KR20080061793A - Production method of air-foil bearing having excellent wear resistivity - Google Patents

Abstract

A manufacturing method of an air-foil bearing with excellent wear resistance is provided to coat a bonding material on an object with enough coupling strength. A manufacturing method of an air-foil bearing with excellent wear resistance includes the steps of: preparing coating powder consisting of amorphous alloy, a bonding material, mixed with solid lubricant; and coating the coating powder on a surface of a journal of an air-foil bearing without a reinforcement material by spraying mixed gas of nitrogen and helium heated at a low temperature ranging 300~500°C.

Description

Production Method of Air Foil Bearing With Excellent Abrasion Resistance

1 is a conceptual diagram illustrating the shape of an airfoil bearing;

2 is a schematic view for explaining a low temperature spray coating process,

3 is a scanning electron microscope (SEM) photograph of the shape of the Ni-based amorphous alloy used in the embodiment of the present invention,

Figure 4 is a scanning electron micrograph of the form of the Ag solid lubricating material used in the embodiment of the present invention,

FIG. 5 is a scanning electron microscope photograph of the BaF ₂ / CaF ₂ process powder used in the embodiment of the present invention,

6 is a photograph photographing a bearing journal of the invention example and comparative example of the present invention,

7 is a graph comparing the coefficient of friction of the invention example and the comparative example,

8 is an apparatus for measuring a friction current generated in the airfoil bearing,

9 is a graph illustrating an operating cycle of an airfoil bearing during friction current measurement, and

10 is a graph showing that the friction current varies as the operating cycle of the airfoil bearing proceeds.

The present invention relates to a method of manufacturing an airfoil bearing having excellent abrasion resistance, and more particularly, to a healthy and good amorphous coating layer without causing oxidation or crystallization of an amorphous coating material by using a low temperature spraying method. The present invention relates to a method for manufacturing an airfoil bearing having a markedly improved wear resistance by forming on the secondary surface.

Bearing is a term that refers to a mechanical element that plays a role in rotating a shaft while fixing the shaft of a rotating machine at a fixed position and supporting the weight of the shaft and the load on the shaft. Play a role of In order to minimize the friction of the bearing part, it is necessary not only to have a shape that does not generate friction, but also to reduce the friction, a lubricating material that needs to be applied to the bearing part needs to be applied.

Conventionally, a liquid lubricant including lubricant is generally applied to the bearing. However, in the case of liquid lubricants, there are problems such as vaporization or deterioration when the bearings are operated at high temperatures, which limits the use of the bearings in harsh conditions.

In order to solve this problem, NASA has developed an airfoil bearing that does not use lubricating oil, etc., and a schematic shape thereof is shown in FIG. 1. As shown in FIG. 1, the air foil bearing is designed to eliminate the need for a conventional liquid lubricant by allowing the air layer to surround the journal as the lubricant rotates around the journal due to the unusual shape of the inner surface of the sleeve. Is a bearing.

In the case of using the bearing as described above, the problem such as deterioration of the lubricant does not occur as in the case of using a liquid lubricant is advantageous. However, as described above, the air layer forming effect is obtained only when the rotational speed of the bearing reaches a steady state, and when the speed decreases from the steady state or when the speed decreases from the steady state (in other words, If there is no sufficient air layer forming effect in the abnormal state), severe friction with the sleeve may occur.

Because of the friction that occurs in such an abnormal state not only increases the temperature of the bearing but also wears out the site where the friction occurs, so as to reduce the life of the bearing, it is necessary to form a coating layer on the surface in preparation for the abnormal state. .

The coating layer is made of a material for providing wear resistance so that the shape of the journal portion is not changed abruptly due to abrasion even when friction occurs with a lubricating material for reducing friction coefficient of the bearing journal part and reducing friction in an abnormal state. . The lubricant is present in the bearing journal as a coated solid phase, unlike conventional liquid lubricants. In addition, the material for imparting wear resistance is usually made of a bonding material that serves to easily attach the coating layer to the bearing journal and a reinforcing material to improve the wear resistance by increasing the hardness of the coating layer.

As a method for forming the coating layer, US Pat. No. 5,866,518 discloses a plasma thermal spray method. The patent document uses a NiCr alloy as a bonding material, Cr ₂ O ₃ powder as a reinforcing phase material, and Ag and BaF ₂ / CaF ₂ (eutectic phase of BaF ₂ and CaF ₂ ) as a solid lubricant. .

However, in the case of spraying using the reinforcement phase component as in the above method, the manufacturing cost according to the use of the reinforcement phase component increases, as well as the thermal physical properties between the components during the spraying because the various components are simply sprayed in a mixed state. Due to the difference in flight behavior, there is a concern that the coating layer becomes inhomogeneous.

In addition, in order not to use the reinforcing phase component, it is necessary to use a bonding material as a hard material. In this case, the base material must not only satisfy good adhesion with the base material (that is, the bearing journal part) to be attached, but also have sufficient hardness. It is necessary to control the composition of. However, this method is also not suitable when using the plasma spray coating method. That is, according to the thermal spray coating method, the bonding material, which is metallic, is sprayed in a molten state. When the bonding material flows from the nozzle to the subject, it is more likely to be oxidized by the surrounding atmosphere. There is a disadvantage that the composition of is hard to be maintained on the surface of the subject as it is.

In addition, when coating the surface of the bearing journal using a crystalline alloy such as NiCr as a bonding material, there is a problem that peeling of the coating layer easily occurs during use.

Therefore, according to one aspect of the present invention, there is provided a method of manufacturing an airfoil bearing having sufficient abrasion resistance without using a reinforcing phase component.

In addition, according to another aspect of the present invention, there is provided a method for manufacturing an airfoil bearing in which the bonding material can be coated on the object surface with sufficient bonding strength in a state in which no composition change or oxidation occurs from initial composition.

As one aspect of the present invention for solving the problems of the present invention, the method of manufacturing an air foil of the present invention comprises the steps of preparing a coating powder mixed with an amorphous alloy and a solid lubricant material; And coating the coating powder on the surface of the airfoil bearing journal in a low temperature spraying manner.

At this time, the solid lubricating material preferably includes a solid solution of Ag and BaF ₂ / CaF ₂ .

In addition, the solid solution of BaF ₂ / CaF ₂ preferably has a composition in process.

In addition, the solid phase lubrication material is effectively prepared by homogeneously mixing a solid solution of Ag particles and BaF ₂ / CaF ₂ by mechanical alloying method.

In addition, the coating powder is preferably made of an amorphous alloy: 65 to 95% by weight, Ag: 2.5 to 20% by weight, solid solution of BaF ₂ / CaF ₂ : 2.5 to 20% by weight.

In addition, the amorphous alloy preferably contains 45% or more of Ni.

In addition, it is effective that the amorphous alloy has an average particle size of 5 ~ 90㎛.

In addition, the gas used during the low-temperature injection is preferably nitrogen, helium or a mixture thereof.

In addition, the pressure immediately before the nozzle of the carrier gas is 20 to 25 bar when the carrier gas is helium, 20 to 29 bar when nitrogen, and 20 to 25 when the mixed gas of nitrogen and helium is used. It is preferable that it is + nitrogen flow fraction / 4) bar.

And, the flow rate of the coating powder used during the low-temperature spraying is effective to 10 ~ 30g / min.

In addition, the distance between the nozzle and the airfoil bearing journal during the low temperature injection is preferably 20 ~ 50mm.

In addition, the gas used during the low temperature spray is effective to be heated at 300 ~ 500 ℃.

In addition, the coating powder during the low temperature spraying is preferably pre-heated and sprayed at 546 ~ 597 ℃.

Hereinafter, the present invention will be described in detail.

The inventors of the present invention focus on the above-mentioned problems of the prior art and study the bonding material as amorphous to form a coating layer having good wear resistance on the journal surface of the airfoil bearing without using a reinforcing phase component. The conclusion was that it needs to be constructed. That is, the coating material used to manufacture the airfoil spring of the present invention is composed of a bonding base material made of an amorphous alloy and a solid lubricant.

The conditions of the alloy composition which can form amorphous are as follows. The composition which is easy to form amorphous has high Tg / Tm value (for example, 0.6 or more) and wide supercooled liquid region (ΔT = Tg-Tx). The size of the supercooled liquid region is associated with thermal stability and processability as well as amorphous formation ability, which is an important factor for wide application of amorphous alloys. Amorphous alloys having the above conditions, that is, high amorphous forming ability, are mainly ① multicomponent alloys having three or more components, ② have an atomic radius ratio of more than 12%, and ③ have an appropriate negative mixed enthalpy among the components. Satisfies the empirical conditions.

Among the three or more amorphous alloys, the Ni-based amorphous alloy may include 45% or more of Ni. Since the types thereof are various, it is difficult to enumerate all of them in the present specification, but it is common knowledge in the technical field to which the present technology belongs. If you have a branch, it will be easy to obtain an amorphous alloy that satisfies the above conditions can be applied to the present invention. However, some examples thereof include an amorphous alloy having a four-component composition represented by the following relational formula (1).

[Relationship 1]

Ni _a (Zr _x Ti _1-x ) _b Si _c

Here, 45? A? 63, 36? B? 48, 1? C? 11, and 0.4? X? 0.6 at%, respectively. The alloy of the component system is not sufficient in the amorphous forming ability outside this range.

In addition, various elements may be added to the quaternary amorphous alloy composition as necessary, and examples thereof include those to which Sn is added. As the amorphous alloy added with Sn, the amorphous alloy used in the test in the present invention may be Ni ₅₇ Ti ₁₈ Zr ₂₀ Si ₃ Sn ₂ .

In addition, in addition to the Ni-based amorphous alloy, an amorphous alloy containing Fe, Zr or Cu as a main component can also be used in the present invention, and those skilled in the art can easily obtain an amorphous alloy having such a component and apply it to the present invention. .

Among the amorphous alloys, Ni-based amorphous alloys are suitable alloys that can be used as a bonding material in a wide temperature range in consideration of mainly containing Ni in the bearing journal. In other words, thermal expansion may occur when the bearing's operating temperature increases. When a material having a large thermal expansion coefficient with the base material is used as the bonding material, stress is generated at the interface between the base material and the coating layer due to thermal expansion. Ni is suitable for use in a wide temperature range since there is a risk of becoming damaged. However, Fe, Zr, Cu-based amorphous alloys can be used when the bearing temperature is lower than 100 ℃. In addition, even when a Ni-based amorphous alloy is used, since the conventional Ni-based amorphous alloy is crystallized at a temperature of about 590 ° C, it is preferable to use it within the above temperature range.

Since the amorphous alloy used as the bonding material described above should be coated by low temperature spraying, it is necessary to have a particle size favorable for low temperature spraying. According to the results of the inventors of the present invention, the amorphous alloy preferably has an average particle size of 5 ~ 90㎛, it is particularly preferable that the particle size of the individual particles satisfy the above range (5 ~ 90㎛).

If the particle size of the amorphous alloy is less than 5㎛, it cannot have sufficient kinetic energy, so that it cannot provide the binding energy required for coating when colliding with the subject.In contrast, if the particle size exceeds 90㎛, the energy required for particle acceleration is excessive. The particle velocity is not sufficient.

The amorphous alloy having the above-mentioned particle size can be produced by a conventional powder metallurgy method, so it is not particularly limited in the present invention. In addition, the amorphous alloy is not limited only when the internal structure is 100% amorphous, it should be noted that all the amorphous alloy having an amorphous degree of 80% or more are all amorphous alloys usable in the present invention.

It is preferable that the solid phase lubrication material, which is another component of the low temperature spray coating material used for manufacturing the airfoil bearing of the present invention, is made of Ag and BaF ₂ / CaF ₂ . In this case, it is preferable to form a solid solution between the BaF ₂ / CaF ₂ materials, and to control the composition so that the two components form a process composition (for example, BaF ₂ : CaF ₂ = 6: 4), it is most preferable for the melting point drop. . Ag is added to lubricate when the bearing is used at a relatively low temperature (for example about 500 ℃ or less), BaF ₂ / CaF ₂ is added to lubricate when used at a relatively high temperature.

At this time, the Ag and BaF ₂ / CaF ₂ preferably has a particle size of 1 ~ 90㎛. If the particle size is too small, there is a small distribution in the coating, so the role of the lubricant is insufficient during friction / wear. On the contrary, if the particle size is excessively large, clogging may occur during the coating process. It is preferable that it is 1-90 micrometers, and it is most preferable that it is 10-30 micrometers in order to prevent said problem more reliably.

Ag and BaF ₂ / CaF ₂ described above may be used by simply mixing with an amorphous alloy powder, but in order to allow two solid phase lubricating materials to be uniformly mixed, the amorphous alloy may be prepared after being prepared in a relatively uniform mixture by a mechanical alloying method. It is preferably used in admixture with the powder.

The mechanical alloying method refers to a method in which an alloy powder is prepared by repeatedly breaking the powder and pressing the powders together when a raw material powder composed of various components is placed in a high energy ball mill and a strong shear force is applied.

The mechanical alloying method is a method that can be understood and used by anyone having ordinary knowledge in the art to which the present invention pertains, and thus the present invention is not particularly limited. However, one effective example may be a method of alloying at a condition of 120 to 180 rpm for 2 to 4 hours using a ball mill using a ceramic ball such as zirconia. The 2 hours means the minimum time required for mechanical alloying, and if less than the time, the degree of alloying is insufficient. On the contrary, the 4 hours is a time sufficient to achieve a sufficient effect. It is difficult to expect a further increase in effect and limited the above four hours because only energy and manufacturing time are required. In addition, the rotational speed of the ball mill means a range required to apply a sufficient shear force.

The Ag-BaF ₂ / CaF ₂ composite powder mechanically alloyed in this manner is mixed with the above-described amorphous alloy to prepare a coating powder. The amorphous alloy contained in the coating powder is preferably 65 to 95% by weight relative to the total coating powder weight, Ag is preferably 2.5 to 20% by weight, BaF ₂ / CaF ₂ process material is preferably included 2.5 to 20% by weight. . The content of the amorphous alloy and the solid phase lubricating substance should be maintained at an appropriate amount to each other as the other side decreases as one increases, but the content of the solid lubricating substance is reduced when the content of the amorphous alloy is exceeded in the above range. Therefore, there is a fear that excessive friction may occur when driving in an abnormal state, and on the contrary, when the content of the amorphous alloy is included in the range below, there is a concern that the coating material is insufficient due to the lack of the bonding material or the wear resistance is insufficient.

The coating powder mixed in the above ratio is then sprayed at a low temperature by a low temperature spraying device.

Cold spray means in the present invention means one of the spraying methods commonly used in the art, at a low temperature that does not melt the coating material in powder form through the spray device of the type shown in FIG. Means how to spray. Looking at the low-temperature powder process through Figure 2 as follows. As can be seen in Figure 2, the low temperature spray coating machine includes a gas supply device, a control panel, a gas heating device, a powder supply device and a de Laval nozzle. The gas supplied from the gas supply device is controlled by the amount of gas in the control panel, and divided into a gas heating device and a powder supply device. The gas heating device heats the gas to a high temperature to induce a speed increase due to the expansion of the gas, and the powder feeding device supplies the powder to the gas supplied from the control panel so that the powder is moved toward the nozzle (de Laval nozzle) by the gas. It serves to be supplied. Immediately after the powder feeding device, a powder heating device capable of heating the powder may be provided. The powder heating device is a device for heating the powder by mounting a heating element on the outside of the tube through which the powder passes, and serves to increase the temperature of the powder to increase the deformation and toughness of the powder when the powder collides with the subject. Immediately before the de Laval nozzle, a mixture of the powder and gas supplied from the powder feeder and the heated high-speed gas supplied from the gas heater meet to form a high-speed gas / powder mixture to form a high-speed gas through the DeLaval nozzle. Sprayed by powder jets. DeLaval nozzle is a nozzle that is used to increase the speed of the gas to the supersonic speed above the speed of sound as it has a form that the inner diameter of the nozzle is reduced (converge) and then diverged again when viewed in the nozzle length direction. The powder transported by the gas injected at supersonic speed through the de Laval nozzle collides with the subject at a high speed close to the velocity of the gas, and the kinetic energy of the powder is converted into the energy required for the coupling between the subject / powder. Thus, a powder-coated subject can be obtained.

In addition, the method of coating the powder using the low temperature spraying method is not particularly limited, but spraying using the following spraying conditions may yield better results.

Type of gas

At this time, the gas used is not particularly limited, but helium, nitrogen or a mixed gas thereof is more preferably used.

Gas pressure

The gas pressure just before the nozzle at the time of injection is slightly different depending on the type of gas, but 20 to 29 bar (nitrogen) for the nitrogen, 20 to 25 bar for the helium is preferred. In the case of a mixed gas of nitrogen and helium, the lower limit may be set equal to 20 bars, and the upper limit is between 25 and 29 bar in proportion to the flow rate ratio of nitrogen and helium (that is, 25+ nitrogen flow rate / 4). You just need to decide on When the pressure of the gas is low, the speed of the powder particles to be coated is sufficient, so that a coating layer is hardly formed on the object. The higher the gas pressure, the higher the particle velocity, but there is a limit there, and if the pressure is increased further, the device may be loaded, so the upper limit of the gas pressure is set in the above range.

Flow rate of coating powder (bonding material + solid lubricant)

The flow rate of the coating powder is preferably in the range of 10-30 g / min based on the mass flow rate. If the coating powder mass flow rate is less than 10 g / min, it is difficult to control the coating powder flow rate during powder feeding. On the contrary, if the coating powder mass flow rate is higher than 30 g / min, the coating powder flow rate is excessively increased compared to the gas to speed up each particle. Is reduced and is not appropriate because the device is overloaded to match the particle velocity.

Gas heating temperature

It is preferable that the temperature of the gas heated by the gas heating apparatus at the said low temperature spraying is 300-500 degreeC. When the gas is injected from the DeLaval nozzle, the gas is adiabatic and expands due to the shape of the dividing portion of the nozzle diameter, which is changed into a gas jet having a high velocity. By this, a sufficient gas velocity can be secured. In order to ensure a sufficient gas velocity, the higher the temperature of the gas is, the better, and therefore, there is no need to specifically set the upper temperature limit of the gas in this respect. However, when the temperature of the gas is high, the load on the device is high, so it is preferable to set the temperature as the upper limit to about 500 ° C in the device currently used.

Preheating temperature of coating powder

In addition, when the coating powder is coated without special preheating, the deformation and toughness of the powder particles may not be good, which may cause problems such as cracking of the particles during coating. This phenomenon is more severe in materials with poor toughness. In order to improve the toughness and deformability of the coating particles, it is necessary to preheat the coating powder to a predetermined temperature range or more. As in the present invention, the composite particles of the amorphous alloy and the solid phase lubricating material are simultaneously coated to form a coating layer on the bearing journal surface. In this case, the temperature in the preheater of the particles (hereinafter, simply preheating temperature) is preferably maintained above Tg (546 ° C). However, if the temperature is too high, problems such as crystallization of the amorphous alloy may occur as well as the device load may increase, so the upper limit of the preheating temperature is set to Tx (597 ° C) ° C.

Distance between nozzle and subject

The distance between the nozzle and the subject is a major factor that allows the particles to be smoothly coated. When the composite coating powder of the amorphous alloy and the solid lubricating powder targeted in the present invention is coated, the distance between the nozzle tip and the subject is 20 to 50 mm. It is preferable. If the distance exceeds 50 mm, the distance from the nozzle to the powder to reach the subject is too far to increase the speed reduction of the coated particles, resulting in a failure to reach the subject at a sufficient speed, resulting in a reduction in the lamination rate. do. On the contrary, when less than 20 mm, nozzle clogging may occur due to the backflow of gas.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, it is necessary to note that the following examples are not intended to limit the scope of the present invention, but are merely illustrative of the present invention described in order to help the understanding of the present invention. This is because the scope of the present invention is determined by the matters described in the claims and the matters reasonably inferred therefrom.

(Example)

Preparation of Coating Powder

Ni ₅₇ Ti ₁₈ Zr ₂₀ Si ₃ Sn ₂ amorphous alloy powder having a particle size of 5 to 90 μm was prepared as a bonding material. 3 shows the shape of the bonding material (amorphous alloy) in a photograph. As can be seen from the photograph, each of the powder particles showed mostly good spherical shape and had a particle size of 5 to 90 mu m.

Mechanical alloying of Ag powder with a particle size of 5-30 μm (see FIG. 4) and BaF ₂ / CaF ₂ process powder with a particle size of 10-40 μm (see FIG. 5) in a ball mill rotating at 200 rpm for 4 hours. To prepare a composite powder having an average size of about 15㎛.

Thereafter, the coating powder was prepared by mixing the amorphous alloy and the composite powder for low temperature spraying.

Manufacture of airfoil bearings

The coating powder prepared in the manner described above was cold spray coated on the journal surface of the air foil bearing. Helium (He) was used as a carrier gas at low temperature and the pressure of the gas was set to 29 bar. The gas was heated to a temperature of 550 ° C. to speed up the gas, and the powder was also preheated at a temperature of 570 ° C. to ensure good coating on the bearing journal surface. When spraying the powder flow rate was set to 36g / min, the distance between the nozzle and the bearing journal was maintained at 30mm and the moving speed of the spray gun was set to 0.01m / s.

By the low temperature spraying it was possible to form a coating layer having a thickness of about 100-400㎛ on the bearing journal surface. Hereinafter, the airfoil bearing journal of the present invention manufactured in this manner is defined as 'invention example'.

NiCr was sprayed by thermal spraying to form a coating layer for comparison with the inventive example. Since the strength of the bonding material used for the thermal spraying was not sufficient, a composite powder was prepared and used in the same manner as in the above example except that Cr 2 O 3, which is a reinforcing phase component, was used together. This method is the same as the coating layer formation method called conventional PS304.

Hereinafter, the airfoil bearing journal prepared by the present comparative method and the coating layer including the NiCr is formed is referred to as 'comparative example'. It was confirmed that the coating layer of the comparative example was formed to a thickness of about 300㎛.

6 shows a photograph comparing the invention example (a) and the comparative example (b).

Wear property test

The abrasion test was done about the said invention example and the comparative example using the pin-on-disc abrasion test apparatus. The wear conditions described in Table 1 were set for the pin-on-disk test.

weight Wear rate Wear distance Counterpart Experimental temperature Experiment time 47N 0.12 m / s 430 m Inconel 718 Room temperature 3.600 seconds

Abrasion test results of the wear conditions are shown in the graph of Figure 7 shown in Table 2 below.

division Friction coefficient Wear (g / h) Inventive Example 0.27-0.34 0.21 Comparative example 0.4 ~ 0.63 0.48

As can be seen in the graph of FIG. 7 and Table 2 in which the results are expressed in specific numerical values, the friction coefficient fluctuates in the range of 0.27 to 0.34 in the case of the invention example, while in the comparative example, about 0.4 to 0.63 is very high. It was found that the coefficient of friction was particularly high at the beginning of the experiment.

In addition, in the case of Inventive Example 1 produced by the method of the present invention, the amount of wear per hour was also very low, less than half of the comparative example. Therefore, the excellent lubricating properties and wear resistance of the invention example produced by the present invention was confirmed.

Friction Current Measurement

The friction current measurement test was done using the apparatus.

 The bearing rig test stops automatically if the friction current rises above 15A and the wear depth exceeds 30µm during repeated cycles. Friction current measurements are performed at two temperatures: room temperature and high temperature (350 ° C).

10 shows the results of measuring the friction current every 500 cycles. In FIG. 10, a fail section means a case in which the friction current rises to 15 A or more.

In addition, Table 3 shows the results of measuring the friction current. In Table 3, the high and low amount of debris is the result of comparative evaluation.

Used bearing Working temperature Limit cycle Friction current Wear loss thickness Fragment Remarks Comparative example Room temperature 48 16A 5㎛ plenty failure Comparative example 350 ℃ 880 16A 30㎛ or more plenty failure Example Room temperature More than 5000 4 ~ 5A Less than 0.2㎛ Less success Example 350 ℃ More than 5000 4 ~ 5A Less than 0.2㎛ Less success

As can be seen from the results of FIG. 10 and Table 3, in the case of the comparative example, in the case of the room temperature and the high temperature (350 ° C.), the current value corresponds to the failure section at less than 500 cycles and 1000 cycles, respectively. It can be seen that it shows a stable friction current value over the entire experimental period.

Thus, the improved wear resistance of the airfoil bearing journal produced by the present invention could be confirmed.

As described above, according to the present invention, an airfoil bearing having high wear resistance and good lubrication characteristics can be manufactured without using a special reinforcing material, and the wear-resistant coating layer is coated by a conventional plasma spraying method. Unlike the case, it is possible to obtain a good airfoil manufacturing method in which the amorphous property of the bonding material during coating or the problem of oxidation of the material is hardly observed.

Claims (13)

Preparing a coating powder in which an amorphous alloy and a solid lubricant are mixed; And Coating the coating powder on a surface of an airfoil bearing journal in a low temperature spray method; Air foil bearing manufacturing method comprising a. The method of claim 1, wherein the solid lubricating material comprises a solid solution of Ag and BaF ₂ / CaF ₂ . The method of claim 2, wherein the solid solution of BaF ₂ / CaF ₂ has a process composition. The method of claim 2, wherein the solid lubricating material is manufactured by homogeneously mixing a solid solution of Ag particles and BaF ₂ / CaF ₂ by a mechanical alloying method. The method of claim 2, wherein the coating powder is 65 to 95% by weight of the amorphous alloy, Ag: 2.5 to 20% by weight, solid solution of BaF ₂ / CaF ₂ : 2.5 to 20% by weight of the airfoil bearing Manufacturing method. 6. The method of claim 5, wherein the amorphous alloy contains 45% or more of Ni. The method of claim 5, wherein the amorphous alloy has an average particle size of 5 ~ 90㎛. The method of claim 1, wherein the gas used for low temperature spraying is nitrogen, helium, or a mixture thereof. According to claim 1, wherein the pressure immediately before the nozzle of the carrier gas is 20 to 25 bar (bar) when the carrier gas is helium, 20 to 29 bar when the nitrogen, a mixed gas of nitrogen and helium A method of manufacturing an airfoil bearing, characterized in that it is 20 to (25+ nitrogen content fraction / 4) bar. The method of manufacturing an airfoil bearing according to claim 1, wherein the flow rate of the coating powder used during the low temperature spraying is 10 to 30 g / min. The method of claim 1, wherein the distance between the nozzle and the airfoil bearing journal during the low temperature spraying is 20 to 50 mm. The method of claim 1, wherein the gas used during the low temperature spraying is heated at 300 to 500 ° C. The method of claim 1, wherein the coating powder is preheated and sprayed at 546 to 597 ° C. during the low temperature spraying.

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