUM>. The deformed particles continue to impact the substrate surface <NUM>. As the illustrated thermal spray deposition process continues, a deposited layer <NUM> forms on the substrate surface <NUM>.

<FIG> is an illustration of a thermal spray process <NUM> that can include the use of a high-velocity flame sprayer or a high-velocity cold sprayer (collectively referred to in <FIG> as the "sprayer"). As shown in <FIG>, and according to aspects of the present disclosure, a sprayer <NUM> is operated to emit and direct a thermoplastic polymer particulate spray <NUM> formed by processing thermoplastic polymer powder feedstock that is directed to the sprayer. The feedstock can be tailored and can be made into a conductive feedstock (that can also be tailored) by adding varying amounts of conductive powder feedstock to the thermoplastic polymer powder feedstock. The thermoplastic polymer particulate spray <NUM> is directed from the sprayer <NUM> to a fastener <NUM> installed into a substrate <NUM>. At least one thermoplastic polymer powder feedstock acts as a feedstock supply (not shown) that is supplied to the sprayer <NUM>. According to further aspects, the feedstock can also be a conductive thermoplastic polymer powder feedstock mixture, with the feedstock mixture comprising a conductive powder feedstock. According to further aspects, when the feedstock comprises multiple components, each component can alternatively be supplied individually and also substantially concurrently to the sprayer via discrete feedstock feedlines (not shown). If desired the predetermined amounts of multiple feedstock components can be delivered to the sprayer via one or more feedstock feedlines by a sequencer and/or controller driven by automatically or manually in conjunction with attendant software and hardware, including the use of a robot. In this way the fastener <NUM> is coated to a predetermined thickness as particles in the particulate spray impact the fastener <NUM>, the substrate <NUM>, and the fastener/substrate interface <NUM>. As shown in <FIG>, the fastener <NUM> can be made from a metal or non-metal and the substrate <NUM> can also be made from a metal or a non-metal. According to aspects of the present disclosure, when at least one of a fastener and the substrate are made from a metal having a different electrical resistivity (or electrical conductivity), a thermoplastic polymer powder feedstock can be "doped" with a predetermined amount of conductive powder feedstock to form a conductive thermoplastic polymer powder feedstock. As the conductive thermoplastic powder feedstock proceeds into and through the high-velocity sprayer, the conductive thermoplastic polymer powder feedstock comprising conductive feedstock particles and thermoplastic polymer feedstock particles is subjected at the sprayer to heat and/or high velocity via gas jets to at least soften and deform the particles in the conductive thermoplastic polymer powder feedstock. The combined feedstock particles leave the sprayer as a conductive thermoplastic polymer particulate spray at a predetermined velocity and impact a desired target such as, for example, the fastener <NUM>, substrate <NUM> and the fastener/substrate interface <NUM> as shown in <FIG>. Upon impact on the selected target(s), the particulate spray forms a coating on the target(s), with the coating having a desired, predetermined, and tailorable resistivity value. Further, the resistivity value of the coating formed can be tailored or "tuned" to a particular resistivity value. If the coated materials are subjected to an electromagnetic effect (EME), such as, for example, from the electrical discharge of static electricity, or a from a lightning strike, the conductivity of the thermoplastic coating will at least ameliorate deleterious effects from the EME that would otherwise be encountered at or near the fastener or at or near the fastener/substrate interface (e.g., adjoined structures) due to dissimilar resistivity values of such adjoined and/or proximately positioned structures. The thermoplastic coatings made possible according to aspects of the present disclosure further obviate the need to stock and employ expensive alternatives including, for example, physically applied fastener caps that are expensive and time-consuming to install, maintain and replace.

<FIG> is an illustration of an assembly comprising two structures adjoined via fastening with fasteners. As shown in <FIG>, an assembly <NUM> comprises a first substrate <NUM> adjoined to a second substrate <NUM>. Fasteners <NUM> are shown fitted, for example, through aligned holes (not shown) in substrates <NUM>, <NUM>, such that, the fasteners, when secured, exert pressure sufficient to hold substrates <NUM>, <NUM> together in an adjoined orientation. As further shown in <FIG>, fasteners <NUM> have a fastener first end 154a contacting a surface (the "upper" surface) of substrate <NUM>, and a fastener second end 154b contacting a surface (the "lower" surface) of substrate <NUM>.

<FIG> is a cross-sectional side-view of a coated fastener in position fastening together two substrates. As shown in <FIG>, a fastener assembly <NUM> comprises first and second substrates <NUM>, <NUM> fastened together by fastener <NUM>. As shown in <FIG>, the fastener <NUM>, along with portions of substrates <NUM>, <NUM> including fastener/substrate interfaces 166a, 166b, 166c and 166d, are coated by thermoplastic polymer fastener coating <NUM>. Though shown as individual points, the fastener/substrate interface is understood to represent a "perimeter", such as a substantially circular perimeter located at the fastener/substrate interface.

According to aspects of the present disclosure, the thermoplastic polymer coating can be conductive having a desired and/or predetermined and tailorable (e.g., "tunable") resistivity. According to further aspects, the substrates <NUM>, <NUM> can be made from a metal or non-metal material. Fastener <NUM> can be made from metal or non-metal material. Each of substrates <NUM>, <NUM> and/or fastener <NUM> can be made from the same or different metals or the same or different non-metals. If the resistivity value of substrates <NUM>, <NUM> differ from each other and/or differ from the resistivity value of the fastener <NUM>, the fastening assembly area or region can be susceptible to deleterious effects when confronted with an EME event (e.g., such as from static discharge or a lightning strike, etc.).

According to present aspects, the resistivity value of the conductive thermoplastic polymer coating <NUM> formed to cover the fastener <NUM> can be tailored or "tuned" to any resistivity value as desired, and preferably ranging from about <NUM>×<NUM><NUM> to about <NUM>×<NUM><NUM> ohm-m, and more preferably ranging from about <NUM>×<NUM><NUM> to about <NUM>×<NUM><NUM> ohm-m. If the coated materials are subjected to an electromagnetic effect (EME), such as, for example, from the electrical discharge of static electricity, or a from a lightning strike, the conductivity of the thermoplastic coating will at least ameliorate deleterious effects from the EME that would otherwise be encountered at or near the fastener or at or near the fastener/substrate interface (e.g., adjoined structures) due to dissimilar resistivity values of such adjoined and/or proximately positioned structures.

<FIG> is an overhead perspective view, or "top" view of a coated fastener according to aspects of the present disclosure. As shown in <FIG>, an area of an assembly <NUM> comprises a fastener <NUM> installed in a substrate <NUM>. A thermoplastic polymer coating <NUM> is shown coating a portion of substrate <NUM> and fastener <NUM> to form a coated fastener <NUM>. As with the fastener <NUM> shown in <FIG>, when the thermoplastic polymer coating comprises a conductive material to form a conductive thermoplastic polymer coating on the fastener and at least a portion of the substrate.

According to present aspects, the resistivity value of the conductive thermoplastic polymer coating formed to cover the fastener can be tailored or "tuned" to a predetermined resistivity value such that, if the coated materials are subjected to an electromagnetic effect (EME), such as, for example, from the electrical discharge of static electricity, or a from a lightning strike, the conductivity of the thermoplastic coating will at least ameliorate deleterious effects from the EME that would otherwise be encountered at or near the fastener or at or near the fastener/substrate interface (e.g., adjoined structures) due to dissimilar resistivity values of such adjoined and/or proximately positioned structures.

<FIG> is a flowchart outlining methods according to aspects of the present disclosure. As shown in <FIG>, according to presently disclosed aspects, a method <NUM> for coating an installed fastener includes delivering <NUM> a thermoplastic polymer powder feedstock to a high-velocity sprayer. The high-velocity sprayer is preferably a high-velocity sprayer that can be a thermal sprayer (e.g. flame sprayer) or a cold sprayer. Further contemplated steps of method <NUM>, include forming <NUM> a thermoplastic polymer coating material followed by directing <NUM> the thermoplastic polymer coating material from the high-velocity sprayer to a fastener and fastener/substrate interface on substrate surface, and depositing <NUM> an amount of the thermoplastic polymer coating material on the fastener to form a thermoplastic polymer coating on the fastener and at the fastener/substrate interface, and coating <NUM> the fastener with the thermoplastic polymer coating. The methods outlined in <FIG> can be used to accomplish the coating methods to prepare the coated fasteners, fastener/substrate interfaces and substrates shown and/or described in one or more of <FIG>.

When a fastener, including a metal fastener is installed into an assembly that, for example, includes fastened first and second parts or substrates, and at least one substrate is made from a metal, according to the present disclosure, the thermoplastic coating material is conductive, and in certain aspects the conductive coating has a resistivity ranging from about <NUM><NUM> to <NUM><NUM> ohm-m. <FIG> is a flowchart outlining methods according to aspects of the present disclosure. As shown in <FIG>, according to presently disclosed aspects, a method <NUM> for coating an installed fastener includes delivering <NUM> a conductive thermoplastic polymer to a high-velocity sprayer. The high-velocity sprayer is preferably a high-velocity sprayer that can be a thermal sprayer (e.g. flame sprayer) or a cold sprayer. Further contemplated steps of method <NUM>, include forming <NUM> a conductive thermoplastic polymer coating material followed by directing <NUM> the conductive thermoplastic polymer coating material from the sprayer to a fastener and fastener/substrate interface on substrate surface, and depositing <NUM> an amount of the conductive thermoplastic polymer coating material on the fastener to form a conductive thermoplastic polymer coating on the fastener and at the fastener/substrate interface, and coating <NUM> the fastener with the conductive thermoplastic polymer coating. The methods outlined in <FIG> can be used to accomplish the coating methods to prepare the coated fasteners, fastener/substrate interfaces and substrates shown and/or described in one or more of <FIG>.

At room temperature, an amount of <NUM> of PEEK powder (KetaSpire® KT820, low melt flow; KetaSpire® KT-<NUM>, high melt flow - Spire Ultra Polymers, Solvay, Brussels Belgium) having a median particle size of about <NUM> was mixed with an amount of <NUM> of conductive titanium powder (TS1374 - Titanium Powder - Stanford Advanced Materials, Irvine, CA) having a nominal particle diameter of about <NUM>. The two powders were mixed using a Mazerustar Mixer (Medisca, LasVegas, NV), to form a thorough conductive thermoplastic polymer powder mixture produced by the combining of the two powders (representing <NUM>% by weight). The mixture was loaded as a feedstock into a reservoir of a thermal sprayer (ASC PG-<NUM> (Alamo Supply Co. , Houston, TX) Three formulations having a varied amount (% by volume) of titanium in the total powder mixture were prepared: <NUM>) <NUM> % titanium powder by volume; <NUM>) <NUM>% titanium by volume; and <NUM>) <NUM>% titanium by volume.

The thermal sprayer was set to a flow rate equal to approximately <NUM> to <NUM>/sec. , and amounts of the three feedstock mixtures (conductive thermoplastic polymer powder mixtures) prepared in Example <NUM> were each directed from the reservoir into the thermal sprayer and to the heated spray head. Each feedstock achieved a phase change, from solid to a flowing, heated sprayable liquid, and was then sprayed as a particulate spray and directed by and from the thermal sprayer to a substrate surface comprising a lap joint interface of an aluminum panel (<NUM>, <NUM> and <NUM> series aluminum) located proximate to a carbon fiber reinforced plastic composite panel. The substrate surface was solvent cleaned (acetone wipe) and dried completely. The head of the thermal sprayer was located at a distance of about <NUM>" (<NUM>) from the substrate surface. The thermal sprayer was moved manually to deposit a visually uniform coverage of the substrate surface. The substrate surface temperature was monitored with a thermostat.

The conductive thermoplastic coatings prepared and deposited according to the processes described in Examples <NUM> and <NUM> were allowed to cool on the substrate surface for not more than <NUM> minutes. The conductive thermoplastic coating had measured resistivity values as set forth in Table <NUM> for three Samples (#<NUM>, #<NUM>, and #<NUM>) having <NUM>%, <NUM>% and <NUM>% by volume of titanium in the conductive thermoplastic polymer powder formulations prepared. Adjusting the amount/concentration/ratio of conductive titanium powder in the thermoplastic polymer (PEEK/Ti) powder feedstock mixture resulted in a measured variance in the resistivity of the conductive thermoplastic polymer coating as noted in Table <NUM>.

Additional amounts of thermoplastic polymer powders were mixed with varying amounts of conductive powders to produce feedstock mixtures the thermal spraying conducted as described above.

Claim 1:
An assembly (<NUM>) (<NUM>) comprising:
a first substrate (<NUM>)(<NUM>);
a second substrate (<NUM>)(<NUM>);
a fastener (<NUM>)(<NUM>) configured to join the first substrate and the second substrate; and
a spray-deposited thermoplastic polymer coating material (<NUM>) configured to coat the installed fastener, said spray-deposited thermoplastic polymer coating material made from a powdered feedstock material, said powdered feedstock material comprising:
a thermoplastic polymer powder feedstock comprising at least one of:
nylon, polyetheretherketone, polyetherketoneketone, polyamide,
polyphenylsulfide, polyphenylsulfone, polysulfone, and polyetheramide.