US20190078191A1

US20190078191A1 - Method and system for promoting adhesion of arc-spray coatings

Info

Publication number: US20190078191A1
Application number: US16/124,754
Authority: US
Inventors: Peter Joseph Yancey
Original assignee: Atmospheric Plasma Solutions Inc
Current assignee: Atmospheric Plasma Solutions Inc
Priority date: 2017-09-14
Filing date: 2018-09-07
Publication date: 2019-03-14
Also published as: WO2019055310A1

Abstract

Methods to promote adhesion of coatings on surfaces, such as promoting adhesion of arc-spray coatings or thermal-spray coatings onto surfaces such as metallic or ceramic surfaces. The method applies a non-thermal plasma stream at atmospheric pressure to an article surface, creating an energized surface region that promotes adhesion of an arc-spray coating. In one aspect, the arc-spray coating is applied onto a metallic or ceramic surface.

Description

FIELD

The present invention is directed to a method to promote adhesion of coatings on surfaces, such as promoting adhesion of arc-spray or thermal-spray coatings onto surfaces such as metallic or ceramic surfaces with use of a non-thermal plasma stream at atmospheric pressure.

BACKGROUND

Arc-spray or thermal spray coatings are frequently applied to article surfaces. Traditionally, the surface to receive the arc-spray coating must be prepared to ensure adequate adhesion of the arc-spray coating. For example, surfaces are commonly roughened by way of grit blasting to create a surface more amenable to bonding to the arc-spray coating. Such surface preparation processes may be complicated, costly, and inconsistent. Using grit or media blasting requires that the user has a sufficient supply of correctly sized and shaped particulates to create a uniform blasted surface profile or texture. The blast media is often only useable once before it becomes contaminated or is fractured upon impact rendering the media ineffective for a second application. The media presents an ongoing source of dusts and the spent abrasive media must be disposed of. The disclosure eliminates or drastically reduces the need to use blast media to prepare the surface prior to arc-spray coating. A method of surface pre-treatment applied to an article that uniformly and predictably enhances the bonding of an arc-spray coating is needed.
Conventional approaches to applying an arc-spray coating to a surface or increasing the adherence of a surface prior to application of an arc-spray coating include: U.S. Pat. No. 4,578,310 to Hatfield. incorporated by reference in entirety. Plasma systems have been used to prepare a surface but are traditionally vacuum plasma systems or various atmospheric plasma systems such as a corona, dielectric barrier discharge, and downstream plasma systems, such as: U.S. Pat. No. 5,913,144 to Nguyen, E. P. patent application Ser. No. 0,265,765 to Chan, and U.S. Pat. Appl. No. 2010/0237043 to Garlough, each of which are incorporated by reference in entirety. Some systems and methods describe removal of materials from substrates using an atmospheric plasma source, such as U.S. Pat. No. 8,133,324 to Claar, U.S. Pat. No. 8,981,251 to Yancey, and U.S. Pat. No. 8,604,379 to Yancey, each of which are incorporated by reference in entirety. WIPO 2017/087991 to Yancey describes a method and device to promote adhesion of metallic surfaces, incorporated by reference in entirety.
What is needed is a method to provide effective and efficient bonding of an arc-spray coating, or a thermal spray coating, to an article. The disclosure solves this need. The disclosure provides a method to promote adhesion of coatings on surfaces. More specifically, the disclosure describes the use of a non-thermal plasma stream at atmospheric pressure to promote adhesion of arc-spray coatings, or thermal spray coatings, onto surfaces such as metallic or ceramic surfaces. In one embodiment, both the article and the arc-spray are metallic. Some benefits of the method are the elimination of the need to grit blast surfaces prior to applying an arc spray coating and creating a stronger and more uniform bond between the coating and the article surface.

SUMMARY

The present disclosure can provide several advantages depending on the particular aspect, embodiment, and/or configuration.
The disclosure involves methods to promote adhesion of coatings on surfaces, such as promoting adhesion of arc-spray coatings, or thermal spray coatings, onto surfaces such as metallic or ceramic surfaces with use of a non-thermal plasma stream at atmospheric pressure. Generally, the method applies a non-thermal plasma stream at atmospheric pressure to an article surface, creating an energized surface region that promotes adhesion of a coating, such as an arc-spray coating or a thermal spray coating. In one aspect, the coating is applied onto a metallic or a ceramic surface.
In one embodiment, a method to adhere an arc-spray coating to a surface of an article is disclosed, the method comprising: generating a non-thermal plasma stream, the non-thermal plasma stream at atmospheric pressure; positioning the surface of the article to receive the non-thermal plasma stream; treating the surface of the article with the non-thermal plasma stream to create an energized surface region; generating an arc-spray coating stream; directing the arc-spray coating stream at the energized surface region; wherein: the arc-spray coating stream forms an arc-spray coating surface associated with the energized surface region of the article.
In one aspect, the energized surface region comprises etched organic residues. In another aspect, the non-thermal plasma stream provides a chemical etching and cleaning of the substrate. In another aspect, the non-thermal plasma stream comprises monatomic oxygen species. In another aspect, the article is metallic, and the surface is a metallic surface. In another aspect, wherein the energized surface region is a metal oxide region. In another aspect, the metal oxide region comprises an outer oxide surface. In another aspect, the arc-spray coating stream is directed at the outer oxide region. In another aspect, the article is metallic, the surface comprises a metallic surface, and the arc-spray stream comprises a metal.
In one aspect, the method further comprises the step of forming chemical bonding sites on the energized surface region, the chemical sites chemically bonding with the metal of the arc-spray stream. In another aspect, the article is metallic, and the surface is a metallic surface, and the method further comprises the step of heating the article. In one aspect, the method further comprises the step of applying an auxiliary gas onto the surface of the article. In one aspect, the non-thermal plasma stream comprises monatomic nitrogen. In one aspect, the arc-spray coating stream is a metallic arc-spray coating stream comprising a stream of projected molten metal surrounded by a sheath of air plasma. In one aspect, the surface is a metallic surface, and the non-thermal plasma stream comprises an energetic species chemically reactive with the metallic surface. In one aspect, the method further comprises applying a gas curtain associated with the non-thermal plasma stream. In one aspect, the arc-spray stream comprises a sheath of air plasma.
In one aspect, the method further comprises the step of forming chemical bonding sites on the energized surface region, the chemical bonding sites promoting chemical bonding with the energized surface region. In one aspect, the article is metallic, and the surface is a metallic surface. In one aspect, the method further comprises the step of applying an auxiliary gas onto the surface of the article. In one aspect, the non-thermal plasma stream comprises monatomic nitrogen. In one aspect, the arc-spray coating stream is a metallic arc-spray coating stream comprising a stream of projected molten metal surrounded by a sheath of air plasma. In one aspect, the surface is a metallic surface, and the non-thermal plasma stream comprises an energetic species chemically reactive with the metallic surface. In one aspect, the energized surface region comprises etched inorganic residues. In one aspect, the article is ceramic, the surface comprises a ceramic surface, and the arc-spray stream comprises a metal. In one aspect, the article is ceramic, the surface comprises a ceramic surface, and the arc-spray stream comprises a cermet. In one aspect, the article is ceramic, the surface comprises a ceramic surface, and the arc-spray stream comprises a ceramic. In one aspect, the non-thermal plasma stream comprises monatomic chemical species. In one aspect, the non-thermal plasma stream comprises a tailored gas that forms a tailored chemical species on the surface. In one aspect, the tailored gas is ammonia and the tailored chemical species comprise amine groups. In one aspect, the tailored gas is water and the tailored chemical species comprise hydroxyl groups.
In another embodiment, a method to bond an arc-spray coating to a metal surface of an article is disclosed, the method comprising: generating a non-thermal plasma stream, the non-thermal plasma stream at atmospheric pressure and comprising monatomic oxygen (and/or other atomic and molecular species); positioning the metal surface of the article to receive the non-thermal plasma stream; treating the metal surface of the article with the non-thermal plasma stream to create a metal oxide region, the metal oxide region comprising an outer oxide surface and etched organic residues; generating a metallic arc-spray coating stream comprising a stream of projected molten metal surrounded by a sheath of air plasma; and directing the metallic arc-spray coating stream at the metal oxide region; wherein: the molten metal bonds with the metal oxide region to bond the arc-spray coating to the metal surface of the article.
In yet another embodiment, a system to adhere an arc-spray coating to a surface of an article is disclosed, the system comprising: a plasma generating device configured to generate a non-thermal plasma stream at atmospheric pressure; and an arc-spray generating device configured to generate an arc-spray coating stream; wherein: the non-thermal plasma stream is directed at the surface of the article to create an energized surface region; the arc-spray coating stream is directed at the energized surface region; and the arc-spray coating is adhered to the surface of the article.
In one aspect, the non-thermal plasma stream comprises monatomic oxygen, the article is metallic with a metallic surface, and the arc-spray stream comprises a metal. In another aspect, the non-thermal plasma generating device is configured to direct an auxiliary gas onto the metallic surface, and the arc-spray coating stream is a metallic arc-spray coating stream comprising a stream of projected molten metal surrounded by a sheath of air plasma.
The word “plasma” generally refers to an ionized gas comprising a mixture of charged species (ions and electrons), metastable (electronically excited) species, and neutral species; the volume of matter in the plasma state additionally emits photons. For convenience, unless specified otherwise or the context dictates otherwise, the word “plasma” encompasses not only fully active (actively generated) plasma but also partially extinguished plasma and afterglow, to the extent that a partially extinguished plasma or an afterglow has properties (composition of species, energy level, etc.) effective for implementing the methods disclosed herein.
The phrases “non-thermal plasma, “non-equilibrium” plasma, and “cold” plasma generally refers to a plasma exhibiting low temperature ions and neutral species (relative to a “thermal” plasma) and high electron temperatures relative to the temperature of the surrounding gas. A non-thermal plasma is distinguished from a thermal plasma in that a thermal plasma exhibits a higher overall temperature and energy density with both high electron temperatures and high ion and neutral temperatures.
The word “generating” in the context of generating plasma refers to the initial step of striking (creating) the plasma from a plasma-precursor gas (or mixture of gases) and also sustaining (maintaining) the plasma after the plasma has been struck. A plasma will be sustained as long as the conditions required for sustaining the plasma are maintained, such as an input of electrical (or electromagnetic) power with the appropriate operating parameters (e.g., voltage, frequency, etc.), a sufficient source of, plasma- precursor gas etc.
The phrase “atmospheric pressure,” such as used the context of “atmospheric pressure plasma,” is not limited to a precise value of pressure corresponding exactly to sea-level conditions. For instance, the value of “atmospheric pressure” is not limited to exactly 1 atm. Instead, “atmospheric pressure” generally encompasses ambient pressure at any geographic location and thus may encompass a range of values less than and/or greater than 1 atm as measured at sea level. Generally, an “atmospheric pressure plasma” is one that may be generated in an open or ambient environment, i.e., without needing to reside in a pressure-controlled chamber or evacuated chamber, although a chamber (at or around atmospheric pressure), may be utilized to confine the plasma to maintain a desired chemical environment, such as excluding oxygen to prevent oxidation.
The word “substrate” generically refers to any structure that includes a surface on which an adhesion-promoting oxide layer may be formed in accordance with the present disclosure. The substrate may present a surface having a simple planar or curved geometry or may have a complex or multi-featured topography.
The phrase “metallic substrate” refers to a substrate composed of a single metal or a metal alloy. Such a substrate is not necessarily pure, in that a trace amount of impurities may exist in its lattice structure.
The phrase “metal oxide” or “metal nitride,” depending on the type of oxide or nitride, generally may refer a stoichiometric or non- stoichiometric formulation of the oxide or nitride. As one non-limiting example, “titanium oxide” may encompass stoichiometric titanium oxide, typically but not exclusively titanium dioxide (T1O2), and/or TiO_Y, where y ranges from 0.7-2. A mixture of stoichiometric metal oxide (or nitride) and non- stoichiometric metal oxide (or nitride) may be present in a layer of metal oxide (or nitride) formed in accordance with the present disclosure.
The word “nanoscale” refers to a dimension (e.g., thickness) on the order of nanometers (nm). A nanoscale dimension is typically one that is less than 1000 nm, i.e., less than 1 micrometer (μm).
The phrase “arc-spray” as used in the phrase “arc-spray coating” or “arc-sprayed coating” means a sprayed molten metal propelled by a gas, such as propelled by compressed air via atomization, applied as a surface coating.
The phrase “thermal spray” means as used in the phrase “thermal spray coating” or “thermal-sprayed coating” means a sprayed coating comprising a heat source and a coating in a molten form that is propelled toward a substrate to form a coating of the molten material.
The phrase “energized surface region” means an elevated surface energy from a nominal surface energy, as typically measured by dyne level (a dyne meaning 10 micronewtons or 10 E-5 newtons).
The phrase “etched organic residue” means an organic remainder that has been embedded into a surface.
The phrase “auxiliary gas” means a gas that is complementary to a primary gas, such as ammonia, water, nitrogen, a combination of an inert gas with a reactive gas, a combination of different gases that creates specific ionization state such as Penning ionization mixture, an inert gas. The primary gas may be composed primarily of oxygen or air.
The phrase “energetic species” means any unstable compound, such as an ionized gas, a neutral gas that is unstable, or any chemical constituent not in an equilibrium state at given temperature and pressure.
The phrases “gas curtain” means a gas stream that surrounds, encircles, or exists adjacent another stream, such as a gas curtain of oxygen that surrounds a stream of molten metal.
The word “sheath” such as used in the phrase “sheath of air plasma” means a formation that surrounds, encircles, or exists adjacent a stream, such as a sheath of air surrounding a stream of molten metal.
The phrase “molten metal” means metal that has been heated to a temperature above its melting point and is in the liquid state.
The phrase “monatomic” such as used in the phrase “monatomic oxygen” means consisting of one atom in a material.
The phrase “organic coating” means a typically carbonaceous coating that depends primarily on its chemical inertness and impermeability to form a layer or coating onto a surface, to include primers, adhesive cements and topcoats such as enamel, varnish and paints.
These and other advantages will be apparent from the disclosure of the inventions contained herein. The above-described embodiments, objectives, and configurations are neither complete nor exhaustive. As will be appreciated, other embodiments of the invention are possible using, alone or in combination, one or more of the features set forth above or described in detail below. Further, this Summary is neither intended nor should it be construed as being representative of the full extent and scope of the present invention, nor its uses. The present invention is set forth in various levels of detail in this Summary, as well as in the attached drawings and the detailed description below, and no limitation as to the scope of the present invention is intended to either the inclusion or non-inclusion of elements, components, etc. in this Summary. Additional aspects of the present invention will become more readily apparent from the detailed description, particularly when taken together with the drawings, and the exemplary claims provided herein.
The phrases “at least one”, “one or more”, and “and/or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.
The term “a” or “an” entity refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. It is also to be noted that the terms “comprising”, “including”, and “having” can be used interchangeably.
The term “automatic” and variations thereof, as used herein, refers to any process or operation done without material human input when the process or operation is performed. However, a process or operation can be automatic, even though performance of the process or operation uses material or immaterial human input, if the input is received before performance of the process or operation. Human input is deemed to be material if such input influences how the process or operation will be performed. Human input that consents to the performance of the process or operation is not deemed to be “material”.
The term “computer-readable medium” as used herein refers to any storage and/or transmission medium that participate in providing instructions to a processor for execution. Such a computer-readable medium is commonly tangible, non-transitory, and non-transient and can take many forms, including but not limited to, non-volatile media, volatile media, and transmission media and includes without limitation random access memory (“RAM”), read only memory (“ROM”), and the like. Non-volatile media includes, for example, NVRAM, or magnetic or optical disks. Volatile media includes dynamic memory, such as main memory. Common forms of computer-readable media include, for example, a floppy disk (including without limitation a Bernoulli cartridge, ZIP drive, and JAZ drive), a flexible disk, hard disk, magnetic tape or cassettes, or any other magnetic medium, magneto-optical medium, a digital video disk (such as CD-ROM), any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, a solid state medium like a memory card, any other memory chip or cartridge, a carrier wave as described hereinafter, or any other medium from which a computer can read. A digital file attachment to e-mail or other self-contained information archive or set of archives is considered a distribution medium equivalent to a tangible storage medium. When the computer-readable media is configured as a database, it is to be understood that the database may be any type of database, such as relational, hierarchical, object-oriented, and/or the like. Accordingly, the disclosure is considered to include a tangible storage medium or distribution medium and prior art-recognized equivalents and successor media, in which the software implementations of the present disclosure are stored. Computer-readable storage medium commonly excludes transient storage media, particularly electrical, magnetic, electromagnetic, optical, magneto-optical signals.
Moreover, the disclosed methods may be readily implemented in software and/or firmware that can be stored on a storage medium to improve the performance of: a programmed general-purpose computer with the cooperation of a controller and memory, a special purpose computer, a microprocessor, or the like. In these instances, the systems and methods can be implemented as program embedded on personal computer such as an applet, JAVA® or CGI script, as a resource residing on a server or computer workstation, as a routine embedded in a dedicated communication system or system component, or the like. The system can also be implemented by physically incorporating the system and/or method into a software and/or hardware system, such as the hardware and software systems of a communications transceiver.
Various embodiments may also or alternatively be implemented fully or partially in software and/or firmware. This software and/or firmware may take the form of instructions contained in or on a non-transitory computer-readable storage medium. Those instructions may then be read and executed by one or more processors to enable performance of the operations described herein. The instructions may be in any suitable form, such as but not limited to source code, compiled code, interpreted code, executable code, static code, dynamic code, and the like. Such a computer-readable medium may include any tangible non-transitory medium for storing information in a form readable by one or more computers, such as but not limited to read only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; a flash memory, etc.
The terms “determine”, “calculate” and “compute,” and variations thereof, as used herein, are used interchangeably and include any type of methodology, process, mathematical operation or technique.
The term “means” as used herein shall be given its broadest possible interpretation in accordance with 35 U.S.C., Section 112, Paragraph 6. Accordingly, a claim incorporating the term “means” shall cover all structures, materials, or acts set forth herein, and all of the equivalents thereof. Further, the structures, materials or acts and the equivalents thereof shall include all those described in the summary, brief description of the drawings, detailed description, abstract, and claims themselves.
The term “module” as used herein refers to any known or later developed hardware, software, firmware, artificial intelligence, fuzzy logic, or combination of hardware and software that can perform the functionality associated with that element.
The preceding is a simplified summary of the disclosure to provide an understanding of some aspects of the disclosure. This summary is neither an extensive nor exhaustive overview of the disclosure and its various aspects, embodiments, and/or configurations. It is intended neither to identify key or critical elements of the disclosure nor to delineate the scope of the disclosure but to present selected concepts of the disclosure in a simplified form as an introduction to the more detailed description presented below. As will be appreciated, other aspects, embodiments, and/or configurations of the disclosure are possible utilizing, alone or in combination, one or more of the features set forth above or described in detail below. Also, while the disclosure is presented in terms of exemplary embodiments, it should be appreciated that individual aspects of the disclosure can be separately claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like elements. The elements of the drawings are not necessarily to scale relative to each other. Identical reference numerals have been used, where possible, to designate identical features that are common to the figures.

FIG. 1 is a flowchart depicting one embodiment of a method to promote adhesion of a surface coating to an article;

FIG. 2A is a schematic elevation view of an article to receive a surface coating consistent with the method of FIG. 1;

FIG. 2B is a schematic elevation view of the article of FIG. 2A after application of a non-thermal plasma stream to a surface of the article;

FIG. 2C is a schematic elevation view of the article of FIG. 2B after application of an arc-spray coating to a surface of the article; and

FIG. 3 is a block diagram of an embodiment of a system to promote adhesion of a surface coating to an article.

It should be understood that the proportions and dimensions (either relative or absolute) of the various features and elements (and collections and groupings thereof) and the boundaries, separations, and positional relationships presented there between, are provided in the accompanying figures merely to facilitate an understanding of the various embodiments described herein and, accordingly, may not necessarily be presented or illustrated to scale, and are not intended to indicate any preference or requirement for an illustrated embodiment to the exclusion of embodiments described with reference thereto.

DETAILED DESCRIPTION

Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. While various embodiments of the present invention have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and alterations are within the scope and spirit of the present invention. Further, the inventions described herein are capable of other embodiments and of being practiced or of being carried out in various ways. In addition, it is to be understood that the phraseology and terminology used herein is for the purposes of description and should not be regarded as limiting. The use of “including,” “comprising,” or “adding” and variations thereof herein are meant to encompass the items listed thereafter and equivalents thereof, as well as, additional items.
The following disclosure generally relates to methods and systems to promote adhesion of coatings on surfaces, such as promoting adhesion of arc-spray or thermal-spray coatings onto surfaces such as metallic or ceramic surfaces with use of a non-thermal plasma stream at atmospheric pressure.
Additional details of the invention are provided in the attached figures and/or tables. With attention to FIG. 1, a flowchart depicting one embodiment of a method 100 to promote adhesion of a surface coating to an article is depicted. The description of the method 100 of FIG. 1 will reference elements of FIGS. 2A-C, which depicts three schematic elevation views of an article 200 receiving a surface coating consistent with the method of FIG. 1, and to FIG. 3, which depicts a system 300 to promote adhesion of a surface coating to an article 200.
Generally, the method 100 applies a non-thermal plasma stream 410 at atmospheric pressure to an article surface 208, creating an energized surface region that promotes adhesion of an arc-spray coating.
The non-thermal plasma stream 410 at atmospheric pressure increases the surface energy of a metallic or ceramic surface which in turn increases the bonding of an arc sprayed metallic surface coating. The non-thermal plasma stream 410 is used as a bonding adhesion promoter that enhances the adhesion of arc-sprayed coating layers, thereby enabling smooth surfaces with little roughness to be coated with an arc spray coating with improved adhesion.
The arc-spray coating is applied to the energized region. In one embodiment, both the article and the arc-spray are metallic.
Generally, the system 300 to promote adhesion of a surface coating to an article comprises a plasma generating device 400 and an arc-spray generating device 500 (or a thermal spray generating device). Each of the plasma generating device 400 and an arc-spray generating device 500 emit a stream directed at a surface 208 of an article 200. In one embodiment, both the article and the arc-spray are metallic. In another embodiment, the arc-spray may be a ceramic, a mixture of a ceramic and a metal (termed a CERMET) In another embodiment, the arc-spray may be a semiconductor, or other material that can be liquefied and sprayed in its molten state to impact on a surface that is at a temperature that is below the melting point of the material being sprayed, such that when the molten/liquid spray impacts the surface it is cooled to a temperature that is lower than the melting point of the liquefied material and solidifies onto the surface forming a coating.
The method 100 starts at step 104 and ends at step 128. Any of the steps, functions, and operations discussed herein can be performed continuously and automatically. In some embodiments, one or more of the steps of the method 100 may comprise computer control, use of computer processors, and/or some level of automation. The steps are notionally followed in increasing numerical sequence, although, in some embodiments, some steps may be omitted, some steps added, and the steps may follow other than increasing numerical order.
After starting at step 104, at step 108 a non-thermal plasma stream 410, at atmospheric pressure, is generated by a plasma generating device 400. Any of several means may be used to generate the non-thermal plasma stream at atmospheric pressure, to include by use of the devices and methods described in the previously-identified patent documents: U.S. Pat. No. 8,981,251 to Yancey, U.S. Pat. No. 8,604,379 to Yancey, and WIPO 2017/087991 to Yancey (collectively, the “Yancey techniques.”)
In one embodiment, the non-thermal plasma stream 410 is provided by a plasma generating device 400 configured to discharge an atmospheric pressure plasma stream (or plasma “plume”) 410 from a nozzle. The plasma generating device 400 may be positioned at some specified distance between the nozzle and the surface of the article 200, and oriented to direct the atmospheric pressure non-thermal plasma stream 410 toward the surface 208 of the article 200. While the atmospheric pressure non-thermal plasma stream 410 is active, the nozzle directink the atmospheric pressure non-thermal plasma stream 410 device may be moved across the surface 208 of the article 200.
The non-thermal plasma stream 410 and/or the plasma generating device 400 may be configured with any combination of the following parameters. Generally, the operating parameters associated with the plasma generating device 400 to generate the non-thermal plasma stream 410 are selected to produce a stable plasma discharge. The operating parameters may vary depending on the composition of the metallic substrate 204 (i.e., the type of metal or metal alloy) on (from) which the energized surface region 212 is to be formed. Examples of operating parameters will now be provided with the understanding that the broad teachings herein are not limited by such examples.
In a preferred embodiment, an air flow rate of between 20 and 200 standard liter per minute (SLM) is used. In a more preferred embodiment, an air flow rate of between 50 and 150 SLM is used. In a most preferred embodiment, an air flow rate of between 75 and 125 SLM is used. In one embodiment, an air flow rate of about 100 SLM is used.
In a preferred embodiment, a plasma power of between 0.3 kW and 5 kW is used. In a more preferred embodiment, a plasma power of between 1.2 and 3.2 kW is used. In a most preferred embodiment, a plasma power of between 1.7 and 2.7 kW is used. In one embodiment, a plasma power of about 2.2 kW is used.
In a preferred embodiment, a plasma power density per flow rate of between 10 SLM/kW and 70 SLM/kW is used. In a more preferred embodiment, a plasma power per flow rate of between 25 SLM/kW and 55 SLM/kW is used. In a most preferred embodiment, a plasma power per flow rate of between 35 SLM/kW and 45 SLM/kW is used. In one embodiment, a plasma power per flow rate of 100 SLM/2.5 kW=40 SLM/kW is used.
In a preferred embodiment, an electrode voltage of between 500V and 4000V is used. In a more preferred embodiment, an electrode voltage of between 1000V and 3000V is used. In a most preferred embodiment, an electrode voltage of between 1000V and 1400V is used. In one embodiment, an electrode voltage of about 1200V is used.
In a preferred embodiment, a frequency of between direct current (DC) and 2540 MHz (i.e. 2.54 GHz) is used. In a more preferred embodiment, a frequency of between 50 kHz and 200 kHz is used. In a most preferred embodiment, a frequency between 100 kHz and 150 kHz is used. After completion of step 108, the method 100 continues to step 112.
At step 112, an article of manufacture (or product) 200 is positioned to receive the non-thermal plasma stream 410. With attention to FIG. 2A, the (unworked or untreated) article 200 comprises a substrate 204, such as a metal substrate, with an untreated upper surface 208. The untreated upper surface 208 is the surface which will undergo treatment per the method 100.
The substrate 204 of the article 200 may be configured with any combination of the following parameters.
In a preferred embodiment, the substrate temperature is between −50 deg C and +80 deg C. In a more preferred embodiment, the substrate temperature is between −20 deg C and +50 deg C. In a most preferred embodiment, the substrate temperature is +10 deg C and +30 deg C. In one embodiment, the substrate temperature is about +20 deg C.
In another preferred embodiment, the substrate temperature may be as high as 0.95 imes the melting point of the surface that is being treated. For example, tin melts at 232C. The tin surface could be as hot as 220 C and still be in a solid state and accept a plasma treatment.
In another preferred embodiment, the substrate temperature may be as low as absolute zero.
In a preferred embodiment, the air flow rate is between 5 SLM and 300 SLM. In a more preferred embodiment, the air flow rate is between 10 SLM and 250 SLM. In a most preferred embodiment, the air flow rate is between 20 SLM and 200 SLM.
In a preferred embodiment, the substrate is descaled metal with a smooth surface roughness of less than 10 mil. In a more preferred embodiment, the substrate is descaled metal with a smooth surface roughness of less than 5 mil. In a most preferred embodiment, the substrate is descaled metal with a smooth surface roughness of less than 0.01 mil. In one embodiment, the substrate is descaled metal with a smooth surface roughness of between 0.01 mil to 5 mil.
(It should be noted that the method of the disclosure generally works to enhance bonding on either atomically flat surfaces or jagged and rough surfaces with, e.g. +/−3 cm roughness. An advantage is that whatever surface roughness is presented may be useable such that no secondary process to create a specific roughness is required. Stated another way, one can use whatever roughness is provided and the method will improve adhesion.)
The substrate 204 may be, in one embodiment, any metal or metal alloy. In one embodiment, the substrate 204 is a composite material, a ceramic, and/or a semiconductor.
After completion of step 112, the method 100 continues to step 116.
At step 116, the untreated upper surface 208 of article 200 is treated with the non-thermal plasma stream 410. The non-thermal plasma stream 410 energies the untreated upper surface 208 (of FIG. 2A) to increase the surface energy of the untreated upper surface 208, creating an energized surface region 212 with treated upper surface 220 (see FIG. 2B). Stated another way, the non-thermal plasma stream 410 creates an energized surface region 212 with higher dyne level than before the surface treatment. The energized surface region 212 acts as an adhesion layer and is disposed above or adjacent a bulk layer 216 of the substrate 204. After undergoing treatment by the non-thermal plasma stream, the article 200 comprises a treated upper surface 220. The treated upper surface 220 in effect replaces the untreated upper surface 208 depicted in FIG. 2A. In one embodiment, the substrate 204 is a metal or metal alloy, the bulk layer 216 is a bulk metallic layer, the energized surface region 212 is a metal oxide layer, and the treated upper surface 220 is an outer oxide surface.
As briefly discussed above, in one embodiment, the non-thermal plasma stream 410 is provided by a plasma generating device 400 configured to discharge an atmospheric pressure plasma stream (or plasma “plume”) 410 from a nozzle. In such an embodiment, the plasma generating device 400 may be positioned at some specified distance between the nozzle and the untreated upper surface 208 of the article 200, and oriented to direct the atmospheric pressure plasma stream 410 toward the surface 208 of the article 200. While the atmospheric pressure plasma stream 410 is active, the nozzle directing the atmospheric pressure plasma stream 410 device may be moved across the untreated upper surface 208 of the article 200.
Among other things, the non-thermal plasma stream 410 promotes or enhances the bonding of the surface 208 of the article 200 to a coating, such as an arc-spray coating or a thermal-spray coating. The non-thermal plasma stream 410 may be generated in close proximity to the substrate surface to ensure the surface is exposed to the non-thermal plasma stream 410 or at least the afterglow thereof. In some embodiments, the generated plasma may be transported toward the substrate surface by a flow of air, or additionally by an electric field, which may be the electric field utilized to generate the plasma. The plasma is generated under conditions that, if desired, can produce a high concentration of monatomic oxygen in the plasma or other chemically reactive atomic or molecular species. The plasma may also produce a high concentration of highly energetic and reactive singlet oxygen in the plasma or other singlet species of various elements.
On some substrates, the plasma can be effectively directed to selectively oxidizing the substrate surface. In other cases, the non-thermal plasma can be utilized to only alter the first few atomic layers of a substrate, effectively just changing the chemical surface groups on the substrate' s surface.
In one embodiment the plasma forms an oxide layer of nanoscale thickness on the metallic substrate to promote bonding. The plasma-formed oxide layer may be grown from the base metal of the metallic substrate itself and may therefore be permanently and rigidly attached to the substrate. Stated another way, in some embodiments, the oxide layer may be characterized as being integral with the underlying bulk of the metallic substrate. The bulk of the metallic substrate may be characterized as that part of the metallic substrate that is substantially free of the metal oxide formed as the overlying oxide laver.
Furthermore, the plasma-formed oxide layer, in some embodiments, is porous, may add a nanoscale surface texture and/or may increase the surface area that is available for bonding to the coating (see steps 120 and 124) as applied by the coating stream 510.
Note that, through the disclosed process, nanoscale roughness may be enhanced to increase (in particular, mechanical) bonding of the arc-spray or thermal-spray. In addition to any increase in nanoscale roughness to promote mechanical bonding, the post plasma treated surface promotes stronger chemical bonds to the surface. The plasma works on atomically smooth surfaces because there is chemical bonding which can be many times higher bond strength. The plasma can promote adhesion on atomically smooth surfaces because there is chemical bonding which can impart higher bond strengths compared to strictly mechanical means.
Another effect of the application, or spraying, of the non-thermal plasma stream 410 to the untreated upper surface 208 of the article 200 is to increase the surface energy of the newly formed plasma-oxidized oxide layer (as compared to the surface energy of the original outer surface of the metallic substrate), which further enhances adhesion when a coating is applied to the surfaces within a certain period of time.
The non-thermal plasma stream 410, as generated by a plasma generating device 400, may be operated with enriched gas mixtures which may increase the flux of oxygen or other desired chemical terminations groups onto the substrate. Different chemical groups may be chosen to enhance the adhesion for the specific chemistry of the substrate and the arc deposited material. For example, a plasma pen may be operated with nitrogen to produce atomic nitrogen species which may be used to nitride surfaces or to from amine groups in the presence of hydrogen.
Furthermore, alternative gases may be used to terminate the surface such as: N, 0, F, Cl, Br, CO2 (carbon dioxide) Ammonia, Water, and Hydrogen.
Also, depending on the type of arc-spray or thermal coating, it may be preferred to use a chemical species other than oxygen to activate a metallic surface, e.g. a nitride may be used to bond with certain nitride forming alloy systems.
In one embodiment, a DBD plasma device may be used to activate the surface but at relatively lower plasma densities and slower treatment times. Alternatively, any atmospheric plasma device that produces enough flux of energetic plasma species could be used to treat the untreated upper surface 208 of the article 200. However, many atmospheric plasma sources that are used for surface treatment do not produce a significant flux of energetic species to enable an industrially feasible process to be created.
The composition of an air plasma is a mixture of different components, including various charged and electronically excited species of oxygen and nitrogen, and other trace gases found in air. The plasma is generated under conditions that produce a high plasma density, which, if desired, can produce a high density of monatomic oxygen ions (and/or other monatomic oxygen species) in the plasma as well as chemically reactive singlet oxygen. In one embodiment, the density of ionized species in the plasma is in a range from 1×10¹³ions/cm³to 1×10^‥ions/cm³, one specific yet non-exclusive example being about 2.55×10¹⁶ions/cm³.
As appreciated by persons skilled in the art, singlet oxygen is a highly energetic and chemically reactive form of diatomic oxygen (O₂), as compared to the ground-state, or triplet, diatomic oxygen (O2) that is a predominant constituent of naturally occurring air. The monatomic oxygen has a much higher diffusivity and chemical reactivity compared to molecular oxygen species such as diatomic oxygen (O2) and ozone (O3), which may also be produced in the air plasma. As a result of the untreated upper surface 208 of the article 200 being exposed to this plasma, monatomic oxygen species penetrate the untreated upper surface 208 of the article 200 and can combine with metal atoms of the metallic substrate 204 to form a metal oxide.n At other times the stand-off distance from the substrate to be treated can be increased to eliminate the monatomic oxygen from reaching the surface to provide a surface treatment that does not cause a surface oxide to form. Consequently, as illustrated in FIGS. 2A-C, a distinct energized surface region 212 is formed from a portion of the metallic substrate 204 and is rigidly attached to the metallic substrate 204. In some cases, the metal oxide layer 212 serves as a highly effective adhesion promoting layer to which a coating may be applied (see step 124 and arc-spray 510).
In one embodiment, the treated upper surface 220 (which in this example is an outer oxide surface) is porous, or at least is superficially porous. Such nanoscale porosity may significantly increase the surface area of the outer oxide surface, thereby providing a significantly increased surface area for bonding and adherence to the arc-spray coating, as compared to a nonporous or less rough surface. In one embodiment, the treated upper surface 220 may not be generally porous and is a few atoms or molecules thick.
It should be noted it is beneficial to have an oxide layer for adhesion only in certain material systems.
In the embodiment in which the substrate 204 is a metal or metal alloy, the bulk layer 216 is a bulk metallic layer, the energized surface region 212 is a metal oxide layer, and the treated upper surface 220 is an outer oxide surface. In such an embodiment the plasma treatment may provide a surface treatment that changes the first few atomic or molecular layers on the surface.
The non-thermal plasma stream 410 is directed toward the surface of substrate at high velocities. In one embodiment, the non-thermal plasma stream 410 impacts the surface of the substrate at near or exceeding sonic velocities. Stated another way, in one embodiment the non-thermal plasma stream 410 impacts the surface of the substrate at a velocity faster than the local environmental speed of sound.
After the treatment of the surface of the article 200 with the non-thermal plasma stream 410, the treated upper surface 220 is more amenable to adhesion of an arc-spray (or thermal) coating. One or more processes occur to enable the heightened adhesion. For example, surface monolayers may be added to change chemical groups which promote adhesion to a substrate's base metallic material. Also, surface monolayers may slightly alter to change surface chemical groups, thereby promoting adhesion to a substrate's base metallic material. Furthermore, plasma treatment may etch organic residues onto the surface and leave the surface nearly atomically clean. Also, energetic species from the plasma may increase the surface energy of the metal surface and reduce the surface tension, which promotes wetting of the surface by the liquid metal produced by the arc spray apparatus. Also, the plasma surface treatment creates active chemical sites that can bond chemically with the arc sprayed metal. Lastly, the high plasma density air plasma produces a high fluence of atomic oxygen which has a much higher diffusivity compared to molecular oxygen species, such as O2 and O3, which allows rapid cleaning of any organic contaminants on the surface.
In one embodiment, the plasma treatment may be performed manually or robotically with overlapping surface coverage to ensure complete treatment area coverage.
After completion of step 116, the method 100 continues to step 120.
At step 120, an arc-spray coating stream is generated. The arc-spray coating stream is directed at the energized surface region 212, to form or create an arc-spray coating 240. Stated another way, the arc-spray coating stream is directed at the energized surface region 224 and adheres or bonds an arc-spray coating to an upper surface of the article 200.
The arc spray may also be a pure metal, a pure metal alloy, a cermet or a mixture of metal and inorganic particulates.
The arc-sprayed metal is sprayed in air and, in some embodiments, includes a sheath of air plasma surrounding the molten metal; this molten metal surface is thus plasma treated as it is being propelled towards the surface to be coated. When both plasma-treated surfaces meet (the molten droplets of metal and the plasma treated substrate), the enhanced chemical reactivity imparted by the air plasma treatment enhances the bonding, creating a chemical as well as a mechanical bond. Because the bonding is now chemical and not just mechanical, strong adhesion can occur on relatively flat and smooth surfaces, doing away with the need for grit blasting, creation of surface roughness, or profiling the surface in another step.
In a preferred embodiment, the arc-spray coating stream 510 (see step 124) is applied within 60 minutes after the completion of spraying of the article with the non-thermal plasma stream 410 (i.e. within 60 minutes after step 116.) In a more preferred embodiment, the arc-spray coating stream 510 (see step 124) is applied within 40 minutes after the completion of spraying of the article with the non-thermal plasma stream 410. In a most preferred embodiment, the arc-spray coating stream 510 (see step 124) is applied within 30 minutes after the completion of spraying of the article with the non-thermal plasma stream 410. After completion of step 120, the method 100 ends at step 128.
With reference to FIG. 2C, the energized surface region 212 is much thinner in thickness than the arc-sprayed coating 240. Generally, the energized surface region 212 is of thickness at the molecular level. In contrast, the thickness of the arc-sprayed coating 240 may vary from micron thickness to inches.
In a preferred embodiment, the arc-sprayed coating 240 is of thickness between 10 micron to 2000 micron. In a more preferred embodiment, the arc-sprayed coating 240 is of thickness between 20 micron and 2000 micron. In a most preferred embodiment, the arc-sprayed coating 240 is of thickness between 25 micron and 1000 micron. In one embodiment, the arc-sprayed coating 240 is of thickness of about 200 micron.
In another embodiment, the arc-sprayed coating 240 is of thickness of more than 12,700 micron (0.50 inch). In another embodiment, the arc-sprayed coating 240 is of thickness of more than 19,050 micron (0.75 inch).
Several benefits ensue from the method 100 and system 300. The benefits include: reduction in the steps required to prepare a surface for arc-spray bonding, vitiate the need to grit blast a surface to make a profile or surface roughness, increase chemical bonding at the interface between the arc splats and the surface instead of just a mechanical bond, reduce the likelihood of user error by elimination of steps in a process, reduce process costs by reducing the time required to prep a surface before bonding, reduce process cost by eliminating chemicals and other materials required to prepare a surface. Also, the raw material required for plasma (air) is infinitely renewable and always on available at any site in the world. Lastly, with some materials, e.g. titanium, there is a clear visual color change which provides a user an indication that plasma processing has been completed; in contrast, most processes that involve multiple critical preparation steps are invisible and thus may easily be skipped given a lack of visual indication.
It is noted that although FIG. 3 depicts the system 300 to promote adhesion of a surface coating to an article comprising both a plasma generating device 400 and an arc-spray generating device 500 (or a thermal spray generating device), these two components (400, 500) may be separated, in one or both of time and physical proximity. Stated another way, the plasma generating device 400 may treat a surface of an article at a first location, and the arc-spray generating device 500 may coat the surface at a second location. The time between treatment of the surface by the plasma generating device 400 and the coating by the arc-spray (or thermal spray) generating device 500 may be several hours, e.g. from 2-5 hours in one embodiment.
Also, the methods and devices of the disclosure may be applied to ceramic surfaces, and inorganic composites, such as metallic matrix composites with embedded ceramic fibers and the like.
Furthermore, the arc-spray (or thermal spray) may be used to deposit varied materials onto varied surfaces, e.g. deposit ceramic on metal, metal on ceramic, cermet on metal, metal on ceramic, etc.
Examples of the processors as described herein may include, but are not limited to, at least one of Qualcomm® Snapdragon® 800 and 801, Qualcomm® Snapdragon® 610 and 615 with 4G LTE Integration and 64-bit computing, Apple® A7 processor with 64-bit architecture, Apple® M7 motion coprocessors, Samsung® Exynos® series, the Intel® Core™ family of processors, the Intel® Xeon® family of processors, the Intel® Atom™ family of processors, the Intel Itanium® family of processors, Intel® Core® i5-4670K and i7-4770K 22 nm Haswell, Intel® Core® i5-3570K 22 nm Ivy Bridge, the AMD® FX™ family of processors, AMD® FX-4300, FX-6300, and FX-8350 32 nm Vishera, AMD® Kaveri processors, Texas Instruments® Jacinto C6000™ automotive infotainment processors, Texas Instruments® OMAP™ automotive-grade mobile processors, ARM® Cortex™-M processors, ARM® Cortex-A and ARM926EJ-S™ processors, other industry-equivalent processors, and may perform computational functions using any known or future-developed standard, instruction set, libraries, and/or architecture.
The exemplary systems and methods of this disclosure have been described in relation to Promoting adhesion of coatings on surfaces, such as promoting adhesion of arc-spray coatings onto surfaces such as metallic or ceramic surfaces with use of a non-thermal plasma stream at atmospheric pressure. However, to avoid unnecessarily obscuring the present disclosure, the preceding description omits a number of known structures and devices. This omission is not to be construed as a limitation of the scopes of the claims. Specific details are set forth to provide an understanding of the present disclosure. It should however be appreciated that the present disclosure may be practiced in a variety of ways beyond the specific detail set forth herein.
Furthermore, while the exemplary aspects, embodiments, and/or configurations illustrated herein show the various components of the system collocated, certain components of the system can be located remotely, at distant portions of a distributed network, such as a LAN and/or the Internet, or within a dedicated system. Thus, it should be appreciated, that the components of the system can be combined in to one or more devices or collocated on a particular node of a distributed network, such as an analog and/or digital telecommunications network, a packet-switch network, or a circuit-switched network. It will be appreciated from the preceding description, and for reasons of computational efficiency, that the components of the system can be arranged at any location within a distributed network of components without affecting the operation of the system. For example, the various components can be in a switch such as a PBX and media server, gateway, in one or more communications devices, at one or more users' premises, or some combination thereof. Similarly, one or more functional portions of the system could be distributed between a telecommunications device(s) and an associated computing device.
Furthermore, it should be appreciated that the various links connecting the elements can be wired or wireless links, or any combination thereof, or any other known or later developed element(s) that is capable of supplying and/or communicating data to and from the connected elements. These wired or wireless links can also be secure links and may be capable of communicating encrypted information. Transmission media used as links, for example, can be any suitable carrier for electrical signals, including coaxial cables, copper wire and fiber optics, and may take the form of acoustic or light waves, such as those generated during radio-wave and infra-red data communications.
Also, while the flowcharts have been discussed and illustrated in relation to a particular sequence of events, it should be appreciated that changes, additions, and omissions to this sequence can occur without materially affecting the operation of the disclosed embodiments, configuration, and aspects.
A number of variations and modifications of the disclosure can be used. It would be possible to provide for some features of the disclosure without providing others.
In yet another embodiment, the systems and methods of this disclosure can be implemented in conjunction with a special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit element(s), an ASIC or other integrated circuit, a digital signal processor, a hard-wired electronic or logic circuit such as discrete element circuit, a programmable logic device or gate array such as PLD, PLA, FPGA, PAL, special purpose computer, any comparable means, or the like. In general, any device(s) or means capable of implementing the methodology illustrated herein can be used to implement the various aspects of this disclosure. Exemplary hardware that can be used for the disclosed embodiments, configurations and aspects includes computers, handheld devices, telephones (e.g., cellular, Internet enabled, digital, analog, hybrids, and others), and other hardware known in the art. Some of these devices include processors (e.g., a single or multiple microprocessors), memory, nonvolatile storage, input devices, and output devices. Furthermore, alternative software implementations including, but not limited to, distributed processing or component/object distributed processing, parallel processing, or virtual machine processing can also be constructed to implement the methods described herein.
In yet another embodiment, the disclosed methods may be readily implemented in conjunction with software using object or object-oriented software development environments that provide portable source code that can be used on a variety of computer or workstation platforms. Alternatively, the disclosed system may be implemented partially or fully in hardware using standard logic circuits or VLSI design. Whether software or hardware is used to implement the systems in accordance with this disclosure is dependent on the speed and/or efficiency requirements of the system, the particular function, and the particular software or hardware systems or microprocessor or microcomputer systems being utilized.
In yet another embodiment, the disclosed methods may be partially implemented in software that can be stored on a storage medium, executed on programmed general-purpose computer with the cooperation of a controller and memory, a special purpose computer, a microprocessor, or the like. In these instances, the systems and methods of this disclosure can be implemented as program embedded on personal computer such as an applet, JAVA® or CGI script, as a resource residing on a server or computer workstation, as a routine embedded in a dedicated measurement system, system component, or the like. The system can also be implemented by physically incorporating the system and/or method into a software and/or hardware system.
Although the present disclosure describes components and functions implemented in the aspects, embodiments, and/or configurations with reference to particular standards and protocols, the aspects, embodiments, and/or configurations are not limited to such standards and protocols. Other similar standards and protocols not mentioned herein are in existence and are included in the present disclosure. Moreover, the standards and protocols mentioned herein, and other similar standards and protocols not mentioned herein are periodically superseded by faster or more effective equivalents having essentially the same functions. Such replacement standards and protocols having the same functions are considered equivalents included in the present disclosure.
The present disclosure, in various aspects, embodiments, and/or configurations, includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various aspects, embodiments, configurations embodiments, sub-combinations, and/or subsets thereof. Those of skill in the art will understand how to make and use the disclosed aspects, embodiments, and/or configurations after understanding the present disclosure. The present disclosure, in various aspects, embodiments, and/or configurations, includes providing devices and processes in the absence of items not depicted and/or described herein or in various aspects, embodiments, and/or configurations hereof, including in the absence of such items as may have been used in previous devices or processes, e.g., for improving performance, achieving ease and\or reducing cost of implementation.
The foregoing discussion has been presented for purposes of illustration and description. The foregoing is not intended to limit the disclosure to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the disclosure are grouped together in one or more aspects, embodiments, and/or configurations for streamlining the disclosure. The features of the aspects, embodiments, and/or configurations of the disclosure may be combined in alternate aspects, embodiments, and/or configurations other than those discussed above. This method of disclosure is not to be interpreted as reflecting an intention that the claims require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed aspect, embodiment, and/or configuration. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the disclosure.
Moreover, though the description has included description of one or more aspects, embodiments, and/or configurations and certain variations and modifications, other variations, combinations, and modifications are within the scope of the disclosure, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative aspects, embodiments, and/or configurations to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.

Claims

What is claimed is:

1. A method to adhere an arc-spray coating to a surface of an article, the method comprising:

generating a non-thermal plasma stream, the non-thermal plasma stream at atmospheric pressure;

positioning the surface of the article to receive the non-thermal plasma stream;

treating the surface of the article with the non-thermal plasma stream to create an energized surface region;

generating an arc-spray coating stream;

directing the arc-spray coating stream at the energized surface region; wherein:

the arc-spray coating stream forms an arc-spray coating surface associated with the energized surface region of the article.

2. The method of claim 1, wherein the energized surface region comprises etched organic residues.

3. The method of claim 1, wherein the non-thermal plasma stream comprises monatomic oxygen species.

4. The method of claim 1, wherein the article is metallic and the surface is a metallic surface.

5. The method of claim 4, wherein the energized surface region is a metal oxide region.

6. The method of claim 5, wherein the metal oxide region comprises an outer oxide surface.

7. The method of claim 6, wherein the arc-spray coating stream is directed at the outer oxide region.

8. The method of claim 1, wherein the article is metallic, the surface comprises a metallic surface, and the arc-spray stream comprises a metal.

9. The method of claim 8, further comprising the step of forming chemical bonding sites on the energized surface region, the chemical bonding sites promoting chemical bonding with the energized surface region.

10. The method of claim 1, wherein the article is metallic and the surface is a metallic surface.

11. The method of claim 1, further comprising the step of applying an auxiliary gas onto the surface of the article.

12. The method of claim 1, wherein the non-thermal plasma stream comprises monatomic nitrogen.

13. The method of claim 1, wherein the arc-spray coating stream is a metallic arc-spray coating stream comprising a stream of projected molten metal surrounded by a sheath of air plasma.

14. The method of claim 1, wherein the surface is a metallic surface, and the non-thermal plasma stream comprises an energetic species chemically reactive with the metallic surface.

15. The method of claim 1, further comprising the application of a gas curtain associated with the non-thermal plasma stream.

16. The method of claim 1, wherein the arc-spray stream comprises a sheath of air plasma.

17. The method of claim 1, wherein the energized surface region comprises etched inorganic residues.

18. The method of claim 1, wherein the article is ceramic, the surface comprises a ceramic surface, and the arc-spray stream comprises a metal.

19. The method of claim 1, wherein the article is ceramic, the surface comprises a ceramic surface, and the arc-spray stream comprises a cermet.

20. The method of claim 1, wherein the article is ceramic, the surface comprises a ceramic surface, and the arc-spray stream comprises a ceramic.

21. The method of claim 1, wherein the non-thermal plasma stream comprises monatomic chemical species.

22. The method of claim 1, wherein the non-thermal plasma stream comprises a tailored gas that forms a tailored chemical species on the surface.

23. The method of claim 22, wherein the tailored gas is ammonia and the tailored chemical species comprise amine groups.

24. The method of claim 22, wherein the tailored gas is water and the tailored chemical species comprise hydroxyl groups.

25. A method to bond an arc-spray coating to a metal surface of an article, the method comprising:

generating a non-thermal plasma stream, the non-thermal plasma stream at atmospheric pressure and comprising monatomic oxygen;

positioning the metal surface of the article to receive the non-thermal plasma stream;

treating the metal surface of the article with the non-thermal plasma stream to create a metal oxide region, the metal oxide region comprising an outer oxide surface and etched organic residues;

generating a metallic arc-spray coating stream comprising a stream of projected molten metal surrounded by a sheath of air plasma; and

directing the metallic arc-spray coating stream at the metal oxide region; wherein:

the molten metal bonds with the metal oxide region to bond the arc-spray coating to the metal surface of the article.

26. A system to adhere an arc-spray coating to a surface of an article, the system comprising:

a plasma generating device configured to generate a non-thermal plasma stream at atmospheric pressure; and

an arc-spray generating device configured to generate an arc-spray coating stream; wherein:

the non-thermal plasma stream is directed at the surface of the article to create an energized surface region;

the arc-spray coating stream is directed at the energized surface region; and

the arc-spray coating is adhered to the surface of the article.

27. The system of claim 26, wherein the non-thermal plasma stream comprises monatomic oxygen, the article is metallic, the surface is a metallic surface, and the arc-spray stream comprises a metal.

28. The system of claim 27, wherein the non-thermal plasma generating device is configured to direct an auxiliary gas onto the metallic surface, and the arc-spray coating stream is a metallic arc-spray coating stream comprising a stream of projected molten metal surrounded by a sheath of air plasma.