EP0093779B1 - Plasma coatings comprised of sprayed fibers - Google Patents
Plasma coatings comprised of sprayed fibers Download PDFInfo
- Publication number
- EP0093779B1 EP0093779B1 EP19830900217 EP83900217A EP0093779B1 EP 0093779 B1 EP0093779 B1 EP 0093779B1 EP 19830900217 EP19830900217 EP 19830900217 EP 83900217 A EP83900217 A EP 83900217A EP 0093779 B1 EP0093779 B1 EP 0093779B1
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- EP
- European Patent Office
- Prior art keywords
- fibers
- matrix
- substrate
- plasma
- spraying
- Prior art date
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- 239000000835 fiber Substances 0.000 title claims abstract description 210
- 238000000576 coating method Methods 0.000 title abstract description 35
- 239000011159 matrix material Substances 0.000 claims abstract description 53
- 239000000758 substrate Substances 0.000 claims abstract description 49
- 229910052751 metal Inorganic materials 0.000 claims abstract description 44
- 239000002184 metal Substances 0.000 claims abstract description 43
- 239000000919 ceramic Substances 0.000 claims abstract description 41
- 238000000034 method Methods 0.000 claims abstract description 32
- 239000002245 particle Substances 0.000 claims abstract description 10
- 238000007750 plasma spraying Methods 0.000 claims abstract description 7
- 239000000463 material Substances 0.000 claims description 31
- 239000000843 powder Substances 0.000 claims description 25
- 238000005507 spraying Methods 0.000 claims description 22
- 229920000642 polymer Polymers 0.000 claims description 15
- 239000007921 spray Substances 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 5
- 229910000601 superalloy Inorganic materials 0.000 claims description 4
- 238000007751 thermal spraying Methods 0.000 claims description 3
- 230000002411 adverse Effects 0.000 claims description 2
- 230000001590 oxidative effect Effects 0.000 claims description 2
- 229910001092 metal group alloy Inorganic materials 0.000 claims 2
- 229910010293 ceramic material Inorganic materials 0.000 abstract description 5
- 239000002861 polymer material Substances 0.000 abstract description 2
- 239000011248 coating agent Substances 0.000 description 17
- 239000010410 layer Substances 0.000 description 14
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 12
- 239000007789 gas Substances 0.000 description 11
- 238000002844 melting Methods 0.000 description 10
- 230000008018 melting Effects 0.000 description 10
- 239000010935 stainless steel Substances 0.000 description 7
- 229910001220 stainless steel Inorganic materials 0.000 description 7
- 239000002131 composite material Substances 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 5
- 229910045601 alloy Inorganic materials 0.000 description 5
- 239000000956 alloy Substances 0.000 description 5
- 238000012546 transfer Methods 0.000 description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 238000013459 approach Methods 0.000 description 4
- 239000011888 foil Substances 0.000 description 4
- 238000002347 injection Methods 0.000 description 4
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- 230000008901 benefit Effects 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 239000010963 304 stainless steel Substances 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- 229910000589 SAE 304 stainless steel Inorganic materials 0.000 description 2
- 239000012159 carrier gas Substances 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
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- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- 229910001111 Fine metal Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229920005479 Lucite® Polymers 0.000 description 1
- NPXOKRUENSOPAO-UHFFFAOYSA-N Raney nickel Chemical compound [Al].[Ni] NPXOKRUENSOPAO-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 238000005524 ceramic coating Methods 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
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- 238000009792 diffusion process Methods 0.000 description 1
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- 238000002474 experimental method Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 239000011229 interlayer Substances 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- -1 nickel chromium aluminum Chemical compound 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 239000011226 reinforced ceramic Substances 0.000 description 1
- 239000012783 reinforcing fiber Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- RUDFQVOCFDJEEF-UHFFFAOYSA-N yttrium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Y+3].[Y+3] RUDFQVOCFDJEEF-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
- C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
Definitions
- the present invention concerns an article comprising a substrate having on its surface a multiplicity of fiber segments in a matrix of layered thermal sprayed particles and a method for forming a thermal sprayed article comprising a substrate having on its surface a multiplicity of fiber segments in a matrix of layered thermal sprayed particles.
- An article and a method of the type indicated above are known from FR-A-1 434 948.
- Plasma spraying offers the ability to create coatings and free standing structures of virtually any material which can be melted.
- the FR-A-1 434 948 discloses a process for fabricating articles provided with coatings comprising a continuous metal phase having therein a discontinuous phase of glass fibers. The process consists in projecting on the substrate by means of a spray gun a composite rod consisting of said metal and glass.
- the FR-A-1 434 948 discloses an article and process according to the precharacterizing portion of claims 1 and 9.
- the US-A-4 141 802 discloses a process for producing a panel comprising the steps of depositing a thin layer of a bonding metal or alloy on a metal substrate, positioning a layer of spaced apart reinforcing fibers on the bonding metal or alloy layer and plasma arc spraying a metal on to and through the fibers to form a metal matrix reinforced fiber coating on the substrate.
- Plasma spray coatings and free standing plasma sprayed structures tend to be materials which have relatively low strength compared to materials which have been formed by other methods.
- fibers will enhance their strengths.
- Boron fiber reinforced aluminum composites are one known combination of fibers with plasma coatings. They are made by laying fibers on thin metal foils and spraying with aluminum to bond the fibers to the foil, to form laminae. Subsequently, many such fiber-foil laminae are pressed together to form generally thin and wide articles, such as airfoils. But the process is costly. Also, there is no feasible way of incorporating fibers transverse to the nominal plane of the articles, owing to the mode of construction from laminae.
- the article according to the present invention is characterized by said structure being obtained in plasma arc spraying metal fiber segments to cause them to melt partially and thereby to adhere to the surface of the substrate.
- the method according to the present invention is characterized by thermal spraying metal fibers to melt portions thereof, without altering their acicular nature, to cause them thereby to adhere to the surface of a substrate, with a portion of the fibers projecting from the surface.
- fibers are partially melted and adhered to one another when they are deposited on a workpiece surface using a thermal spray process, such as plasma spraying.
- the fibers are adhered to the workpiece surface, as well.
- the surface is optionally made more receptive by the use of a preliminary bond coating.
- the deposited fibers may be caused to have a random pattern or a more normally aligned pattern, according to the fiber aspect ratios and the spraying parameters which are used. In both instances, a substantial portion of the fibers project from the surface, as opposed to aligning generally parallel to it. During spraying, only portions of the fibers are melted.
- the fibers are injected into the hot plasma gas stream at a point between the plasma generating nozzle and the workpiece.
- Matrix material can be infiltrated among the fibers, after they are deposited on the workpiece surface.
- the matrix may be applied by a variety of techniques, but the invention will be found principally useful when the matrix is comprised of a layered plasma sprayed coating.
- the fibers aid in holding the plasma sprayed matrix onto the substrate.
- the invention provides greater strength to the matrix.
- a bonding coat may be deposited on the fibers, before the principal matrix material is applied.
- the invention is particularly suitable for forming a metal-ceramic airseal for a gas turbine engine.
- the substrate is a superalloy and the matrix material is a zirconia base ceramic material; the fibers are a metal having high temperature strength and corrosion resistance.
- This embodiment is further improved by the following practice of the invention: Afterthe fibers have been deposited, but before the matrix is deposited, a fugitive material, such as a polymer, is placed on the substrate so that it fully envelopes a portion of the fibers on the workpiece. But the fiber portions which project furthest from the workpiece are not fully enveloped by the polymer. Thus, when the matrix material is subsequently sprayed, it envelopes the projecting ends of the fibers.
- the fugitive polymer material is removed, such as by combustion.
- This network of metal fibers has relatively good structural compliance. That is, it is adapted to deform with relatively low resistance, to accommodate differences in thermal expansion between the ceramic and the metal substrate. Thus, the ceramic is held closely to the substrate, but is not subject to damaging strains.
- the inclusion of fibers in coatings will increase strength or other properties, such as thermal conductivity.
- the invention is felt useful with all manner coatings, in addition to plasma coatings.
- the fibers may be of any material which may be plasma sprayed. Fibers alone, without any matrix material, will be useful when adhered to a substrate to increase its surface area.
- the invention is described in terms of the application of a zirconia ceramic coating to a stainless steel substrate using stainless steel fibers. However, it will be seen that the invention is equally applicable to other material combinations.
- Figure 1 illustrates generally the preferred steps in the invention.
- a bond coat 22 is first plasma sprayed onto the clean surface of a metal substrate or workpiece 20, as shown in Figure 1 (a), to provide a particularly receptive surface 23 for the later deposited materials.
- fine metal fibers 24 are plasma sprayed so they adhere to the bond coated workpiece surface. As illustrated by Figure 1 (b), many of the fibers will project above the surface of the workpiece.
- the next step is to plasma spray powders to form a typical layered ceramic structure 26, which will envelope the projecting fibers, as shown in Figure 1(c). Prior to this step it may be preferred to plasma spray a light bond coat of metal powder onto the adhered fibers, although generally we have not found this necessary.
- the resultant article 27, seen in Figure 1(d), is comprises of a substrate 20 with a fiber and ceramic matrix coating 27 adhered to its surface 23.
- FIG. 1(e)-(g) An optional procedure, illustrated by Figures 1(e)-(g), is to produce an article where the ceramic matrix-fiber composite material is separated from the substrate, by a compliant low stiffness structure of fibers.
- a polymer layer 30 is plasma or otherwise sprayed onto the workpiece surface 23, so that it envelopes a portion of the fibers which project from the surface.
- the thickness of the layer 30 is chosen so that portions of the projecting fibers 24 protrude above the mean surface of the layer.
- the ceramic matrix material is sprayed onto the polymer layer, as illustrated by Figure 1(f), using a procedure analogous to that which resulted in the structure shown in Figure 1 (c).
- the layered ceramic material 26' will adhere to the polymer surface and envelope the portions of the fiber which protrude above the polymer.
- the surface 28' of ceramic is optionally ground to produce a smooth and even finish.
- the article is placed in a furnace having an oxidizing atmosphere to cause the polymer to combust, converting it to a gas which is carried away.
- Figure 1 (g) wherein the fiber and ceramic matrix structure 26' is spaced apart from the bond coated surface 23' of the substrate, but it is joined to it by many fibers.
- the polymer has functioned as a fugitive material, to temporarily bar the infiltration of ceramic materials into the said space. When its function has been fulfilled, it has been removed without adverse effect on the workpiece or coating.
- the coating on the substrate can be characterized as having a first portion 26' comprised of fiber reinforced ceramic matrix, and second portion 30' comprised of fibers substantially free of matrix particles.
- Figure 2 shows in cross section an actual article corresponding to Figure 1(c) comprised of fibers 24a, 24b of stainless steel, a substrate 20a also of stainless steel, and a matrix 26a of predominantly zirconia.
- the matrix is about 2.5 mm thick.
- Nominally normal fibers 24a are seen in combination with portions of fibers 24b which are either parallel or inclined to the workpiece.
- Protuberances 28a are caused by plasma build up on the fibers.
- Figure 3 shows in perspective and cross section an analogous specimen corresponding with Figure 1(g), except the ceramic surface protuberances 28b have not been removed. Between the composite structure of matrix 26b and fibers is a space 30b about 0.1 mm wide created by polymer which has been removed. A fiber 24c crossing the space and holding the ceramic 26.
- Specimens like those in Figures 2 and 3 were made as follows.
- a piece of AISI 304 stainless steel was cleaned with solvent and grit blasted in a conventional manner.
- the bond coat was a nickel chromium aluminum alloy powder sized 45-120 x 10- 6 m (Alloy 443, Metco, Inc., infra).
- the fibers were AISI 304 stainless steel, with a 0.25 x 0.25 mm square cross section and a length of about 30 mm.
- the ceramic powder was an admixture of 80% zirconia and 20% yttria, sized 10-90 x 10- 6 m (Metco Material 202NS).
- a conventional gun and power supply were used, namely, a Metco Model 7M systems and gun with a style G tapered nozzle having a 7.8 mm exit dia. (Metco, Inc., Westbury, New York).
- the gun was traversed across the flat workpiece at a rate of about 0.3 m/s, with each successive pass being offset about 3 mm from the preceding pass.
- Fibers were fed using a Thermal Arc P1-AOV-2 Feeder (Sylvester & Co., Cleve- land, Ohio). The fibers were injected into the plasma stream outside the nozzle, as more particularly described below.
- the powders were injected into the stream immediately downstream from the exit face of the conventional manner, with feed rates at about 0.05 g/s.
- the bond coat was applied to a thickness of about 0.05-0.14 mm.
- the fibers were applied to the surface in a manner which caused them to adhere.
- the fibers When the fibers are injected, they are entrained in the plasma stream and impelled toward the workpiece. Only portions of the fibers are melted, and they adhere to the workpiece.
- the heat transfer a function of plasma gas enthalpy and residence time in the stream, must be sufficient to melt a portion of the fibers, to cause them to adhere to the workpiece and to each other. However, the heat transfer must not be so high as to cause complete melting of the fibers, which because of surface tension forces, would cause them to be converted into droplets.
- the density of sprayed fibers was estimated to be in the range of 10-25% of the bulk metal density of 7.9 g/cc. Nominally it is characterized herein as being of about 15% density.
- the ceramic powders were sprayed in a conventional manner, with the gun nozzle oriented 90 degrees to the substrate.
- Parameters for spraying the powders were conventional, generally comprising a gun to workpiece distance of about 64 mm, 700 amps, 70 volts, about 62 cm 3 / s nitrogen in combination with 9 cm 3 /s hydrogen.
- the same parameters were used for spraying the fibers, as described below.
- the ceramic penetrated through to the workpiece and gave a relatively uniform density. Usually, it is expectable that there will be some shielding of the areas underneath fibers which project across the plane of the workpiece. But this did not seem to cause significant voids in the particular example.
- the gun may be inclined at varied oblique angles to the workpiece surface, to better deposit ceramic under the fibers, and obtain higher density.
- the ceramic will be able to penetrate the fiber layer.
- a polymer or other coating is used as a fugitive material, to produce an absence of ceramic matrix near the substrate surface when this is desired.
- the polyester Metalco 600 material
- a polymer or other coating was used as a fugitive material, to produce an absence of ceramic matrix near the substrate surface when this is desired.
- the polyester Metalco 600 material
- Other fugitive materials may be used, such as Lucite 4F acrylic resin (Dupont Co., Wilmington, Delaware). Polymers are preferred because they may be removed easily by oxidation and moderate heating.
- Also usable will be soluble or meltable materials, such as salts, and other materials used to coat mandrels when free-standing structures are created by plasma coating.
- the substrate would be a nickel, iron or cobalt superalloy.
- the fibers would be a material with strength and corrosion resistance at high temperature. They may have a similar composition to the substrate, or another composition.
- One specific example of another useful high temperature fiber is Hoskins 875 alloy (by weight, 22.5 Cr, 5.5 Al, 0.5 Si, 0.1 C, balance Fe) produced by the Hoskins Manufacturing Co., Detroit, Michigan, USA.
- the previously described zirconia base ceramic would be useful.
- Ceramics which will be useful will be meltable refractory compounds of metals with melting points over 1400°C, preferably oxides, but also including borides, nitrides, carbides, as pure compounds or combinations.
- the spacing between the ceramic and the substrate, where they are only fibers may be varied over the range of about 0.25-12 mm, by applying sufficient fibers and sufficient fugitive material. The thickness of the space having fibers only will depend on the particular application. Greater spacings will provide greater capability for absorbing thermal mis-match strains.
- a plasma gun 32 is positioned a distance D from a workpiece or substrate 34.
- the plasma gas stream 36 issues from the opening 38 of the nozzle 39.
- the conventional powder injection conduit 42 Located Immediately downstream, adjacent to the nozzle face 40, is the conventional powder injection conduit 42.
- fibers 44 are injected by means of a separate conduit, tube 46, spaced a distance from the nozzle face.
- Tube 46 is preferably positioned normal to the centerline 47 of the plasma gas stream, although some inclination of the pipe toward the workpiece may be used.
- the pipe outlet 48, through which the fibers 44 exit, is spaced apart from the centerline of the plasma stream a distance E, sufficient to ensure that it will not be directly impacted by the stream.
- Fibers are conveyed through the tube 46 by a carrier gas; e.g., a flow of about 10 cm 3 /s was used to convey the aforementioned 0.25 mm stainless steel fibers through a 6 mm dia. tube 46. Upon exiting from the outlet 44 of the tube, the fibers become entrained in the gas stream.
- a carrier gas e.g., a flow of about 10 cm 3 /s was used to convey the aforementioned 0.25 mm stainless steel fibers through a 6 mm dia. tube 46.
- the exact position of the fiber injection tube may be varied, dependent on the specific operating conditions, and fiber size and results desired.
- the tube axis 57 will approximately intersect the centerline 47 of the plasma stream.
- the point of injection of fibers preferably is located downstream from the point at which powders are ordinarily injected. This is reflective of the need for comparatively less heating of the fibers, relative to powders, to carry out the objects of the invention and have the fibers adhere to the workpiece with substantially an acicular configuration, as described further herein.
- the aforementioned 0.25 mm dia. steel fibers were injected at a distance F of approximately 8 mm from the nozzle face when the nozzle face to workpiece distance D was about 64 mm.
- the spacing E, off the centerline 47 was about 6 mm.
- the distance F at which the fibers are introduced we vary the distance F at which the fibers are introduced, to control the precise degree of fiber melting which is needed. Generally, fibers in which less energy is needed for melting will be introduced at points closer to the workpiece surface.
- the plasma stream power level may be set more independently. Thus, high velocities associated with high power levels may be attained, but the fiber residence time will not be so great as to cause undue melting.
- our approach enables the power setting of the gun to be set at that required by a powder being sprayed, thus facilitating practice of various embodiments of our invention, especially, that involving simultaneous introduction of powder and fibers.
- the fibers will be introduced at distances E which are within 5-80% of the nozzle face to workpiece surface distance D; preferably, the foregoing range will be 10-50%.
- This distance D will vary as it does for spraying powders. Generally it will be in the range 50-175 mm, depending on materials being sprayed, ambient environment, etc.
- the fibers may still be included within a plasma coating if powders are impinged on the surface simultaneously.
- Figure 5 shows 0.35 mm dia. by 3-6 mm long copper fibers deposited onto a Metco Alloy 443 coated workpiece. The fiber-density was estimated at about 40%.
- Figures 6 and 7 are higher magnification views from a 30 degree angle off surface perpendicular. It is seen from Figure 5 that the fibers 50 have a variety of orientations with substantial numbers of the fibers projecting, at various angles approaching normal, up to 3 mm into space from the plane of the workpiece 52. This is in contrast to a 1.8 mm thick fiber mat which might be brazed on the workpiece in accord with the prior art in U.S.
- Patent 4,273,824 where all the fibers would lie approximately parallel to the plane of the workpiece surface.
- Figures 6 and 7 show that portions 54 of the fibers are melted. Also seen is some fiber fracture 56 and oxidation scale 58. Some of the bond coated substrate surface 60 is visible. Usually, the ends of the fibers are melted, and applying force to the fibers shows they are mostly bonded to the workpiece surface. There is also some surface melting along the length of the fibers, which provide bonding between the fibers where they contact one another. While some are broken and some excessively melted, the preponderance maintain an acicular shape, substantially of their original diameter.
- metal fibers In our practice of the invention thus far, we have utilized metal fibers. Basically, these have been chopped up pieces of commercial wrought wire or pieces of foil which have been slit to very narrow widths (which results in a fiber with essentially a square or rectangular cross section).
- diameter of our fiber for non-circular cross section fibers, we mean the diameter of the mean circle which fits within the non-circular cross section.
- the diameters between about 0.05 and 0.35 mm to be useful with conventional plasma spray equipment.
- the minimum fiber diameter will be determined by the minimum plasma gun heat transfer conditions which result in an effective coating. When we sprayed 0.01 mm dia. fibers, it was not possible to avoid entirely melting them with our equipment.
- the maximum diameter will be a function of heat transfer condition also, especially the residence time of the fiber in the plasma stream before it contacts the workpiece.
- the fibers should be of substantially uniform diameters. If undersize fibers are included, they are likely to melt; too many would defeat the objects of the invention. However, the fibers within a lot may vary in length, since this parameter will not substantially affect the results, except regarding the orientation, as discussed elsewhere.
- the fibers will be incorporated into the matrix in a manner which provides the strengthening or property improvement most desired.
- a major limitation of plasma coatings is their bonding to the substrate.
- Plasma coatings are deposited in successive passes, and thus are characterizable as layers of solidified particles. There is a propensity for failure between the layers, and thus when the fibers are incorporated so that they project through the layers, strengthening is provided.
- a layer may have a thickness of the order of 0.08 mm, and thus a fiber would project through at least half of two such abutting layers, for a total fiber length of about 0.08 mm, to provide a benefit.
- the fibers must be adequately bonded to the matrix.
- the fiber length along which bonding must be present to strengthen the matrix is a function of the shear strength of the bond. This will vary with the composition of the fiber and matrix, but generally, we believe that a fiber must be bonded along a length equal to about three fiber diameters to provide adequate strength. Thus, for this application, the minimum fiber aspect ratio would be 6:1.
- the aspect ratio is an important parameter. First, it affects the pattern which the fibers form when they adhere to the workpiece. Based on limited observation, it appears that if fibers have high aspect ratios, e.g., about 20:1 for 0.25 mm dia. stainless steel fibers, they will tend to be deposited in a random orientation fashion. However, when the aspect ratio of such fibers is less than about 15: 1, they tend to be deposited in a more aligned pattern, that is, more nearly normal to the surface of the workpiece. Thus when one orientation or the other is preferred, the fiber aspect ratio would be selected accordingly. It is not fully understood why the foregoing effects are observed. But, it is believed that all fibers tend to become aligned parallel to the flow direction of the plasma gas stream. However, when they impact the workpiece the longer fibers will tend to bend over more, and thus become more randomly oriented.
- the useful lengths of fibers will range between about 0.1-4 mm.
- the aspect ratio preferably will range from about 3:1 to 80:1. The foregoing ranges may change with further development.
- the density of the fibers which are deposited prior to the matrix may be varied by selection of parameters, especially fiber size, feed rate, carrier gas flow, and stream conditions. Generally, for fibers deposited independently, the bulk density will range up to 60% of the solid metal density. The density of articles comprised of deposited fibers and subsequently sprayed matrix will depend on the degree to which the matrix is able to penetrate the fibers. (Of course the matrix will have an inherent density of its own, irrespective of the presence of fibers.) Because our fibers tend to be oriented in more nearly normal orientation, higher matrix-fiber composite density can be obtained, compared to fiber mats in previous use, such as described in U.S. Patent 4,273,824. Based on limited evidence, for fiber deposits such as shown in Figure 3, we are able to get approximately normal matrix density where fiber densities range up to about 50%.
- a plasma coating which can especially benefit from the inclusion of metal fibers is a porous (40% density) metal coating, used as a relatively soft abradable material, such as is made by spraying in combination a polymer and nichrome powder, and subsequently removing the polymer.
- a porous (40% density) metal coating used as a relatively soft abradable material, such as is made by spraying in combination a polymer and nichrome powder, and subsequently removing the polymer.
- thermal conductivity of the metal article will be enhanced.
- the degree of bonding between fiber and matrix is of less importance, but it is desired that the fibers be aligned to the best degree possible, along the direction in which the heat transfer is desired.
- One application for such a material would be as an abradable seal used in the compressor of a gas turbine.
- plasma coatings can be used for forming free-standing articles, such as crucibles, rocket nozzles, and the like.
- Our fiber spraying techniques may be used to improve the properties of such articles, in accord with the foregoing embodiments of the invention.
- Separate guns may be used for spraying the fibers and the powders when they are to be sprayed simultaneously, to enable independent control of the parameters for each material.
- a single gun with a single powder/fiber injection port might be used, where the fibers and powders are mixed together. This would require experiment to determine the compatibility of the parameters with the selected sizes of powders and fibers, and the point of introduction.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Coating By Spraying Or Casting (AREA)
- Manufacture Of Alloys Or Alloy Compounds (AREA)
- Chemical Or Physical Treatment Of Fibers (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US32213281A | 1981-11-17 | 1981-11-17 | |
US322132 | 2002-12-18 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0093779A1 EP0093779A1 (en) | 1983-11-16 |
EP0093779A4 EP0093779A4 (en) | 1984-06-29 |
EP0093779B1 true EP0093779B1 (en) | 1987-09-23 |
Family
ID=23253582
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19830900217 Expired EP0093779B1 (en) | 1981-11-17 | 1982-11-15 | Plasma coatings comprised of sprayed fibers |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0093779B1 (ja) |
JP (1) | JPS58501944A (ja) |
DE (2) | DE3277364D1 (ja) |
WO (1) | WO1983001751A1 (ja) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104763119A (zh) * | 2015-03-16 | 2015-07-08 | 烟台安祺板业有限公司 | 一种防辐射保温装饰一体板 |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5966966A (ja) * | 1982-10-09 | 1984-04-16 | Toyota Motor Corp | 耐熱性軽合金部材およびその製造方法 |
DE3467775D1 (en) * | 1983-02-22 | 1988-01-07 | Tateho Kagaku Kogyo Kk | Spraying materials containing ceramic needle fiber and composite materials spray-coated with such spraying materials |
JPS62188769A (ja) * | 1986-02-13 | 1987-08-18 | Yoshiki Tsunekawa | 複合溶射法による複合材料製造方法 |
DE68910072T2 (de) * | 1988-09-20 | 1994-03-24 | Plasma Technik Ag | Verschleissfeste Beschichtung und Verfahren zu ihrer Herstellung. |
US5211776A (en) * | 1989-07-17 | 1993-05-18 | General Dynamics Corp., Air Defense Systems Division | Fabrication of metal and ceramic matrix composites |
US5897922A (en) * | 1997-04-07 | 1999-04-27 | National Research Council Of Canada | Method to manufacture reinforced axi-symmetric metal matrix composite shapes |
ITUB20160308A1 (it) * | 2016-01-22 | 2017-07-22 | Beamit S P A | Metodo di deposizione per produrre un rivestimento rugoso, ricoprimento ottenuto e componenti ricoperti con detto metodo |
CA3036769A1 (en) | 2016-11-30 | 2018-06-07 | Continental Structural Plastics, Inc. | Fiber mat formation for structural applications |
Family Cites Families (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB821690A (en) * | 1955-03-03 | 1959-10-14 | Armour Res Found | High strength-variable porosity sintered metal fiber articles and method of making the same |
US3233697A (en) * | 1960-06-07 | 1966-02-08 | Owens Corning Fiberglass Corp | Muffler internally coated with highly refractory fibers |
US3427185A (en) * | 1964-02-19 | 1969-02-11 | United Aircraft Corp | Composite structural material incorporating metallic filaments in a matrix,and method of manufacture |
FR1434948A (fr) * | 1964-11-18 | 1966-04-15 | Sfec | Perfectionnement aux procédés de fabrication de pièces et revêtements renforcés de fibres |
US3519282A (en) * | 1966-03-11 | 1970-07-07 | Gen Electric | Abradable material seal |
FR1537043A (fr) * | 1967-06-29 | 1968-08-23 | Csf | Perfectionnement aux scellements céramique-métal |
DE2113177A1 (de) * | 1971-03-18 | 1972-09-28 | Battelle Institut E V | Schutzschicht auf metallischen Oberflaechen |
US3723165A (en) * | 1971-10-04 | 1973-03-27 | Metco Inc | Mixed metal and high-temperature plastic flame spray powder and method of flame spraying same |
US3975165A (en) * | 1973-12-26 | 1976-08-17 | Union Carbide Corporation | Graded metal-to-ceramic structure for high temperature abradable seal applications and a method of producing said |
FR2337040A1 (fr) * | 1975-12-31 | 1977-07-29 | Poudres & Explosifs Ste Nale | Perfectionnements aux panneaux metalliques monocouches a fibres a hautes proprietes mecaniques et a leurs procedes de fabrication |
US4273824A (en) * | 1979-05-11 | 1981-06-16 | United Technologies Corporation | Ceramic faced structures and methods for manufacture thereof |
US4269903A (en) * | 1979-09-06 | 1981-05-26 | General Motors Corporation | Abradable ceramic seal and method of making same |
DE3009240A1 (de) * | 1980-03-11 | 1981-10-15 | Elektroschmelzwerk Kempten GmbH, 8000 München | Verfahren zur herstellung von praktisch porenfreien polykristallinen formkoerpern durch isostatisches heisspressen |
US4336276A (en) * | 1980-03-30 | 1982-06-22 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Fully plasma-sprayed compliant backed ceramic turbine seal |
-
1982
- 1982-11-15 DE DE8383900217T patent/DE3277364D1/de not_active Expired
- 1982-11-15 DE DE1983900217 patent/DE93779T1/de active Pending
- 1982-11-15 JP JP83500280A patent/JPS58501944A/ja active Pending
- 1982-11-15 WO PCT/US1982/001614 patent/WO1983001751A1/en active IP Right Grant
- 1982-11-15 EP EP19830900217 patent/EP0093779B1/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104763119A (zh) * | 2015-03-16 | 2015-07-08 | 烟台安祺板业有限公司 | 一种防辐射保温装饰一体板 |
Also Published As
Publication number | Publication date |
---|---|
DE93779T1 (de) | 1984-03-01 |
EP0093779A4 (en) | 1984-06-29 |
WO1983001751A1 (en) | 1983-05-26 |
EP0093779A1 (en) | 1983-11-16 |
DE3277364D1 (en) | 1987-10-29 |
JPS58501944A (ja) | 1983-11-17 |
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