US20070295833A1 - Thermal Spraying Nozzle Device and Thermal Spraying System - Google Patents

Thermal Spraying Nozzle Device and Thermal Spraying System Download PDF

Info

Publication number
US20070295833A1
US20070295833A1 US11/791,333 US79133306A US2007295833A1 US 20070295833 A1 US20070295833 A1 US 20070295833A1 US 79133306 A US79133306 A US 79133306A US 2007295833 A1 US2007295833 A1 US 2007295833A1
Authority
US
United States
Prior art keywords
nozzle
thermal spraying
gas
particles
atomized
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.)
Abandoned
Application number
US11/791,333
Other languages
English (en)
Inventor
Tsuyoshi Oda
Toshiya Miyake
Hideo Hata
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kobe Steel Ltd
Original Assignee
Kobe Steel Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kobe Steel Ltd filed Critical Kobe Steel Ltd
Assigned to KABUSHIKI KAISHA KOBE SEIKO SHO reassignment KABUSHIKI KAISHA KOBE SEIKO SHO ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HATA, HIDEO, MIYAKE, TOSHIYA, ODA, TSUYOSHI
Publication of US20070295833A1 publication Critical patent/US20070295833A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • 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
    • B05B7/168—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 with means for heating or cooling after mixing
    • 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
    • B05B7/14—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 designed for spraying particulate materials
    • B05B7/1404—Arrangements for supplying particulate material
    • B05B7/1463—Arrangements for supplying particulate material the means for supplying particulate material comprising a gas inlet for pressurising or avoiding depressurisation of a powder container
    • 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
    • C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
    • C23C4/123—Spraying molten metal

Definitions

  • the present invention relates to a thermal spraying nozzle device, as well as a thermal spraying system, wherein with use of gas a thermal spraying material is atomized and brought into collision with a base material to form a film or a deposition layer.
  • a thermal spraying process has been known as a technique of heating a coating material and the resulting melted or half-melted fine particles are brought into collision at high speed with the surface of a base material to form a film.
  • a film can be formed on any material insofar as the material can be melted.
  • the film formed can satisfy various conditions required in surface treatment, including abrasion resistance, corrosion resistance and heat insulating property, and is therefore utilized widely in various fields.
  • a spraying material is brought into collision with a base material as a supersonic flow together with inert gas and as it is in a solid phase without being melted or gasified, to form a film.
  • the cold spraying method is advantageous in that there occurs no thermal change in characteristics of the material and that it is possible to suppress oxidation in the resulting film.
  • FIG. 32 shows a schematic construction of a cold spraying system.
  • high pressure gas supplied from a gas source 30 is branched into two pipes 31 and 32 .
  • the gas as a main flow in the pipe 31 is heated by a gas heater 33 , while the remaining gas flowing in the pipe 32 is introduced into a powder supply unit 34 .
  • the gas heated by the gas heater 33 is introduced into a chamber 36 through a pipe 35 , while the powder supply unit 34 supplies powder particles to the chamber 36 through a pipe 37 .
  • the gas and the powder particles are mixed together within the chamber 36 and the resulting mixture passes through a convergent portion 38 a and a diffusion portion 38 b in a supersonic nozzle 38 , whereby the mixture is accelerated and collides as a supersonic jet flow onto a base material 39 (see, for example, Japanese Patent Laid-Open No.2004-76157, Patent Literature 1).
  • Patent Literature 1
  • Patent Literature 2
  • the present invention has been accomplished in view of the above-mentioned problems involved in the conventional spraying systems and provides a thermal spraying nozzle device and a thermal spraying system both able to supply a thermal spraying material at a constant rate and control the state of a film or a deposit.
  • the thermal spraying nozzle device is, in the gist thereof, a thermal spraying nozzle device wherein carrier gas is introduced from an inlet side of a nozzle to form a supersonic gas flow and a thermal spraying material is atomized and ejected by the gas flow, the thermal spraying nozzle device comprising, a storage section storing molten metal as the thermal spraying material connected to an end on the inlet side of the nozzle through a connecting pipe, and, the nozzle having a throat portion and a divergent region in a downstream of the throat portion toward an outlet side to form the supersonic gas flow, wherein the thermal spraying nozzle device is configured such that metal particles atomized by the supersonic gas flow are cooled to a solidified or semi-solidified state in the divergent region and then ejecting in a predetermined direction from the outlet side of the nozzle.
  • a molten metal outlet pipe is extended from the storage section toward the center in the throat portion or the center on the downstream side of the throat portion and an outside portion of the molten metal outlet pipe constitutes a channel for the carrier gas to flow therethrough in an accelerated state.
  • a divergent angle of the divergent region formed on the downstream side of the throat portion is not larger than 15° in terms of a half-cone angle.
  • an inlet pressure of the carrier gas is p 0 and a nozzle outlet pressure thereof is P B
  • the carrier gas is introduced into the nozzle in a state in which the inlet pressure P 0 satisfies the following expression: p 0 ⁇ p B ⁇ ( 1 + ⁇ - 1 2 ⁇ M 2 ) ⁇ ⁇ - 1 ( 1 )
  • ⁇ specific heat ratio of compressed gas
  • M Mach number in the expanded nozzle portion on the downstream side of the throat portion.
  • the thermal spraying system in the gist thereof, comprises the thermal spraying nozzle device constructed as above, a carrier gas supply unit connected to the nozzle through a conduit to introduce the carrier gas under pressure into the nozzle, a sealed chamber accommodating the nozzle and a base material for collision therewith of the ejected particles, and pressure reducing means for reducing the internal pressure of the sealed chamber.
  • the thermal spraying system in the gist thereof, comprises the thermal spraying nozzle device constructed as above, a molten metal supply unit connected to the storage section through a connecting pipe to supply molten metal under pressure continuously to the molten metal in the storage section, and a base material supply unit for continuous supply of the base material.
  • the present invention is advantageous in that the thermal spraying material can be supplied constantly and that it is possible to control the state of a film or a deposit.
  • FIG. 1 is a perspective view showing the construction of a thermal spraying device according to the present invention
  • FIGS. 2 ( a ) and 2 ( b ) are explanatory diagrams showing the definition of an expanded portion of a nozzle.
  • FIG. 3 is a graph explaining a relation between Mach number and drag coefficient.
  • FIG. 4 is a graph showing nozzle lengths according to particle diameters.
  • FIG. 5 is an explanatory diagram showing a conventional nozzle divergent angle.
  • FIG. 6 is an explanatory diagram showing a case where a shock wave is generated within the nozzle.
  • FIG. 7 is an explanatory diagram showing a case where a supersonic flow is formed throughout the entire region of the nozzle.
  • FIG. 8 is a graph showing a typical example of a nozzle shape.
  • FIG. 9 is a graph showing a nozzle outlet diameter providing an appropriate expansion.
  • FIG. 10 is a graph showing nozzle length vs. Mach number at a particle diameter of 20 ⁇ m and a throat diameter of 25 mm.
  • FIG. 11 is a graph showing nozzle length vs. gas temperature/velocity distribution at a particle diameter of 20 ⁇ m and a throat diameter of 25 mm.
  • FIG. 12 is a graph showing nozzle length vs. particle temperature/velocity distribution at a particle diameter of 20 ⁇ m and a throat diameter of 25 mm.
  • FIG. 13 is a graph showing nozzle length vs. Mach number at a particle diameter of 20 ⁇ m and a throat diameter of 35 mm.
  • FIG. 14 is a graph showing nozzle length vs. gas temperature/velocity distribution at a particle diameter of 20 ⁇ m and a throat diameter of 35 mm.
  • FIG. 15 is a graph showing nozzle length vs. particle temperature/velocity distribution at a particle diameter of 20 ⁇ m and a throat diameter of 35 mm.
  • FIG. 16 is a graph showing nozzle length vs. Mach number at a particle diameter of 50 ⁇ m and a throat diameter of 25 mm.
  • FIG. 17 is a graph showing nozzle length vs. gas temperature/velocity distribution at a particle diameter of 50 ⁇ m and a throat diameter of 25 mm.
  • FIG. 18 is a graph showing nozzle length vs. particle temperature/velocity distribution at a particle diameter of 50 ⁇ m and a throat diameter of 25 mm.
  • FIG. 19 is a graph showing nozzle length vs. Mach number at a particle diameter of 50 ⁇ m and a throat diameter of 35 mm.
  • FIG. 20 is a graph showing nozzle length vs. gas temperature/velocity at a particle diameter of 50 ⁇ m and a throat diameter of 35 mm.
  • FIG. 21 is a graph showing nozzle length vs. particle temperature/velocity distribution at a particle diameter of 50 ⁇ m and a throat diameter of 35 mm.
  • FIG. 22 is a graph showing nozzle length vs. Mach number at a particle diameter of 100 ⁇ m.
  • FIG. 23 is a graph showing nozzle length vs. gas temperature/velocity distribution at a particle diameter of 100 ⁇ m.
  • FIG. 24 is a graph showing nozzle length vs. particle temperature/velocity distribution at a particle diameter of 100 ⁇ m.
  • FIG. 25 is an explanatory diagram showing the construction of a thermal spraying system to be applied to a batch process.
  • FIG. 26 is an explanatory diagram showing the construction of a thermal spraying system to be applied to a continuous molding process.
  • FIG. 27 is a diagram corresponding to FIG. 1 , showing a nozzle of a second embodiment according to the present invention.
  • FIG. 28 is a diagram corresponding to FIG. 1 , showing a nozzle of a third embodiment according to the present invention.
  • FIG. 29 is a diagram corresponding to FIG. 1 , showing a nozzle of a fourth embodiment according to the present invention.
  • FIG. 30 is a diagram corresponding to FIG. 1 , showing a nozzle of a fifth embodiment according to the present invention.
  • FIG. 31 is a diagram corresponding to FIG. 1 , showing a nozzle of a sixth embodiment according to the present invention.
  • FIG. 32 is an explanatory diagram showing the construction of a conventional cold spraying system.
  • FIG. 1 illustrates a basic construction of a thermal spraying nozzle device according to the present invention.
  • the thermal spraying nozzle device shown in the same figure and indicated at 1 supplies molten metal M directly into a supersonic nozzle (hereinafter referred to simply as “nozzle”) 2 .
  • gas flows at a supersonic velocity, while the molten metal supplied into the nozzle 2 flows at low speed.
  • a shearing force acts between the two and so does a surface tension of the molten metal, whereby the molten metal is atomized downstream of a throat portion 2 a of the nozzle 2 .
  • Atomized metal particles (hereinafter referred to simply as “particles”) are accelerated within the nozzle 2 and are cooled rapidly into a solidified state.
  • the throat portion 2 a wherein the atomizing process is performed and a divergent region 2 b wherein a flying/cooling process follows the atomizing process are formed integrally with each other.
  • the particles ejected from the nozzle 2 just after solidification come into collision with a base material 3 at a velocity of about 450 m/s.
  • the particles generate heat due to deformation caused by the collision and a portion thereof rise in temperature up to a level of the melting point thereof or higher, whereby the particles adhere to the base material 3 (see the impact depositing process in the figure).
  • the numeral 4 in the figure denotes a storage section for storing the molten metal M, the storage section 4 having a connecting pipe 4 a communicating with the nozzle 2 .
  • a front end portion of the connecting pipe 4 a is extended as a molten metal outlet pipe 4 b toward the center of a cylindrical hole of the throat portion 2 a and accelerated carrier gas flows over the outer periphery of the molten metal outlet pipe 4 b.
  • the principle of collision of solidified particles against the base material 3 is the same as in the conventional cold spraying. That is, collided particles undergo a marked plastic deformation and are depressed like a crater, affording a compact void-free structure within a film (or a deposit layer). Therefore, a molding material thus formed with the film need not be subjected to HIP (Hot Isostatic Pressing) as a post-treatment, i.e., application of pressure to remove remaining voids.
  • HIP Hot Isostatic Pressing
  • gas nitrogen gas as carrier gas
  • gas carrier gas
  • the particles are solidified within only 1 ms as a flight time thereof through the nozzle 2 , it is possible to prevent the progress of nitriding.
  • molten metal is used as the thermal spraying material and the particles thereof are brought into collision with the base material 3 at a temperature slightly lower than the solidifying point thereof. Therefore, in comparison with cold spraying, even when the collision is performed at a low Mach number (e.g., a Mach number of 2 or so), the surface temperature of the base material 3 reaches a level of not lower than the melting point and thus the particles can be adhered positively to the base material 3 .
  • the Mach number means gas velocity/sound velocity.
  • the nozzle 2 has a nozzle length of the expanded portion set at 100 mm or more and is configured so as to operate in a state in which a total carrier gas pressure p 0 satisfies the following expression (1): p 0 ⁇ p B ⁇ ( 1 + ⁇ - 1 2 ⁇ M 2 ) ⁇ ⁇ - 1 ( 1 ) where p 0 : total carrier gas pressure (throat upstream-side inlet pressure), P B : throat outlet back pressure, M: Mach number in the thermal spraying material melting section, ⁇ : specific heat ratio of the carrier gas.
  • the Mach number M is associated with a sectional area A* of the throat portion 6 and an intra-nozzle enlarged sectional area A.
  • the enlarged sectional area includes a conical enlarged portion of a gradually increasing diameter from the narrowest portion A* as the throat portion toward the downstream side, as shown in FIG. 2 ( a ), and an enlarged portion whose diameter suddenly increases from the narrowest portion A* toward the downstream side and then becomes nearly constant, as shown in FIG. 2 ( b ).
  • a A * 1 M ⁇ [ ( ⁇ - 1 ) ⁇ M 2 + 2 ⁇ + 1 ] ⁇ + 1 2 ⁇ ( ⁇ - 1 ) ( 2 )
  • a particle diameter of the aluminum alloy after atomization is about 20 ⁇ m.
  • the particles after atomization undergo both accelerating and cooling actions by a supersonic gas flow and are eventually ejected from the nozzle 2 while having a supersonic velocity.
  • the said acceleration and cooling can be estimated by numerical analysis. More particularly, a mass, momentum and energy conservation expression as a quasi-one-dimensional compressive fluid conservation type representation is solved by making an expression (4) simultaneous with a particles motion equation (6).
  • s and e stands for a momentum generation term and an energy generation term, respectively, which represent an interaction between gas phase and second phase.
  • the distance from the nozzle outlet to the deposit is set extremely short because the device is configured so that the atomized particles collide with the deposit before deceleration of the particles' velocity. Therefore, it is approximately presumed that the particle velocity and enthalpy in the nozzle output are substantially maintained, allowing the particles to be deposited.
  • the state of the deposit depends much on the state of the particles being deposited, but in case of the particles being brought into collision and deposited at a subsonic velocity as in the conventional thermal spraying nozzle device, the particles cannot be adhered to the base material or the deposit if the particles are in a solidified state.
  • the thermal spraying nozzle device defines as an operating condition that semi-solidified or solidified particles with a greater solid phase ratio so far not utilized should be brought into collision and deposited at a supersonic velocity.
  • molten metal changes into a semi-solidified state while being atomized and flying, and a minimum flight distance required until that time-point is determined.
  • This flight distance is presumed to be a minimum nozzle length required for the device.
  • the expression (6) is convenient for numerical calculation using a fixed calculation lattice because it is described from the Euler's coordinate system which stands still together with the nozzle.
  • the drag coefficient C D can be expressed by a function of Reynolds number in the case where the relative velocity U is a subsonic velocity, as shown in the expression (12), but in the state just after atomization the relative velocity U is very likely to be a supersonic velocity. Therefore, in the graph of FIG. 3 (an explanatory diagram of a sphere obtained from bullet route measurement, as well as drag coefficient of cone-cylinder and Mach number dependence), the drag coefficient in question is approximated by the following expression (16) from an experimental result on drag coefficient of Mach number and the sphere (see an approximate line E in the figure).
  • FIG. 3 was quoted from “2nd edition McGraw-Hill Series in Aeronautical and Aerospace Engineering, Modern Compressible Flow with historical Perspective.”
  • determining a minimum nozzle length means determining the shortest flight time t f until the particles becomes semi-solidified.
  • the shortest flight time t f from the expression (22) and substituting it into the expression (18) there is determined the shortest flight time, i.e., minimum nozzle length l f .
  • the thermal spraying nozzle device is characterized by being a device using a nozzle with a length of not smaller than the above nozzle length l f , and by accelerating the particles up to a supersonic velocity the particles even in a solidified state adhere to the base material or deposit.
  • the nozzle length has no upper limit theoretically.
  • FIG. 4 is a graph of having determined minimum nozzle lengths concretely with use of aluminum and copper.
  • the nozzle lengths shown therein are considered necessary when particles of various diameters assume a semi-solidified state with a solid phase ratio exceeding 0.5.
  • the particle diameter is plotted along the axis of abscissa and the nozzle length along the axis of ordinate.
  • Carrier gas conditions are the same as in Table 1 which will be described later.
  • a required nozzle length is 0.17 m in case of aluminum and 0.12 m in case of copper.
  • the said half-cone angle means the angle between the central nozzle axis and the nozzle inner wall.
  • the sectional area ratio A/A* increases abruptly and so does Mach number (see the expression (2)), but a shock wave front appears upon arrival at Mach number M 1 which is determined from the isentropic change expression (23) and the vertical shock wave relationship (24), and with this as a boundary the gas flow on the downstream side becomes a subsonic flow and the divergent angle of the nozzle inner wall is large, so that the gas flow near the inner wall surface peels off the inner wall surface.
  • the Mach number M 1 is determined from the expression (25) and the sectional area ratio A/A* at the position where the shock wave front appears is determined from the expression (26).
  • Such a nozzle has heretofore been suitable for atomization, but the intra-nozzle gas flow immediately becomes a subsonic flow and the concept of accelerating particles is not existent.
  • the particles after atomization are accelerated up to a supersonic velocity while setting the divergent angle of the nozzle at 15° or less to prevent separation of the gas flow and so that the particles even in a semi-solidified state can be adhered to the base material or deposit.
  • the distance from the narrowest portion of the nozzle up to the shock wave front generating position is extended long until the particles reach a solidified or semi-solidified state.
  • p 0 p 1 ( 1 + ⁇ - 1 2 ⁇ M 1 2 ) ⁇ ⁇ - 1 ( 23 )
  • p 1 p B 2 ⁇ ⁇ ⁇ ⁇ ⁇ M 1 2 - ( ⁇ - 1 ) ⁇ + 1 ( 24 )
  • p 0 p B 2 ⁇ ⁇ ⁇ ⁇ ⁇ M 1 2 - ( ⁇ - 1 ) ⁇ + 1 ⁇ ( 1 + ⁇ - 1 2 ⁇ M 1 2 ) - ⁇ ⁇ - 1 ( 25 )
  • a 1 A * 1 M 1 ⁇ [ ( ⁇ - 1 ) ⁇ M 1 2 + 2 ⁇ + 1 ] ⁇ + 1 2 ⁇ ( ⁇ - 1 ) ( 26 )
  • conditions for the supersonic nozzle in the present invention can be defined by the following (a) to (c):
  • the divergent angle of the nozzle should be ⁇ 15° in terms of a half-cone angle.
  • the divergent angle of the nozzle should be ⁇ 15° in terms of a half-cone angle, and when a shock wave upstream Mach number M 1 is determined by the expression (25) on the basis of the total carrier gas pressure p 0 and the nozzle outlet back pressure P B and is substituted into the expression (26) to determine the sectional area A 1 of the nozzle, the nozzle length l f up to the position corresponding to the sectional area A 1 of the nozzle should be not shorter than a minimum nozzle length l f determined from both the expression (18) and the relationship (22) which defines the shortest flight time until the particles become semi-solidified.
  • FIG. 6 shows a case where a shock wave is generated within the nozzle.
  • the divergent angle of the nozzle should be ⁇ 15° in terms of a half-cone angle
  • the nozzle length l f should be not shorter than the shortest nozzle length l f determined from both the expression (18) and the relationship (22) which defines the shortest flight time until the particles become semi-solidified
  • a shock wave upstream Mach number M 1 is determined by the expression (25) on the basis of the total carrier gas pressure p 0 and the nozzle outlet back pressure P B and is substituted into the expression (26) to determine the sectional area A 1 of the nozzle
  • the sectional area A 1 should be larger than the nozzle outlet sectional area A e .
  • maximum half-cone angle in the above table is meant a maximum angle between the nozzle axis and the nozzle inner wall.
  • the mass flow rate of gas at the throat diameter of 25 mm and that at the throat diameter of 35 mm correspond to 0.9 [kg/s] and 1.8 [kg/s], respectively.
  • a typical example of a nozzle shape designed for spray acceleration is shown in the graph of FIG. 8 .
  • the maximum half-cone angle of the nozzle is set at 5° (see Table 1).
  • This nozzle is configured with a view to (a) expanding dispersed droplets after atomization quickly up to the maximum diameter so as not to adhere to the nozzle wall and (b) taking long a straight pipe portion at the maximum diameter at which the velocity becomes maximum so as to accelerate the particles.
  • the nozzle of this embodiment is inconvenient in that the whole of a straight pipe portion which occupies most of the nozzle becomes subsonic in the case where a pressure ratio is lower than a design value or when a lot of cold particles are supplied.
  • the nozzle of this embodiment is unsuitable for operation in a deviated state from the design value, but is suitable for production equipment in which operation is repeated under the same conditions.
  • the graph of FIG. 9 shows nozzle outlet diameters affording an appropriate expansion on the premise that operation is performed under the same conditions as just referred to above.
  • the reason why the nozzle outlet diameter increases with an increase in flow rate of molten metal no matter which of 25 mm and 35 mm of the nozzle throat diameter may be is that the gas receives the heat carried in by the molten metal, creating an expandable state.
  • Table 2 shows a relation between nozzle throat diameters resulting from design calculation in the actual nozzle and mass flow rate of gas in case of heating being not performed. TABLE 2 Results of nozzle design calculation of this time and mass flow rate of gas Nozzle Mass Flow Rate of Throat Outlet Mass Flow Rate of Gas, kg/s Molten Metal Dia. Dia.
  • FIGS. 10 to 12 there are shown intra-nozzle Mach number distributions, gas temperature/velocity distributions, and particle temperature/velocity distributions, respectively, assuming that the particle diameter after atomization is 20 ⁇ m and the nozzle throat diameter is 25 mm.
  • Distance plotted along the axis of abscissa represents the nozzle length, while in the axis of ordinate, Mach number, Gas temp, Gas Velc, Solid temp, and Solid Velc, represent Mach number, gas temperature, gas velocity, particle temperature, and particle velocity, respectively.
  • FIGS. 13 to 15 there are shown intra-nozzle Mach number distributions, gas temperature/velocity distributions, and particle temperature/velocity distributions, respectively, assuming that the particle diameter after atomization is 20 ⁇ m and the nozzle throat diameter is 35 mm.
  • the nozzle outlet diameter is determined so as to give an appropriate expansion after heating, the static pressure of gas is almost equal to the atmospheric pressure and gas velocities are all 510 m/s or so.
  • the difference between the throat diameters 25 mm and 35 mm appears in the gas temperature, but does not appear in the gas velocity, as shown in FIGS. 11 and 14 . Therefore, as to the particles influenced by the gas temperature, a difference appears in the particle temperature, but does not appear in the particle velocity.
  • the particle diameter is 20 ⁇ m
  • solidification is completed at a nozzle length of about 160 mm, but the particle velocity is only about 400 m/s.
  • the nozzle length is extended to 500 mm, it is possible to accelerate the particle velocity to 480 m/s, but the particles are cooled to a temperature of 400K.
  • FIGS. 16 to 18 there are shown intra-nozzle Mach number distributions, gas temperature/velocity distributions, and particle temperature/velocity distributions, respectively, assuming that the particle diameter after atomization is 50 ⁇ m and the nozzle throat diameter is 25 mm.
  • FIGS. 19 to 21 there are shown intra-nozzle Mach number distributions, gas temperature/velocity distributions, and particle temperature/velocity distributions, respectively, assuming that the particle diameter after atomization is 50 ⁇ m and the nozzle throat diameter is 35 mm.
  • Mach number, gas temperature and particle velocity show a tendency not greatly different from that in the case of the particle diameter being 20 ⁇ m, but a conclusive different point resides in the particle temperature cooling velocity shown in FIGS. 18 and 21 .
  • this condition the particles are ejected from the nozzle at a particle temperature of 750K and a particle velocity of 470 m/s and thus this condition is most preferred as an impact depositing condition for the base material.
  • FIGS. 22 to 24 there are shown intra-nozzle Mach number distributions, gas temperature/velocity distributions, and particle temperature/velocity distributions, respectively, in case of the particle diameter after atomization being 100 ⁇ m.
  • This calculation result shows that a nozzle length of 5 m is needed until solidification after a lowering of the cooling velocity in case of the particle diameter being 100 ⁇ m. Since particle acceleration has already ended at the time point corresponding to the nozzle length of 3 m and the particle velocity now reaches about 450 m/s, cooling becomes later. Such a situation occurs when atomization cannot be done to a satisfactory extent.
  • FIG. 25 shows a construction in case of a thermal spraying system according to the present invention being applied to a batch process.
  • carrier gas helium gas of a low molecular weight, which is preferred in point of a sound velocity becoming high when accelerating particles, is used in place of nitrogen gas.
  • Carrier gas supplied from a helium gas cylinder 10 is branched into two pipes 11 and 12 .
  • the carrier gas flowing in the pipe 11 imparts a head pressure to molten metal stored in a storage section 4
  • the carrier gas flowing in the pipe 12 is introduced into a nozzle 2 and passes through a throat portion 2 a of the nozzle 2 , whereby it is accelerated to a supersonic velocity.
  • the helium gas cylinder 10 and the pipes 11 , 12 function as a carrier gas supply unit for the supply of carrier gas under pressure.
  • the molten metal flowing down from the storage section 4 is atomized by the supersonic gas flow in the nozzle 2 , then the atomized particles are cooled in the nozzle 2 and ejected from a front end of the nozzle 2 .
  • the ejected particles collide with and adhere to the surface of a base material 3 .
  • the nozzle 2 and the base material 3 are accommodated within a chamber 13 which is a sealed chamber.
  • the chamber 13 is connected to a gas storage tank 16 via a cyclone unit 14 as an exhaust unit and an exhaust vacuum pump (pressure reducing means) 15 .
  • the cyclone unit 14 recovers particles suspended in exhaust air and supplies only gas to the exhaust vacuum pump 15 .
  • the exhaust unit is provided for increasing the Mach number of carrier gas and thereby increasing the particle velocity.
  • the helium gas recovered into the gas storage tank 16 is compressed by a compressor 17 and is re-utilized.
  • FIG. 26 shows a basic construction in case of applying a thermal spraying system according to the present invention to a continuous molding process.
  • a continuous melting furnace 20 is connected to a storage section 4 and the storage section 4 and the continuous melting furnace 20 are in communication with each other through a connecting pipe 21 .
  • the height of the continuous melting furnace 20 is set so that the inner pressure of the storage section 4 is held at 0.8 MPa by a head pressure.
  • the continuous melting furnace 20 disposed at the above predetermined height functions as a molten metal supply unit for continuous supply of molten metal under pressure.
  • molten metal can be supplied to a nozzle 2 continuously from the storage section 4 .
  • FIGS. 27 to 31 show other embodiments of nozzles 2 according to the present invention.
  • the nozzle itself is fabricated using a non-metal such as a ceramic material or carbon to deteriorate the surface affinity, whereby metal particles adhered to the inner surface of the nozzle can be blown off easily by a supersonic gas flow.
  • a non-metal such as a ceramic material or carbon to deteriorate the surface affinity, whereby metal particles adhered to the inner surface of the nozzle can be blown off easily by a supersonic gas flow.
  • the same constituent elements as in FIG. 1 are identified by the same reference numerals, and explanations thereof will be omitted.
  • a nozzle 41 is fabricated using zirconium for thermal spraying of aluminum alloy, the outside of the nozzle 41 being covered with a ceramic cylinder 42 , and a nozzle heater 43 capable of raising temperature up to a maximum of 900° C. is wound plural turns round the cylinder 42 .
  • the nozzle itself is constituted by a ceramic fiber heater 45 . More specifically, a material consisting principally of alumina and silica is made into a high temperature insulating ceramic fiber, followed by embedding a heating element into the ceramic fiber and subsequent integral molding. Numerals 46 a and 46 b in the figure denote electrode connecting portions of the heater.
  • a carbon heater 49 is disposed around an outer wall of a body portion of a ceramic nozzle 48 and heating is performed by radiation.
  • the carbon heater 49 is divided into plural portions by slits 51 d and 51 e which are formed a predetermined length alternately from both upper and lower sides of a cylindrical nozzle 48 .
  • Numerals 49 a and 49 b denote electrode connecting portions of the carbon heater 49 .
  • Numeral 50 denotes a cylindrical reflection case having a specular-finished inner wall and it is provided for enhancing the radiation efficiency.
  • the carbon heater 49 when electric power is fed from a power supply (not shown) to the carbon heater 49 via the electrode connecting portions 49 a and 49 b, the carbon heater 49 generates heat from the interior thereof due to Joule heat induced by the supply of electric power. As a result, the ceramic nozzle 48 is heated by radiation heat transfer from the carbon heater 49 and the metal adhered to the inner wall of the nozzle 37 is melted.
  • the nozzle itself is fabricated by a carbon heater 52 .
  • Numerals 52 a and 52 b denote electrode connecting portions of the carbon heater.
  • the presence of oxygen causes an oxidation reaction of carbon itself, so for avoiding such an inconvenience, the whole of the system is covered with a chamber and gas such as argon or nitrogen gas is used as high pressure gas to purge the interior of the chamber with an inert atmosphere.
  • gas such as argon or nitrogen gas is used as high pressure gas to purge the interior of the chamber with an inert atmosphere.
  • a nozzle with a metallic material superior in thermal conductivity e.g., copper
  • thermal spraying of a ceramic material to the inner wall of the nozzle thus fabricated to form a ceramic film it is possible to deteriorate the surface affinity as is the case with each of the foregoing nozzles.
  • a zirconium film (the portion indicated by a thick broken line in the figure) 55 is formed on an inner surface of a copper nozzle 54 and a nozzle heater 43 is wound plural turns round an outer periphery surface of the nozzle.
  • the thermal spraying nozzle device and the thermal spraying system according to the present invention are suitable in a field in which it is required to supply a thermal spraying material constantly onto a base material and control the state of a film or deposit formed on the base material.

Landscapes

  • 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)
  • Nozzles (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)
US11/791,333 2005-01-07 2006-01-06 Thermal Spraying Nozzle Device and Thermal Spraying System Abandoned US20070295833A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2005002535 2005-01-07
JP2005-002535 2005-01-07
JP2006000065 2006-01-06

Publications (1)

Publication Number Publication Date
US20070295833A1 true US20070295833A1 (en) 2007-12-27

Family

ID=36647647

Family Applications (1)

Application Number Title Priority Date Filing Date
US11/791,333 Abandoned US20070295833A1 (en) 2005-01-07 2006-01-06 Thermal Spraying Nozzle Device and Thermal Spraying System

Country Status (4)

Country Link
US (1) US20070295833A1 (zh)
EP (1) EP1834699A4 (zh)
CN (1) CN101098759A (zh)
WO (1) WO2006073171A1 (zh)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070278324A1 (en) * 2006-05-18 2007-12-06 Frank Gartner Device for cold gas spraying
US20120240852A1 (en) * 2011-03-23 2012-09-27 Kevin Wayne Ewers System for spraying metal particulate
CN112049993A (zh) * 2020-07-24 2020-12-08 中国航天空气动力技术研究院 能够快速更换的高压气流量测量与控制装置及更换方法
US11905978B2 (en) 2019-04-08 2024-02-20 Norma Germany Gmbh Jet pump

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100404142C (zh) * 2006-07-24 2008-07-23 南开大学 超声喷雾热分解喷头
DE102006055703A1 (de) * 2006-11-23 2008-05-29 Walter Dr.-Ing. Lachenmeier Verfahren und Vorrichtung zur Partikelerzeugung
US8744251B2 (en) * 2010-11-17 2014-06-03 3M Innovative Properties Company Apparatus and methods for delivering a heated fluid
JP6472139B2 (ja) * 2015-06-15 2019-02-20 富士フイルム株式会社 オリフィス、及びこれを用いた送液装置、塗布装置、並びに光学フィルムの製造方法
JP2017043791A (ja) * 2015-08-24 2017-03-02 トヨタ自動車株式会社 溶射皮膜形成装置
SE541122C2 (en) 2017-08-25 2019-04-16 Saab Ab Method of combusting aluminium and system therefor
JP6879878B2 (ja) * 2017-09-28 2021-06-02 三菱重工業株式会社 溶射ノズル、及びプラズマ溶射装置
CN108745677B (zh) * 2018-07-25 2023-06-20 上海莘临科技发展有限公司 超音速氧乙炔爆炸燃烧喷嘴及沙粒熔融方法
CN109647240B (zh) * 2018-12-28 2020-08-28 西安交通大学 一种喷雾式射流与主流气体掺混的组织方法
CN109985745B (zh) * 2019-04-10 2020-07-28 业成科技（成都）有限公司 可提高曲面喷涂均匀性之喷涂装置
CN110848065B (zh) * 2019-11-13 2021-07-02 北京工业大学 一种自动识别柴油喷雾破碎过程自动实现喷雾连续计算的方法

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2639490A (en) * 1948-08-12 1953-05-26 Joseph B Brennan Formation of metal strip under controlled pressures
US2978189A (en) * 1958-05-14 1961-04-04 A R B E D Acieries Reunies De Nozzle
US4111150A (en) * 1977-03-28 1978-09-05 Ppg Industries, Inc. Apparatus for coating an advancing substrate
US4619845A (en) * 1985-02-22 1986-10-28 The United States Of America As Represented By The Secretary Of The Navy Method for generating fine sprays of molten metal for spray coating and powder making
US5368657A (en) * 1993-04-13 1994-11-29 Iowa State University Research Foundation, Inc. Gas atomization synthesis of refractory or intermetallic compounds and supersaturated solid solutions
US5529809A (en) * 1994-02-07 1996-06-25 Mse, Inc. Method and apparatus for spraying molten materials
US5589199A (en) * 1990-10-09 1996-12-31 Iowa State University Research Foundation, Inc. Apparatus for making environmentally stable reactive alloy powders
US6481638B1 (en) * 1997-12-17 2002-11-19 Gunther Schulz Method and device for producing fine powder by atomizing molten material with gases

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4919853A (en) * 1988-01-21 1990-04-24 The United States Of America As Represented By The United States Department Of Energy Apparatus and method for spraying liquid materials
GB9004214D0 (en) * 1990-02-24 1990-04-18 Rolls Royce Plc An apparatus and method for atomising a liquid
WO1992006797A1 (en) * 1990-10-18 1992-04-30 United States Department Of Energy A low temperature process of applying high strength metal coatings to a substrate and article produced thereby
US6296043B1 (en) * 1996-12-10 2001-10-02 Howmet Research Corporation Spraycast method and article
CA2433613A1 (en) * 2002-08-13 2004-02-13 Russel J. Ruprecht, Jr. Spray method for mcralx coating

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2639490A (en) * 1948-08-12 1953-05-26 Joseph B Brennan Formation of metal strip under controlled pressures
US2978189A (en) * 1958-05-14 1961-04-04 A R B E D Acieries Reunies De Nozzle
US4111150A (en) * 1977-03-28 1978-09-05 Ppg Industries, Inc. Apparatus for coating an advancing substrate
US4619845A (en) * 1985-02-22 1986-10-28 The United States Of America As Represented By The Secretary Of The Navy Method for generating fine sprays of molten metal for spray coating and powder making
US5589199A (en) * 1990-10-09 1996-12-31 Iowa State University Research Foundation, Inc. Apparatus for making environmentally stable reactive alloy powders
US5368657A (en) * 1993-04-13 1994-11-29 Iowa State University Research Foundation, Inc. Gas atomization synthesis of refractory or intermetallic compounds and supersaturated solid solutions
US5529809A (en) * 1994-02-07 1996-06-25 Mse, Inc. Method and apparatus for spraying molten materials
US6481638B1 (en) * 1997-12-17 2002-11-19 Gunther Schulz Method and device for producing fine powder by atomizing molten material with gases

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070278324A1 (en) * 2006-05-18 2007-12-06 Frank Gartner Device for cold gas spraying
US20100181391A1 (en) * 2006-05-18 2010-07-22 Gaertner Frank Device for cold gas spraying
US20120240852A1 (en) * 2011-03-23 2012-09-27 Kevin Wayne Ewers System for spraying metal particulate
US8544408B2 (en) * 2011-03-23 2013-10-01 Kevin Wayne Ewers System for applying metal particulate with hot pressurized air using a venturi chamber and a helical channel
US11905978B2 (en) 2019-04-08 2024-02-20 Norma Germany Gmbh Jet pump
CN112049993A (zh) * 2020-07-24 2020-12-08 中国航天空气动力技术研究院 能够快速更换的高压气流量测量与控制装置及更换方法

Also Published As

Publication number Publication date
CN101098759A (zh) 2008-01-02
WO2006073171A1 (ja) 2006-07-13
EP1834699A4 (en) 2008-06-25
EP1834699A1 (en) 2007-09-19

Similar Documents

Publication Publication Date Title
US20070295833A1 (en) Thermal Spraying Nozzle Device and Thermal Spraying System
Stoltenhoff et al. An analysis of the cold spray process and its coatings
JP2006212624A (ja) 溶射ノズル装置および溶射装置
EP1289699B1 (en) Rapid solidification processing system for producing molds, dies and related tooling
Li et al. Optimal design of a novel cold spray gun nozzle at a limited space
US6074194A (en) Spray forming system for producing molds, dies and related tooling
JP4989859B2 (ja) コールドスプレー用ノズルならびにこれを利用したコールドスプレー装置及び方法
JP3784404B1 (ja) 溶射ノズル装置およびそれを用いた溶射装置
US6623796B1 (en) Method of producing a coating using a kinetic spray process with large particles and nozzles for the same
EP1579921A2 (en) Improved kinetic spray nozzle system design
US6142382A (en) Atomizing nozzle and method
Sobolev et al. Dynamic processes during high velocity oxyfuel spraying
US6845929B2 (en) High efficiency nozzle for thermal spray of high quality, low oxide content coatings
US8651394B2 (en) Laval nozzle for thermal spraying and kinetic spraying
Grujicic et al. Flow analysis and nozzle-shape optimization for the cold-gas dynamic-spray process
US7475831B2 (en) Modified high efficiency kinetic spray nozzle
EP2110178A1 (en) Cold gas-dynamic spray nozzle
Stoltenhoff et al. Optimization of the cold spray process
CN111962059A (zh) 利用冷喷涂对太空构件在轨制造和修复的固态3d打印系统及方法
Dolatabadi et al. Effect of a cylindrical shroud on particle conditions in high velocity oxy-fuel spray process
Smith et al. Cold spray direct fabrication-high rate, solid state, material consolidation
Champagne et al. The effects of gas and metal characteristics on sprayed metal coatings
Helfritch et al. Optimal particle size for the cold spray process
Qi et al. Predication and measurement of deflected trajectory and temperature history of uniform metal droplets in microstructures fabrication
RU2099442C1 (ru) Способ газодинамического нанесения покрытий из порошковых материалов

Legal Events

Date Code Title Description
AS Assignment

Owner name: KABUSHIKI KAISHA KOBE SEIKO SHO, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ODA, TSUYOSHI;MIYAKE, TOSHIYA;HATA, HIDEO;REEL/FRAME:019377/0422

Effective date: 20060601

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION