EP0331519B1 - Production of aluminum matrix composite coatings of metal structures - Google Patents
Production of aluminum matrix composite coatings of metal structures Download PDFInfo
- Publication number
- EP0331519B1 EP0331519B1 EP89302156A EP89302156A EP0331519B1 EP 0331519 B1 EP0331519 B1 EP 0331519B1 EP 89302156 A EP89302156 A EP 89302156A EP 89302156 A EP89302156 A EP 89302156A EP 0331519 B1 EP0331519 B1 EP 0331519B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- metal
- aluminum
- matrix
- filler
- coating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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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
- C23C4/06—Metallic material
Definitions
- This invention relates to the application of corrosion and mechanical wear resistant coatings to metal surfaces and, more particularly, to the coating of steel structures with aluminum matrix composite coatings.
- aluminum matrix composite compositions have been used as coatings on steel substrates to give not only high cathodic protection but also good wear resistance to the steel structure.
- These coatings have in the past been applied by techniques such as flame spraying a body of molten metal onto the substrate to be coated, with particulate refractory or ceramic particles introduced into the spray. Flame spraying of metal powder together with refractory or ceramic particles has also been used. It is also known to use thermal spraying or plasma spraying in place of the above mentioned flame spraying technique.
- an aluminum matrix composite coating is applied to metal substrates by directly flame spraying or arc spraying a preformed aluminum matrix composite material.
- the preformed material is in the form of a wire or rod which acts as a feedstock for the flame spraying or arc spraying process.
- Metal matrix composites are well known in the art and are formed of a metal matrix having distributed therein a divided solid filler, i.e. a fibrous or particulate material which is capable of being incorporated in and distributed through the metal matrix and which at least substantially maintains its integrity as incorporated rather than losing its form or identity by dissolution in or chemical combination with the metal.
- a divided solid filler i.e. a fibrous or particulate material which is capable of being incorporated in and distributed through the metal matrix and which at least substantially maintains its integrity as incorporated rather than losing its form or identity by dissolution in or chemical combination with the metal.
- solid filler materials that have been used for the above purpose, there may be mentioned alumina, titanium diboride, silica, zirconia, silicon carbide, silicon nitride, etc.
- Aluminum-TiB2 composites for instance, have been used for applications requiring high strength and/or high resistance to wear.
- the aluminum matrix composite materials utilized as feedstocks in the process of this invention are manufactured by techniques known in the art and typically contain 5 to 60 volume % of the refractory or ceramic filler. A range of 5 to 40 volume % of filler is preferred, with a range of 10 to 20 volume % being particularly preferred.
- the coating is preferably applied to a thickness in the range of about 50 to 5000 ⁇ m (microns).
- the substrate to be treated is typically a ferrous metal, e.g. steel, structure.
- Other substrates that may be coated according to the invention include a heat treatable, high strength aluminum alloy structure, e.g. an AA 7000 series alloy. Such aluminum alloys are sometimes subject to stress corrosion in service.
- the surface of the substrate to be treated is preferably prepared by grit blasting, e.g. using alumina particles. It has also been found to be advantageous, but not essential, to preheat the substrate to at least about 120°C to remove surface moisture prior to application of the coating. Of course, this is not always feasible, particularly for marine applications. In some instances, it may also be advantageous to precoat the substrate by conventional metallizing with aluminium prior to the application of the aluminum matrix composite coating.
- the-composite coating formed by the method of this invention are generally superior to those obtained by the prior methods.
- the composite coatings obtained by the present invention have improved adhesion, low porosity and generally a sound structure.
- a cast ingot comprising an AA 1350 aluminum containing about 15 volume % of silicon carbide particles uniformly distributed throughout.
- the ingot was made according to the method disclosed in PCT application WO87/06624, published November 5, 1987.
- the ingot was extruded and drawn into a wire having a diameter of about 2.3 mm and this became the feedstock for an arc spray process.
- a steel substrate was used in the form of a steel cylinder and an arc was struck between a pair of feed wires formed of the above aluminum matrix composite material.
- the arc was held at a distance of approximately 10 cm from the cylinder while the cylinder was rotated, with an arc current of approximately 150 amps being used.
- a coating having a thickness of approximately 3000 ⁇ m (microns) was deposited on the cylinder.
- the product obtained was subjected to metallographic examination and the coating had good adhesion, a low porosity and a generally sound structure.
- Tests were conducted to compare a composite coating produced by the method of this invention with a composite coating produced by a prior art method.
- Example 2 Following the same general procedure as in Example 1, a cast ingot was obtained containing about 10 volume % of silicon carbide particles uniformly distributed in an AA 6061 aluminum alloy.
- the ingot was extruded and drawn into a wire having a diameter of about 2.3 mm and this was used as a feedstock for an arc spray process.
- a steel substrate in the form of a flat bar was used and an arc was struck between a pair of feed wires formed of the above ingot.
- the arc was held at a distance of about 10 cm from the steel bar with an arc current of about 150 amps being used.
- a coating having a thickness of about 3000 ⁇ m (microns) was deposited on the bar.
- An AA 6061 aluminum alloy was formed into a wire having a diameter of about 2.3 mm and this was used as a feedstock for an arc spray process.
- a steel substrate in the form of a flat bar was used and an arc was struck between a pair of feed wires formed of the above alloy.
- the arc was held at a distance of about 10 cm from the steel bar with an arc current of about 150 amps being used.
- silicon carbide particles were fed between the arcing wires to be deposited with the aluminum, the silicon carbide particles being fed at a rate of about 10 volume % relative to the aluminum alloy fed.
- a composite coating having a thickness of about 5000 ⁇ m (microns) was deposited on the bar.
- Example 2 Following the same general procedure as in Example 1, a cast ingot was formed comprising an AA-1060 aluminum containing about 15 volume % of aluminum oxides particles uniformly distributed throughout. The ingot was extruded and drawn into wires having diameters of 3.2 and 2.4 mm and this became the feedstock for a flame spray process.
- the steel samples were flame sprayed within 10 minutes after grit blasting with either 3.2 or 2.4 mm composite wire.
- the flame spray system was operated at an oxygen gas setting of 2.45 Kg./sq./cm. at 1.4 m3/h, an acetylene gas setting of 1.4 Kg./sq./cm. at 1.1 m3/h and an air setting of 4.55 Kg./sq./cm. at 1.6 m3/h.
- the spray gun was held at a distance of approximately 15 cm from the steel samples.
Description
- This invention relates to the application of corrosion and mechanical wear resistant coatings to metal surfaces and, more particularly, to the coating of steel structures with aluminum matrix composite coatings.
- It is known to form aluminum coatings on steel structures to provide protection against corrosion and mechanical wear. Such coatings are used in all environments where marine, industrial or urban corrosion are linked with mechanical wear. Such coatings are typically applied by a thermal spraying process and zinc and pure aluminum wires have been used for this purpose, particularly in marine environments where aluminum shows high resistance to salt water. This process remains in use today.
- While pure aluminum provides some cathodic protection, it is mainly a barrier coating having relatively low strength and wear resistance. To solve this problem, aluminum matrix composite compositions have been used as coatings on steel substrates to give not only high cathodic protection but also good wear resistance to the steel structure. These coatings have in the past been applied by techniques such as flame spraying a body of molten metal onto the substrate to be coated, with particulate refractory or ceramic particles introduced into the spray. Flame spraying of metal powder together with refractory or ceramic particles has also been used. It is also known to use thermal spraying or plasma spraying in place of the above mentioned flame spraying technique.
- The above techniques are very difficult to control in commercial operation and it is most difficult to obtain a uniform distribution of the refractory or ceramic particles throughout the coating. In particular, problems have been encountered with poor adhesion, high coating porosity and generally an unsound coating structure.
- It is the object of the present invention to provide a method for application of metal matrix composite material coatings and in particular aluminum matrix composite material coatings of improved quality on metal structures.
- The aforementioned object is realized by the subject-matter of claim 1.
- More particularly, according to the present invention an aluminum matrix composite coating is applied to metal substrates by directly flame spraying or arc spraying a preformed aluminum matrix composite material. The preformed material is in the form of a wire or rod which acts as a feedstock for the flame spraying or arc spraying process.
- Metal matrix composites are well known in the art and are formed of a metal matrix having distributed therein a divided solid filler, i.e. a fibrous or particulate material which is capable of being incorporated in and distributed through the metal matrix and which at least substantially maintains its integrity as incorporated rather than losing its form or identity by dissolution in or chemical combination with the metal.
- It is known that the strength of aluminum and aluminum alloy articles can be significantly enhanced by incorporation of fibrous or particulate solid fillers in the form of short, discontinuous, more or less randomly oriented particles. For many applications it is known to distribute the fibers substantially uniformly throughout the metal article.
- As examples of solid filler materials that have been used for the above purpose, there may be mentioned alumina, titanium diboride, silica, zirconia, silicon carbide, silicon nitride, etc. Aluminum-TiB₂ composites, for instance, have been used for applications requiring high strength and/or high resistance to wear.
- The aluminum matrix composite materials utilized as feedstocks in the process of this invention are manufactured by techniques known in the art and typically contain 5 to 60 volume % of the refractory or ceramic filler. A range of 5 to 40 volume % of filler is preferred, with a range of 10 to 20 volume % being particularly preferred. The coating is preferably applied to a thickness in the range of about 50 to 5000 µm (microns).
- The substrate to be treated is typically a ferrous metal, e.g. steel, structure. Other substrates that may be coated according to the invention include a heat treatable, high strength aluminum alloy structure, e.g. an AA 7000 series alloy. Such aluminum alloys are sometimes subject to stress corrosion in service.
- The surface of the substrate to be treated is preferably prepared by grit blasting, e.g. using alumina particles. It has also been found to be advantageous, but not essential, to preheat the substrate to at least about 120°C to remove surface moisture prior to application of the coating. Of course, this is not always feasible, particularly for marine applications. In some instances, it may also be advantageous to precoat the substrate by conventional metallizing with aluminium prior to the application of the aluminum matrix composite coating.
- It has surprisingly been found that the-composite coating formed by the method of this invention are generally superior to those obtained by the prior methods. In particular, the composite coatings obtained by the present invention have improved adhesion, low porosity and generally a sound structure.
-
- Figure 1 is a photomicrograph showing a prior art coating;
- Figure 2 is a photomicrograph showing a coating according to this invention;
- Figure 3 is a photomicrograph of a further coating according to this invention; and
- Figure 4 is a photomicrograph of a still further coating according to this invention.
- The following specific examples illustrate certain preferred features of the present invention.
- A cast ingot was formed comprising an AA 1350 aluminum containing about 15 volume % of silicon carbide particles uniformly distributed throughout. The ingot was made according to the method disclosed in PCT application WO87/06624, published November 5, 1987. The ingot was extruded and drawn into a wire having a diameter of about 2.3 mm and this became the feedstock for an arc spray process.
- A steel substrate was used in the form of a steel cylinder and an arc was struck between a pair of feed wires formed of the above aluminum matrix composite material. The arc was held at a distance of approximately 10 cm from the cylinder while the cylinder was rotated, with an arc current of approximately 150 amps being used. A coating having a thickness of approximately 3000 µm (microns) was deposited on the cylinder.
- The product obtained was subjected to metallographic examination and the coating had good adhesion, a low porosity and a generally sound structure.
- Tests were conducted to compare a composite coating produced by the method of this invention with a composite coating produced by a prior art method.
- Following the same general procedure as in Example 1, a cast ingot was obtained containing about 10 volume % of silicon carbide particles uniformly distributed in an AA 6061 aluminum alloy.
- The ingot was extruded and drawn into a wire having a diameter of about 2.3 mm and this was used as a feedstock for an arc spray process.
- A steel substrate in the form of a flat bar was used and an arc was struck between a pair of feed wires formed of the above ingot. The arc was held at a distance of about 10 cm from the steel bar with an arc current of about 150 amps being used. A coating having a thickness of about 3000 µm (microns) was deposited on the bar.
- The product was subjected to metallographic examination and the results obtained are shown in Figure 2.
- An AA 6061 aluminum alloy was formed into a wire having a diameter of about 2.3 mm and this was used as a feedstock for an arc spray process.
- A steel substrate in the form of a flat bar was used and an arc was struck between a pair of feed wires formed of the above alloy. The arc was held at a distance of about 10 cm from the steel bar with an arc current of about 150 amps being used. Simultaneously, silicon carbide particles were fed between the arcing wires to be deposited with the aluminum, the silicon carbide particles being fed at a rate of about 10 volume % relative to the aluminum alloy fed. A composite coating having a thickness of about 5000 µm (microns) was deposited on the bar.
- The product was subjected to metallographic examination and the results obtained are shown in Figure 1.
- Comparing Figure 2 with Figure 1, it is readily evident that the process of this invention produces a much more uniform coating with fewer voids (shown as black areas) than does the coating produced by the prior art process.
- Following the same general procedure as in Example 1, a cast ingot was formed comprising an AA-1060 aluminum containing about 15 volume % of aluminum oxides particles uniformly distributed throughout. The ingot was extruded and drawn into wires having diameters of 3.2 and 2.4 mm and this became the feedstock for a flame spray process.
- Prior to flame spraying, flat steel sheet was solvent degreased and then grit blasted with No. 16 alumina. A 75 to 80 µm (micron) anchor tooth pattern was obtained on the steel.
- The steel samples were flame sprayed within 10 minutes after grit blasting with either 3.2 or 2.4 mm composite wire.
- The flame spray system was operated at an oxygen gas setting of 2.45 Kg./sq./cm. at 1.4 m³/h, an acetylene gas setting of 1.4 Kg./sq./cm. at 1.1 m³/h and an air setting of 4.55 Kg./sq./cm. at 1.6 m³/h. The spray gun was held at a distance of approximately 15 cm from the steel samples.
- The coated samples were subjected to metallographic examination and the results obtained are shown in Figures 3 and 4, Figure 3 being with the 2.4 mm wire and Figure 4 being with the 3.2 mm wire. Both photomicrographs show uniform coatings with very few voids.
Claims (11)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US16423488A | 1988-03-04 | 1988-03-04 | |
US164234 | 1988-03-04 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0331519A1 EP0331519A1 (en) | 1989-09-06 |
EP0331519B1 true EP0331519B1 (en) | 1992-07-01 |
Family
ID=22593568
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP89302156A Expired - Lifetime EP0331519B1 (en) | 1988-03-04 | 1989-03-03 | Production of aluminum matrix composite coatings of metal structures |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0331519B1 (en) |
JP (1) | JP2694996B2 (en) |
DE (1) | DE68901935T2 (en) |
NO (1) | NO173946C (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102839344A (en) * | 2012-08-08 | 2012-12-26 | 南京航空航天大学 | High-performance arc spraying Zn-Al powder core wire and preparation method thereof |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU3262393A (en) * | 1992-01-10 | 1993-08-03 | Alcan Aluminium Uk Limited | Wear surface |
US7229700B2 (en) * | 2004-10-26 | 2007-06-12 | Basf Catalysts, Llc. | Corrosion-resistant coating for metal substrate |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3322515A (en) * | 1965-03-25 | 1967-05-30 | Metco Inc | Flame spraying exothermically reacting intermetallic compound forming composites |
US3332752A (en) * | 1963-08-22 | 1967-07-25 | Raybestos Manhattan Inc | Composite flame spraying wire |
IT948422B (en) * | 1971-02-05 | 1973-05-30 | Pyrotenax Ltd | METHOD OF MAKING AN ELECTRODE WIRE AND ITS APPLICATION IN ARC SPRAYING |
US3864093A (en) * | 1972-11-17 | 1975-02-04 | Union Carbide Corp | High-temperature, wear-resistant coating |
US4039318A (en) * | 1976-07-19 | 1977-08-02 | Eutectic Corporation | Metaliferous flame spray material for producing machinable coatings |
US4208019A (en) * | 1978-08-10 | 1980-06-17 | John Dusenbery Co., Inc. | Turret winder for pressure-sensitive tape |
US4276353A (en) * | 1978-08-23 | 1981-06-30 | Metco, Inc. | Self-bonding flame spray wire for producing a readily grindable coating |
JPS58104173A (en) * | 1981-12-17 | 1983-06-21 | Nissan Motor Co Ltd | Wire rod for wire explosion spraying |
JPS60255964A (en) * | 1984-06-01 | 1985-12-17 | Tomio Suzuki | Thermal spraying material for thermal spraying machine |
-
1989
- 1989-03-03 JP JP1052747A patent/JP2694996B2/en not_active Expired - Lifetime
- 1989-03-03 NO NO890923A patent/NO173946C/en unknown
- 1989-03-03 EP EP89302156A patent/EP0331519B1/en not_active Expired - Lifetime
- 1989-03-03 DE DE8989302156T patent/DE68901935T2/en not_active Expired - Lifetime
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102839344A (en) * | 2012-08-08 | 2012-12-26 | 南京航空航天大学 | High-performance arc spraying Zn-Al powder core wire and preparation method thereof |
Also Published As
Publication number | Publication date |
---|---|
NO173946B (en) | 1993-11-15 |
NO890923L (en) | 1989-09-05 |
JP2694996B2 (en) | 1997-12-24 |
JPH0270053A (en) | 1990-03-08 |
NO173946C (en) | 1994-02-23 |
DE68901935T2 (en) | 1993-01-14 |
EP0331519A1 (en) | 1989-09-06 |
NO890923D0 (en) | 1989-03-03 |
DE68901935D1 (en) | 1992-08-06 |
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