WO2021246377A1

WO2021246377A1 - Wear-resistant member and faucet valve and piston/cylinder unit using same

Info

Publication number: WO2021246377A1
Application number: PCT/JP2021/020731
Authority: WO
Inventors: 憲一古舘; 美恵子八嶋
Original assignee: 京セラ株式会社
Priority date: 2020-06-02
Filing date: 2021-05-31
Publication date: 2021-12-09
Also published as: JPWO2021246377A1; CN115485253B; CN115485253A

Abstract

A wear-resistant member according to the present disclosure comprises a ceramic having silicon carbide as the main component, and has a plurality of open pores on a sliding surface, wherein the value (C) provided by subtracting the average value (B) of the circle-equivalent diameter of the open pores from the average value (A) of the distance between the centers of gravity of adjacent open pores, is at least 6-times that of the average value (B).

Description

Abrasion resistant member and faucet valve, piston / cylinder unit using it

The present invention relates to a wear-resistant member and a faucet valve, piston / cylinder unit using the wear-resistant member.

Conventionally, carbon is compounded with ceramics as a base material to improve the sliding characteristics of the base material, and by filling the open pores on the sliding surface with a lubricant, the sliding characteristics can be improved even in a dry state. Composite ceramics that can be maintained are provided. As such a composite ceramic, Patent Document 1 proposes a silicon carbide-carbon composite material in which a liquid, grease-like or solid lubricant is filled in the open pores, and the composite ceramic material can be used for a water supply (fosset) valve. Has been described.

Japanese Unexamined Patent Publication No. 9-165281

The wear-resistant member of the present disclosure is made of ceramics containing silicon carbide as a main component, has a plurality of open pores on a sliding surface, and has an open pore circle from the average value (A) of the distance between the centers of gravity of adjacent open pores. The value (C) obtained by subtracting the average value (B) of the corresponding diameter is 6 times or more the average value (B).

The wear-resistant member of the present disclosure is made of ceramics containing silicon carbide as a main component, has a plurality of open pores on a sliding surface, and has an open pore circle from the average value (A) of the distance between the centers of gravity of adjacent open pores. The value (C) obtained by subtracting the average value (B) of the equivalent diameter is 50 μm or more and 170 μm or less.

The faucet valve of the present disclosure includes a fixed valve body and a movable valve body that abut and slide on each other's sliding surfaces, and at least one of the fixed valve body and the movable valve body is made of the above-mentioned wear-resistant member. .. Further, the piston / cylinder unit of the present disclosure includes a piston equipped with a piston ring and a cylinder equipped with a cylinder liner having an inner peripheral surface that slides on an outer peripheral surface of the piston ring, and includes a cylinder liner and a piston ring. At least one of the above is made of the wear resistant member.

(A) is a micrograph showing a sliding surface of a wear-resistant member according to an embodiment of the present disclosure, and (B) and (C) are micrographs of an enlarged portion A of (A). .. It is a micrograph which shows the state which etched the sliding surface of the wear-resistant member which concerns on one Embodiment of this disclosure. It is a figure which shows the faucet valve which concerns on one Embodiment of this disclosure, (A) is the perspective view which shows the state which opened the fluid passage, (B) is the perspective view which shows the state which the fluid passage is closed. .. It is sectional drawing which shows the main part of the piston / cylinder unit which concerns on one Embodiment of this disclosure.

When the open pores on the sliding surface are ubiquitous as in the conventional silicon carbide-carbon composite material, the lubricant held inside the open pores is also ubiquitous. When such a state occurs, it is likely that the material is stuck to the opposing material that is in sliding contact with the material, and that galling, abnormal noise, or the like is likely to occur. Further, when the sliding surfaces in which the open pores are close to each other receive high pressure, cracks connecting the open pores are likely to develop. As a result, when many open pores are connected by cracks, there is a problem that the mechanical strength of the portion is lowered and the fluid flows out to the outside.

By having the above-mentioned configuration, the wear-resistant member according to the present disclosure suppresses the generation of sticking, galling, abnormal noise, etc. to the facing material that is in sliding contact with the wear-resistant member, further reduces the mechanical strength, and causes the fluid to flow out to the outside. It is possible to provide a wear-resistant member capable of suppressing the above.

Hereinafter, the wear-resistant member according to the embodiment of the present disclosure will be described in detail with reference to the drawings. However, in all the drawings of the present specification, the same parts are designated by the same reference numerals and the description thereof will be omitted as appropriate as long as they do not cause confusion.

1 (A) is a micrograph showing a sliding surface of a wear-resistant member according to an embodiment of the present disclosure, and FIGS. 1 (B) and 1 (C) show a part A of FIG. 1 (A). This is a magnified micrograph. The wear-resistant member provided with the sliding surface shown in FIG. 1 is made of ceramics containing silicon carbide as a main component.

The main component in the present disclosure means a component that occupies 80% by mass or more in the total 100% by mass of the components constituting the ceramics. In particular, the main component is preferably a component that accounts for 90% by mass or more of the total 100% by mass of the components constituting the ceramics.

The components constituting the ceramics may be obtained by using an X-ray diffractometer (XRD). The content of each component can be determined by determining the content of the elements constituting the component using a fluorescent X-ray analyzer (XRF) or an ICP emission spectroscopic analyzer after identifying the component and converting it into the identified component. good.

The sliding surface shown in FIG. 1 has a plurality of open air holes 1, and is obtained from the average value (A) of the distances between the centers of gravity of the adjacent open air holes 1a, 1b, 1c, ... The value (C) obtained by subtracting the average value (B) of the circle equivalent diameters d1, d2, d3, ... Of the open pores 1a, 1b, 1c, ... Is 6 times or more the average value (B). .. When the value (C) is 6 times or more the average value (B), the flatness of the sliding surface can be controlled within an appropriate range. Therefore, the gap between the mating material and the sliding surface to be in contact with the sliding surface is narrowed, and the outflow of the liquid from the gap to the outside can be suppressed.

The above value (C) may be 12 times or less of the average value (B). When the value (C) is 12 times or less the average value (B), the arrangement of the open pores becomes appropriate. Therefore, the arrangement of the lubricants is not unevenly distributed, and the lubrication performance can be maintained for a long period of time.

The sliding surface shown in FIG. 1 has a plurality of open air holes 1, and is obtained from the average value (A) of the distances between the centers of gravity of the adjacent open air holes 1a, 1b, 1c, ... The value (C) obtained by subtracting the average value (B) of the circle equivalent diameters d1, d2, d3, ... Of the open pores 1a, 1b, 1c, ... Is 50 μm or more and 170 μm or less. When the value (C) is 50 μm or more, the flatness of the sliding surface can be controlled within an appropriate range. Therefore, the gap between the mating material and the sliding surface to be in contact with the sliding surface is narrowed, and the outflow of the liquid from the gap to the outside can be suppressed. When the value (C) is 170 μm or less, the arrangement of the open pores becomes appropriate. Therefore, the arrangement of the lubricants is not unevenly distributed, and the lubrication performance can be maintained for a long period of time.

The distance between the centers of gravity of the open pores can be obtained by the following method. Observe the sliding surface at a magnification of 50 times and select an average range, for example, an area of 1.768 mm ² (horizontal length 1.36 mm, vertical length 1.3 mm). The area to be observed is photographed with a CCD camera to obtain an observation image. Using the image analysis software "A image-kun (ver2.52)" (registered trademark, manufactured by Asahi Kasei Engineering Co., Ltd.) for this observation image, the center of gravity of the open pore is measured by the distance between the centers of gravity. You can find the distance. Hereinafter, when the image analysis software "A image-kun" is described, the image analysis software manufactured by Asahi Kasei Engineering Co., Ltd. is shown.

As the setting conditions of this method, for example, the threshold value indicating the lightness and darkness of the image may be 156, the lightness may be dark, the small figure removal area may be 20 μm ² , and the noise removal filter may be omitted. The threshold value may be adjusted according to the brightness of the observation image, the brightness is darkened, the binarization method is manual, the small figure removal area is 20 μm ^2, and the noise removal filter is omitted. The threshold may be adjusted so that the marker appearing in the image matches the shape of the open pore. The reason why the small figure removal area is ^{set to a relatively large value of 20 μm 2} is that the open pores smaller than this value have low lubricant holding performance.

The equivalent circle diameter of the open pore can be obtained by the following method. For the above observation image, the diameter equivalent to the circle of the open pores may be obtained by a technique called particle analysis. The setting conditions of this method may be the same as the setting conditions used in the distance between the centers of gravity of the dispersion measurement.

The kurtosis Ku of the distance between the centers of gravity of the open pores may be 0.3 or more and 4 or less. When the kurtosis Ku of the distance between the centers of gravity of the open pores is 0.3 or more, the distribution of the distance between the centers of gravity of the open pores becomes narrow. On the other hand, when the kurtosis Ku of the distance between the centers of gravity is 4 or less, there are no open pores extremely separated from each other. When the kurtosis Ku of the distance between the centers of gravity is 0.3 or more and 4 or less, the lubricant can be evenly supplied between the sliding surfaces, and the sliding performance can be maintained for a long period of time. ..

Here, kurtosis Ku is an index (statistic) showing how much the peak and tail of the distribution differ from the normal distribution. When the kurtosis Ku> 0, the distribution has a sharp peak and a long and thick hem. When the kurtosis Ku = 0, the distribution is normal. When the kurtosis Ku <0, the distribution has a rounded peak and a short, thin tail. The kurtosis of the distance between the centers of gravity may be obtained by using the function Kurt provided in Excel (registered trademark, Microsoft Corporation).

The area ratio of the open air hole 1 on the sliding surface is, for example, 1.2% or more and less than 5%, and can be obtained by the above-mentioned particle analysis method. In particular, the area ratio of the open air hole 1 on the sliding surface is preferably 2% or more and 4.5% or less.

FIG. 2 is a micrograph showing a state in which the sliding surface of the wear-resistant member according to the embodiment of the present disclosure is etched. This etched surface is obtained by immersing the wear resistant member in a heat-melted solution of sodium hydroxide and potassium nitrate in a mass ratio of 1: 1 for 20 seconds. This etched surface is observed with an optical microscope at a magnification of 50 times, and the surface on which crystal particles of various sizes are observed on average is selected. The surface on which crystal particles of various sizes are observed on average is not the surface on which the region without coarse-grained crystal particles is intentionally selected by observing the etched surface widely, but the surface of coarse-grained crystal particles or It means a surface in which fine-grained crystal particles are present on average. The area of the surface is, for example, 2.7 × 10 ⁻² μm ² (horizontal length is 0.19 μm, vertical length is 0.14 μm).

As shown in FIG. 2, the sliding surface has coarse-grained crystal particles 2 and fine-grained crystal particles 3 containing silicon carbide as a main component. The average value (D) of the equivalent circle diameters of the fine granular crystal particles 2 is smaller than the average value (B) of the equivalent circle diameters of the open pores 1. The coarse-grained crystal particles 2 are crystal particles having an area of 1000 μm ² or more, and the fine-grained crystal particles 3 are crystal particles having a circle-equivalent diameter of 8 μm or less. Needless to say, there may be crystal particles having an equivalent circle diameter of more than 8 μm and an area of ^{less than 1000 μm 2.}

When the average value (D) of the equivalent circle diameter of the fine granular crystal particles 3 is smaller than the average value (B) of the equivalent circle diameter of the open pore 1, it becomes difficult to thresh from the contour of the open pore 1. As a result, the risk of damaging the sliding surface of the opposing material that comes into contact is reduced. In particular, it is preferable that the difference between the average value (D) of the equivalent circle diameter of the fine granular crystal particles 3 on the sliding surface and the average value (B) of the equivalent circle diameter of the open pore 1 is 5 μm or more.

The average value (D) of the equivalent circle diameters of the fine granular crystal particles 3 is, for example, 1 μm or more and 6 μm or less. The average value (B) of the equivalent circle diameter of the open pore 1 is, for example, 8 μm or more and 30 μm or less. The equivalent circle diameter of the fine granular crystal particles 3 is, for example, the image analysis software (for example, manufactured by Mitani Shoji Co., Ltd.) for the etched surface having ^{an area of 2.7 × 10 −2} μm ^{2 by the method described above.} , Win ROOF). In the analysis, the threshold value of the equivalent circle diameter is set to 0.21 μm, and the particle size less than 0.21 μm is not included in the calculation of the average value (B) of the equivalent circle diameter.

The coarse-grained crystal particles 2 are preferably 6 area% or more and 15 area% or less. When the coarse-grained crystal particles 2 are 6 area% or more, even if fine cracks are generated due to thermal shock, the coarse-grained crystal particles 2 can suppress the growth of cracks. When the coarse-grained crystal particles 2 are 15 area% or less, mechanical properties such as strength, rigidity, and fracture toughness can be enhanced.

The coarse-grained crystal particles 2 may contain a plurality of intragranular pores 4. When the coarse-grained crystal particles 2 include a plurality of intragranular pores, the thermal stress generated in the coarse-grained crystal particles 2 in a high-temperature environment is easily relaxed by the intra-grain pores 4, so that the heat resistance is improved. The equivalent circle diameter of the intragranular pores 4 is, for example, 6 μm or less.

The coarse-grained crystal particles 2 and the fine-grained crystal particles 3 are crystal particles containing silicon carbide as a main component. Using a wavelength dispersive X-ray microanalyzer device, each distribution of Si and C is confirmed, and when the distributions of Si and C are overlapped, these overlap, and as a result, crystal particles containing silicon carbide as the main component. You just have to confirm that.

The relative density of the ceramics forming the wear-resistant member of the present disclosure is preferably 96% or more and 99% or less, and particularly preferably 96.7% or more and 98.8% or less. This relative density is a percentage of the apparent density of the wear resistant member to the theoretical density of the ceramics. The theoretical density of ceramics may be obtained as follows. The content of each of the wear-resistant members is determined by an ICP (Inductively Coupled Plasma) emission spectroscopic analyzer or a fluorescent X-ray analyzer. Identification of each component is performed by an X-ray diffractometer using CuKα rays. For example, if the identified component is SiC or B ₄ C, it can be obtained by converting it into _{SiC or B 4} C using the Si and B content values obtained by ICP emission spectroscopic analysis or fluorescent X-ray analysis. Just do it. The apparent density of the wear-resistant member may be determined in accordance with JIS R 1634-1998.

When the main component constituting the ceramic is silicon carbide and the components other than the main component are boron carbide, assuming that the contents are a mass% and b mass%, respectively, the theoretical densities of silicon carbide and boron carbide, respectively. (Silicon carbide = 3.21 g / cm ³ , boron carbide = 2.52 g / cm ³ ), the theoretical density (TD) of the silicon carbide sintered body is obtained by the following formula (1). be able to.
T. D = 1 / (0.01 × (a / 3.21 + b / 2.52)) ... (1)

For example, when the content of the components constituting the ceramics is 99.6% by mass for silicon carbide and 0.4% by mass for boron carbide, the theoretical density of the ceramics (1) is calculated using the formula (1). T.D) is 3.21 g / cm ³ . The relative density can be obtained by dividing the apparent density of the ceramics obtained in accordance with JIS R 1634-1998 by this theoretical density (TD) 3.21 g / cm ^3.

The graphite content in the ceramics may be less than 1% by mass, particularly 0.1% by mass or less, and may not be contained. This is because when graphite is contained, the sliding characteristics are improved, but the sliding surface is easily worn, so that the life of the wear-resistant member is shortened. When the wear-resistant member contains graphite in the identification of the component by the X-ray diffraction method, the graphite content may be determined by using the Rietveld method.

The ceramics may contain sulfur. The sulfur content may be 0.02% by mass or less in terms of _{oxide (SO 3).} After the start of sliding, if sulfur is contained in the sliding surface, it tends to be the starting point of cracks, but if the sulfur content is _{within the above range in terms of oxide (SO 3} ), it will be the starting point of cracks. The risk of becoming is reduced.

The wear-resistant member described above includes, for example, a valve body of a faucet valve, a piston / cylinder unit, a bearing, a fuel injection nozzle, a rolling roll, a ball bearing, a roll bearing, a rotary shaft mounted on a flow control valve, or rotation thereof. It can be used as a sliding member such as a washer with which the shaft rotatably engages.

3A and 3B are views showing a faucet valve according to an embodiment of the present disclosure, FIG. 3A is a perspective view showing a state in which the fluid passage is open, and FIG. 3B is a perspective view showing a state in which the fluid passage is closed. It is a perspective view which shows the state.

The faucet valve 20 shown in FIG. 3 includes a fixed valve body 21 and a movable valve body 22 that abut and slide the sliding surfaces 21a and 22a of each other. The fixed valve body 21 is fixed to a resin case (not shown), and the movable valve body 22 is configured to move on the fixed valve body 21 inside the resin case.

Fluid passages

21b and 22b are formed in the fixed valve body 21 and the movable valve body 22 in the thickness direction, respectively, and both

fluid passages

21b and 22b are connected on the sliding surfaces 21a and 22a. A lever 23 is fixed to the movable valve body 22, and the movable valve body 22 can be moved by moving the lever 23 in the vertical direction or the rotational direction. In the faucet valve 20, the wear-resistant member 10 according to the embodiment of the present disclosure is used for both the fixed valve body 21 and the movable valve body 22. The wear resistant member 10 may be used only for either the fixed valve body 21 or the movable valve body 22.

As shown in FIG. 3A, in the faucet valve 20, when the

fluid passages

21b and 22b are open, fluids such as water and hot water flow sequentially from the direction of the white arrow to the

fluid passages

21b and 22b, and the faucet valve 20 is set. A fluid is discharged from a faucet (not shown) connected to the valve 20. At this time, the fluid inserted between the sliding surfaces 21a and 22a together with the silicon grease previously applied to any of the sliding surfaces 21a and 22a becomes a lubricating liquid and acts to maintain the sliding characteristics. The contact between the sliding surfaces 21a and 22a includes a state in which the respective surfaces are in contact with each other via such a lubricating liquid.

On the other hand, as shown in FIG. 3B, the movable valve body 22 can be moved in either the vertical direction by the lever 23 to close the space between the

fluid passages

21b and 22b, and the discharge of the fluid from the faucet is stopped. be able to. By moving the movable valve body 22 in the rotational direction, the area of the end face to which the

fluid passages

21b and 22b are connected is adjusted. As a result, the flow rate of the fluid discharged from the faucet can be adjusted.

In the faucet valve 20 shown in FIG. 3, the fixed valve body 21 may have a smaller value (C) than the movable valve body 22. Normally, the area of the sliding surface 21a of the fixed valve body 21 is larger than that of the sliding surface 22a of the movable valve body 22. Therefore, the sliding surface 22a is always in contact with the sliding surface 21a. On the other hand, a part of the sliding surface 21a is not in a state of being in constant sliding contact with the sliding surface 22a. Therefore, by reducing the above value (C), the amount of silicon grease contained in the open pores can be increased, and the holding performance of the silicon grease is also improved. The difference between the above values (C) is, for example, 3 μm or more and 15 μm or less.

FIG. 4 is a cross-sectional view showing a main part of the piston / cylinder unit according to the embodiment of the present disclosure. The piston / cylinder unit 30 includes a piston 32 to which a plurality of piston rings 31 are mounted, and a cylinder 34 to which a cylinder liner 33 having an inner peripheral surface that slides on an outer peripheral surface of the piston ring 31 is mounted.

The outer peripheral surface of the piston ring 31 slides along the axial direction on the inner peripheral surface of the cylinder liner 33. The outer peripheral surface of the piston ring 31 and the inner peripheral surface of the cylinder liner 33 are both sliding surfaces having a plurality of open holes. The inner peripheral surface of the cylinder liner 33 has a larger area than the outer peripheral surface of the piston ring 31. Therefore, it does not always come into contact with the outer peripheral surface of the piston ring 31. On the other hand, the outer peripheral surface 7 of the piston ring 31 is in constant contact with the inner peripheral surface of the cylinder liner 33.

The cylinder 34 is made of, for example, an aluminum or iron casting. The cylinder liner 33 is, for example, an abrasion-resistant member made of ceramics containing silicon carbide as a main component. The piston 32 is made of, for example, an aluminum or iron casting. Although the piston 32 is integrally formed in FIG. 4, the piston head portion 32a and the piston skirt portion 32b may be separate.

When the piston head portion 32a and the piston skirt portion 32b are separate, the piston head portion 32a is made of ceramics containing silicon nitride, silicon carbide or the like as main components. The piston ring 31 is, for example, a wear-resistant member made of ceramics containing silicon carbide as a main component.

In the piston / cylinder unit 30 according to the embodiment of the present disclosure, at least one of the cylinder liner 33 and the piston ring 31 is the wear resistant member of the present disclosure. In particular, the cylinder liner 33 and the piston ring 31 may be made of the wear-resistant member of the present disclosure, and the cylinder liner 33 may have a smaller value (C) than the piston ring 31. The area of the inner peripheral surface of the cylinder liner 33 is larger than that of the outer peripheral surface of the piston ring 31. Therefore, the outer peripheral surface is always in sliding contact with the inner peripheral surface. On the other hand, a part of the inner peripheral surface is not always in sliding contact with the outer peripheral surface. Therefore, by reducing the value (C), the amount of the lubricant such as oil contained in the open pores can be increased, and the lubricant holding performance can be improved. The difference between the above values (C) is, for example, 3 μm or more and 15 μm or less.

Next, an example of a method for manufacturing a wear-resistant member according to an embodiment of the present disclosure will be described. First, a hydrophobic pore-forming agent consisting of α-type silicon carbide powder having an average particle size (D ₅₀ ) of 0.5 μm or more and 2 μm or less, a sintering aid, and resin beads, and pore dispersion in which the pore-forming agent is dispersed. Prepare the agent. Next, these raw materials are wet-mixed and pulverized with a ball mill or a bead mill using a barrel mill, a rotary mill, a vibration mill, a bead mill, an attritor or the like to obtain a slurry. A dispersant that disperses the silicon carbide powder may be added.

Sintering aids can be a combination of boron carbide powder and an aqueous phenol solution or a combination of lignin sulfonate and lignin carboxylate powder as a carbon source, or aluminum oxide powder and rare earth oxide powder such as yttrium oxide. May be combined with. When the sintering aid is composed of the former combination, for example, the boron carbide powder is 0.2 parts by mass or more and 0.6 parts by mass or less with respect to 100 parts by mass of the α-type silicon carbide powder, and the phenol. The aqueous solution or the powder of lignin sulfonate and lignin carboxylate is 0.5 parts by mass and 4.0 parts by mass in terms of carbon. The salt of lignin sulfonate and lignin carboxylate may be at least one of lithium, sodium and ammonium.

The pore-forming agent is, for example, silicone beads and suspension-polymerized crosslinkable resin beads consisting of at least one of polyacrylic-styrene. In order to obtain a wear-resistant member having a plurality of open pores on the sliding surface and having the above value (C) 6 times or more the average value (B), the content of the pore forming agent should be set to α-type silicon carbide. _{The average particle size (D 50} ) may be 36 μm or more and 45 μm or less, particularly 40 μm or more and 45 μm or less, with respect to 100 parts by mass of the powder. Even when a wear-resistant member having the above value (C) of 50 μm or more and 170 μm or less is obtained, the content of the pore forming agent and the average particle size (D ₅₀ ) may be the same as described above.

The range of the particle size of the pore forming agent is, for example, 5 μm or more and 125 μm or less. For example, in order to obtain a wear-resistant member having a kurtosis Ku of the distance between the centers of gravity of the open pores of 0.3 or more and 4 or _{less, pore formation having an average particle size (D 50} ) of 42.5 μm or more and 44.5 μm or less. An agent may be used.

The pore dispersant is used to disperse the pore forming agent. Examples of the pore dispersant include anionic surfactants such as carboxylates, sulfonates, sulfates and phosphates. By adsorbing the anionic surfactant to the pore-forming agent, the pore-forming agent is easily wetted and penetrated into the slurry. Further, the charge repulsion of the hydrophilic group of the anionic surfactant further suppresses the aggregation of the pore-forming agent. Therefore, the pore-forming agent can be sufficiently dispersed without agglutinating in the slurry. The anionic surfactant is highly effective in wetting and infiltrating the pore-forming agent into the slurry. The pore dispersant may be added in an amount of 0.14% by mass or more and 0.24% by mass or less with respect to 100% by mass of the pore forming agent.

Next, in this slurry, as a binder, celluloses such as methyl cellulose and carboxymethyl cellulose and their variants, saccharides, starches, dextrin and various variants thereof, various water-soluble synthetic resins such as polyvinyl alcohol, vinyl acetate and the like are added. Granules are obtained by adding a synthetic resin emulsion, arabic rubber, casein, alginate, glucomannan, glycerin, sorbitan fatty acid ester and the like, mixing them, and then spray-drying them. Most of the obtained granules contain a pore-forming agent.

Before spray drying, coarse impurities and dust are removed by passing through a mesh with a particle size number of 2000 or a mesh finer than this mesh described in ASTM E 11-61. Further, iron and its compounds may be removed by a method such as removing iron with an iron remover using a magnetic force.

Next, the granules having the adjusted powder bulk density are filled in a molding die, and the pressure is applied to the filled granules at, for example, 78 Pa or more and 118 Pa or less, and the raw density is, for example, 1.8 g / cm ³ or more. Obtain a molded product having a weight of .95 g / cm ^{3 or less.}

The molded product is degreased in a nitrogen atmosphere at a temperature of 450 to 650 ° C. and a holding time of 2 to 10 hours to obtain a degreased body. The wear-resistant member of the present disclosure can be obtained by holding the degreased body in a vacuum atmosphere or a reduced pressure atmosphere of an inert gas such as argon gas at a temperature of 1800 ° C. or higher and 2200 ° C. or lower for 3 hours or longer and 5 hours or lower. Can be done.

Hereinafter, examples of the present embodiment will be specifically described, but the present embodiment is not limited to these examples.

(Example 1)
First, a predetermined amount of a sintering aid and a pore-forming agent was added to the α-type silicon carbide powder forming the main component. As the sintering aid, a boron carbide powder and an aqueous phenol solution were used. As the pore-forming agent, suspension-polymerized crosslinkable resin beads made of polyacrylic-styrene were used.

In order to obtain a fixed valve body, the content of the pore-forming agent and the average particle size (D ₅₀ ) with respect to 100 parts by mass of the powder of α-type silicon carbide were as shown in Table 1. Further, sodium polycarboxylate as a pore dispersant was added to each sample in an amount of 0.2% by mass based on 100% by mass of the pore forming agent to prepare a compounding raw material. After putting this compounding raw material into a ball mill for each sample, it was mixed for 48 hours to form a slurry. A binder was added to this slurry, mixed, and then spray-dried to obtain silicon carbide granules having an average particle size of 80 μm.

Next, the granules were filled in a molding die and pressed with a pressure of 98 MPa in the thickness direction to form a molded body. The obtained molded product was heated in a nitrogen atmosphere for 20 hours, held at 600 ° C. for 5 hours, and then naturally cooled to be degreased to obtain a degreased body. Next, the degreased body was held at 2030 ° C. for 5 hours in a vacuum atmosphere to obtain a fixed valve body 21 made of ceramics containing silicon carbide as a main component. On the other hand, the movable valve body 22 was adjusted so as to be made of dense ceramics containing silicon carbide as a main component without adding a pore forming agent and a pore dispersant.

The relative density of the ceramics forming the movable valve body 22 was set to 99%. Then, the surfaces of the fixed valve body 21 and the movable valve body 22 facing each other were polished to obtain sliding surfaces 21a and 22a. In each case, the flatness of the sliding surfaces 21a and 22a was 1 μm or less, and the arithmetic mean roughness (Ra) was 0.2 μm or less.

The average value (A) of the distance between the centers of gravity of the open pores on the sliding surface 21a of the fixed valve body 21 of each sample obtained, the average value (B) of the circle equivalent diameter of the open pores, and the average value from the average value (A). Table 1 shows the magnification of the value (C) obtained by subtracting (B) and the value (C) with respect to the average value (B).

Next, the faucet valve 20 shown in FIG. 3 was manufactured and a sliding test was performed. The faucet valve 20 used in this sliding test consists of a movable valve body 22 having a fluid passage 22b having a diameter of 5 mm in a disk-shaped body having an outer diameter of 30 mm and a wall thickness of 10 mm, and a disk having an outer diameter of 20 mm and a film thickness of 8 mm. It is composed of a fixed valve body 21 having a fluid passage 21b having a diameter of 5 mm in the shape.

After applying silicon grease to the sliding surface 21a of the fixed valve body 21, hot water at 80 ° C. is applied to the

fluid passages

21b and 22b while the fixed valve body 21 and the movable valve body 22 are pressed by the casing with an axial force of 294N. The injection was performed at a pressure of 1 MPa, and the operating force required to slide the movable valve body 22 by the lever 23 was measured. The measurement position of the lever 23 was set to a position 83 mm away from the fulcrum of the lever 23 in a straight line distance.

According to the evaluation criteria based on this sliding test, it was judged that the lever 23 having an operating force of 0.8 kg or less after sliding the movable valve body 20 100,000 times had good slidability. After sliding the movable valve body 20 160,000 times, the presence or absence of a leak (water leak) between the sliding surfaces 21a and 22a was examined. The results are shown in Table 1.

As shown in Table 1, sample No. The values (C) of 1 to 4 and 6 to 10 are 6 times or more the average value (B). Therefore, the sample No. It can be said that 1 to 4 and 6 to 10 have good slidability and can suppress the outflow of the fluid to the outside. Sample No. In 1 to 4, 6 to 10, the value (C) obtained by subtracting the average value (B) from the average value (A) is also 50 μm or more and 170 μm or less.

1 Open pores 2 Coarse granular silicon carbide particles 3 Fine granular silicon carbide particles 4 Intragrain pores 20 Faucet valve 21 Fixed valve body 22 Movable valve body 23 Lever 30 Piston cylinder unit 31 Piston ring 32 Piston 32a Piston head part 32b Piston skirt Part 33 Cylinder liner 34 Cylinder

Claims

It consists of ceramics whose main component is silicon carbide.
The value (C), which has a plurality of open pores on the sliding surface and is obtained by subtracting the average value (B) of the circle-equivalent diameters of the open pores from the average value (A) of the distance between the centers of gravity of the adjacent open pores, is the said. A wear resistant member that is 6 times or more the average value (B).
It consists of ceramics whose main component is silicon carbide.
A value (C) having a plurality of open pores on the sliding surface, obtained by subtracting the average value (B) of the equivalent circle diameters of the open pores from the average value (A) of the distance between the centers of gravity of the adjacent open pores, is 50 μm. A wear resistant member having a diameter of 170 μm or less.
The wear-resistant member according to claim 1 or 2, wherein the kurtosis Ku of the distance between the centers of gravity of the open pores is 0.3 or more and 4 or less.
The sliding surface has coarse-grained crystal particles and fine-grained crystal particles, and has
The wear-resistant member according to any one of claims 1 to 3, wherein the average value (D) of the equivalent circle diameters of the fine granular crystal particles is smaller than the average value (B) of the equivalent circle diameters of the open pores.
The wear-resistant member according to claim 4, wherein the difference between the average value (D) of the equivalent circle diameters of the fine granular crystal particles and the average value (B) of the equivalent circle diameters of the open pores is 5 μm or more. ..
The wear-resistant member according to claim 4 or 5, wherein the coarse-grained crystal particles are 5 area% or more and 15 area% or less.
The wear-resistant member according to any one of claims 4 to 6, wherein the coarse-grained crystal particles include intragranular pores.
Any of claims 1 to 7, wherein the ceramic contains sulfur, and the sulfur content is 0.02% by mass or less (excluding 0% by mass) in terms of oxide (SO 3). Abrasion resistant member according to.
It is equipped with a fixed valve body and a movable valve body that abut and slide on each other's sliding surfaces.
A faucet valve in which at least one of the fixed valve body and the movable valve body is made of the wear-resistant member according to any one of claims 1 to 8.
It is equipped with a fixed valve body and a movable valve body that abut and slide on each other's sliding surfaces.
The fixed valve body and the movable valve body are made of the wear-resistant member according to any one of claims 1 to 8, and the fixed valve body has a smaller value (C) than the movable valve body. ..
It comprises a piston equipped with a piston ring and a cylinder equipped with a cylinder liner having an inner peripheral surface that slides on the outer peripheral surface of the piston ring.
A piston / cylinder unit in which at least one of the cylinder liner and the piston ring is made of the wear-resistant member according to any one of claims 1 to 8.
It comprises a piston equipped with a piston ring and a cylinder equipped with a cylinder liner having an inner peripheral surface that slides on the outer peripheral surface of the piston ring.
A piston / cylinder unit in which the cylinder liner and the piston ring are made of the wear-resistant member according to any one of claims 1 to 8, and the value (C) of the cylinder liner is smaller than that of the piston ring.