JP5508814B2 - Cold spray equipment - Google Patents

Description

  The present invention relates to a cold spray apparatus.

  In the field of film formation technology, as a substitute for conventional electroplating, electroless plating, sputtering deposition method, plasma spraying method, etc., cold spray spraying method (hereinafter referred to as “cold spray spraying method”) that forms a film using raw material powder in the solid state , Referred to as “CS spraying method”). The CS spraying method is a method in which a raw material powder conveyed by a carrier gas is jetted from the tip of a powder port into a carrier gas that is a supersonic flow at the outlet of a cold spray gun (hereinafter referred to as “CS gun”). This is a method for forming a film by charging and making the raw material powder collide with the base material in the solid state. At this time, the temperature of the carrier gas in the CS gun is set to a temperature lower than the melting point or softening point of the raw material powder such as metal, alloy, intermetallic compound, ceramics, etc. forming the film. The metal film formed using this CS spraying method has less oxidation and thermal deterioration than the same type of metal film formed using the conventional method, and it is dense, dense and has good adhesion and at the same time is conductive. It is known that heat conductivity is high.

  The concept of the CS spraying method will be described with reference to FIG. 4 which is a schematic diagram of a general cold spray apparatus (hereinafter referred to as “CS apparatus”). A gas supply line from the compressed gas cylinder 2 in which high-pressure gas such as nitrogen gas, helium gas, and air is stored is branched into a carrier gas line 3 and a carrier gas line 4. One carrier gas is heated to a temperature below the melting point or softening point of the raw material powder by passing through a heater 10 that generates heat by energizing a part of a metal pipe that is a flow path for the carrier gas. Into the chamber 12. The other carrier gas is introduced into the raw material powder supply device 15 and is accompanied by the raw material powder, and supplies the raw material powder into the carrier gas from the tip of the powder port 1h in the chamber 12. The carrier gas entrains the supplied raw material powder, passes through the throat portion 1a from the conical compression portion, becomes supersonic flow, and is ejected from the nozzle outlet located at the tip of the conical expansion portion. While colliding with the surface of the base material 18 in the solid state, the film is deposited.

  The subject of this CS spraying method is that it cannot make the film which forms all the raw material powder ejected from the nozzle tip on the substrate surface. That is, the efficiency with which the sprayed raw material powder forms a film ([the amount of raw material powder that became a film] / [the amount of sprayed raw material powder]) × 100% (hereinafter referred to as “spraying efficiency”) is 100%. It can not be. When the thermal spraying efficiency is low, the raw material powder that has not contributed to the formation of the coating is scattered around the base material, which wastes resources and energy. In addition, the operation time of the CS apparatus necessary for forming the desired film is also increased. Therefore, when the thermal spraying efficiency is increased, the operation time of the CS device is shortened, and the raw material powder that is scattered without being able to form a film is also reduced. That is, improvement of the productivity of the CS device and effective utilization of resources and energy can be achieved, and the film formation cost can be greatly reduced.

  By the way, the thermal spraying efficiency of the CS thermal spraying method is greatly affected by the temperature of the raw material powder and the critical velocity on the surface of the substrate. However, when the critical speed of the raw material powder is increased, damage to the base material is increased, so that the temperature of the raw material powder, that is, the temperature of the carrier gas is preferably increased. However, even if the temperature of the raw material powder is made close to the melting point or the softening point by increasing the carrier gas, in the invention disclosed in Patent Document 1, the upper limit temperature at which the carrier gas can be heated using the electric resistance heating element as the heater is 400. It is about ℃. Thus, in the CS spraying method, how to raise the temperature of the carrier gas, that is, the temperature of the raw material powder, is a problem for improving the spraying efficiency.

  In the invention disclosed in Patent Document 2, as shown in FIG. 5, the carrier gas heated by the preheater 105 is supplied to the CS gun 101 through the flexible tube 104, and the carrier gas is supplied by the post heater 103 attached to the CS gun 101. This is a technology for further heating. According to the description of the claims, the technology is such that the carrier gas temperature is set to 100 ° C. to 600 ° C., more preferably 200 ° C. to 500 ° C. in the preheater 105, and the carrier gas temperature is set to 100 ° C. The temperature is set to 1200 ° C, more preferably 200 ° C to 1000 ° C, and further preferably 500 ° C to 800 ° C. Further, according to the embodiment, the heating capacity of the heater used at this time is about 10 KW for the pre-heater 105 and about 20 KW for the post-heater 103. Further, when a fluororesin is adopted as the material of the flexible tube 104, the carrier gas temperature at the outlet of the preheater 105 is set to about 230 ° C.

  Patent Document 3 discloses a configuration of a CS gun including the pre-heater 105 and the post-heater 103 shown in FIG. Specifically, a plurality of electric resistance heating wires 106 are arranged in a post heater 103 having a length of 50 mm to 250 mm, and the temperature of the carrier gas passing through the post heater 103 can be heated to 400 ° C. or higher and up to 700 ° C. It is said. According to the technical data disclosed by CGT GmbH, the guaranteed value of the maximum gas temperature of the CS device including the pre-heater and the post-heater is 800 ° C.

US Pat. No. 5,302,414 Patent International Publication WO2006 / 034777 US Patent Publication No. 2007-221746

  In the invention disclosed in Patent Document 2 described above, the carrier gas is heated using a preheater and a postheater connected by a flexible flexible tube such as a fluororesin so as not to impair the operability of the CS gun. As a result, since the carrier gas temperature at the preheater outlet is about 230 ° C., the upper limit of the outlet temperature of the post heater is 500 ° C. to 800 ° C. When the carrier gas temperature at the outlet of the post heater is set to 800 ° C. to 1000 ° C., the carrier gas temperature at the outlet of the pre heater is set to 600 ° C., and the capacity of the post heater is increased to 25 KW. That is, if the operation of the cold spray at a carrier gas temperature exceeding 800 ° C. is assumed, the post heater becomes large. Moreover, it is necessary to use a metal flexible tube for connecting the preheater and the postheater. Therefore, if the technology disclosed in Patent Document 2 is applied to a CS device that can set the carrier gas temperature to a high temperature exceeding 800 ° C., there are many restrictions on the design specifications, and the size of the CS gun equipped with the post heater is increased and handled. Becomes difficult.

  When a carrier gas is caused to flow through a post heater having a structure in which a plurality of electric resistance heating wires disclosed in Patent Document 3 are arranged in parallel and energized, the temperature of the carrier gas inside the post heater is changed from the inlet side to the outlet side. Ascend towards. Accordingly, the temperature of the electric resistance heating wire is higher on the outlet side than on the inlet side. In addition, since the flow rate of the carrier gas is reduced in the post heater, the flow rate of the carrier gas varies in a cross section perpendicular to the flow of the carrier gas. As a result, due to the influence of the flow velocity distribution, there is a temperature distribution in the electric resistance heating wire provided in the post heater. In general, the electric resistance of the electric resistance heating wire has a specific value with respect to its own temperature. Therefore, even if a constant current is passed through the electric resistance heating wires arranged in parallel, if the carrier gas flow velocity distribution in the post heater fluctuates, the amount of heat generation will vary greatly. That is, the technique disclosed in Patent Document 3 is difficult to find a correlation between the energization amount and the carrier gas temperature, and is difficult to control and heat the carrier gas at the outlet of the post heater to a stable temperature. is there.

  Therefore, there has been a need for a CS device that can stably heat the raw material powder to a temperature at which the spraying efficiency is improved without impairing the operability of the CS gun, and eliminates the above-described variation generating elements.

  As a result of intensive research, the present inventors have conceived the following invention as a means for solving the above problems.

CS device according to the present invention: The CS device according to the present invention is a method in which a raw material powder conveyed by a carrier gas is injected from a powder port tip into a carrier gas that is made a supersonic flow at the outlet of a CS gun. A CS device that forms a film by colliding powder with a base material in a solid state, and the carrier gas heater provided in the CS device generates heat resistance by heating the carrier gas that flows into the inside by generating electric resistance when energized. It is a gas tube with a heating function (hereinafter, simply referred to as “heating gas tube”) composed of a body, and the heating gas tube has an energization distance of 1 m to 5 m and a wall thickness of 0. A heating resistor having an inner diameter of 5 mm to 3.0 mm and an inner diameter of 4 mm to 16 mm is used as one unit of a gas tube unit with a heating function (hereinafter simply referred to as “tube unit”). A plurality of tube units are arranged in series, and the amount of current supplied to each gas tube unit is individually controlled. Of these gas tube units with a heating function, heating is arranged on the side connected to the cold spray gun. The heat generating capacity of the gas tube unit with function is set to be higher than the heat generating capacity of other gas tube units, and the upper limit set temperature is 1000 ° C. or higher .

  In the CS device according to the present invention, the heating gas tube has a length of the heating resistor provided in one unit of the tube unit arranged on the side connected to the CS gun, and the heating resistor provided in the other unit of tube unit. It is preferable that the length is longer than the length.

  In the CS device according to the present invention, the heating gas tube has an inner diameter of the heating resistor provided in one unit of the tube unit disposed on the side connected to the CS gun, and the heating resistor provided in the other one unit of the tube unit. It is preferably smaller than the inner diameter.

  In the CS apparatus according to the present invention, one unit of the tube unit has a length of the heating resistor of a linear distance of 10 connecting the energizing terminal provided on the carrier gas inlet side and the energizing terminal provided on the carrier gas outlet side. The coil shape is preferably 3 to 30 times and 3 to 10 turns.

  In the CS device according to the present invention, it is preferable that one unit of the tube unit has a carrier gas inlet and outlet disposed on a central axis of a coil shape.

  In the CS device according to the present invention, it is preferable that one unit of the tube unit includes a joint in which an energizing terminal is connected to one end on the carrier gas inlet side and the other end on the outlet side.

  In the CS device according to the present invention, it is preferable that the energization amount to the plurality of one-unit tube units is individually controlled.

  In the CS device according to the present invention, it is preferable to use a CS gun having a length from the powder port to the throat portion of 200 mm to 1000 mm.

  In the CS device according to the present invention, it is preferable that the carrier gas heater is fixed and integrated with the CS gun so that the central axis of the coil shape is parallel to the central axis of the CS gun.

  The cold spray apparatus according to the present invention includes a carrier gas heater in which a plurality of gas tube units with a heating function are arranged in series, and can stably heat the carrier gas to a high temperature exceeding 900 ° C. Therefore, the spraying efficiency when using the raw material powder, which has been difficult to obtain high spraying efficiency by the conventional cold spray spraying method, is improved, and a sprayed coating having a smoother surface state can be obtained. That is, it is a cold spray device that can contribute to resource saving and energy saving as well as stabilization of the film quality.

FIG. 1 is a schematic diagram showing the configuration of a carrier gas heater. FIG. 2 is a schematic view showing a state in which the carrier gas heater shown in FIG. 1 is fixed to the CS gun and integrated. FIG. 3 is a graph showing a comparison result between the U3 set temperature and the saturation temperature in the example. FIG. 4 is a schematic diagram showing an overall configuration of a general CS device. FIG. 5 is a diagram showing a heater configuration of the CS device disclosed in Patent Document 2. As shown in FIG. FIG. 6 is a schematic diagram illustrating a configuration of a CS apparatus including a preheater and a postheater.

Form of CS Device According to Present Invention: The CS device according to the present invention forms a carrier gas heater with a heating resistor tube that generates electrical resistance when energized. If the carrier gas heater uses a heating resistor, the carrier gas flow rate in the heated gas tube is fast, and even if there is a temperature distribution in the length direction, the variation in the temperature distribution in the sectional direction of the heated gas tube is There is little heat transfer between the heated gas tube and the carrier gas. Therefore, the carrier gas heater using the heating gas tube of the heating resistor can heat the carrier gas to a stable temperature.

  As the heat generating resistor for the CS device, any material selected from metals, ceramics, and the like can be used as long as it is a material that generates heat when energized. However, it is preferable to use an alloy material in consideration of the degree of freedom of shape processing and mechanical strength. An alloy material is usually superior in corrosion resistance and heat resistance to a pure metal constituting the alloy, and usually has a large electric resistance. And many alloy-based metal tubes are manufactured by drawing for uses such as piping for high-pressure gas, and are easily procured in the market, and the quality is stable. In addition, when a plurality of heating resistors are connected and used, a joint can be formed by welding. Above all, there are many types of stainless steels, which are iron-based alloys, and their processing techniques have been established, which is advantageous in terms of cost. However, considering that the carrier gas is heated to 900 ° C. or higher, stainless steel is uneasy about heat resistance and corrosion resistance.

Therefore, the heating resistor is formed using a heat-resistant and corrosion-resistant material selected from an iron-based alloy system, a cobalt-based alloy system, and the like having heat resistance characteristics equivalent to or higher than those of Inconel 600, which is a nickel-based alloy system. Specifically, an optimum material may be selected in consideration of the type and pressure amount of the carrier gas to be used, the maximum temperature for heating the carrier gas, the manufacturing cost, and the like. For alloys other than Inconel, for example, Hastelloy can be used for nickel-based alloys, Incoloy can be used for iron-based alloys, and S810 can be used for cobalt-based alloys. For example, if the upper limit temperature for heating is set to 950 ° C., the heat resistance characteristic that is equal to or higher than that of Inconel 600 is defined as a tensile strength in the temperature atmosphere of 5.0 kgf / mm ² or more. You can also

  By the way, in the heating method of the carrier gas using the heating gas tube of the heating resistor, it is considered that the temperature of the carrier gas is uniquely determined from the electric resistance, that is, the length of the heating resistor if the energization amount is constant. It is normal. However, if the heating resistor is short, the contact time between the carrier gas and the heating resistor is shortened, so that sufficient heating may not be possible. On the other hand, even if the amount of energization is increased in order to lengthen the heating resistor and heat it to a higher temperature, a phenomenon that there is a so-called saturation temperature at which the temperature of the carrier gas hardly increases can be seen. This is because the electrical resistance of the metal has temperature dependence, so the longer the heating resistor, the greater the temperature variation in the length direction, and the greater the variation in electrical resistance, and the greater the variation in heat generation. It is thought that this is a phenomenon.

  Therefore, in order to ascertain the length of the heating resistor that enables stable heating, an experiment was conducted in which tube units with different intervals between energizing terminals were connected to a CS gun with a slot diameter of 2 mm and the carrier gas temperature was heated to 800 ° C. or higher. . At this time, nitrogen was selected as the carrier gas and the pressure was set to 3 MPa, and a tube made of Inconel 600 having an inner diameter of 6 mm and an outer diameter of 8 mm was used as the heating resistor. As a result, when the interval between the energization terminals is 1 m or less, the carrier gas temperature rises as the energization amount increases, but the carrier gas temperature reaches 800 ° C. even when the tube unit temperature is set to the upper limit of 1150 ° C. There wasn't. This is considered to be because the contact time between the carrier gas and the tube unit is short. On the other hand, when the interval between the energizing terminals is 5 m, the temperature of the carrier gas exceeds 800 ° C., but the tendency of the temperature of the carrier gas to increase in proportion to the increase in the energization amount is not clearly seen. The fluctuations have also increased. From the results of the above experiments, in order to heat the carrier gas to a predetermined temperature, the length of the heating resistor provided in one unit of the tube unit is preferably in the range of 1 m to 5 m, and the fluctuation of the carrier gas temperature is To further reduce the length, it was determined that the length of the heating resistor is preferably 2 m to 3 m.

  The carrier gas passing through the heating resistor is usually supplied at a high pressure of 3 MP or more. Therefore, the heat generating resistor can be stably transported with a larger thickness without worrying about pinholes and the like. However, if the thickness exceeds 3.0 mm, the electrical resistance decreases, and the amount of current necessary to obtain the desired amount of heat generation increases, and the wiring for supplying power to the heating resistor is routed. Etc. become difficult. In addition, the mass of the heating resistor is increased and handling becomes difficult, and at the same time, a large cost is required for the power source for energization and the heating resistor itself, which is not preferable. On the other hand, when the wall thickness is less than 0.5 mm, the mechanical strength is reduced, and appearance damage such as folds and dents is likely to occur during handling. In particular, when a fold occurs, pinholes are generated at the fold portion, and corrosion is likely to occur at a portion where the deformation is large, leading to leakage of the carrier gas. From the viewpoint described above, the thickness of the heating resistor used in the present invention is preferably 0.5 mm to 3.0 mm, and more preferably 1.0 mm to 2.0 mm.

  By the way, as described above, the flow velocity of the carrier gas ejected from the throat portion of the CS gun having an inner diameter of about 2 mm is almost sonic. Therefore, when the inner diameter of the heating resistor is less than 4 mm, the flow velocity of the carrier gas flowing inside the heating resistor becomes a high speed of 1/4 or more of the sound speed. Since the pressure loss is large at such a high flow rate, when the pressure in the cylinder storing the carrier gas is lowered, the flow rate of the carrier gas flowing inside the heating resistor is changed. The fluctuation of the carrier gas flow rate is not preferable because it directly affects the quality variation of the sprayed coating to be formed. In addition, vibrations may occur in the heated gas tube as the flow rate fluctuates, and in a tube unit or the like having a coil shape, the risk of short circuiting due to contact between adjacent heating resistors increases, which is preferable. Absent. On the other hand, when the inner diameter of the heating resistor exceeds 16 mm, the flow rate of the carrier gas flowing inside the heating resistor becomes about 1/16 or less compared to the case where the inner diameter is 4 mm, so there is no problem due to pressure loss. However, the contact area between the heating resistor and the carrier gas is reduced. Further, when the flow velocity is reduced, the laminar boundary layer formed in the carrier gas flowing inside the heating resistor is thickened, and the heat transfer rate from the heating resistor to the carrier gas is reduced. As a result, there is a tendency for the heat transfer efficiency to decrease, which is not preferable. From the viewpoint described above, in the present invention, the inner diameter of the heating resistor is preferably 4 mm to 16 mm, and more preferably 5 mm to 10 mm.

  And the heating gas tube used by this invention shall have arranged the multiple tube unit in series. If a heated gas tube configured by combining a plurality of tube units as described above is used, the carrier gas temperature can be easily controlled. As a specific arrangement configuration, in FIG. 1, the carrier gas heater 10 is arranged in series with the coil units U1 to U3 formed in a coil shape, and each of the tube units is provided with energization terminals T1 to T4. An example is shown in which the tube units U1, U2, and U3 are driven in parallel by the power sources 9-1, 9-2, and 9-3.

    Here, consider a case where n (however, n ≧ 2) tube units are arranged in series to heat the carrier gas. In such a case, it is usual to increase the calorific value for a while from the first tube unit arranged at the inlet of the carrier gas to the nth tube unit connected to the CS gun, and gradually increase the temperature of the carrier gas. is there. However, if the nth tube unit and the (n-1) tube unit have the same specification, the nth tube unit will reach a higher temperature when the (n-1) tube unit exhibits its heating capacity sufficiently. The carrier gas may not be heated.

  In such a case, if the heating gas tube has a configuration in which a plurality of types of tube units having different lengths, inner diameters, and thicknesses of the heating resistors are mixed, effective heating may be possible. At this time, assuming that the materials are the same, in order to clarify the effect of the difference in specifications, if the length is different, the inner diameter and the wall thickness are the same, and if the inner diameter is different, Usually, the wall thickness and length are the same.

  Therefore, in the heated gas tube used in the present invention, the length of the heating resistor included in the tube unit disposed on the side connected to the CS gun is longer than the length of the heating resistor included in the other tube unit. Increasing the length of the heating resistor increases the electrical resistance. That is, if the length of the heating resistor provided in the nth tube unit arranged on the side connected to the CS gun is longer than the heating resistor provided in the (n-1) th tube unit, the nth tube unit Becomes larger than that of the (n-1) th tube unit, and the temperature of the carrier gas can be raised more efficiently.

  Moreover, the heating gas tube used by this invention can also make the internal diameter of the heating resistor with which the tube unit arrange | positioned at the side connected with CS gun is smaller than the internal diameter of the heating resistor with which other tube units are equipped. As in the case where the heating resistor is lengthened, the electrical resistance increases as the inner diameter of the heating resistor is reduced. That is, if the inner diameter of the nth tube unit disposed on the side connected to the CS gun is smaller than the inner diameter of the (n-1) th tube unit, the heat generation capacity of the nth tube unit is (n-1). ) It becomes larger than the tube unit, and the temperature of the carrier gas can be raised more efficiently. As described above, in order to effectively heat the carrier gas, it is also preferable to set different lengths and inner diameters of the heating resistors included in each tube unit.

  By the way, when a heating operation is performed using a heater, in general, measures are taken such as keeping the heater in a narrow space and then keeping the heat, thereby reducing heat radiation and stabilizing the heating. Therefore, when a long heater or heat exchanger is used, it is usually folded into a hairpin shape, or the storage space is reduced as a coil shape to reduce the heat radiation area. However, in the case of a heating resistor, if there is a contact part in the middle of the hairpin shape or coil shape, the flow of electricity will change and the desired amount of heat generation will not be obtained, and the heating resistor may be damaged by discharge Therefore, there is a limit to narrowing the storage space.

  Therefore, in the tube unit of the present invention, the length of the heating resistor is 10 to 30 times the linear distance connecting the energizing terminal provided on the carrier gas inlet side and the energizing terminal provided on the carrier gas outlet side, The coil shape has 3 to 10 turns. If it is a coil shape, the deflection | deviation by own weight will also be small and it will be hard to contact adjacent heating resistors. In addition, the flow of the carrier gas is stabilized.

  However, if the length of the heating resistor is less than 10 times the length between the current-carrying terminals, the ratio of the surface area of the storage space to the heat generation area increases, and the heat dissipation area per unit heat generation amount increases. As a result, there is a tendency for fluctuations in the carrier gas temperature due to heat dissipation to increase, such being undesirable. On the other hand, if the length of the heating resistor exceeds 30 times the length between the current-carrying terminals, the number of turns of the coil must be increased to reduce the surface area of the storage space, and the pitch of the coil shape is narrow. Become. As a result, if the carrier gas is vibrated when passing through the interior, the risk of contact between adjacent heating resistors increases, which is not preferable.

  Further, when the number of turns of the coil is less than 3, the coil diameter is increased, and the surface area ratio of the storage space to the heat generation area is increased. On the other hand, when the number of turns of the coil exceeds 10, the coil diameter becomes small, but the pitch of the coil shape becomes narrow, and the risk of contact between adjacent heating resistors increases. Therefore, from the viewpoint described above, in order to reduce the amount of heat dissipation and heat the carrier gas with stable energization heat generation, the length between the energization terminals is set to about 150 mm, and the length between the energization terminals is 15 to 25 times longer. It is more preferable to use a heating resistor having a coil shape of 5 to 7 turns.

  Furthermore, if the inlet and outlet of the carrier gas provided in the tube unit are arranged on the central axis of the coil shape, the centers of gravity are aligned on a straight line even when three or more tube units are connected. As a result, there is no large variation in the amount of deflection in the length direction of the heated gas tube, and this is preferable because there is less opportunity for adjacent heating resistors to contact each other. Moreover, even if a heat insulating material is applied to the connecting portion, it does not protrude from the outer periphery of the heat insulating material applied to the coil-shaped portion, and a stable heat insulating effect is obtained.

  Here, let us consider heat transfer from the heated gas tube generating electric resistance to the carrier gas. If there is a region in the heated gas tube that does not generate heat, the carrier gas is not heated in this region and is cooled in some cases. Therefore, it is preferable to minimize the area that does not generate heat. Therefore, in the present invention, an energization terminal is connected to joints at both ends of the heating resistors provided in the plurality of tube units, and the entire length of the tube unit is used as the heating resistor. If it is this structure, since it can be used for the heating of carrier gas effectively through the substantially full length of a heating gas tube, energy efficiency is also favorable.

  In addition, with the above-described configuration, if the connection portions between the plurality of tube units are insulated, each tube unit can be energized in series, and therefore, a plurality of tube units can be heated with a single power source. it can. However, considering the influence of the temperature difference between the carrier gas and the heating resistor on the heating operation, the heat transfer efficiency is improved when the temperature difference is large, and the temperature of the carrier gas is stabilized when the temperature difference is small. Therefore, in a tube unit in which a plurality of units are connected in series, it is preferable to stabilize the heating of the carrier gas by supplying a different current as necessary so that the set temperature can be adjusted. Therefore, in the present invention, the energization amount to the tube unit is individually controlled. Specifically, since the energization amount to each tube unit varies depending on the type and flow rate of the carrier gas, the maximum temperature reached by the carrier gas, the variation in allowable temperature, and the like, the optimum condition is obtained in advance by experiments. Is preferred.

  Furthermore, arranging the plurality of tube units in series in the present invention aims to stably heat the carrier gas to 900 ° C. or higher. However, when two tube units are arranged, the carrier gas temperature varies even when the energization amount is increased and the temperature does not reach 900 ° C. Therefore, the carrier gas is stably heated to a high temperature exceeding 900 ° C. It will be difficult to do. Therefore, the heated gas tube according to the present application includes three or more tube units. By the way, there is no restriction | limiting in the upper limit of the number of tube units arrange | positioned in series. And the more tube units (U1-U3-Un) are arranged, the temperature of the carrier gas heated by the tube unit Un arranged on the side connected to the CS gun approaches the temperature of the tube unit itself. However, except for special cases, even if Un is added, if the temperature increase ratio, which will be described in detail later, falls below 0.3, there is a tendency to waste resources and energy. Therefore, from the viewpoint mentioned above, it is more preferable to arrange 3 to 6 tube units that can heat the carrier gas most efficiently. Furthermore, as described above, if the specification of the tube unit Un arranged on the side connected to the CS gun is made longer or thinner than that of the previous tube unit, more effective heating is possible.

  In the CS spraying method, if the flow rate of the carrier gas is constant, the quality of the sprayed coating and the spraying efficiency are greatly affected by the temperature of the raw material powder. That is, even if the carrier gas temperature is set to 900 ° C. or higher, the desired effect may not be obtained unless the raw material powder accompanying the carrier gas is heated sufficiently and uniformly. In order to reduce the temperature distribution between and within the particles of the raw material powder, it is necessary to contact the carrier gas and the raw material powder for a predetermined time or more. However, the raw material powder that needs to be heated at a high temperature for thermal spraying with CS usually has a smaller heat transfer coefficient than that of pure metal. Therefore, if the raw material powder having a small heat transfer coefficient is sufficiently heated with the carrier gas, the structure that enables the carrier gas and the raw material powder to be contacted for a longer time than when the metal powder is heated with the carrier gas. Required for CS Gun.

  However, if a CS gun with a length from the powder port to the throat of less than 200 mm is used for raw material powder with a small heat transfer coefficient, the raw material powder cannot be heated uniformly due to the influence of particle size distribution and shape. This is not preferable. On the other hand, if the purpose is to uniformly heat the raw material powder with the carrier gas, there is no need to set an upper limit for the length from the powder port to the throat. However, with regard to the raw material powder with experience in handling, even if the raw material powder has a small heat transfer coefficient when the length from the powder port to the throat portion is about 1000 mm, uniform heating is performed. In addition, if a CS gun having a length longer than necessary is used, the operability is deteriorated, and at the same time, the temperature may decrease while passing through the CS gun, resulting in a decrease in spraying efficiency and the like. . Therefore, from the viewpoint described above, in the CS gun according to the present invention, the length from the powder port to the throat portion is set to 200 mm to 1000 mm. In addition, in actual CS spraying, the length from the powder port to the throat is set so as to be optimal for the combination of raw material powder and carrier gas, taking into account the operability of the CS gun. .

  In order to supply the CS gun with a minimum temperature drop of the carrier gas heated by the carrier gas heater, it is preferable to arrange the carrier gas heater and the CS gun close to each other. Therefore, in the present invention, when the carrier gas heater 10 is fixed to the CS gun 11, the coil-shaped central axis 21 is integrated with the central axis 20 of the CS gun 11 as shown in FIG. If the center axis 21 of the coil shape and the center axis 20 of the CS gun are parallel, the center of gravity balance of the CS gun integrated with the carrier gas heater will be good. In addition, since high heat resistance is not required for connection between the gas cylinder for supplying the carrier gas and the carrier gas heater, it can be connected with a flexible pressure-resistant plastic tube, and the operability of the CS gun can be maintained in a good state. .

<Heating gas tube>
In the example, a heated gas tube in which three tube units U1, U2, and U3 are connected in series via a joint as shown in FIG. The heating resistor used in each tube unit is an Inconel 600 pipe having an inner diameter of 6 mm, an outer diameter of 8 mm, and a length of about 3 m, and approximately 150 mm in distance between the current-carrying terminals connected to the joint portion. The outer diameter is about 180 mm, the pitch is about 13 mm, and a coil with 5 turns is formed. In this configuration, the energizing terminal T2 shared by U1 and U2 is provided at the joint connecting U1 and U2, and the energizing terminal T3 shared by U2 and U3 is provided at the joint connecting U2 and U3. The independent power sources 9-1 to 9-3 that drive the respective tube units U1 to U3 have a maximum heating set temperature of 1150 ° C. in consideration of the heat resistance characteristics of the Inconel 600. The heated gas tube was surrounded by glass wool for heat insulation.

<Heating test>
In the heating test, nitrogen was used as the carrier gas, the outlet pressure of the gas cylinder was set to 3 MPa, and the gas was supplied from the U1 side of the carrier gas heater. And the energization amount from the connected electric power source was automatically controlled so that the temperature set to each tube unit of U1-U3 was maintained, and carrier gas was heated. In this test, the temperature of the tube unit itself was measured on the outer peripheral surface of the heating resistor in the vicinity of the joint end portion between the outlet heating resistor and the joint. And the temperature of carrier gas was measured in the flow path of the part substantially the same as the temperature measurement position of a heating resistor only at the exit of U3.

  And the heating capability of the carrier gas heater was evaluated by three indexes. The first index was the maximum temperature reached by the carrier gas at the outlet of U3 (hereinafter referred to as “saturation temperature”). The second index is the ratio of the saturation temperature to the set temperature of U3 ([saturation temperature] / [set temperature of U3]: hereinafter referred to as “temperature ratio”), and the third index is the setting of U3. Ratio of change width of carrier gas temperature at outlet of U3 with respect to change width of temperature (change in carrier gas temperature at outlet of U3) / [change width of set temperature of U3]: hereinafter referred to as “temperature increase ratio”) It was.

[Test 1]
In Test 1, with the carrier gas supplied to the heated gas tube, the energization was started with the set temperature of U1 / U2 / U3 being 1000 ° C / 800 ° C / 750 ° C, and the carrier gas saturation temperature and the saturation temperature were set. The time to reach was measured. As a result, the carrier gas temperature reached a saturation temperature of 627 ° C. in 320 seconds after the start of energization. Therefore, the temperature ratio of Test 1 is 0.836. And if the temperature at the time of an energization start shall be 25 degreeC, a temperature increase ratio will be 0.830. The setting conditions and results are shown in Table 1 and Table 2 below.

[Test 2]
In Test 2, the set temperature of U1 / U2 / U3 from Test 1 was changed to 1000 ° C / 1000 ° C / 900 ° C, and the saturation temperature reached by the carrier gas and the time to reach the saturation temperature were measured. . As a result, after changing the set temperature, the carrier gas temperature reached the saturation temperature of 735 ° C. in 110 seconds. Therefore, the temperature ratio of Test 2 is 0.817, and the temperature increase ratio is 0.720. The setting conditions and results are shown in Table 1 and Table 2 below.

[Test 3]
In Test 3, the set temperature of U1 / U2 / U3 was changed to 1000 ° C / 1000 ° C / 1000 ° C from Test 2, and the saturation temperature reached by the carrier gas and the time until the saturation temperature was reached were measured. . As a result, after changing the set temperature, the carrier gas temperature reached the saturation temperature of 801 ° C. in 90 seconds. Therefore, the temperature ratio of Test 3 is 0.801, and the temperature increase ratio is 0.660. The setting conditions and results are shown in Table 1 and Table 2 below.

[Test 4]
In Test 4, the set temperature of U1 / U2 / U3 from Test 3 was changed to 1050 ° C./1050° C./1050° C., and the saturation temperature reached by the carrier gas and the time to reach the saturation temperature were measured. . As a result, after changing the set temperature, the carrier gas temperature reached the saturation temperature of 830 ° C. in 60 seconds. Therefore, the temperature ratio of Test 4 is 0.790, and the temperature increase ratio is 0.580. The setting conditions and results are shown in Table 1 and Table 2 below.

[Test 5]
In Test 5, the set temperature of U1 / U2 / U3 from Test 4 was changed to 1100 ° C / 1100 ° C / 1100 ° C, and the saturation temperature reached by the carrier gas and the time to reach the saturation temperature were measured. . As a result, the carrier gas temperature reached a saturation temperature of 858 ° C. in 80 seconds after the set temperature was changed. Therefore, the temperature ratio of Test 5 is 0.780, and the temperature increase ratio is 0.560. The setting conditions and results are shown in Tables 1 and 2 below. Furthermore, the comparison results of the U3 set temperature shown in Table 2, the temperature ratio, and the temperature rise ratio are graphed and shown in FIG.

[Summary]
As is apparent from Tables 1 and 2, if the carrier gas heater manufactured in the example is used and the set temperature of each of the tube units of U1 to U3 is 1000 ° C., the temperature of the carrier gas exceeds 800 ° C. It was confirmed that the carrier gas could be stably heated to a temperature of 850 ° C. or higher when the temperature was set to ℃.

[Discussion]
As apparent from FIG. 3, the temperature ratio and the temperature increase ratio become smaller as the temperature becomes higher, and is almost linear in the temperature range in which the experiment was performed (temperature ratio: first-order correlation coefficient r = −0.994, temperature increase). Ratio: first order correlation coefficient r = −0.991). As described above, when the set temperature of the tube unit is changed, the temperature ratio and the temperature increase ratio also change almost linearly, so that it was confirmed that the heat transfer from the heated gas tube to the carrier gas is stable. From FIG. 3, it is clear that the carrier gas can be heated to 900 ° C. if the set temperature of U3 is 1150 ° C. or higher. Moreover, it is suggested that the carrier gas temperature can be heated to 1000 ° C. or more by using a material having better heat resistance than Inconel 600 for the heating resistor and controlling the set temperature of U3 to 1400 ° C. ing. Furthermore, since the heat transfer from the heated gas tube to the carrier gas is stable, even when the carrier gas is heated to a temperature lower than 800 ° C., the temperature control is more stable than the heater provided in the conventional CS device. Can be determined to be possible.

  Since the cold spray apparatus according to the present invention can stably heat the carrier gas to a high temperature of 900 ° C. or higher, the thermal spraying efficiency of the raw material powder is improved. Furthermore, if the combination with the heating resistor constituting the carrier gas heater is adjusted, the carrier gas can be heated to a high temperature of 1000 ° C. or higher. It is also possible to form a film using them.

U1 to U3 Tube unit with heating function 1 to Tube unit 3 with heating function
T1 to T4 energizing terminal 1 to energizing terminal 4
DESCRIPTION OF SYMBOLS 1 Cold spray nozzle 1a Throat part 1b Compression part 1d Expansion part 1h Powder port 2 Compressed gas cylinder 3 Carrier gas line 4 Carrier gas line 5a, 5b Pressure regulator 6a, 6b Flow control valve 7a, 7b Flowmeter 8a, 8b Pressure gauge 9 Power source 10 Carrier gas heater (gas tube with heating function)
DESCRIPTION OF SYMBOLS 11 Cold spray gun 12 Chamber 13 Pressure gauge 14 Thermometer 15 Raw material powder supply apparatus 16 Meter 17 Raw material powder supply line 18 Base material 20 Center axis (cold spray gun)
21 Center axis (gas tube unit with heating function)
30 Control panel 101 Cold spray gun 102 Mixing chamber 103 Post heater 104 Flexible tube 105 Pre heater 106 Electric resistance heating wire

Claims (9)

The raw material powder transported by the carrier gas is injected from the tip of the powder port into the carrier gas that makes the supersonic flow at the outlet of the cold spray gun, and the raw material powder is allowed to collide with the base material in the solid state. Forming a cold spray device,
Carrier gas heater in which the cold spray device comprises, in electrical resistance heating by energization, a heat function gas tube made of a heating resistor for heating the carrier gas flowing therein, the heat function Gas tube Is a gas tube unit with a heating function of a heating resistor having a length of energization of 1 m to 5 m and capable of generating heat at 1000 ° C. or higher .
Three or more gas tube units with one unit of heating function are arranged in series, and the energization amount to each gas tube unit is individually controlled.
Among these gas tube units with a heating function, the heat generation capacity of the gas tube unit with a heating function arranged on the side connected to the cold spray gun is set to be higher than the heat generation capacity of other gas tube units, and the set temperature is 1000 ° C. A cold spray device characterized by the above . In the gas tube with a heating function, the length of the heating resistor provided in one unit of the gas tube with a heating function arranged on the side connected to the cold spray gun is the same as that of the other gas tube unit with a heating function. The cold spray device according to claim 1, wherein the cold spray device is longer than a length of the heating resistor provided. In the gas tube with a heating function, the inner diameter of the heating resistor included in one unit of the gas tube unit with a heating function arranged on the side connected to the cold spray gun is included in the gas tube unit with another unit of heating function. The cold spray device according to claim 1 or 2 , wherein the cold spray device is smaller than the inner diameter of the heating resistor. In the gas tube unit with one unit of heating function, the length of the heating resistor is 10 to 30 times the linear distance connecting the energizing terminal provided on the carrier gas inlet side and the energizing terminal provided on the carrier gas outlet side. The cold spray device according to any one of claims 1 to 3, wherein the cold spray device has a coil shape with a winding number of 3 to 10 times. 5. The cold spray device according to claim 4, wherein the one-unit gas tube unit with a heating function has a carrier gas inlet and outlet disposed on a central axis of the coil shape. The carrier gas heater, the central axis of the coil shape, according to claim 4 or claim 5 is obtained by integrally fixed to the cold spray gun so as to be parallel to the central axis of the cold spray gun Cold spray device. 7. The gas tube unit with a heating function of one unit includes a joint in which the energization terminal is connected to one end on the carrier gas inlet side and the other end on the outlet side, respectively. 7. The cold spray apparatus according to one item . The cold spray device according to any one of claims 1 to 7, wherein the gas tube with a heating function includes three or more gas tube units with a heating function. The cold spray device according to any one of claims 1 to 8, wherein a cold spray gun having a length from the powder port to the throat portion of 200 mm to 1000 mm is used.