EP1016333A1 - Element applicateur de revetement par projection thermique et appareil l'utilisant - Google Patents
Element applicateur de revetement par projection thermique et appareil l'utilisantInfo
- Publication number
- EP1016333A1 EP1016333A1 EP98901489A EP98901489A EP1016333A1 EP 1016333 A1 EP1016333 A1 EP 1016333A1 EP 98901489 A EP98901489 A EP 98901489A EP 98901489 A EP98901489 A EP 98901489A EP 1016333 A1 EP1016333 A1 EP 1016333A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- coating
- propellant
- coating applicator
- applicator element
- target
- 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.)
- Withdrawn
Links
- 238000005507 spraying Methods 0.000 title claims abstract description 30
- 238000000576 coating method Methods 0.000 claims abstract description 111
- 239000011248 coating agent Substances 0.000 claims abstract description 109
- 239000003380 propellant Substances 0.000 claims abstract description 60
- 239000000843 powder Substances 0.000 claims abstract description 47
- 238000000034 method Methods 0.000 claims abstract description 23
- 230000008569 process Effects 0.000 claims abstract description 20
- 238000003860 storage Methods 0.000 claims abstract description 4
- 239000000463 material Substances 0.000 claims description 16
- 230000007246 mechanism Effects 0.000 claims description 8
- 238000006073 displacement reaction Methods 0.000 claims description 5
- 230000000977 initiatory effect Effects 0.000 claims description 5
- 238000001816 cooling Methods 0.000 claims description 4
- 230000009977 dual effect Effects 0.000 claims description 3
- 239000002245 particle Substances 0.000 description 29
- 239000007789 gas Substances 0.000 description 25
- 238000002485 combustion reaction Methods 0.000 description 10
- 238000005474 detonation Methods 0.000 description 10
- 239000000203 mixture Substances 0.000 description 7
- 238000002309 gasification Methods 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000012159 carrier gas Substances 0.000 description 4
- 239000011247 coating layer Substances 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 238000010304 firing Methods 0.000 description 4
- 239000000446 fuel Substances 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 229920003023 plastic Polymers 0.000 description 3
- 239000004449 solid propellant Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000007751 thermal spraying Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 239000000567 combustion gas Substances 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 230000003628 erosive effect Effects 0.000 description 2
- 239000011888 foil Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229920001903 high density polyethylene Polymers 0.000 description 2
- 239000004700 high-density polyethylene Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 230000005291 magnetic effect Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- 229920002799 BoPET Polymers 0.000 description 1
- 229910001369 Brass Inorganic materials 0.000 description 1
- 229910000881 Cu alloy Inorganic materials 0.000 description 1
- 239000005041 Mylar™ Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 230000001464 adherent effect Effects 0.000 description 1
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-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
- 230000003190 augmentative effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000010951 brass Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- SBYXRAKIOMOBFF-UHFFFAOYSA-N copper tungsten Chemical compound [Cu].[W] SBYXRAKIOMOBFF-UHFFFAOYSA-N 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 238000010891 electric arc Methods 0.000 description 1
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 1
- 239000002737 fuel gas Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910052756 noble gas Inorganic materials 0.000 description 1
- 239000000615 nonconductor Substances 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000011236 particulate material Substances 0.000 description 1
- -1 polyethylene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 230000032258 transport Effects 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F41—WEAPONS
- F41A—FUNCTIONAL FEATURES OR DETAILS COMMON TO BOTH SMALLARMS AND ORDNANCE, e.g. CANNONS; MOUNTINGS FOR SMALLARMS OR ORDNANCE
- F41A21/00—Barrels; Gun tubes; Muzzle attachments; Barrel mounting means
- F41A21/22—Barrels which have undergone surface treatment, e.g. phosphating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
- B05B7/16—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
- B05B7/16—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed
- B05B7/20—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed by flame or combustion
- B05B7/201—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed by flame or combustion downstream of the nozzle
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
- B05B7/16—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed
- B05B7/22—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed electrically, magnetically or electromagnetically, e.g. by arc
- B05B7/222—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating or cooling the material to be sprayed electrically, magnetically or electromagnetically, e.g. by arc using an arc
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
- H05H1/26—Plasma torches
- H05H1/32—Plasma torches using an arc
- H05H1/42—Plasma torches using an arc with provisions for introducing materials into the plasma, e.g. powder or liquid
Definitions
- the present invention relates to thermal spraying of powders in the production of high quality coatings. More particularly, the invention relates to novel apparatus for thermal spray coating, and an applicator element that is used therewith.
- Thermal spray coating refers to a variety of processes characterized in that a fusible material such as plastic, metal, ceramic or the like in a particulate form is soften by heat applied thereon and then accelerated towards a target to be coated.
- the soften particles hit the target where they are quenched to form a solidified layer of the coating material.
- the plasma spray coating device consists, in general, of a confined passage between an anode and a cathode.
- a plasma forming inert gas typically argon or nitrogen, is introduced into the passage and the plasma is usually initiated by a high frequency electric pulse which causes a high current arc discharge between the cathode and anode.
- the arc heats and ionizes the plasma gases to a high temperature of about 12000°K or even higher, and then, the heated and expanded plasma is exhausted at high speed through a nozzle orifice in the cathode.
- the feedstock which is usually used in a powder form, is suspended in a carrier gas.
- the powder particles are injected into the plasma jet and the carrier gas provides the particles with a sufficient momentum to reach the plane of the plasma discharge.
- the feedstock powder must have a narrow particle size distribution
- the heat and momentum transfer rates to the particles must be controlled to provide the particles with a narrow range of velocities, and, a sharp surface
- the velocity of the injected particles is typically limited to low values of 100-300 m/s in accordance with the speed of sound in the propelling media, which consists of both the gases and the dispersed
- the powder application rate which is also limited by the plasma parameters, would typically be in the range of 2-6 kg per hour.
- the second type of thermal spray coating process is high velocity flame spray coating which utilizes the hot gases produced in a combustion process for heating or melting a particulate material.
- the heated particles are then accelerated to high velocities (300-1000 m/s) towards a target to be coated by a gas jet being at approximately 3000°K.
- the particles' thermal and kinetic energies thus acquired are converted so as to form a dense adherent coating on the surface, whereas the heat input required for the process is obtained by fuel combustion (where the fuel is in a gas or liquid state) with air or oxygen.
- a typical configuration of a high velocity thermal spraying device comprises a central orifice for injecting the feedstock powder material and means to feed the fuel and the oxidizer into the reaction zone.
- the combustion process occurs within the reaction zone and the hot combustion gases evolving therefrom expand to create a jet that accelerates the particles.
- the powder particles, absorbing heat in the reaction and the expansion zones, are impinged onto the target in a molten or soften state. As a result of the impact they are flattened while generating discrete coated zones on the target. Each of the discrete coated zones tends to adhere to the adjacent ones as well as to the target itself to form the required coating of the target.
- Devices where such a technology is applied are disclosed for example in US 4,358,053 and US 4,370,538.
- GB Application 2,104,268 which describes an apparatus comprising a detonation chamber, made in a form of a barrel closed at one end, a gas mixture supply system and a feedstock powder supply system wherein a carrier gas is used for transferring the powder particles.
- a carrier gas is used for transferring the powder particles.
- the coating powder and the gas mixture which typically consists of a fuel gas such as acetylene, an oxidizing gas such as oxygen and an inert powder carrying gas such as nitrogen, are introduced batch-wise into the detonation chamber forming a solid-gas mixture.
- the solid-gas mixture thus obtained is ignited by an ignition device such as a spark plug, initiating a detonation in the chamber.
- the detonation products traveling at a high velocity to the exit of the barrel, heat and accelerate the powder particles of the coating material, carrying them away from the barrel and impinge them upon the target to be coated, while forming a coating layer thereon.
- the coating layer consists of a large number of flattened spots of material which are adhered to each other. Such a process has been disclosed for example in US 2,714,563 and 2,774,625.
- the major disadvantages in the detonation coating are the inherent complexity in the gas and powder feed control as well as in regulating and controlling the conditions in the detonation chamber. Since the mixture of the gases has to reach the maximum pressure value permitted in the barrel within a very short time interval, the applicable amount of gases and powder per batch, is highly limited.
- a coating applicator element for use in a thermal spray coating process that comprises a coating powder and a non-gaseous propellant .
- the coating powder may either be mixed with the non-gaseous propellant or be separated therefrom.
- the propellant of the present invention may either be an energetic material e.g. a combustible material such as a solid propellant, or a non-energetic material e.g. water, liquid ammonia and the like.
- a combustible material such as a solid propellant
- a non-energetic material e.g. water, liquid ammonia and the like.
- the energy required to gasify the propellant may be derived its combustion
- an external source such as plasma discharge is used to deliver the energy required to gasify the propellant.
- the propellant is gasified, and the gaseous product(s) formed is used to motivate the powder particles.
- the energetic non-gaseous propellant of the coating applicator element according to the invention may be ignited in any way known per se in the art.
- a preferred way according to the present invention to initiate the propellant of the applicator element is by using plasma discharge, e.g. by using plasma generating assembly which may be either external to the coating applicator element or located within the applicator element itself.
- the energy obtained from the plasma generated is used to initiate the propellant, and the gases formed from its initiation, are used to motivate the powder particles.
- the propellant is of the energetic type
- only a small portion of the energy required for motivating the powder particles should be derived from the plasma generated, as the substantial part of this energy may be derived from the combustion of the propellant itself. Therefore, the energy obtained from the plasma generated is used mainly for the ignition of the propellant and possibly to provide a minor addition to the energy derived from the propellant combustion.
- the coating applicator element further comprises a device for plasma generation.
- a coating applicator element has a front and rear sections, wherein the non-gaseous propellant and coating powder are located in the front section and the device for plasma generation is located in the rear section.
- the coating applicator element according to the invention is used with an application apparatus which initiates the propellant and the resulting mixture of a high pressure and high density hot gas and coating powder is ejected onto the target to be coated.
- the ignition pulse causes plasma generation and the plasma in turn ignites the propellant.
- the plasma ignition of the propellant leads to its combustion, a process that in many aspects resembles the combustion of a propellant in a regular firing device.
- the plasma formed is mixed with the non-gaseous propellant, causing the gasification of the latter.
- a high gasification rate can be obtained for example when using a liquid propellant, due to a substantial increase of the propellant surface area exposed to the plasma as a consequence of hydrodynamic instabilities.
- a high pressure and high density hot gas is formed. This gas flows at high velocity towards the target, dragging the coating powder along.
- the drag force, F D that accelerates the powder particles may be described according to the following expression:
- Sp is a coefficient which depends on the Reynolds number, Re, that characterizes the flow around the particles; dp is the particles' mean diameter; p is the gas density; and N g and V P are the gas and the particle corresponding velocities.
- the mechanism for accelerating the coating powder particles with a propellant that is initiated by plasma generated is essentially similar to that characterizing the acceleration of a projectile in an electrothermal (ET), electrothermal-chemical (ETC) or solid-propellant electrothermal-chemical (SPETC) guns.
- the process parameters such as gas production rate as well as the pressure and temperature profiles may be predetermined and controlled.
- This capability of designing and controlling the characteristics of the discharge of the particles' carrying gas in each coating applicator element presents an important advantage of the present invention, as it allows designing a coating of various characteristics of a target, or alternatively, obtain a highly uniform coating of the target.
- an apparatus for thermal spray coating a target by means of coating applicator elements comprising a non-gaseous propellant and a coating powder
- which apparatus comprises a barrel, an initiation assembly, storage and feeding means for the coating applicator elements, and optionally means for connection to a power supply.
- the feeding means of the apparatus of the invention is a dual feed mechanism.
- the coating applicator elements of the present invention may be applied either in a single mode operation, or preferably, in an automatic mode operation.
- the single mode operation refers to the thermal spraying of a single coating applicator element onto a target. Thereafter the coating apparatus may be re-loaded with the next coating applicator element that may be identical with or different from the former coating applicator element used.
- a plurality of coating applicator elements are arranged so that they can be fed into the coating apparatus continuously, preferably automatically, (e.g. arranged in a chain-like formation which resembles the loading in a machine gun).
- the rate of feeding may be in the range of 5-20 coating applicator elements per second, but of course the invention is not limited to any such rate. As may be appreciated, this rate depends primarily on the coating apparatus characteristics, the powder quantity in each coating applicator element, the power source available, etc.
- the coating applicator elements when applied in the automatic mode, may either be similar to each other or different in any one or more of their components, namely the propellant, the coating powder and/or even the medium for plasma generation. Such variations may be for example in types, amounts, particles' size, geometry and the like. Therefore, in accordance with the present invention, a pre-programmed, functionally graded, multi-layered coating of a target may be achieved in a single process as the target being coated by a series of coating applicator elements, containing each different coating powder.
- a system for thermal spray coating of a target comprising a spray coating apparatus as described above, an enclosure comprising a target support and optionally cooling and control systems.
- the target support is provided with means for the translatory and angular displacement of the target, and means to coordinate this displacement with the feeding and ignition of the coating applicator elements.
- Fig. 1 presents schematically a thermal spray coating system of the present invention
- Fig. 2 presents a cross sectional view of the apparatus for thermal spray coating
- Fig. 3 presents a schematic cross sectional view of the coating applicator element of the present invention
- Fig. 4 presents another embodiment of the coating applicator element of the invention.
- Fig. 5 presents a mechanism for an externally driven apparatus for automatic operation.
- FIG. 1 presents a system in accordance with the present invention, comprising a spray coating apparatus 2, an enclosure 3 comprising a target support 5 and auxiliary sub-systems such as a control system, a cooling system (which may be used for both the coating apparatus and the target), not shown in this figure.
- the target to be coated 4 is placed on a support 5 of enclosure 3, where support 5 is connected to motors 8 so as to provide a possibility of displacing target 4 in different directions and/or rotate it about its horizontal or vertical axis.
- a control system may further be connected to apparatus 2 to monitor several important features of the process, such as the displacement of the target, the coating rate, identification of malfunctions in the operation of the apparatus, control of the cooling system, etc.
- Apparatus 2 comprises the following components: a barrel 10, a plasma generating assembly 11, a connection to power supply unit 12, and a mechanism 13 for feeding the coating applicator elements in a continuous operation mode.
- the apparatus further comprises feeding means 14 and storage means 15 for storing the coating applicator elements to be fed.
- One way of attaching apparatus 2 to enclosure 3, shown in Fig. 1, is by using flexible bellows 9.
- Fig 2. shows a cross section of a spray coating apparatus in accordance 0 with the single operation mode embodiment of the invention.
- the coating apparatus shown here comprises a barrel 20 with an axial bore 21 extending therethrough.
- the rear part of the bore has a broader shape so as to form a breech 22, adapted to receive the coating applicator element 23.
- a plasma ignition device 30 aligned coaxially with the coating applicator element 23 is attached to the inlet 5 opening of barrel 20.
- the plasma ignition device 30 typically comprises metallic detachable enclosures 31 and 32 designed to withstand very high pressures, e.g. up to 600 MPa.
- the plasma ignition device 30 further comprises a first electrode 41, usually a cathode, being on one side in contact with the rear part of the coating applicator element 23 and on the other side, electrode 41 is placed 0 relatively to a second electrode 42, usually an anode, so that together they are capable of providing an electric ignition pulse within a narrow bore 43 inside electrically shielding member 45.
- a second electrode 42 usually an anode
- Bore 43 in turn is highly pressurized by the gases evolving during the combustion process and the plasma formed.
- such a bore may be a capillary which walls are 5 made of a dielectric material e.g. polyethylene.
- Both electrodes 41 and 42 are located so as to allow the generation as required.
- the connection of the plasma ignition device 30 to a power supply is not shown in the figure.
- Member 47 is incorporated to provide a mechanical support, preferably while electrically shielding anode 42 from the metallic detachable enclosure 32.
- Fig. 3 shows a coating applicator element 70 of the invention.
- the coating applicator element is adapted to fit within the breech at the inlet of the barrel.
- the rear part of element 70 is provided with a cavity 72 designed to receive a hollow cathode so that the plasma generated in the medium for plasma generation 74, will penetrate and ignite propellant 76.
- the propellant may be, for example, a conventional solid propellant having the following burning rate Z:
- ⁇ and ⁇ are constants depending upon the propellant chemistry.
- S is the surface area of the propellant
- P is the pressure developing
- ⁇ and ⁇ are constants depending upon the propellant chemistry.
- a bulk of the coating powder 78 may be placed either in the front section of the coating applicator element (as shown in the figure) or be mixed with the propellant.
- the various components described, are contained according to this embodiment in a cartridge envelope 89.
- a coating applicator element comprises a powder which weight is in the range of 20-200% of the propellant weight.
- the propellant will be completely consumed still in the barrel and the particles will gain a velocity sufficient to properly adhere to the target and form high quality coating thereon.
- the ignition assembly (not shown in the figure) is located externally to the coating applicator element, for example at the rear part of the breech of the apparatus shown in FIG. 2.
- plasma generating electrodes are integrated in the coating applicator element, to eliminate the need for external electrodes and a plasma passage means, which may all be subjected to extensive erosion when used repeatedly.
- the ignition is also simpler in the latter case as a single medium voltage power supply can be used for both the arc ignition and the generation of the plasma.
- the ignition itself may be carried out by using a metallic fuse as known per se in the art.
- FIG. 4 presents another embodiment of the invention for a coating applicator element that further comprises plasma generation electrodes.
- An anode 120, and a hollow cathode 121 preferably having a thick ring shape, both of which are preferably made of low cost metal such as iron, may be used as plasma generating electrodes for coating applicator element 122.
- anode 120 is firmly pressed into the center of a cylinder 123, which is used as an electrical insulator and provides within the required dielectric plasma channel 124 extending between the anode and the cathode.
- Cylinder 123 may be made of a plastic material such as high-density polyethylene.
- a socket 125 located in the rear part of anode 120 is adapted to receive a firing pin that constitutes a part of the breech assembly (not shown in the figure). This pin provides the electrical connection between the power supply and the anode.
- a thin fuse that may be made for example of aluminum foil 128 is inserted between both electrodes to provide the discharge starter.
- separator 130 e.g. a thin mylar foil.
- Envelope 134 of coating applicator element 122 may be made of various materials, e.g. brass, polymer or any other suitable material.
- Powder 136 as shown in FIG. 4 is contained in a bulk form in front of the propellant. Alternatively, the powder depending on various requirements that stem from the desired characteristics of the coating, may be placed at different sites in respect of the propellant, or may be mixed therewith.
- the operation highly resembles that of an automatic or semi-automatic rifle or a machine-gun, i.e. which fire an uninterrupted series of rounds by a single generation of a continuous firing trigger, where all requisite operational processes follow automatically.
- the energy required for feeding the ammunition, loading the weapon and ejecting the empty cartridge cases is either derived from the firing energy or sometimes provided externally.
- Semi-automatic weapons perform similarly to the automatic weapon with the exception of their triggering that must be actuated for each round.
- the present invention provides an apparatus adapted to operate in an automatic mode.
- This apparatus functions similarly to an automatic or semi-automatic weapon as explained above.
- the apparatus may be characterized as being one of the following types, namely, gas-operated, drum-type or as having an external drive.
- FIG. 5 presents one of the options provided by the invention for a mechanism to operate the apparatus provided.
- the mechanism presented is a dual feed mechanism used for an externally driven apparatus that operates automatically.
- One of the feed sprockets 142 transports a belt 144 containing a plurality of coating applicator elements 148, past a belt link extractor 146.
- the coating applicator elements 148 are combed out and the belt links 150 are disengaged.
- As the coating applicator elements pass on they are deflected by a deflector 152, the position of which depends on the specific choice of the coating applicator elements content, from sprocket 142 into the stationary indexing wheel 154.
- the indexing wheel 154 turns anti-clockwise through about one third of a revolution. Drive may be provided by a gear-unit (not shown in this figure).
- the rotary motion of the indexing wheel 154 brings a fresh coating applicator element into the feed position 158, whereas the empty case is brought to the discharge position 160.
- Subsequent forward movement of the breech bolt in the coating applicator element being fed into chamber 162 and the spent case being discharged by an ejector 164.
- locking and ignition of the coating applicator element fed is effected by a rotating bolt and the spent case is withdrawn again into the indexing wheel.
- a recoil of the barrel releases interlock, which in turn allows the chain to move on. If ignition does not occur within a given interval of time, a control system would determine a failure in following the operating cycle, and the process may automatically be interrupted.
- the igniting assembly which provides the spark required to initiate the plasma, must be adapted to operate at the rate in which the coating applicator elements are to be applied.
- Such a device is different from a device for a single mode operation, as it should operate at a relatively high voltage to allow an immediate breakdown between the anode and the cathode of the igniting device.
- Typical values for breakdown voltage required are about 40-60 kV for 10 mm gap between both electrodes. However, filling the gap between both electrodes with a noble gas such as argon, may reduce this value to about 2-4 kV.
- Typical energies provided by the plasma to the propellant are 500-5000 Joules, per unit of a coating applicator element.
- the plasma should provide the required energy for the gasification of the propellant (in the range of 30-50 kJ per pulse).
- Typical value for the pulse duration is about 0.1 - 2 ms (where the power is in the range of 10-100 MW).
- Such set of operating conditions would allow about 30 minutes of continuous operation when using endurable discharge chamber and electrodes, made of materials such as tungsten or tungsten copper alloys.
- the coating applicator element comprised 6g of tungsten carbide powder, and 6g of solid M8M type propellant, augmented by lkJ plasma jet.
- the calculated velocity achieved was over 1500m/s. 4g, out of the initial 6g of the powder content in the coating applicator element, reached the 5 cm diameter said target located 50 cm away from the apparatus to form a uniform coating thereon of up to 300 microns thickness. No pretreatment of the target was required.
- Measured hardness of the coating was found to be 1800 kg/mm and supreme adhesion of the coated layer to the target was observed.
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- General Engineering & Computer Science (AREA)
- Electromagnetism (AREA)
- Nozzles (AREA)
Abstract
L'invention concerne un élément applicateur de revêtement destiné à être utilisé dans un processus de revêtement par projection thermique. L'élément comprend une poudre de revêtement ainsi qu'un propulseur non gazeux, et facultativement un dispositif producteur de plasma. L'invention concerne également un appareil de revêtement par projection thermique d'une cible, lequel appareil comprend un cylindre, un ensemble d'allumage, un dispositif de stockage et d'alimentation destiné aux éléments applicateurs de revêtement, ainsi qu'un dispositif de connexion à une alimentation.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IL12014097 | 1997-02-04 | ||
| IL12014097A IL120140A (en) | 1997-02-04 | 1997-02-04 | Thermal spray coating element and method and apparatus for using same |
| PCT/IL1998/000055 WO1998034440A1 (fr) | 1997-02-04 | 1998-02-04 | Element applicateur de revetement par projection thermique et appareil l'utilisant |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP1016333A1 true EP1016333A1 (fr) | 2000-07-05 |
Family
ID=11069760
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP98901489A Withdrawn EP1016333A1 (fr) | 1997-02-04 | 1998-02-04 | Element applicateur de revetement par projection thermique et appareil l'utilisant |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP1016333A1 (fr) |
| AU (1) | AU5779398A (fr) |
| IL (1) | IL120140A (fr) |
| WO (1) | WO1998034440A1 (fr) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19919688A1 (de) * | 1999-04-30 | 2000-11-02 | Rheinmetall W & M Gmbh | Verfahren zur Innenbeschichtung eines Waffenrohres |
| DE19919687A1 (de) | 1999-04-30 | 2000-11-02 | Rheinmetall W & M Gmbh | Verfahren zur Innenbeschichtung eines Waffenrohres |
| US20020092616A1 (en) * | 1999-06-23 | 2002-07-18 | Seong I. Kim | Apparatus for plasma treatment using capillary electrode discharge plasma shower |
| DE10041114A1 (de) * | 2000-08-22 | 2002-03-07 | Rheinmetall W & M Gmbh | Verfahren zur Beseitigung von Beschichtungs-und/oder Erosionsschäden |
| US20100034979A1 (en) * | 2006-06-28 | 2010-02-11 | Fundacion Inasmet | Thermal spraying method and device |
| DE202007014907U1 (de) * | 2007-10-25 | 2009-03-05 | Viseco Gmbh | Zerstäuber |
| RU2499968C1 (ru) * | 2012-07-13 | 2013-11-27 | Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Самарский государственный технический университет" | Способ упрочнения стволов огнестрельного оружия |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3202048A1 (de) * | 1982-01-23 | 1983-07-28 | Ingo 4600 Dortmund Stibane | Verfahren zur sicherung der ortsbrust und vorrichtung zur durchfuehrung |
| IL85622A (en) * | 1988-03-03 | 1992-08-18 | Israel Atomic Energy Comm | Method and apparatus for accelerating projectiles |
| US5233903A (en) * | 1989-02-09 | 1993-08-10 | The State Of Israel, Atomic Energy Commission, Soreq Nuclear Research Center | Gun with combined operation by chemical propellant and plasma |
| DE69128715D1 (de) * | 1991-03-27 | 1998-02-19 | Inst Elektroswarki Patona | Verfahren und vorrichtung zum herstellen von metallprodukten durch plasma-detonation |
| JP3349590B2 (ja) * | 1994-06-28 | 2002-11-25 | 株式会社アイ・エイチ・アイ・エアロスペース | 泡発生装置 |
| AU1294497A (en) * | 1995-12-26 | 1997-07-17 | Aerostar Coatings, S.L. | Detonation gun apparatus and method |
-
1997
- 1997-02-04 IL IL12014097A patent/IL120140A/xx not_active IP Right Cessation
-
1998
- 1998-02-04 AU AU57793/98A patent/AU5779398A/en not_active Abandoned
- 1998-02-04 WO PCT/IL1998/000055 patent/WO1998034440A1/fr not_active Ceased
- 1998-02-04 EP EP98901489A patent/EP1016333A1/fr not_active Withdrawn
Non-Patent Citations (1)
| Title |
|---|
| See references of WO9834440A1 * |
Also Published As
| Publication number | Publication date |
|---|---|
| WO1998034440A1 (fr) | 1998-08-06 |
| IL120140A0 (en) | 1997-06-10 |
| IL120140A (en) | 2001-01-11 |
| AU5779398A (en) | 1998-08-25 |
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