JP2018199856A - Manufacturing method of thermal spray material, thermal spray material, thermal spray method and thermal spray product - Google Patents

Abstract

To provide a thermal spray material capable of forming a dense coating.SOLUTION: A mixture is obtained by mixing a fine particle and a liquid state thermoset resin, the mixture having the fine particle dispersed evenly (step S11). The fine particle is formed by a base fine particle formed by a base material of ceramic or metal and an auxiliary material for densification of a thermal spray coating, the auxiliary material being different from the base material. The fine particle includes an auxiliary fine particle of which volume ratio is smaller than that of the base fine particle in the mixture. The mixture is hardened by heating (step S12), and a hardened material is crushed into a particle with a particle size larger than that of the fine particle (step S13). This provides a thermal spray material capable of forming a dense coating in a plasma spray, a flame spray, or a laser spray.SELECTED DRAWING: Figure 2

Description

  The present invention relates to thermal spraying.

  In plasma spraying, flame spraying, and laser spraying, powder materials such as metals and ceramics are introduced into a high-temperature plasma flow, flame flow, or focused laser beam, and molten material particles are sprayed onto the substrate surface to deposit them. To form a coating. These thermal spraying methods have been established as industrial manufacturing techniques, and it is not necessary to arrange an object in a sealed space, and can be applied to large areas and long objects.

  Patent Document 1 proposes a thermal spray material in which ceramic or metal fine particles are dispersed in resin particles having a particle size larger than that of the fine particles. The thermal spray material is used for plasma spraying, flame spraying, or laser spraying.

Japanese Patent Laying-Open No. 2015-45068

  By the way, as in Patent Document 1, when a thermal spray material containing fine particles and a resin is used, it is possible to perform thermal spraying using nano-sized fine particles that are difficult to handle by air conveyance. It may not be easy to form a film. In addition, in the above-mentioned thermal spray material, it may be difficult to increase the rate of fine particles and increase the deposition rate during thermal spraying. Accordingly, there is a need for a thermal spray material capable of forming a dense coating and a thermal spray material capable of increasing the deposition rate during thermal spraying.

  The present invention has been made in view of the above problems, and aims to provide a thermal spray material capable of forming a dense coating and a thermal spray material capable of increasing the deposition rate during thermal spraying. Yes.

  The invention described in claim 1 is a method for producing a thermal spray material used for plasma spraying, flame spraying, or laser spraying, in which a) a step of dispersing fine particles in a liquid resin, and b) the step a). A step of curing the obtained mixture, and c) a step of pulverizing the cured product obtained in the step b) into particles having a larger particle diameter than the fine particles to obtain a thermal spray material, the fine particles comprising: Base fine particles formed of a base material that is ceramic or metal, and auxiliary fine particles that are different from the base material and are made of an auxiliary material for densifying the thermal spray coating, and whose volume ratio in the mixture is smaller than the base fine particles Including.

  Invention of Claim 2 is a manufacturing method of the thermal spray material of Claim 1, Comprising: The said auxiliary material is glass.

  Invention of Claim 3 is a manufacturing method of the thermal spray material of Claim 1, Comprising: The said auxiliary material is a metal, and melting | fusing point of the said auxiliary material is lower than melting | fusing point of the said base material.

  Invention of Claim 4 is a manufacturing method of the thermal spray material as described in any one of Claim 1 thru | or 3, Comprising: The average particle diameter of the said base microparticle is larger than the average particle diameter of the said auxiliary | assistant microparticle .

  The invention according to claim 5 is a thermal spray material used for plasma spraying, flame spraying or laser spraying, and is a particle formed by fine particles and a resin existing between the fine particles, and the fine particles are ceramics. Alternatively, it includes base fine particles formed of a base material that is a metal, and auxiliary fine particles that are different from the base material and are formed of an auxiliary material for densifying the sprayed coating and have a volume ratio smaller than that of the base fine particles.

  The invention according to claim 6 is a method for producing a thermal spray material used for plasma spraying, flame spraying or laser spraying, comprising a) dispersing ceramic or metal fine particles in a liquid resin; and b) a) curing the mixture obtained in step c), c) crushing the cured product obtained in step b) into particles having a particle size larger than the fine particles to obtain a thermal spray material, The fine particles include first fine particles and second fine particles having an average particle size smaller than that of the first fine particles.

  The invention according to claim 7 is the method for producing a thermal spray material according to claim 6, wherein the average particle diameter of the first fine particles is 10 times or more the average particle diameter of the second fine particles.

  The invention according to claim 8 is the method for producing a thermal spray material according to claim 6 or 7, wherein the average particle diameter of the first fine particles is larger than 1 μm.

  The invention according to claim 9 is the method for producing a thermal spray material according to any one of claims 6 to 8, wherein a volume ratio of the fine particles in the mixture is 52% or more.

  The invention according to claim 10 is a thermal spray material used for plasma spraying, flame spraying or laser spraying, and is a particle formed by ceramic or metal fine particles and a resin existing between the fine particles, The fine particles include first fine particles and second fine particles having an average particle size smaller than that of the first fine particles.

  Invention of Claim 11 is a thermal spraying method, Comprising: d) The thermal spray material manufactured with the manufacturing method as described in any one of Claim 1 thru | or 4 and Claim 6 thru | or 9 is prepared. And e) performing a plasma spray, a flame spray, or a laser spray using the thermal spray material to bond the heated fine particles on the substrate to form a coating.

  According to a twelfth aspect of the present invention, a coating film is formed on a substrate by the thermal spraying method according to the eleventh aspect.

  According to the first to fifth aspects of the present invention, it is possible to provide a thermal spray material capable of forming a dense film. According to the sixth to tenth aspects of the present invention, it is possible to increase the deposition rate during thermal spraying. Thermal spray material can be provided.

It is a figure which shows the structure of a thermal spraying apparatus. It is a figure which shows the flow of manufacture of a thermal spray material. It is a figure which shows a thermal spray material. It is a figure which shows a thermal spray material. It is a figure which shows the flow of the thermal spraying by a thermal spraying apparatus. It is a figure which shows the cross section of a film. It is a figure which shows the cross section of a film. It is a figure which shows a thermal spray material. It is a figure which shows a thermal spray material. It is a figure which shows the cross section of a film. It is a figure which shows the cross section of a film. It is a figure which shows a thermal spray material. It is a figure which shows a thermal spray material. It is a figure which shows a thermal spray material. It is a figure which shows a thermal spray material. It is a figure which shows a thermal spray material. It is a figure which shows a thermal spray material. It is a figure which shows the other example of a thermal spraying apparatus. It is a figure which shows the cross section of a film. It is a figure which shows the cross section of a film. It is a figure which shows the component analysis result in the cross section of a film.

  FIG. 1 is a diagram showing a configuration of the thermal spraying apparatus 1. The thermal spraying apparatus 1 is an apparatus that performs plasma spraying on the base material 9. The thermal spraying apparatus 1 includes a thermal spray gun 11, a plasma gas supply unit 12, a material storage unit 13, a transport gas supply unit 14, and a material transport unit 15. The thermal spray gun 11 generates a plasma flare 8. The plasma gas supply unit 12 supplies plasma gas to the thermal spray gun 11. The plasma gas is, for example, argon gas and hydrogen gas. The plasma gas may be helium gas or other gas. The material storage unit 13 stores a thermal spray material used for thermal spraying. The carrier gas supply unit 14 supplies a carrier gas to the material carrier unit 15. The carrier gas is, for example, argon gas. The carrier gas may be a gas other than argon gas. The material transfer unit 15 supplies the thermal spray material into the plasma flare 8 using the transfer gas from the transfer gas supply unit 14.

  The thermal spray gun 11 is an ejection nozzle that performs thermal spraying. A plasma gas flow path 21 is provided in the thermal spray gun 11. A cathode 22 is disposed at the center of the channel 21, and an anode 23 is disposed on the downstream side of the cathode 22 so as to surround the channel. The plasma flare 8 is ejected from the ejection port 24 by the discharge between the cathode 22 and the anode 23.

  The material transport unit 15 includes a fixed amount supply unit 31 and a transport pipe 32. The fixed amount supply unit 31 takes out a certain amount of thermal spray material per unit time from the material storage unit 13 and merges it with the carrier gas. An end portion of the transfer pipe 32 serves as a jet port 33, and the thermal spray material is jetted together with the carrier gas from the jet port 33. The thermal spray material is introduced vertically from the side in the traveling direction of the plasma flare 8 toward the center of the plasma flare 8.

  The thermal spray material is powder, and each particle (hereinafter referred to as “thermal spraying particle”) has a size that does not clog the conveying tube 32. As will be described later, each thermal spraying particle is a resin particle containing finer fine particles. The fine particles contained in the particles for thermal spraying are ceramic particles or metal particles. The resin of the thermal spray material (spraying particles) is burned out by the plasma flare 8, and fine particles in a molten state or a semi-molten state flow together with the plasma flare 8 toward the substrate 9. As a result, fine particles are deposited on the substrate 9, and a coating (that is, a thermal spray coating) is formed.

  Next, manufacture of a thermal spray material is demonstrated, referring the example (henceforth "manufacturing example") which actually manufactured the thermal spray material. FIG. 2 is a diagram showing a flow of manufacturing a thermal spray material. First, ceramic or metal fine particles are prepared, and further a liquid resin having thermosetting properties is prepared. Here, the first fine particles and the second fine particles that are formed of the same material and have different average particle diameters are used as the fine particles. The average particle size of the first fine particles is larger than the average particle size of the second fine particles. The first fine particles used in the production examples are stabilized zirconia fine particles having an average particle diameter of 3.6 μm (micrometer) (manufactured by Daiichi Kagaku Kagaku Kogyo Co., Ltd., product number “UZY-8H”). The fine particles are stabilized zirconia fine particles (manufactured by Kyoritsu Material Co., Ltd., product number “KZ-8YF”) having an average particle diameter of 200 nm (nanometers).

  Here, the average particle diameter of the first and second fine particles is calculated from, for example, a particle size distribution obtained by a laser diffraction / scattering method. Typically, the median diameter (d50) calculated from the particle size distribution of the particle group prepared as the first fine particles is the average particle size of the first fine particles. The same applies to the average particle diameter of the second fine particles. The fine particles may be prepared in a state where the first and second fine particles are mixed. In this case, for example, when two significant peaks are confirmed in the particle size distribution of the fine particles, the center value of the section (particle size) to which the larger particle size belongs is treated as the average particle size of the first fine particles. In other words, the center value of the section to which the peak having the smaller particle size belongs may be treated as the average particle size of the second fine particles. In the particle size distribution of the fine particles in which the first and second fine particles are mixed, the average particle size of the first fine particles and the average particle size of the second fine particles may be obtained by a statistical method. The average particle diameter of the first fine particles only needs to be a representative particle size in the particle size distribution of the first fine particles, and the average particle diameter of the second fine particles is the same. In addition, when it is difficult to measure the average particle diameter of the fine particles by the laser diffraction / scattering method, the measurement may be performed by the dynamic light scattering method. When the average particle size indicated by the manufacturer of the first fine particles is sufficiently different from the average particle size indicated by the manufacturer of the second fine particles (for example, one is 10 times or more of the other), the manufacturer The average particle size indicated by may be adopted as it is.

  The average particle diameter of the first fine particles is, for example, larger than 1 μm, preferably 2 μm or more, and more preferably 2.5 μm or more. The average particle size of the first fine particles is smaller than the average particle size of the particles for thermal spraying. The average particle diameter of the second fine particles is preferably 25 nm or more and 1000 nm or less. In other words, the second fine particles are preferably so-called nanoparticles. More preferably, the average particle diameter of the second fine particles is not less than 50 nm and not more than 500 nm, which is easily available from the manufacturer. Moreover, it is preferable that the average particle diameter of 1st microparticles is 10 times or more of the average particle diameter of 2nd microparticles. The reason will be described later.

The material of the fine particles is not limited to the above-described zirconia (ZrO ₂ ), and may be variously changed. For example, as the ceramic material of fine particles, aluminum oxide, silicon oxide, mullite (Al ₂ O ₃ · SiO ₂ ), zirconium oxide, zircon (ZrO ₂ · SiO ₂ ), forsterite (2MgO · SiO ₂ ), steatite ( MgO · SiO ₂ ), barium titanate (BaTiO ₃ ), lead zirconate titanate (Pb (Zr, Ti) O ₃ ), titanium oxide, zinc oxide, calcium oxide, magnesium oxide, chromium oxide, manganese oxide, iron oxide Oxides and composite oxides including nickel oxide, copper oxide, gallium oxide, germanium oxide, yttrium oxide, silver oxide, cobalt oxide, tungsten oxide, vanadium oxide, barium oxide, etc .; aluminum nitride, silicon nitride, etc. Nitride group including: Carbide group including silicon carbide, etc .; W A cermet group including C / C, WC / Ni, WC / CrC / Ni, WC / Cr / Co, CrC / NiCr, sialon (SiN ₄ · Al ₂ O ₃ ), and the like can be used. Various materials such as aluminum and copper can be used as the material for the fine particles in the case of metal.

  The liquid thermosetting resin used in the production example is an acrylic resin (manufactured by JSR Corporation, product number “KC1280”). Various liquid resins may be employed as long as they are mainly composed of organic substances, and may be photocurable. Of course, other curable resins may be used. Various curable resins can be used. For example, thermosetting plastics including phenol, urea resin, melamine resin, unsaturated polyester resin, diallyl phthalate resin, epoxy resin, silicon resin, alkyd resin, polyimide, polyaminobismaleimide, casein resin, furan resin, urethane resin, etc. One kind or plural kinds selected from the above can be used.

When the fine particles and the thermosetting resin are prepared, they are mixed (step S11). In the production example, first, second fine particles having an average particle diameter of 200 nm and a liquid resin are placed in a sealed container of 150 cm ³ . The volume ratio of the second fine particles to the volume of the entire material in the sealed container is 42 vol% (mass ratio is 78.1 wt%). Then, a paste-like mixture in which the second fine particles are uniformly monodispersed is obtained by an agitation / defoaming device (product number “SK-350T”, manufactured by Photochemical Co., Ltd.) accompanied with rotation and revolution. As conditions for stirring and defoaming, for example, both rotation and revolution are 1340 rpm, and the operation time is 840 seconds.

  Subsequently, first fine particles having an average particle size of 3.6 μm are added to the mixture in a plurality of times. At this time, every time a predetermined amount of the first fine particles is added to the mixed paste, stirring and defoaming are performed. The final volume ratio of the first fine particles in the mixture (volume ratio with respect to the entire mixture) is 48.3 vol%, and the final volume ratio of the second fine particles is 21.7 vol%. The volume ratio of the entire fine particles including the first and second fine particles is 70 vol%. As a result, the mixture is in a state in which the fine particles are packed to some extent in the liquid resin, in other words, the fine particles are uniformly dispersed. The mass ratio of the first fine particles in the mixture is 63.4 wt%, the mass ratio of the second fine particles is 28.5 wt%, and the mass ratio of the entire fine particles is 92.0 wt%.

  In the curing of the mixture described later, it is preferable that the dispersion state of the fine particles is maintained to some extent in the mixture. Here, it is assumed that the fine particles are ideal spheres having a constant particle diameter, and that the fine particles have a simple cubic structure in the mixture. In this case, since the filling rate of the simple cubic structure is about 52.4%, if the volume ratio of the entire fine particles including the first and second fine particles is 52 vol% or more, the dispersion state of the fine particles is appropriately maintained in the mixture. It can be said that. Actually, the fine particles include first fine particles and second fine particles having different average particle diameters. Therefore, in order to more reliably maintain the dispersed state of the fine particles, the volume ratio of the fine particles is preferably 60 vol% or more, and more preferably 65 vol% or more. In the thermal spraying of the thermal spray material, the higher the volume ratio of the fine particles, the higher the deposition rate, and the deposition efficiency (productivity) is improved. The volume ratio of the fine particles in the mixture is, for example, 90 vol% or less. When the amount of the resin entering between the fine particles is increased to some extent, the volume ratio of the fine particles is preferably 85 vol% or less.

  As described above, the average particle diameter of the first fine particles is preferably 10 times or more the average particle diameter of the second fine particles. Here, the diameter of a small sphere that can be inscribed in a gap between the large spheres in a space filled with large spheres having a diameter of 1 will be considered. When three large spheres are arranged at the vertices of an equilateral triangle, the diameter of the small sphere inscribed in these large spheres is 0.155, and when four large spheres are arranged at the vertices of a regular tetrahedron, The diameter of the small sphere inscribed in these large spheres is 0.225. When six large spheres are arranged at the vertices of the regular octahedron, the diameter of the small sphere inscribed in these large spheres is 0.414, and when eight large spheres are arranged at the vertices of the regular hexahedron. The diameter of the small sphere inscribed in these large spheres is 0.732. Therefore, the value of the ratio between the diameter of the large sphere and the diameter of the small sphere is 1.37 to 6.45.

  The large sphere and the small sphere can be considered to correspond to the first fine particle and the second fine particle, respectively, and if the particle size of the first fine particle is 6.45 times the particle size of the second fine particle, the second fine particle is It is possible to inscribe the gap between the first fine particles. Actually, in order to ensure fluidity in the mixture, a certain amount of gap is required between which the resin is interposed between the second fine particles and the first fine particles. Therefore, it can be said that the average particle size of the first fine particles is preferably 10 times or more the average particle size of the second fine particles. In order to further increase the gap, the average particle size of the first fine particles is preferably 15 times or more than the average particle size of the second fine particles. From the viewpoint of filling the gaps between the first fine particles with the second fine particles, the volume ratio of the first fine particles in the mixture is preferably larger than the volume ratio of the second fine particles.

  Subsequently, the mixture of the fine particles and the liquid resin is heated by a hot plate or the like. Thereby, the said mixture hardens | cures, maintaining the dispersion state of microparticles | fine-particles, and hardened | cured material is obtained (step S12). In the production example, the pasty mixture is heated at about 150 ° C. for 30 minutes. The cured product is naturally cooled to room temperature. When a photocurable resin is used as the liquid resin, a cured product is obtained by irradiating the mixture with light such as ultraviolet rays. The liquid resin only needs to have curability, and may be, for example, a resin that is naturally cured when left standing.

  Thereafter, the cured product is pulverized using a vibration mill (so-called high-speed vibration sample pulverizer) (step S13). The cured product after pulverization is fractionated using a sieve. Thereby, the thermal spray material which is a particle | grain (namely, particle | grains for thermal spraying) larger than a microparticle is obtained. In the production example, the pulverized cured product is fractionated in a particle size range of 45 μm to 106 μm. The particles remaining on the sieve (that is, coarse particles having a particle size larger than the particle size range) may be returned to the above mill and pulverized again, for example. Moreover, the over-pulverized particles having a particle size smaller than the particle size range may be mixed with the liquid resin together with the fine particles in step S11, for example.

  3A and 3B are diagrams showing a thermal spray material of a manufacturing example, and are photographs taken using a scanning electron microscope (FIGS. 5A, 5B, 6A, 6B, 7A, and 7B described later). The same applies to FIGS. 8A, 8B, 9A, and 9B.) In the thermal spray material shown in FIGS. 3A and 3B, fine particles including first fine particles having an average particle diameter of 3.6 μm and second fine particles having an average particle diameter of 200 nm are bonded to each other by a resin existing between the fine particles and sprayed. Particles are formed. Thus, each thermal spraying particle includes a plurality of fine particles and a resin portion that holds these fine particles. The particles for thermal spraying can also be regarded as resin particles having a larger particle size than the respective fine particles (first fine particles or second fine particles). In this case, the fine particles are dispersed inside the resin particles. It can be said that. The volume ratio (average volume ratio) of the fine particles in the particles for thermal spraying is substantially the same as the volume ratio in the mixture.

  The particle size range of the particles for thermal spraying may be variously changed as long as it can be used in the thermal spraying apparatus 1. The particle size range can be defined by the opening of the sieve used for classification. The particle diameter of the thermal spray particles obtained by pulverizing the cured product may be variously determined as long as it is larger than the contained fine particles. Here, about the powder which has a particle size of 10 micrometers or less, it is not easy to perform gas conveyance stably in a normal powder supply apparatus, and it may clog a conveyance pipe | tube. Therefore, in order to carry the gas easily with the thermal spraying apparatus 1, the particle size of the thermal spraying particles is preferably larger than 10 μm. Further, from the viewpoint of including a certain number of the first fine particles in each thermal spraying particle, the particle size of the thermal spraying particle is preferably not less than 5 times the average particle size of the first fine particles. In order to prevent the particles for thermal spraying from being clogged in the conveying pipe 32 of the thermal spraying apparatus 1, the particle size of the particles for thermal spraying is less than the inner diameter of the conveying pipe 32, for example, 1500 μm or less. Preferably, the particle size of the particles for thermal spraying is 350 μm or less.

  FIG. 4 is a diagram showing a flow of thermal spraying by the thermal spraying apparatus 1. When the thermal spray material (aggregate of thermal spray particles) manufactured by the manufacturing method of steps S11 to S13 described above is prepared (step S21), the thermal spray material is filled in the material reservoir 13 (step S22). Thereafter, plasma spraying is performed using the thermal spray material (step S23). Thereby, the heated fine particles are bonded on the base material 9, and a film is formed on the base material 9. Actually, a thermal spray product is manufactured by forming a film on the substrate 9.

  5A and 5B are views showing an enlarged cross section of a coating formed on the base material 9 by the thermal spraying apparatus 1 using the thermal spray material of the above manufacturing example. Here, a 50 mm × 50 mm × 6 mm stainless steel (SUS316) plate was used as the substrate 9, and the surface of the plate was preliminarily blasted. In addition, a spray gun manufactured by Sulzer Metco (trade name “F4 Spray Gun”) was used as the thermal spray gun 11, and a powder feeder (trade name “TWIN-120”) manufactured by Sulzer Metco was used as the material transport unit 15. . The applied power to the spray gun 11 was 33.6 kW. Argon gas and hydrogen gas were used as the plasma gas, and argon gas was used as the carrier gas. The distance between the spray gun 11 and the substrate 9 is set to 50 mm, and the relative movement (traverse) of the spray gun 11 in the direction along the surface of the substrate 9 is repeated 11 times at a speed of 9.9 m / min. Thus, a film was formed on the substrate 9. The thickness of the coating was 340 μm, and the thickness of the coating formed by one relative movement of the thermal spray gun 11, that is, the deposition rate was 30.9 μm. The film formation rate is sufficiently higher than the film formation rate in general suspension spraying.

  5A and 5B, a film including a dense portion and a rough portion is formed. In the dense portion, the fine particles are melt-bonded, and it is assumed that the hardness is equivalent to the hardness (1100 to 1300 HV) of the sintered body using zirconia particles. In the rough portion, the second fine particles having an average particle diameter of 200 nm are present in an unmelted state. In this way, a coating film having a rough density can be obtained by using the thermal spray material of the above production example. The reason why the density is formed is not clear, but in the second fine particles having an average particle diameter of 200 nm, the movement when colliding with the base material 9 in the thermal spraying is compared with the first fine particles having an average particle diameter of 3.6 μm. This is thought to be due to the low energy and difficulty in forming a dense structure. In other words, when the fine particles include the second fine particles having a relatively small particle size, a coarse portion is formed in the coating. Similarly, when the fine particles include the first fine particles having a relatively large particle size, a dense portion is formed in the coating. Thus, from the viewpoint of forming a dense portion in the coating, the average particle diameter of the first fine particles is preferably larger than 1 μm. In order to more reliably form the dense portion, the average particle size of the first fine particles is preferably 2 μm or more, and more preferably 2.5 μm or more.

  As described above, the structure having a density is called a bimodal microstructure, and the mechanical properties of the film can be adjusted by controlling the ratio of the density. For example, when many dense portions are provided in the coating, the adhesion force (interface toughness, bond strength) between the substrate 9 and the coating is improved. Since the spread of cracks is also suppressed, high toughness and wear resistance can be obtained. Moreover, when many rough parts are provided in the coating, a coating having a characteristic that is easily scraped, that is, an abradable coating can be obtained. Furthermore, depending on the ratio of density, it is possible to realize a thermal barrier coating with low thermal diffusivity and high thermal expansion.

  Next, another example of the thermal spray material will be described. In the other production example, stabilized zirconia fine particles (manufactured by Showa Denko KK, product number “SHOCOAT K-90”) having an average particle diameter of 26.4 μm are used as the first fine particles. In the particle size distribution of the stabilized zirconia fine particles, about 90% of the particles are included in the particle size range of 10 to 45 μm. The second fine particles and the liquid resin are the same as in the above production example.

  In step S11 of FIG. 2, the second fine particles and the liquid resin are mixed at the same volume ratio as in the above production example, and a paste-like mixture is obtained in which the second fine particles are uniformly monodispersed by the same treatment. . Subsequently, the first fine particles having an average particle diameter of 26.4 μm are added to the mixture in a plurality of times. At this time, every time a predetermined amount of the first fine particles is added to the mixed paste, stirring and defoaming are performed. The final volume ratio of the first fine particles in the mixture is 65.6 vol% (mass ratio is 77.9 wt%), and the final volume ratio of the second fine particles is 14.5 vol% (mass ratio is 17.5%). 2 wt%). The volume ratio of the entire fine particles including the first and second fine particles is 80 vol% (mass ratio is 95.2 wt%). As a result, the mixture is in a state in which the fine particles are packed to some extent in the liquid resin, in other words, the fine particles are uniformly dispersed. Curing of the mixture and pulverization of the cured product (Steps S12 and S13) are the same as in the above production example.

  6A and 6B are diagrams showing the thermal spray material of the other production example. 6A and 6B, fine particles including first fine particles having an average particle diameter of 26.4 μm and second fine particles having an average particle diameter of 200 nm are bonded to each other by a resin to form particles for thermal spraying. ing.

  7A and 7B are views showing an enlarged cross section of the coating formed on the base material 9 by the thermal spraying apparatus 1 using the thermal spray material of the other production example. The conditions for thermal spraying are the same as the formation of the coating film in FIGS. 5A and 5B. The thickness of the coating was 305 μm, and the thickness of the coating formed by one relative movement of the thermal spray gun 11, that is, the deposition rate was 27.7 μm.

  7A and 7B, as in FIGS. 5A and 5B, a film including a dense portion and a rough portion is formed. In the dense part, the fine particles are melt-bonded. In the rough portion, the second fine particles having an average particle diameter of 200 nm are present in an unmelted state. As described above, a coating film having a rough density can be obtained by using the thermal spray material of the other production example.

  Here, manufacture of the thermal spray material of a comparative example is described. In the production of the thermal spray material of the comparative example, the same treatment as that in FIG. 2 was performed using only one of the first fine particles and the second fine particles in the production example as fine particles. In detail, the thermal spray material of the 1st thru | or 4th comparative example was manufactured. In the first comparative example, only the first fine particles having an average particle diameter of 3.6 μm are used, and the volume ratio of the first fine particles in the mixture is set to 60 vol% (hereinafter referred to as “3.6 μm-60 vol% sprayed material”). The same applies hereinafter.). Similarly, in the second to fourth comparative examples, 3.6 μm-65 vol% sprayed material, 200 nm-57 vol% sprayed material, and 200 nm-60 vol% sprayed material were manufactured. When a coating was formed under the same conditions as in the above examples using the thermal spray materials of the first to fourth comparative examples, the deposition rates were 11.8 μm, 15.5 μm, 13 μm, and 20.9 μm, respectively. .

  Here, in the 2nd comparative example which manufactures a 3.6-65 volume% thermal spray material, dilatancy develops in the mixture which mixed the 1st fine particle and liquid resin (same in the 1st comparative example). Thereby, it becomes impossible to stir the mixture quickly, and it is not easy to further increase the volume ratio of the first fine particles in the mixture. Also in the fourth comparative example for producing a sprayed material of 200 nm-60 vol%, if the volume ratio of the second fine particles in the mixture is further increased, a lump of second fine particles is generated and it is not easy to disperse the second fine particles. .

  On the other hand, in the production of the thermal spray material of FIG. 2, fine particles including the first fine particles and the second fine particles having an average particle size smaller than the first fine particles are used. Accordingly, in the mixture of the fine particles and the liquid resin, the second fine particles that are fine particles can be introduced into the gaps between the first fine particles that are coarse particles, and the volume ratio of the fine particles in the mixture is easily increased. be able to. As a result, with the thermal spray material manufactured by the process of FIG. 2, it is possible to increase the deposition rate during thermal spraying. It should be noted that a dense coating may be formed using the above-mentioned sprayed material, for example, by employing a different spraying method. In this case, the average particle diameter of the second fine particles may be larger than 1 μm, for example, 25 nm or more and 10 μm or less.

  In the thermal spray material, the first and second fine particles are the same material, but the first and second fine particles may be different materials. Next, the production of a thermal spray material, which is a material in which the first and second fine particles are different, will be described with reference to production examples. In the following description, the above-mentioned sprayed material in which the first and second fine particles are the same material is referred to as a “single material type sprayed material”.

First, fine particles including first and second fine particles and a thermosetting liquid resin are prepared. In the thermal spray material manufactured by the following treatment, when the thermal spraying is performed, the base portion of the thermal spray coating is formed by the first microparticles. Therefore, the first microparticles are hereinafter referred to as “base microparticles”. The base fine particles are formed of a base material that is ceramic or metal. Further, the second fine particles are hereinafter referred to as “auxiliary fine particles” in order to assist the formation of the film with the base material during the thermal spraying. As will be described later, the auxiliary fine particles contribute to densification of the thermal spray coating mainly composed of the base material. The auxiliary fine particles are formed of an auxiliary material different from the base material. The base fine particles used in the production examples are stabilized zirconia fine particles having an average particle size of 26.4 μm (manufactured by Showa Denko KK, product number “SHOCOAT K-90”), and the auxiliary fine particles have an average particle size of 0. is a _.6μm, glass frit mainly composed of _{Bi 2 O 3 · ZnO · B} 2 O 3 ( manufactured by Asahi glass Co., Ltd., part number "ASF-4001B") is.

  As in the case of the single material type thermal spray material, the average particle diameter of the base fine particles (first fine particles) is, for example, larger than 1 μm, preferably 2 μm or more, and more preferably 2.5 μm or more. The average particle size of the base fine particles is smaller than the particle size of the particles for thermal spraying. The average particle size of the auxiliary fine particles (second fine particles) is preferably 25 nm or more and 10 μm or less. Typically, the average particle size of the auxiliary fine particles is smaller than the average particle size of the base fine particles, that is, the average particle size of the base fine particles is larger than the average particle size of the auxiliary fine particles. In order to increase the deposition rate during thermal spraying, the average particle size of the base particles is preferably 10 times or more, more preferably 15 times or more the average particle size of the auxiliary particles.

The base material zirconia (ZrO ₂ ) is, for example, stabilized zirconia in which CaO, MgO, Y ₂ O ₃ or the like is dissolved, or partially stabilized zirconia (PSZ), and preferably yttria stabilized zirconia. (YSZ). As the base material, various ceramics or metals can be used as well as the fine particles in the single-material type thermal spray material. As the base material, a plurality of types of ceramics or a plurality of types of metals may be mixed. In one example, a combination of ZrO ₂ and Al ₂ O ₃ can form a coating having excellent toughness of zirconia reinforced alumina or alumina reinforced zirconia. Further, ceramic and metal may be mixed as the base material.

The auxiliary _{material, SiO 2, B 2 O 3} , Bi 2 O 3, Al 2 O 3, ZnO, PbO, BaO, CaO, MgO, SrO, Li 2 O, Na 2 O, K 2 O, V 2 O Glass containing one kind or plural kinds selected from ₅ grades can be used. A metal or the like may be used as an auxiliary material. As the auxiliary material in the case of a metal, one or more selected from Mn, Zn, Mg, Al, Cu, Ni, Co, Fe, Cr, Mo, W, and the like can be used. The auxiliary material may be an alloy such as MCrAlY (M: Co, Co—Ni, Ni—Co, Ni, Fe).

  The liquid thermosetting resin used in the production example is an acrylic resin (manufactured by JSR Corporation, product number “KC1280”). Similar to the production of the single material type thermal spray material, various liquid resins may be adopted as long as they are mainly composed of organic substances, and other curable resins may be used.

  When the base fine particles, the auxiliary fine particles, and the thermosetting resin are prepared, they are mixed in the same manner as in the production of the single material type thermal spray material (FIG. 2: Step S11). In the production example, first, auxiliary fine particles and a liquid resin are mixed to obtain a paste-like mixture in which auxiliary fine particles are uniformly dispersed. Then, the base fine particles are added to the mixture in a plurality of times. The final volume ratio of the base fine particles in the mixture is 63.0 vol%, and the final volume ratio of the auxiliary fine particles is 7.0 vol%. That is, the volume ratio of the base fine particles to the auxiliary fine particles is 90:10. Further, the volume ratio of the entire fine particles including the base fine particles and the auxiliary fine particles is 70 vol%. As a result, the mixture is in a state in which the fine particles are packed to some extent in the liquid resin, in other words, the fine particles are uniformly dispersed.

  Similarly to the production of the single material type thermal spray material, the volume ratio of the fine particles including the base fine particles and the auxiliary fine particles in the mixture is preferably 52 vol% or more, and more preferably 60 vol% or more. Further, from the viewpoint of filling the gaps between the base fine particles with the auxiliary fine particles, the volume ratio of the base fine particles in the mixture is larger than the volume ratio of the auxiliary fine particles, that is, the volume ratio of the auxiliary fine particles is smaller than the volume ratio of the base fine particles. It is preferable.

  Subsequently, the mixture is heated to cure the mixture while maintaining the dispersed state of the fine particles, thereby obtaining a cured product (step S12). In the production example, the mixture is heated at a temperature lower than the softening temperature of the auxiliary material (472 ° C.). Thereafter, the cured product is pulverized using a vibration mill (step S13). The cured product after pulverization is fractionated using a sieve. Thereby, the thermal spray material which is a particle | grain (namely, particle | grains for thermal spraying) larger than a base microparticle and an auxiliary | assistant microparticle is obtained. Since the thermal spray material includes base fine particles formed of the base material and auxiliary fine particles formed of the auxiliary material as fine particles, the thermal spray material is hereinafter referred to as a “composite material type thermal spray material”. In the production example, the pulverized cured product is fractionated in a particle size range of 45 μm to 106 μm. The particle size range of the particles for thermal spraying may be variously changed as long as it can be used in the thermal spraying apparatus 1.

  8A and 8B are diagrams showing a thermal spray material of a manufacturing example. 8A and 8B, fine particles including base fine particles having an average particle diameter of 26.4 μm and auxiliary fine particles having an average particle diameter of 0.6 μm are bonded to each other by a resin existing between the fine particles and sprayed. Particles are formed. The particles for thermal spraying can also be regarded as resin particles having a larger particle size than the respective fine particles (base fine particles or auxiliary fine particles). In this case, the fine particles are dispersed inside the resin particles. It can be said that. The volume ratio (average volume ratio) of the fine particles in the particles for thermal spraying is substantially the same as the volume ratio in the mixture.

  When thermal spraying is performed on the base material 9 by the thermal spraying apparatus 1 using the thermal spray material of the above production example, the base fine particles are melt-bonded to form a coating mainly composed of the base material. At this time, a dense portion is formed in the coating film by the base fine particles having a large average particle diameter and high kinetic energy when colliding with the base material 9. Further, the auxiliary fine particles whose softening temperature is sufficiently lower than the melting point of the base fine particles are easily melted by the plasma flare 8 and the gap between the base materials (dense portions) is filled with the molten auxiliary material. Thereby, a dense film is obtained. The base material 9 (sprayed product) on which the coating is formed is a member used for, for example, a furnace wall of an incinerator, and the coating in this case is, for example, an anticorrosion coating.

Next, another production example of the composite material type thermal spray material will be described. In this other production example, the average particle size is 0.9 μm, and glass frit (manufactured by Okamoto Glass Co., Ltd.) containing SiO ₂ .Al ₂ O ₃ .RO (R: Mg, Ca, Sr, Ba) as a main component is used. , Product number “CAS9”) is used as auxiliary fine particles. The base fine particles and the liquid resin are the same as in the above production example.

  In step S11 of FIG. 2, the auxiliary fine particles and the liquid resin are mixed as in the above production example, and then the base fine particles are added to the mixture in a plurality of times. The final volume ratio of the base fine particles in the mixture is 63.0 vol%, and the final volume ratio of the auxiliary fine particles is 7.0 vol%. That is, the volume ratio of the base fine particles to the auxiliary fine particles is 90:10. Further, the volume ratio of the entire fine particles including the base fine particles and the auxiliary fine particles is 70 vol%. As a result, the mixture is in a state in which the fine particles are packed to some extent in the liquid resin, in other words, the fine particles are uniformly dispersed. Curing of the mixture and pulverization of the cured product (Steps S12 and S13) are the same as in the above production example. In addition, the softening temperature of this auxiliary material is 855 degreeC, and is sufficiently higher than the heating temperature of the mixture at the time of hardening.

  9A and 9B are diagrams showing a thermal spray material of another manufacturing example. 9A and 9B, fine particles including base fine particles having an average particle diameter of 26.4 μm and auxiliary fine particles having an average particle diameter of 0.9 μm are bonded to each other by a resin existing between the fine particles and sprayed. Particles are formed. Even when the thermal spraying is performed on the base material 9 using the present thermal spray material, a film mainly composed of the base material is formed, and the gap between the base materials is filled with the molten auxiliary material. Thereby, a dense film is obtained.

  Next, still another production example of the composite material type thermal spray material will be described. Here, stabilized zirconia fine particles having an average particle size of 3.6 μm (manufactured by Daiichi Elemental Chemical Co., Ltd., product number “UZY-8H”) are used as the base fine particles. The auxiliary fine particles and the liquid resin are the same as those in the manufacturing examples of FIGS. 9A and 9B.

  In step S11 of FIG. 2, the auxiliary fine particles and the liquid resin are mixed as in the above production example, and then the base fine particles are added to the mixture in a plurality of times. The final volume ratio of the base fine particles in the mixture is 54.0 vol%, and the final volume ratio of the auxiliary fine particles is 6.0 vol%. That is, the volume ratio of the base fine particles to the auxiliary fine particles is 90:10. Further, the volume ratio of the whole fine particles including the base fine particles and the auxiliary fine particles is 60 vol%. As a result, the mixture is in a state in which the fine particles are packed to some extent in the liquid resin. Curing of the mixture and pulverization of the cured product (Steps S12 and S13) are the same as in the above production example.

  10A and 10B are diagrams showing a thermal spray material of this production example. 10A and 10B, fine particles including base fine particles having an average particle diameter of 3.6 μm and auxiliary fine particles having an average particle diameter of 0.9 μm are bonded to each other by a resin existing between the fine particles and sprayed. Particles are formed. Even when the thermal spraying is performed on the base material 9 using the present thermal spray material, a film mainly composed of the base material is formed, and the gap between the base materials is filled with the molten auxiliary material. Thereby, a dense film is obtained. In addition, the film formed on the base material 9 using the thermal spray material of FIG. 10A and FIG. 10B is mentioned later.

  By the way, the raw material powder handled by normal thermal spraying is coarse with a particle size of about 10 to 100 μm, and defects such as pores and cracks inevitably occur in the formed coating. Accordingly, there are problems such as a decrease in the mechanical properties of the coating and a decrease in the corrosion resistance of the substrate due to incomplete blocking of the external environment by the coating. A measure usually taken is to perform further treatment after the coating is formed by thermal spraying. Examples thereof include densification by permeation and sintering of a metal melt such as Mn into the coating and sealing treatment. Regarding the sealing treatment, when a sprayed coating is used at high temperatures, it cannot be used with an organic sealing agent. Therefore, after applying and infiltrating a liquid sealing agent containing a glass component, the solvent is evaporated. Generally, a technique for solidifying glass-based components is used. However, these densification techniques require additional processing steps after thermal spraying, and special heating equipment is also required when performing the sintering process.

  On the other hand, in the manufacture of a composite material type thermal spray material, the fine particles used include base fine particles formed of a base material and auxiliary fine particles formed of an auxiliary material for densifying the spray coating. That is, a thermal spray material in which metal particles and glassy particles are dispersed in addition to the particles serving as the base of the thermal spray coating is manufactured. And by spraying the said thermal spray material, the precise | minute film | membrane with which the metal component and the glass component were filled in the defective part of a thermal spray coating is formed, and densification of a coating film can be achieved only by a thermal spraying construction process.

  The volume ratio between the base fine particles and the auxiliary fine particles in the thermal spray material is preferably determined with reference to the porosity of the coating formed in the case of a single material. When ordinary raw materials are used, the thermal spray coating has a porosity of several% to several tens%. The YSZ film that is the top coat of the thermal barrier coating may have a porosity of up to about 40%. Therefore, when a dense coating is formed using a composite material type thermal spray material, a coating base component (base fine particles such as YSZ particles) and a component filling glass defects (glass particles or metal particles) are used. The volume ratio of a certain auxiliary fine particle is, for example, (60 ± 10) :( 40 ± 10), (80 ± 10) :( 20 ± 10), (95 ± 5) :( 5 ± 5), and the like.

  Further, the sizes of the base fine particles and the auxiliary fine particles can be arbitrarily selected. The combination of the average particle diameter of the base fine particles and the average particle diameter of the auxiliary fine particles is, for example, 10 to 100 μm and 1 to 10 μm, 10 to 100 μm and 25 to 1000 nm, and 1 to 10 μm and 25 to 1000 nm. In some cases, the coating tends to form a structure in which the auxiliary material fills the gaps in the base material. Therefore, when forming a dense film, it is preferable that the average particle diameter of the base fine particles is larger than the average particle diameter of the auxiliary fine particles. In this case, similarly to the single material type thermal spray material, the volume ratio of the fine particles in the mixture can be easily increased, and the film formation rate during thermal spraying can be improved.

  In the composite material type thermal spray material, the auxiliary material is glass, so that a dense coating can be more reliably formed. However, as described above, the auxiliary material may be a metal. In this case, since the melting point of the auxiliary material is lower than the melting point of the base material, the gap between the base materials is easily filled with the molten auxiliary material during spraying. As a result, a dense coating can be more reliably formed.

  The single material type thermal spray material and the composite material type thermal spray material may be used for thermal spraying other than plasma thermal spraying. FIG. 11 is a view showing another example of the thermal spraying apparatus. The thermal spraying apparatus 1a of FIG. 11 is an apparatus that performs gas flame spraying on the substrate 9. The thermal spraying device 1 a includes a thermal spray gun 16, a fuel gas supply unit 17, a compressed air supply unit 18, and a material conveyance unit 15. The thermal spray gun 16 includes a material conveyance path 25, a fuel gas flow path 26, and a compressed air flow path 27. The material conveyance path 25 extends along a predetermined central axis J1. The fuel gas channel 26 is a cylindrical channel extending along the central axis J1 and surrounds the periphery of the material conveyance path 25. The compressed air channel 27 is a cylindrical channel extending along the central axis J <b> 1 and surrounds the periphery of the fuel gas channel 26.

  The fuel gas supply unit 17 supplies the fuel gas to the fuel gas channel 26. The fuel gas is, for example, a mixed gas of oxygen and acetylene. The fuel gas may be other gas such as propane. The combustion flame 8 a is generated by the fuel gas ejected from the tip of the fuel gas flow path 26. The material transport unit 15 has the same structure as that of the thermal spraying apparatus 1 of FIG. 1 and supplies the thermal spray material into the combustion frame 8a using the transport gas from the transport gas supply unit 14 (see FIG. 1). In the thermal spraying device 1a, the thermal spray material is introduced in the same direction as the injection direction of the combustion frame 8a toward the center of the combustion frame 8a. The resin of the thermal spray material is burned out by the combustion frame 8a, and the fine particles are in a molten state or a semi-molten state. The compressed air supply unit 18 supplies compressed air to the compressed air channel 27. The fine particles in a molten state or a semi-molten state flow toward the base material 9 by the compressed air ejected from the tip of the compressed air flow path 27. As a result, fine particles are deposited on the substrate 9, and a film is formed. As described above, also in the thermal spraying apparatus 1a of FIG. 11, it is possible to form an appropriate coating on the base material 9 by using a single material type thermal spray material and a composite material type thermal spray material. .

  12A and 12B are views showing an enlarged cross section of a coating formed on the substrate 9 by the thermal spraying apparatus 1a using the thermal spray material of FIGS. 10A and 10B. 12A and 12B show that a dense film is obtained. FIG. 13 is a diagram showing a component analysis result in the cross section of the coating. The upper right image in FIG. 13 shows the distribution of Zr contained in the base material, the lower left image in FIG. 13 shows the distribution of Al contained in the auxiliary material, and the lower right image in FIG. The distribution of Si contained in the auxiliary material is shown. In these images, it can be seen that the region where Zr is small (black region) is the region where Al and Si are large (white region), and the gap between the base materials is filled with the auxiliary material.

  Various modifications can be made in the above-described thermal spray material manufacturing and thermal spraying apparatuses 1 and 1a.

  In the thermal spray material described as the single material type thermal spray material, the first and second fine particles may be formed of a plurality of types of materials. The material of the first fine particles may be different from the material of the second fine particles. In the composite material type thermal spray material, the average particle size of the base particles may be equal to or less than the average particle size of the auxiliary particles.

  In the thermal spraying apparatuses 1 and 1a, even if two or more kinds of coatings are laminated by providing a plurality of material storage portions 13 for storing different thermal spraying materials and sequentially changing the thermal spraying materials supplied to the thermal spraying guns 11 and 16, respectively. Good. Of course, two or more kinds of coatings may be repeatedly laminated.

  The thermal spraying in the above embodiment can be used for manufacturing various thermal sprayed products in which a coating is formed on a substrate. Furthermore, it is also possible to use only the coating portion as a product. When forming a dense structure, thermal spraying can be used for the production of catalyst carriers, various battery electrodes, filters, thermal barrier coatings, thermal insulation covers, and the like. When forming a dense structure, thermal spraying can be used, for example, for the production of anticorrosion coatings, machined parts (such as cutters), and heat resistant parts (such as crucibles and boiler tubes).

  The thermal spraying device may be a device that performs laser spraying. The thermal spray material manufactured by the above-described manufacturing method can be used for plasma spraying, flame spraying, or laser spraying. In any of the thermal spraying methods, the thermal spray coating can be formed with little or no change to existing apparatuses.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

1,1a Thermal spraying device 9 Base material S11-S13, S21-S23 Step

Claims (12)

A method for producing a thermal spray material used for plasma spraying, flame spraying or laser spraying,
a) dispersing fine particles in a liquid resin;
b) curing the mixture obtained in step a);
c) crushing the cured product obtained in the step b) into particles having a particle size larger than the fine particles to obtain a thermal spray material;
With
The fine particles are
Base fine particles formed of a base material that is ceramic or metal;
Auxiliary fine particles formed of an auxiliary material for densifying the thermal spray coating different from the base material, and having a volume ratio in the mixture smaller than that of the base fine particles,
The manufacturing method of the thermal spray material characterized by including. It is a manufacturing method of the thermal spray material of Claim 1,
The method for producing a thermal spray material, wherein the auxiliary material is glass. It is a manufacturing method of the thermal spray material of Claim 1,
The method for producing a thermal spray material, wherein the auxiliary material is a metal, and the melting point of the auxiliary material is lower than the melting point of the base material. A method for producing a thermal spray material according to any one of claims 1 to 3,
The method for producing a thermal spray material, wherein an average particle size of the base fine particles is larger than an average particle size of the auxiliary fine particles. A thermal spray material used for plasma spraying, flame spraying or laser spraying,
A particle formed by fine particles and a resin existing between the fine particles,
The fine particles are
Base fine particles formed of a base material that is ceramic or metal;
Auxiliary fine particles formed of an auxiliary material for densifying the thermal spray coating different from the base material, and having a volume ratio smaller than the base fine particles,
A thermal spray material characterized by containing. A method for producing a thermal spray material used for plasma spraying, flame spraying or laser spraying,
a) dispersing ceramic or metal particles in a liquid resin;
b) curing the mixture obtained in step a);
c) crushing the cured product obtained in the step b) into particles having a particle size larger than the fine particles to obtain a thermal spray material;
With
The fine particles are
First particulates;
Second fine particles having an average particle size smaller than that of the first fine particles;
The manufacturing method of the thermal spray material characterized by including. It is a manufacturing method of the thermal spray material according to claim 6,
The method for producing a thermal spray material, wherein an average particle size of the first fine particles is 10 times or more an average particle size of the second fine particles. A method for producing a thermal spray material according to claim 6 or 7,
The average particle diameter of said 1st microparticles | fine-particles is larger than 1 micrometer, The manufacturing method of the thermal spray material characterized by the above-mentioned. A method for producing a thermal spray material according to any one of claims 6 to 8,
The method for producing a thermal spray material, wherein a volume ratio of the fine particles in the mixture is 52% or more. A thermal spray material used for plasma spraying, flame spraying or laser spraying,
It is a particle formed of ceramic or metal fine particles and a resin existing between the fine particles,
The fine particles are
First particulates;
Second fine particles having an average particle size smaller than that of the first fine particles;
A thermal spray material characterized by containing. A thermal spraying method,
d) preparing a thermal spray material manufactured by the manufacturing method according to any one of claims 1 to 4 and claims 6 to 9;
e) forming a film by bonding the heated fine particles on a substrate by performing plasma spraying, flame spraying or laser spraying using the thermal spray material;
A thermal spraying method comprising:   A thermal spray product, wherein a coating is formed on a substrate by the thermal spraying method according to claim 11.