JP2003336751A - Alumina ceramics valve element and warm water faucet valve using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve element made of alumina ceramics as a base substance and has high corrosion resistance of its slideway, and also to provide a warm water faucet valve using the valve element and having excellent durability. <P>SOLUTION: The alumina ceramics valve element is made of alumina ceramics as the base substance, the slideways of the base substance is covered with amorphous alumina and the top of it is covered with diamond-like carbon. The warm water faucet valve has at least a pair of valve elements which slide each other, and the alumina ceramics valve element of this constitution is used for at least one valve element. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alumina ceramics valve body based on alumina ceramics, and particularly to a hot water faucet valve such as a water faucet including a single lever mixing stopper, a switching lever mixing stopper and the like, and a mixing faucet. The present invention relates to an alumina ceramic valve body suitable as a movable valve body or a fixed valve body.

[0002]

2. Description of the Related Art Conventionally, a hot water faucet valve such as a single lever mixing tap or a switching lever mixing tap, which is composed of a movable valve element and a fixed valve element, has one of two disc-shaped valve elements. By sliding on one valve element, a fluid passage is formed or closed between the two valve elements. In this case, the sliding surfaces of the two valve bodies are always in sliding contact with each other, so the surface roughness is minimized by lapping, etc., and abnormal weight is applied during sliding to damage the sliding surfaces. It was devised not to receive it. As such a valve element, a valve element made of ceramics such as alumina ceramics has been used.

However, during use of such a valve element, the sliding surface is worn out, and thus is seized (caused by the uneven state of the sliding surface of the valve element and the inclusion of foreign matter,
This is a phenomenon in which frictional resistance becomes excessive and sliding does not occur. ), Or there was a problem that water leakage occurred. For this reason, many attempts have been made to solve these problems by coating the sliding surface with a diamond-like carbon film that is extremely smooth and has excellent self-lubricating properties. For example, JP-A-9
Japanese Patent Publication No. 963667 discloses a hot water faucet valve in which a valve body surface is directly coated with a diamond-like carbon film by an ECR plasma CVD method, and the diamond-like carbon film contains hydrogen at a ratio of 35 atomic% or less. Have been described.

On the other hand, various methods have been disclosed in which the diamond-like carbon film is not directly coated on the valve body surface, but the diamond-like carbon film is coated through an intermediate layer. For example, JP-A-5
JP-A-79069 discloses a hot water faucet valve in which a thin film of at least one kind selected from metals or their carbides, nitrides and carbonitrides is interposed while providing a graded composition, and a diamond-like carbon film is coated thereon. Is disclosed. Further, JP-A-6-227882 and JP-A-9-227882.
Japanese Unexamined Patent Publication No. 96368 discloses that the surface of the valve body is coated with diamond-like carbon as an intermediate layer via a Si-based non-oxide film such as silicon carbide. Further, Japanese Patent Application Laid-Open No. 9-292039 discloses coating a diamond-like carbon film on the surface of a ceramic valve body via an intermediate layer in which a Ti film and a Si film are laminated in this order.
Further, in Japanese Unexamined Patent Publication No. 10-89506, an intermediate layer made of titanium Ti or chromium Cr is provided on a sliding surface, another intermediate layer made of silicon Si or silicon carbide SiC is provided thereon, and a diamond is provided thereon. Disclosed is a hot water faucet valve coated with a carbon film. In addition, JP-A-10-
Japanese Patent No. 281312 discloses a hot water faucet valve in which silicon Si is used as an intermediate layer and a diamond-like carbon film is coated thereon.

On the other hand, attempts have been made to add elements other than the coating structure to the sliding surface of the valve body. For example, Japanese Patent Application Laid-Open No. 9-96368 discloses the shape and distribution of pores existing on the sliding surface of the valve body. Further, JP-A-9-31792 discloses that the surface of a valve body is coated with diamond-like carbon through a Si-based non-oxide film such as silicon carbide as an intermediate layer and the sliding surface of the other valve body. Is made of a silicon carbide sintered body, which has open pores with a three-dimensional mesh structure, so that the structure of a hot water faucet valve in which the pores are impregnated with a lubricant composed of at least one of fluorine oil and silicon oil Disclosure.

However, the hot water faucet valve using the valve element according to the technique disclosed in each of the above publications is used under high temperature and high humidity, or under a rapid temperature change due to hot water and cold water, Also, it may be used under severe conditions where a large load due to sliding is applied.
When used under such harsh conditions, all of the disclosed examples have low adhesion of the coating on the sliding surface, poor corrosion resistance to water, or a combination of these factors. It has made long-term use very difficult. Further, the hot water faucet valve by these techniques has a problem that the manufacturing cost is high and it is uneconomical.

That is, more specifically, the hot water faucet valve using the valve element according to the technique disclosed in each of the above publications has the following problems.

First, in the technique disclosed in JP-A-9-96367, the diamond-like carbon film is not easily adhered to the alumina ceramics constituting the sliding surface, so that the diamond-like carbon film is easily peeled off during use. However, galling occurred on the sliding surface.

Further, in the technique disclosed in Japanese Patent Laid-Open No. 5-79069, since the adhesion between the metal film as the intermediate layer and the diamond-like carbon film is low, the diamond-like carbon film is easily peeled off during use. However, galling occurred on the sliding surface.

Further, in the technique disclosed in Japanese Patent Laid-Open No. 6-227882, when alumina ceramics is used as the base body of the valve body, sufficient adhesion cannot be obtained with the intermediate layer made of amorphous Si. However, this may cause a problem of peeling at that portion.

On the other hand, in Japanese Patent Laid-Open No. 9-96368, a silicon carbide is formed using a PVD method such as ion plating as an intermediate layer on the sliding surface of an alumina valve, a CVD method, a sputtering method or the like. It is disclosed to coat the film, and in particular, it is explained that the silicon carbide film and the diamond-like carbon film can be continuously coated at a low temperature by using the ion plating method.
However, if the coating is carried out by a physical vapor deposition method such as the ion plating method, sufficient corrosion resistance cannot be obtained because the coating around the inside of the pores on the sliding surface of alumina becomes insufficient. It had a drawback.

Further, with the technique disclosed in Japanese Patent Laid-Open No. 9-292039, it is difficult to withstand long-term use because the corrosion resistance under the use environment is extremely low.

Further, in the technique disclosed in Japanese Patent Application Laid-Open No. 10-89506, when silicon Si is used as the intermediate layer, it is difficult to withstand long-term use because the corrosion resistance under the use environment is extremely low. . Also, when a metal compound other than Si is used as the intermediate layer, these intermediate layers are covered by a physical vapor deposition method such as a sputtering method, and therefore have low corrosion resistance in a use environment and cannot withstand long-term use. Met.

In the technique disclosed in Japanese Unexamined Patent Publication No. 9-31792, a valve body on the other side other than the valve body coated with the diamond-like carbon film is made of a silicon carbide sintered body. Since the silicon sintered body is an extremely hard ceramic and has extremely poor workability, it has an economical problem that the manufacturing cost becomes high.

[0015] Generally, a hot-water faucet valve using a valve body made of alumina ceramics coated with diamond-like carbon according to the prior art as disclosed in each of the above publications has a coating film when used. Due to lack of sufficient adhesion, the diamond-like carbon or the thin film of the intermediate layer was peeled off, and the alumina ceramics of the base was exposed at the peeled-off portion, causing a so-called galling phenomenon. Further, the exposed surface of the alumina ceramics was in a very rough state. On the other hand, even if the diamond-like carbon is not peeled off, the side wall surface of the pores existing on the sliding surface of the alumina ceramics is eroded, the particles of alumina fall off, and the particles cling between the two valve bodies. Was occurring.

[0016]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide high adhesion and high corrosion resistance to a sliding surface of an alumina ceramic valve body. It is intended to provide an alumina ceramics valve body having high sliding characteristics and excellent durability by coating the same with a coating having the above, and to provide a hot water faucet valve using the valve body.

[0017]

The present inventors have earnestly pursued a mechanism in which the diamond-like carbon film is peeled off or the inner wall of the pore is eroded on the sliding surface of the valve body based on alumina ceramics. In order to prevent these peeling and erosion, it is necessary to prevent the alkaline water from entering the inside of the pores existing on the sliding surface and prevent the grain boundaries existing therein from coming into contact with the alkaline aqueous solution. Based on this finding, further research was continued based on this finding, and the present invention was finally completed.

That is, the present invention is a valve body based on alumina ceramics, characterized in that the sliding surface of the base body is coated with amorphous alumina, and the sliding surface is coated with diamond-like carbon. A ceramic valve body is provided.

Further, the present invention is a valve body using alumina ceramics as a base, wherein the sliding surface of the base is coated with amorphous alumina, the upper surface of which is coated with an intermediate layer, and the upper surface of which is diamond-shaped. There is also provided an alumina ceramic valve body characterized by being coated with carbon.

The intermediate layer of the alumina ceramic valve body of the present invention is preferably coated by a physical vapor deposition method.

On the other hand, the above-mentioned amorphous alumina of the alumina ceramic valve body of the present invention is preferably coated by a chemical vapor deposition method.

According to the present invention, there is provided a hot water faucet valve having at least a pair of valve bodies that slide with each other, wherein the alumina ceramic valve body is used as at least one of the valve bodies. Will be provided.

The present invention has such a structure, and its technical background is as follows.

That is, (i) general tap water may become alkaline when heated for a long time, and this alkaline water promotes corrosion of the valve body.
i) The above corrosion easily proceeds inside the pores existing on the sliding surface of the valve body, particularly from the grain boundary phase of the alumina ceramic particles present there, and (iii) Corrosion resistance to alkali such as Si film A low coating is not suitable for coating this type of sliding surface. (Iv) When coating the sliding surface by physical vapor deposition, it is not possible to coat the inside of the pores uniformly regardless of the type of coating material. Be very difficult,
And (v) the coating film of diamond-like carbon has a high internal stress, and therefore promotes peeling of the coating film when the above-described corrosion occurs.

The inventors of the present invention have conducted further research based on the above-mentioned findings obtained by the research of the inventors as a technical background. According to the alumina ceramic valve body having the above-mentioned constitution, It was found that the problem could be solved in a hurry. Therefore, the alumina ceramic valve body of the present invention exhibits the following excellent effects.

The alumina ceramic valve body of the present invention has a structure in which the sliding surface made of alumina ceramics is coated with amorphous alumina as described above. Then, this amorphous alumina is preferably coated by using a chemical vapor deposition method. By adopting such a configuration, the present invention can evenly coat the sliding surface with amorphous alumina even if the sliding surface has a complicated three-dimensional shape. Even if pores of various sizes and shapes are present on the moving surface, it is possible to completely cover even the inner surface of the pores. Moreover, the amorphous alumina is more excellent in alkali resistance than the Si film.

Therefore, conventional coating layers employing physical vapor deposition (eg titanium Ti, silicon Si, chromium C).
single metal film or non-metal film such as r, or silicon S
The coating of the inside of the pores, which was almost impossible with the coating method using the carbide of i), is completely possible with the amorphous alumina that employs the chemical vapor deposition method, and the amorphous alumina has excellent alkali resistance. These effects work together to completely cover the grain boundary phase between the alumina ceramic particles exposed inside the pores, and completely prevent the intrusion of alkaline water that causes valve corrosion. Was achieved.

Further, since the sliding surface is coated with an amorphous material, the problem of surface irregularity, which has been a problem when coated with a crystalline material, does not occur at all. In other words, the surface coated with amorphous alumina does not generate sharp peaks and dips due to the crystal grains grown from the sliding surface, and it is possible to eliminate the problem of galling and film peeling caused by the bumps and dips. Became possible. Further, when an object is coated with an amorphous coating, it is generally possible to coat at a temperature lower than the temperature at which the coating is coated with a crystalline coating, which is economically superior.

Further, since the surface of the alumina ceramics is coated with the amorphous alumina, the adhesion between them is very excellent, and the amorphous ceramics other than the amorphous alumina are used. In some cases, peel resistance properties that cannot be obtained at all are obtained.

In the present invention, as a result of synergistically exhibiting the above-mentioned effects, the adhesion of diamond-like carbon to the sliding surface is dramatically improved, and the alkali that causes corrosion of the valve body and valve is also improved. It has become possible to completely prevent the ingress of water. Therefore, the alumina ceramics valve body of the present invention has high sliding characteristics and excellent corrosion resistance, and the hot water faucet valve using this valve body exhibits extremely excellent durability because these excellent characteristics are exhibited. Will have.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION <Structure of the Invention> The structure of an alumina ceramic valve body of the present invention and a hot water faucet valve using the same will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a schematic cross-sectional view of an example of the valve body of the present invention. A sliding surface 3 of a base 2 made of alumina ceramics is coated with amorphous alumina 4, and diamond-like carbon 5 is formed on the sliding surface 3. Alumina ceramic valve body 1 coated with
Is represented. FIG. 2 is a schematic sectional view showing an example of another valve body of the present invention, which is characterized in that an intermediate layer is provided. The sliding surface 13 of the base 12 made of alumina ceramics is shown in FIG. Coated with amorphous alumina 14,
This shows an alumina ceramic valve body 11 in which the intermediate layer 16 is coated thereon and the diamond-like carbon 15 is coated thereon. The structure of the valve body of the present invention is not limited to those shown in FIGS. 1 and 2.

<Alumina Ceramics Valve Body> The alumina ceramics valve bodies 1 and 11 of the present invention are composed of alumina ceramics as substrates 2 and 12, respectively. Here, the alumina ceramics are not particularly limited in composition as long as they are conventionally known alumina ceramics, and any of them can be used. As an example, there may be mentioned one having an alumina content of 90% by mass or more and the balance being SiO ₂ or MgO.

<Sliding Surface> In the present invention, the sliding surfaces 3 and 13 of the valve body are naturally made of alumina ceramics. The sliding surface is preferably subjected to lapping or the like for the purpose of preventing galling during sliding so that the surface roughness is made as small as possible. As a preferred surface roughness, the surface roughness Ra is 0.01 to 0.1 μ.
m, and more preferably about 0.01 to 0.05 μm. Further, it is preferable that pores are present on the sliding surface in order to make the sliding more lubricous. This is because a very small amount of water accumulates in these pores, which serves as a lubricant. The size of such pores is not particularly limited, but is usually 2 to 10 μm, preferably 3 to
About 8 μm is preferable, and the proportion of such pores is preferably 10 to 5 with respect to the entire area of the sliding surface.
It is suitable to be 0%, more preferably about 30 to 40%.

<Amorphous Alumina> In the present invention, the sliding surfaces 3 and 13 made of alumina ceramics are coated with amorphous alumina 4 and 14. The amorphous alumina referred to in the present invention can be confirmed to be in an amorphous state by X-ray diffraction. Such amorphous alumina 4, 14 can be obtained by reacting a component containing aluminum such as aluminum chloride with a component containing oxygen such as carbon dioxide. In the present invention, the sliding surface 3 made of amorphous alumina 4, 14
As a coating method for No. 13, it is necessary to adopt a chemical vapor deposition method. According to such a chemical vapor deposition method, even a three-dimensionally complex shape can be uniformly coated,
In particular, it becomes possible to sufficiently cover the inner surfaces of various pores existing on the sliding surface, which is difficult to perform by the physical vapor deposition method. Further, as such a chemical vapor deposition method, for example, a plasma CVD method can be cited. An example thereof is a method of keeping the temperature in the reaction furnace at 400 to 700 ° C. and reacting aluminum chloride with carbon dioxide gas. However, the method is not limited to this, and various known methods are used for coating. can do. Amorphous alumina 4, 14 of the invention coated in this way
Is preferably coated so that the thickness of the coating is 0.05 to 1.0 μm, preferably 0.1 to 0.5 μm. If the thickness is less than 0.05 μm, the grain boundary phase of the alumina ceramics exposed on the inner surface of the pore may not be sufficiently covered, and if it is coated at about 1.0 μm, it can usually be sufficiently covered. On the other hand, conversely, it is uneconomical to coat the coating with 1.0 μm or more.

<Intermediate Layer> In the present invention, the sliding surfaces 3, 13 of the alumina ceramic valve bodies 1, 11 are coated with the amorphous aluminas 4, 14 as described above. An intermediate layer 16 may be further coated on the alumina coating. Examples of such an intermediate layer 16 include a single layer film or a composite film made of a metal such as silicon Si, titanium Ti, or chromium Cr and / or a nitride, a carbide, or a carbonitride of these metals. By providing such an intermediate layer 16, it becomes possible to further improve the adhesion of diamond-like carbon described later. Such an intermediate layer 16 is preferably formed by a conventionally known physical vapor deposition method such as a sputtering method such as magnetron sputtering or RF sputtering, or an ion plating method. Such an intermediate layer 16 is usually 0.05 to 1.0 μm, preferably 0.1 to 0.8 μm.
It is preferable to coat with a thickness of m. The thickness is 0.0
When the thickness is less than 5 μm, the adhesion of the diamond-like carbon film is low, while when the thickness is more than 1.0 μm, the adhesion is not significantly improved but rather uneconomical. Intermediate layer 16 coated by such a physical vapor deposition method
Covers at least the sliding surface 13 of the valve body, and also covers a part of the inside of the pores existing on the sliding surface. The physical vapor deposition method is generally performed at room temperature or a temperature near room temperature.
After coating 14 with the same object, the same object can be cooled in the same apparatus and continuously treated, while after being coated with the amorphous alumina 4 and 14 once taken out of the apparatus and transferred to another dedicated apparatus. It can be changed and processed.

<Diamond-like carbon> Diamond-like carbon 5 coated on the above-mentioned amorphous alumina 4, 14 or, if the intermediate layer 16 is provided, if necessary, on the intermediate layer 16. , 15 and DLC (D
iamond Like Carbon), hard carbon, or amorphous carbon, and is amorphous, and at least some of the carbon-carbon bonds include carbon composed of sp ³ carbon bonds. Say. Such diamond-like carbons 5 and 15 are
It is suitable for use in fields where high sliding characteristics are required because it has a characteristic of being extremely hard against opponent attack while being hard. As a method for coating the above-mentioned amorphous alumina 4 and the intermediate layer 16 with the diamond-like carbons 5 and 15, any of the conventionally known physical vapor deposition method and chemical vapor deposition method may be adopted. However, it is not limited as long as it can cover at least the sliding surface. The diamond-like carbon 5, 15 has a thickness of 0.1 to 2 μm, preferably 0.5 to
It is preferably 1.5 μm. When the thickness is less than 0.1 μm, the sliding characteristics cannot be sufficiently exhibited, while when the thickness is more than 2 μm, the diamond-like carbon may peel off due to high internal stress of the coating film.

<Hot Water Valve> The hot water valve of the present invention is
One having at least a pair of valve bodies (for example, a movable valve body and a fixed valve body) that slide with each other, and at least one of these valve bodies is composed of the alumina ceramic valve body of the present invention as described above. Is. The pair of valve bodies slide with each other to open and close the fluid passage between the valve bodies. Examples of such a hot water faucet valve include a single lever mixing stopper and a switching lever mixing stopper.

[0039]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

Example 1 Using alumina ceramics having an alumina content of 94 mass% and the balance of SiO ₂ and MgO, two alumina ceramics valve bodies were formed on the basis of the alumina ceramics. Subsequently, after lapping the sliding surfaces of the two valve bodies, the surface roughness Ra was 0.02 μm when the surface roughness of the sliding surfaces was measured.
Met. When the sliding surface was observed, a large number of pores with a maximum diameter of 15 μm and an average of 6 μm were observed in both valve bodies, and the ratio of the area occupied by all the pores to the total area of the sliding surface was 35%. .

The two valve bodies were set in a film forming apparatus, and the sliding surface of each valve body was coated with amorphous alumina by a plasma CVD method which is one of the chemical vapor deposition methods. As a specific condition of the plasma CVD method, the temperature inside the furnace of the apparatus was heated to 500 ° C., and aluminum chloride and carbon dioxide were used to react them by RF discharge. The thickness of the amorphous alumina coating thus coated was 0.4 μm, and it was confirmed by X-ray diffraction that the coating was amorphous.

Next, the valve body thus coated with amorphous alumina is continuously set in the same film forming apparatus as described above, and plasma CVD is performed on the amorphous alumina coating.
By coating diamond-like carbon with a thickness of 1.4 μm by the method, an alumina ceramic valve body of the present invention was obtained.

When the valve body thus obtained was cut and the cross section thereof was observed, it was confirmed that the inner walls of the pores present on the sliding surface were substantially sufficiently covered with amorphous alumina. did.

When a hot water faucet valve was produced using such a valve body, the hot water faucet valve had excellent sliding characteristics, as is apparent from the following evaluation test.

Example 2 Two amorphous alumina valve bodies coated with amorphous alumina were obtained in the same manner as in Example 1 up to the point of coating with amorphous alumina.

Next, this valve body is set in a film forming apparatus capable of both the plasma CVD method and the sputter deposition method,
On the amorphous alumina coating, a Si film as an intermediate layer was coated to a thickness of 0.2 μm by a sputter deposition method, and then diamond-like carbon was deposited to 1.4 μm by a plasma CVD method.
The alumina ceramic valve body of the present invention was obtained by forming a coating with a thickness of m.

When the valve body thus obtained was cut and the cross section thereof was observed, it was confirmed that the inner walls of the pores present on the sliding surface were substantially sufficiently covered with amorphous alumina. did. Further, it was confirmed that the Si film as the intermediate layer covers a part of the inside of the pore, but it was confirmed that it was limited to only the region near the sliding surface and the deep part inside the pore was not covered.

When a hot water faucet valve was produced using such a valve body, the hot water faucet valve had excellent sliding characteristics, as is apparent from the following evaluation test.

<Comparative Example 1> In Example 2, except that the Si film and the diamond-like carbon film, which are intermediate layers, were directly formed on the sliding surface of the valve body without coating the amorphous alumina. A valve body was manufactured under the same conditions as in Example 2 except for the above.

After the valve body thus produced was cut, its cross section was observed in the same manner as in Examples 1 and 2 above. As a result, the intermediate Si film was the same as in Example 2 above. It was confirmed that only the region close to the sliding surface was covered, and the deep part inside the pore was not covered.

<Evaluation Test 1> The valve bodies obtained in Examples 1 and 2 and the valve body obtained in Comparative Example 1 were placed in hot water at 90 ° C. for 1 day.
Hold for 50 hours. The temperature of the hot water was set so that the temperature of 90 ° C could be maintained during that period.

After the passage of the above time, these valve elements were taken out from the hot water and the sliding surfaces of the respective valve elements were observed using a scanning electron microscope. The sliding surfaces of the valve elements of Examples 1 and 2 were While no phenomenon such as peeling occurred without any change from the state before being subjected to this evaluation test, the sliding surface of the valve body of Comparative Example 1 did not peel at the periphery of the pore of the sliding surface. Many were observed. Further, elemental analysis of this peeling portion by EDX confirmed that the peeling occurred at the interface between the Si film and the alumina ceramic substrate, because aluminum Al and oxygen O were detected. It was also confirmed that inside the pores of the valve body of Comparative Example 1, the grain boundary phase of alumina ceramics was eluted on the inner wall of the pores.

<Evaluation Test 2> The valve bodies of Examples 1 and 2 and the valve body of Comparative Example 1 were subjected to the evaluation test 1 described above, and then a hot water faucet valve was produced using each valve body, When 200,000 times of sliding was repeated while flowing hot water through the valve, the valves using the valve bodies of Examples 1 and 2 had low torque and were stable, whereas the valve body of Comparative Example 1 was stable. With the valve using, the torque became abnormally high after sliding 40,000 times.

From the results of these evaluation tests 1 and 2, the valve element of the embodiment of the present invention in which the sliding surface made of alumina ceramics was coated with amorphous alumina was obtained.
It is clear that the sliding characteristics are greatly improved.

The embodiments and examples disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

[0056]

The alumina ceramic valve body of the present invention is
By coating the sliding surface composed of alumina ceramics with amorphous alumina, the diamond-like carbon film existing on the surface of the valve body is not peeled off, and the amorphous alumina can be used as the sliding surface. It completely covers the inside of various existing pores, especially the grain boundary phase of alumina ceramics, so it is possible to completely prevent the intrusion of alkaline water that causes corrosion. It was

Therefore, the hot water faucet valve using the alumina ceramics valve body of the present invention has excellent sliding characteristics and excellent corrosion resistance.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an alumina ceramic valve body of the present invention.

FIG. 2 is a schematic cross-sectional view of an alumina ceramic valve body of the present invention when an intermediate layer is provided.

[Explanation of symbols]

1,11 Alumina ceramic valve body, 2,12 base,
3,13 Sliding surface, 4,14 Amorphous alumina, 5,15
Diamond-like carbon, 16 intermediate layer.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C23C 16/40 C23C 16/40 F16K 11/074 F16K 11/074 B (72) Inventor Akihiko Ikegaya Itami Hyogo Prefecture 1-1 1-1, Kunyo Kita, Ichi, Sumitomo Electric Industries, Ltd. Itami Works (72) Inventor, Yasushi Fujinami 575, Kuze-Denjo-cho, Minami-ku, Kyoto-shi, Kyoto Prefecture IT F Co., Ltd. (72) Inventor Hisanori Ohara 575, Kuze-Donojo-cho, Minami-ku, Kyoto-shi, Kyoto Prefecture F-term in ITF Co., Ltd. (Reference) 3H053 AA23 BA16 BA38 DA02 DA03 3H067 AA13 CC23 EA23 EA29 4K029 AA04 BA07 BA17 BA35 BA55 BA58 BA60 BC01 BD03 FA07 GA03 4K030 BA28 BA43 BB05 LA11

Claims (5)

[Claims] 1. A valve body based on alumina ceramics, wherein the sliding surface of the base body is coated with amorphous alumina, and the top surface is coated with diamond-like carbon. 2. A valve body based on alumina ceramics, the sliding surface of which is coated with amorphous alumina, which is covered with an intermediate layer, and which is further coated with diamond-like carbon. Alumina ceramic valve body made by. 3. The alumina ceramic valve body according to claim 2, wherein the intermediate layer is coated by a physical vapor deposition method. 4. The alumina ceramic valve body according to claim 1, wherein the amorphous alumina is coated by a chemical vapor deposition method. 5. A hot water faucet valve having at least a pair of valve bodies that slide with each other, wherein the alumina ceramics valve body according to any one of claims 1 to 4 is used for at least one of the valve bodies. There was a hot water valve.