KR20000027033A - High hydrophilic and low fractional ceramic folding products - Google Patents

Abstract

PURPOSE: A ceramic folding product for a switch valve is provided to have high mechanical strength and high hydrophilic property, and low frictional and low abrasion properties in the water. CONSTITUTION: A ceramic folding product(2) is spreaded homogeneously a composite oxide of spinel structure(4) of anhydrous aluminum(MAl2O4) having as the same particle size as aluminum in the a mother material(3) of alpha-aluminum (alpha-Al2O3), in the form of a solid solution or a compound, in which M is one metal selected from Mg, Zn, Co, Ni, Cu, Mn and Fe, the content of MAl2O4 is 5-50wt%. The ceramic product is produced in a low price and used for a valve of a tap.

Description

High Hydrophilic Low Friction Ceramics Sliding Member

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high hydrophilic low friction ceramic sliding member used for on / off valves such as taps of water.

Conventionally, as disclosed in JP-A-6-932117 or JP-A-7-108774, a material for reducing the friction coefficient in water is coated with diamond-like carbon on the surface of an alumina material. Background Art A coating of a mixture of silicon carbide and carbon on a surface, ceramics in which many pores of water flow are uniformly dispersed, solid lubricant impregnated ceramics, oil impregnated ceramics, and the like are known. However, the conventional materials have problems such as insufficient strength, a lubricating coating peeling off, and a high manufacturing cost.

Disclosure of Invention An object of the present invention is to provide a high hydrophilic low friction ceramic sliding member having low manufacturing cost, high mechanical strength, and excellent lubricity in water in view of the above problems.

Structure diagram schematically showing a high hydrophilic low friction ceramic sliding member of the first embodiment of the present invention.

2 is a diagram showing the characteristics of the high hydrophilic low friction ceramic sliding member.

3 is a diagram showing the characteristics of the copper high hydrophilic low friction ceramic sliding member.

4 is a diagram showing the characteristics of the copper high hydrophilic low friction ceramic sliding member.

5 is a diagram showing the characteristics of the high hydrophilic low friction ceramic sliding member.

6 is a schematic structural diagram of a high hydrophilic low friction ceramic sliding member of a second embodiment of the present invention;

7 is a diagram showing the relationship between the anhydrous aluminate (MAl ₂ O ₄ ) and the friction coefficient contained in the copper ceramic sliding member.

8 is a diagram showing the relationship between the content of anhydrous aluminate (MAl ₂ O ₄ ) contained in the copper sliding member, and the coefficient of friction and strength, respectively.

9 is a schematic structural diagram showing a high hydrophilic low friction ceramic sliding member of a third embodiment of the present invention;

10 is a diagram showing the friction characteristics between the copper ceramic sliding member and a conventional aluminum material.

Fig. 11 is a graph showing the relationship between the amount of ZnO.nAl ₂ O ₃ added and the strength in the copper ceramic sliding member.

Fig. 12 is a graph showing the relationship between the aspect ratio and the strength of ZnO.nAl ₂ O ₃ particles in the copper sliding member.

Fig. 13 is a schematic diagram schematically showing a high hydrophilic low friction ceramic sliding member of a fourth embodiment of the present invention.

Fig. 14 is a diagram showing the friction characteristics between the copper ceramic sliding member and a conventional aluminum material.

Fig. 15 is a diagram showing the amount of ZnAl ₂ O ₄ added and the friction characteristics in the copper sliding member.

16 is a diagram showing wear resistance between a ceramic sliding member of the present invention and a conventional aluminum material.

17 is a diagram showing wear resistance of the ceramic sliding member of the present invention and a conventional aluminum material.

Explanation of symbols on the main parts of the drawings

2: high hydrophilic low friction ceramic sliding member

3. Mother Phase of α-Al ₂ O ₃

4: composite oxide particles mainly composed of ZnAl ₂ O ₄

5: compound particle of titanium (Ti)

12: high hydrophilic low friction ceramic sliding member

13: α-alumina (α-Al ₂ O ₃₎ matrix of

14: composite oxide particles mainly containing ZnAl ₂ O ₄

22: high hydrophilic low friction ceramic sliding member

23: mother phase 24: needle (plate) composite oxide particles

25: composite oxide particles of spinel crystal structure

32: high hydrophilic low friction ceramic sliding member

33: matrix 34: needle (plate) composite oxide particles

35: composite oxide particles with spinel crystal structure

42: high hydrophilic low friction ceramic sliding member

43: matrix 44: needle (plate) composite oxide particles

45: composite oxide particles of spinel crystal structure

In order to solve the above problems, the constitution of the present invention is that a composite oxide particle containing zinc aluminate (ZnAl ₂ O ₄ ) as a main component in a matrix of α-alumina (α-Al ₂ O ₃ ) is a solid solution or Uniformly dispersed as a compound, at least one of titanium (Ti) compound particles and iron (Fe) compound particles at the grain boundaries of the α-alumina (α-Al ₂ O ₃ ) and the composite oxide particles Characterized by the presence of.

In addition, the configuration of the present invention is a needle (針相) and / or plate-like composite oxide particles as a main component therein, zinc (Zn) and aluminum (Al) in a matrix of α-alumina (α- Al ₂ O ₃₎ It is characterized by being uniformly dispersed.

In addition, the configuration of the present invention is α-alumina (α- Al ₂ O ₃₎ in the interior of a matrix of zinc (Zn) and aluminum needle and / or the composite oxide particles of plate-like as a main component (Al) and, ZnAl ₂ O _It is characterized by uniformly dispersing a composite oxide particle having a spinel crystal structure of ₄ .

In the present invention, a composite oxide composed of aluminum (Al) and niobium (Nb) containing AlNbO ₄ as a main component is dispersed as a compound or a solid solution in a mother phase made of alumina (Al ₂ O ₃ ), or alumina (Al ₂ A composite oxide composed of aluminum (Al) and zinc (Zn) mainly containing ZnAl ₂ O ₄ as a main phase of O ₃ ) is dispersed as a compound or a solid solution.

[Embodiment of the Invention]

In the present invention, by adding a compound of zinc (Zn) as an auxiliary component to the alumina (Al ₂ O ₃ ) -based ceramic sliding member, the affinity with water is increased and the coefficient of friction in water is reduced.

By adding one or both of titanium (Ti) compounds and iron (Fe) compounds as sintering aids to the alumina (Al ₂ O ₃ ) -based ceramic sliding members, the sintering properties are increased and the mechanical strength of the sintered bodies is increased. will be.

Alumina (Al ₂ O ₃₎ in anhydrous aluminate (MAl ₂ O ₄₎ the writing by firing by the addition of a divalent metal compound which can generate, alumina anhydrous aluminate in the interior of the matrix of (Al ₂ O ₃₎ in (MAl ₂ O ₄ ) is dispersed. As a result, the ceramic sintered body exhibits high water adsorption and low friction in the presence of water, and is suitable for sliding members.

ZnO · nAl ₂ O ₃ acicular composite oxide particles and ZnAl ₂ O ₄ composite oxide particles (or ZnAl ₂ O ₄ ) on the matrix of α-Al ₂ O ₃ to satisfy hydrophilicity, strength, toughness and friction coefficient Composite oxide particles of AlNbO ₄ ) are uniformly dispersed.

The composite oxide particles of ZnAl ₂ O ₄ , which have a spinel crystal structure with strong water absorption characteristics, enhance the hydrophilicity of the material. Acicular composite oxide particles of ZnO.nAl ₂ O ₃ secure the strength and toughness of the material.

EXAMPLE

As shown in FIG. 1, the high hydrophilic low friction ceramic sliding member 2 according to the present invention has an average particle diameter of 6 μm in the inside of the mother phase ₃ of α alumina (α-Al ₂ O ₃ ) having an average particle diameter of 6 μm. of the composite oxide particles (4) mainly composed of ZnAl ₂ O ₄ is uniformly dispersed as solid solution or compound, and, α-alumina (α-Al ₂ O ₃₎ of which the main component is a matrix (3), and ZnAl ₂ O ₄ Titanium (Ti) compound particles 5 are present at the grain boundaries with the composite oxide particles 4.

Instead of titanium (Ti) compound particles, iron (Fe) compound particles may be present at the grain boundaries, and both titanium (Ti) compound particles and iron (Fe) compound particles may be present at the grain boundaries.

The high hydrophilic low friction ceramic sliding member according to the present invention can be obtained by adding a divalent metal compound capable of producing anhydrous aluminate (MAl ₂ O ₄ ) to alumina (Al ₂ O ₃ ) and then firing it. .

As shown in FIG. 6, the sintered body as the ceramic sliding member 12 is anhydrous aluminate having the same particle diameter as that of the alumina (Al ₂ O ₃ ) in the base 13 of the alumina (α-Al ₂ O ₃ ). (MAl ₂ O ₄ ) The composite oxide particles 14 of the spinel crystal structure are uniformly dispersed as a solid solution or a compound. Here, M represents a metal element that combines with Al ₂ O ₃ to form a salt.

The content of anhydrous aluminate (MAl ₂ O ₄ ) in the ceramic sliding member is ₅ to 50 wt%. The metal (M) of the anhydrous aluminate represented by the formula MAl ₂ O ₄ is magnesium (Mg), zinc (Zn), cobalt (Co), nickel (Ni), copper (Cu), manganese (Mn), iron ( Fe) at least one.

As shown in FIG. 9, the high hydrophilic low friction ceramic sliding member 32 according to the present invention includes zinc (Zn) and aluminum () in the α alumina (α-Al ₂ O ₃ ) mother phase 33. Needle-shaped or plate-shaped composite oxide particles 34 mainly composed of Al) are uniformly dispersed. The needle-like or plate-shaped composite oxide particles 34 have an average composition ratio (ZnO; Al ₂ O ₃ ) of 1: 3 or more when zinc (Zn) and aluminum (Al) of the main components are converted into oxides. The aspect ratio of the needle-shaped composite oxide particles 34 is three or more.

As shown in Fig. 13, the high hydrophilic low friction ceramic sliding member 42 according to the present invention is formed of zinc (Zn) and aluminum () in the matrix 43 of α-alumina (α-Al ₂ O ₃ ). A needle-like or plate-shaped composite oxide particle 44 composed of ZnO.nAl ₂ O ₃ mainly composed of Al) and a composite oxide particle 45 having a spinel crystal structure of ZnAl ₂ O ₄ are uniformly dispersed.

The content of the composite oxide particles 45 having the spinel crystal structure of ZnAl ₂ O ₄ contained in the high hydrophilic low friction ceramic sliding member according to the present invention is 30 wt% or less.

The high hydrophilic low friction ceramic sliding member according to the present invention exhibits excellent durability and low friction in the presence of water.

(Specific Example 1)

A plurality of molded bodies were produced by varying the amount of addition of zinc oxide (ZnO) powder using alumina (Al ₂ O ₃ ) powder as a main raw material. Each compact was calcined for 3 hours in an atmosphere at a temperature of 1550 ° C to obtain a sintered compact. FIG. 1: is a schematic diagram which shows the structure of the ceramic sliding member 2 as an obtained sintered compact. The test piece for ceramic sliding members having a diameter of 35 mm and a thickness of 5 mm was produced from the sintered body described above, and the surface of the test piece for ceramic sliding members was smoothed to a smoothness (Rmax) of 0.4 or less by lapping. Tap water was dropped on the surface of the test piece for ceramic sliding members obtained as described above, and the contact angle of the water droplets was measured. The alumina (Al ₂ O ₃ ) test piece was polymerized on the test piece for the ceramic sliding member according to the present invention, and the friction coefficient was measured by performing a sliding test in which both were rubbed with a pressing load of 23.6 Kgf in water at a temperature of 25 ° C. .

In addition, a four-point bending strength test piece for a rod-shaped ceramic sliding member having a width of 4 mm, a thickness of 3 mm, and a length of 40 mm was produced from the sintered body described above, and a four-point bending strength test (JIS R 601) was performed.

As apparent from Fig. 2, the ceramic sliding member 2 according to the present invention has a contact angle (wetting angle) of water droplets as small as 25 ° by adding zinc oxide (ZnO) powder to an alumina (Al ₂ O ₃ ) powder raw material. The friction coefficient is reduced to 0.25. That is, it can be seen that the ceramic sliding member according to the present invention has high hydrophilicity and low friction. However, when the amount of zinc oxide (ZnO) powder added to the alumina (Al ₂ O ₃ ) powder raw material is 8 wt% or less, the effect on the sinterability of the molded body is not sufficient, and the oxidation to the alumina (Al ₂ O ₃ ) powder raw material is not sufficient. When the addition amount of zinc (ZnO) powder exceeds 30%, as shown in FIG. 3, the sinterability of a molded object will deteriorate remarkably, and mechanical strength will also fall rapidly. It was also found that due to the deterioration of sinterability, crystal grains dropped during the sliding test of the test piece obtained from the sintered body and the friction coefficient increased.

(Specific Example 2)

As a main raw material, alumina (Al ₂ O ₃ ) powder was added, 10 wt% of zinc oxide (ZnO) powder was added, and a plurality of molded bodies were prepared by changing the addition amount of titanium oxide (TiO ₂ ) powder from 0 wt% to 10 wt%. . The test piece was processed into the sintered compact obtained by baking each molded object similarly to the case of Example 1, and the contact angle, friction coefficient, and 4-point bending strength of the water droplet were measured.

As apparent from FIG. 4, by using alumina (Al ₂ O ₃ ) powder as a main raw material and adding titanium oxide (TiO ₂ ) powder in addition to zinc oxide (ZnO) powder, the sinterability of the molded body is improved and the four-point bending strength is 300. It was recognized that the mechanical strength was increased to -380 MPa. However, when the addition amount of the titanium oxide (TiO ₂ ) powder to the alumina (Al ₂ O ₃ ) powder and zinc oxide (ZnO) powder is 0.5wt% or less, the effect on the sinterability of the molded body is not sufficient, and the alumina (Al ₂ O ₃ ) When the addition amount of the titanium oxide (TiO ₂ ) powder to the powder and the zinc oxide (ZnO) powder exceeds 5%, it was found that the mechanical strength of the test piece rapidly decreased. Moreover, the sinterability of a molded object deteriorates remarkably, and mechanical strength also falls rapidly. In addition, it was recognized that the crystal grains dropped during the sliding test of the test piece obtained from the sintered body due to the deterioration of the sintering property and the friction coefficient increased.

(Example 3)

A test piece using the iron oxide (Fe ₂ O ₃ ) powder instead of the titanium oxide (TiO ₂ ) powder as an additive was tested in the same manner as in Example 2, and a ceramic sliding member having excellent sinterability without impairing hydrophilicity and low friction was obtained. I could see what I could get.

(Example 4)

10 wt% of zinc oxide (ZnO) powder and 1 wt% of titanium oxide (TiO ₂ ) powder are added using alumina (Al ₂ O ₃ ) powder as a main raw material, and the addition amount of iron oxide (FeO ₃ ) powder is added from 0 wt% The several molded object was produced by changing to 10 wt% in various ways. Each molded body was baked in the same manner as in Example 1, and the test piece was processed into the obtained sintered body, and the contact angle, friction coefficient, and four-point bending strength of the water droplets were measured.

As apparent from FIG. 5, the mechanical strength of the ceramic sliding member obtained by adding appropriate amounts of titanium oxide (TiO ₂ ) powder and iron oxide (Fe ₂ O ₃ ) powder as a sintering aid to alumina (Al ₂ O ₃ ) powder as a main raw material is It was found to improve.

(Specific Example 5)

Using alumina (Al ₂ O ₃ ) powder as a main raw material, 10 wt% of one of metal oxides of Mg, Zn, Co, Ni, Cu, Mn, and Fe was added, and a small amount of a sintering aid was added to form a molded body.

The molded body was fired in an atmosphere having a temperature of 1300 to 1600 ° C. to obtain a sintered body (sample). FIG. 6: is a schematic diagram which showed the structure of the ceramic sliding member 12 as an obtained sintered compact. The sintered compact (sample) of this invention produced the disk-shaped test piece of diameter 35mm and thickness 5mm, and smoothed the surface roughness Rmax to the plane of 0.4 or less by lapping finishing. The two test pieces thus obtained were polymerized with each other and subjected to a sliding friction test in water at a temperature of 25 ° C. to measure the friction coefficient.

As apparent from FIG. 7, the ceramic sliding member (sample) of the sintered compact of the present invention forms an anhydrous aluminate (MAl ₂ O ₄ ) in the alumina (Al ₂ O ₃ ), so that the coefficient of friction in water is higher than that of the alumina alone. It was confirmed that is small and the water adsorption property is strong. The reason for this is that the pores that are not coordinated with the cation of the anhydrous aluminate (MAl ₂ O ₄ ) spinel structure compound exhibit polarity and strongly adsorb water.

(Specific Example 6)

The alumina (Al ₂ O ₃ ) powder was used as the main raw material, and the amount of zinc oxide (ZnO) was changed to measure the sliding characteristics and strength of the ten sintered bodies (samples) having different contents of zinc aluminate (ZnAl ₂ O ₄ ). .

As shown in Figure 8 is apparent, the ceramic sliding member (specimen) as a sintered body according to the present invention is to aluminate, zinc is many, the content of the 10% aluminate of zinc (ZnAl ₂ O _4), the content of (ZnAl ₂ O ₄₎ It can be seen that the friction coefficient decreases accordingly. According to the present invention, when the content of zinc aluminate (ZnAl ₂ O ₄ ) occupied in the sintered compact is 10 to 55 wt%, the friction coefficient exhibits good sliding characteristics of 0.3 or less. As for the strength of the sintered body according to the invention the content of the aluminate of zinc (ZnAl ₂ O ₄₎ aluminate, zinc (ZnAl ₂ O ₄₎ is occupied in, and sintered body strength is gradually decreased according to many, the content of which occupies the sintered body 50 If it exceeds%, the strength is significantly reduced, making it unsuitable for use as a sliding member.

(Specific Example 7)

ZnO · nAl ₂ O ₃ acicular composite oxide powder containing zinc (Zn) and aluminum (Al) and a small amount of sintering aid powder are added to α alumina (α-Al ₂ O ₃ ) powder as a main raw material. A molded article of a predetermined shape was produced. The molded body was fired in the air to obtain a ceramic sliding member (sample) 32 as a sintered body. 9 is a schematic diagram schematically showing the structure of the obtained ceramic sliding member 32. The ceramic sliding member 32 of the present invention is a needle and / or ZnO.nAl ₂ O ₃ mainly composed of zinc (Zn) and aluminum (Al) in the mother phase 33 of α-alumina (α-Al ₂ O ₃ ). The plate-shaped composite oxide particles 34 are uniformly dispersed. As the ceramic sliding member 32 of the present invention, a disk-shaped test piece having a diameter of 35 mm and a thickness of 5 mm was produced, and the plane of the test piece was smoothed by lapping at a smoothness (Rmax) of 0.4 or less. The two test pieces obtained were polymerized, and the friction coefficient was measured by sliding friction test in water at a temperature of 25 ° C.

As apparent from FIG. 10, the ceramic sliding member 32 of the present invention is frictionally formed by forming a needle-like composite oxide 34 of ZnO.nAl ₂ O ₃ on the mother phase 33 of α-alumina (α-Al ₂ O ₃ ). It was confirmed that the coefficient decreased, exhibited high water adsorption, and exhibited low friction in water.

The reason why the ceramic sliding member 32 of the present invention exhibits low friction in water is that the acicular composite oxide 34 of ZnO.nAl ₂ O ₃ has a crystal structure similar to that of the spinel type, and the hollow hole is the same as that of the spinel type crystal structure. This is because it exists and also has a polarity and thus strongly adsorbs water.

Next, nine kinds of ceramic sliding members (samples) 32 in which the addition amount of the composite oxide powder of ZnO.4Al ₂ O _{3 to} the alumina (α-Al ₂ O ₃ ) powder which is the main raw material were variously described above were described. Produced by the same method as described above, the strength and fracture toughness of the same ceramic sliding member were measured by the same method as described above. As shown in FIG. 11, the strength of the ceramic sliding member 32 of the present invention is hardly changed even if the amount of addition of the composite oxide powder of ZnO.nAl ₂ O ₃ is changed. As shown in FIG. The fracture toughness value of the ceramic sliding member 32 is alumina (α-Al), which is a main raw material, because the composite oxide particles 34 of a needle (having a high aspect ratio) made of ZnO.4Al ₂ O ₃ exist inside the material. ₂ O ₃₎ significantly higher than the ZnO · 4Al ₂ O ₃ composite oxide powder, the ceramic sliding member was not added to the powder.

In a specific example 7, a mixture consisting of a needle-like crystal oxide powder having a fennel type crystal structure composed of ZnAl ₂ O ₄ and a small amount of sintering aid powder was added to α alumina (α-Al ₂ O ₃ ) powder as a main raw material. It was confirmed that the same characteristics can be obtained in the ceramic sliding member obtained by producing a molded body of a predetermined shape and firing the molded body in the same manner as described above.

(Specific Example 8)

A molded article having a predetermined shape was prepared from a mixture obtained by adding zinc oxide (ZnO) powder and a small amount of sintering aid powder to α alumina (α-Al ₂ O ₃ ) powder as a main raw material. The molded body was fired in an air at a temperature of 1500 ° C. for 3 hours to obtain a ceramic sliding member (sample) 42 as a sintered body. FIG. 13: is a structure diagram which shows typically the structure of the obtained ceramic sliding member 42. As shown in FIG. In the ceramic sliding member 42 of the present invention, ZnO.nAl ₂ O ₃ mainly composed of zinc (Zn) and aluminum (Al) in the mother phase 43 on the mother phase 43 of α-alumina (α-Al ₂ O ₃ ). Needle-like or plate-shaped composite oxide particles 44 and the composite oxide particles 45 having a spinel crystal structure of ZnAl ₂ O ₄ are uniformly dispersed. A disk-shaped test piece having a diameter of 35 mm and a thickness of 5 mm was produced with the ceramic sliding member 42 of the present invention, and the plane of the test piece was smoothed by lapping at a smoothness (Rmax) of 0.4 or less. The two test pieces obtained were polymerized, and the friction coefficient was measured by sliding friction test in water at a temperature of 25 ° C.

As is apparent from FIG. 14, the ceramic sliding member 42 is composed of α-alumina (α-Al ₂ O ₃ ) as a base 43, and ZnAl ₂ O ₄ composite oxide particles 45 and ZnO.nAl ₂ O _3. By uniformly dispersing the acicular composite oxide particles 44, it was confirmed that the friction coefficient was further lowered, had high water adsorption property, and exhibited low friction in water.

The reason why the ceramic sliding member 42 of the present invention exhibits high hydrophilicity and low friction is that the composite oxide particles 45 of ZnAl ₂ O ₄ have a spinel crystal structure, empty pores and polarity. This is because water is adsorbed more strongly than the acicular composite oxide particles 44 of ZnO.nAl ₂ O ₃ .

Next, in the above-mentioned ceramic sliding member 42, the ceramic sliding member (sample) in which the addition amount of the composite oxide powder of ZnAl ₂ O _{3 to} the α alumina (α-Al ₂ O ₃ ) powder is changed to 0 to 50 wt%. ) 42 was fabricated in the same manner as described above, and the friction coefficient of the copper ceramic sliding member 42 was measured in the same manner as described above. As shown in FIG. 15, it was found that increasing the amount of ZnAl ₂ O ₄ composite oxide added increased the coefficient of friction of the ceramic sliding member 42. However, it was found that the frictional coefficient rapidly increased when the amount of the ZnAl ₂ O ₄ composite oxide powder added exceeded 30 wt%. This is because the amount of the soft ZnAl ₂ O ₄ composite oxide particles 45 falling off from the surface of the ceramic sliding member 42 increases.

Next, the reciprocating friction test in water was carried out to evaluate the wear resistance of the ceramic sliding members (samples) 32 and 42 and the conventional aluminum material (samples) according to the specific examples 7 and 8 of the present invention described above. It was. As shown in Fig. 16, it was found that each of the ceramic sliding members 32 and 42 of the present invention can reduce the amount of wear by about 20% compared with the conventional alumina material. In addition, since the ceramic sliding members 32 and 34 of the present invention have a higher fracture toughness value as compared with conventional alumina materials, wear resistance is improved.

In order to evaluate the wear resistance of the above-mentioned ceramic sliding members 32 and 42 and the conventional alumina material, iron oxide powder was applied to sliding surfaces of each material, and a reciprocating friction test in water was carried out. As shown in Fig. 17, it was found that each of the ceramic sliding members 32 and 42 of the present invention can reduce the amount of wear by about 30% compared with the conventional aluminum material. The wear pattern in the reciprocating sliding friction test described above belongs to aggressive wear, and the wear amount W _s of each sliding member 32, 42 is inversely proportional to the fracture toughness value and hardness, as shown in the following equation.

W _s = E ^4/5 × KIc ^-1/2 × HV ^-57/40

E: Young's modulus

KI _c : fracture toughness

HV: Hardness

Therefore, since the ceramic sliding member 32 according to the seventh embodiment of the present invention has a higher fracture toughness value than the conventional alumina material, wear resistance is improved.

In addition, the ceramic sliding member 32 of the present invention does not produce ZnAl ₂ O ₄ composite oxide particles 45 which are slightly inferior in wear resistance as compared with the ceramic sliding member 42, and has a higher fracture toughness value, thereby further improving wear resistance. It became.

(Specific Example 9)

The ceramic sliding member of the present invention is a ceramic sintered body, which is mainly used in a water stop valve for mixing taps, and has AlNbO ₄ containing niobium (Nb) generating a strong electric field based on alumina (Al ₂ O ₃ ) having a relatively high mechanical strength. Or ZnAl ₂ O ₄ containing zinc (Zn) as a main component.

The ceramic sintered body as the sliding member of the present invention was analyzed by an X-ray lime (RD) analyzer to find that niobium (Nb) or zinc (Zn) and aluminum (Al) were formed on a matrix made of alumina (Al ₂ O ₃ ). It was confirmed that a compound or a solid solution of a composite oxide containing as a member or a compound or a solid solution of titania (TiO ₂ ) is dispersed.

The ceramic sliding member of the present invention may select a homogeneous ceramic sliding member as the friction partner, but alumina (Al ₂ O ₃ ), silicon carbide (Si ₃ C ₄ ), and silicon nitride (Si ₃ N ₄ ) as the friction partner. It has the same hydrophilicity when selected, and shows excellent low friction and wear resistance in water.

Eight kinds of molded articles were prepared in which the addition amount of niobium oxide (Nb ₂ O ₅ ) powder was changed using alumina (Al ₂ O ₃ ) powder as a main raw material. The molded body was baked in an air at a temperature of 1400 ° C. for 3 hours to obtain a sintered body. The test piece (1A-1H) of diameter 35mm and thickness 5mm was produced from this sintered compact, and the plane of the test piece was smoothed by the lap finishing of Rmax 0.4 or less. Tap water was dropped on the surface of these test pieces 1A-1H, and the contact angle was measured. In addition, the friction coefficient was measured by carrying out sliding test in the hot water of 80 degrees C by laminating two test pieces. Here, the contact angle refers to the angle from the interface between the solid and the liquid to the interface between the air and the liquid where the surface of the liquid contacts the surface of the solid, and the smaller the contact angle is, the liquid spreads to the solid surface to wet the solid surface. Properties. That is, the smaller the contact angle, the higher the liquid lubrication of the sliding surfaces of the solids.

As is apparent from the characteristics of the test pieces 1A to 1H shown in Table 1, the ceramic sliding member according to the present embodiment has a contact angle and friction coefficient by adding niobium oxide (Nb ₂ O ₅ ) to alumina (Al ₂ O ₃ ). It was confirmed that it lowered and exhibits high hydrophilicity and low friction. However, when the amount of niobium oxide (Nb ₂ O ₅ ) added to the alumina (Al ₂ O ₃ ) exceeds 30 wt%, the sinterability of the molded body is remarkably deteriorated and the strength is also sharply decreased. It was found that when the sinterability of the molded body deteriorated, crystal grains of the sintered body dropped during the sliding test, and the friction coefficient increased.

Table 1

Test piece Al ₂ O ₃ added amount (wt%) TiO ₂ added amount (wt%) Nb ₂ O ₅ Amount (wt%) Contact angle (。) Coefficient of friction Strength (MPa) 1A1B1C1D1E1F1G1H 10097959080757060 00000000 0351020253040 50301711109910 0.580.30.20.120.090.150.40.45 32031030030027025013080 2A2B2C2D2E2F2G2H 9592908575706555 55555555 0351020253040 5332181089109 0.590.330.210.110.080.150.390.46 33032031030028026013085 3A3B3C3D3E3F3G3H 9087858070656050 1010101010101010 0351020253040 5834181211101010 0.620.350.230.130.110.180.410.44 33031031030027026012080 11A11B11C 856545 151515 02040 604020 0.70.40.42 33520060

(Specific Example 10)

Eight types of molded articles were prepared, in which 5 wt% of titania (TiO ₂ ) powder was added with alumina (Al ₂ O ₃ ) powder as the main raw material, and the addition amount of niobium oxide (Nb ₂ O ₅ ) powder was changed to 0 to 40 wt%. . The molded body was sintered under the same conditions as in Example 1, the same test pieces 2A to 2H were produced from the sintered body, and the contact angles and the friction coefficients of the test pieces 2A to 2H were measured by the same test.

As is apparent from the characteristics of the test specimens 2A to 2H shown in Table 1, the ceramic sliding member according to the present embodiment was prepared by adding niobium oxide (Nb ₂ O ₅ ) to alumina (Al ₂ O ₃ ) and the contact angle and friction coefficient of the test specimen. It was confirmed that lowers and exhibits high hydrophilicity and low friction. However, when the amount of niobium oxide (Nb ₂ O ₅ ) added to the alumina (Al ₂ O ₃ ) exceeds 30 wt%, the sinterability of the molded body was significantly deteriorated and the strength was also sharply decreased.

It was found that when the sinterability of the molded body deteriorated, the coefficient of friction increased because crystal grains of the sintered body dropped during the sliding test. In addition, it was found that the addition of titania (TiO ₂₎ stronger than the non-promoted densification of the sintered body, and the addition of titania (TiO ₂₎ to alumina (Al ₂ O ₃₎ sintered on an alumina (Al ₂ O _3).

(Specific Example 11)

Eight types of molded articles were prepared, in which 10 wt% of titania (TiO ₂ ) powder was added using alumina (Al ₂ O ₃ ) powder as the main raw material, and the addition amount of niobium oxide (Nb ₂ O ₅ ) powder was changed to 0 to 40 wt%. . The molded body was sintered under the same conditions as in Example 1, the same test pieces 3A to 3H were produced from the sintered body, and the contact angles and the friction coefficients of the test pieces 3A to 3H were measured by the same test.

The ceramic sliding member according to the present embodiment was found to be able to improve hydrophilicity and friction characteristics without losing strength by adding an appropriate amount of niobium oxide (Nb ₂ O ₅ ) to alumina (Al ₂ O ₃ ).

As Comparative Examples 11A to 11C, the addition amount of titania (TiO ₂ ) powder to the alumina (Al ₂ O ₃ ) powder was 15wt%, and the addition amount of niobium oxide (Nb ₂ O ₅ ) powder was 0wt%, 20wt%, 40wt The molded article changed to% was produced. The molded body was sintered under the same conditions as in Example 1, and the same test pieces 11A to 11c were made of the sintered body, and the contact angle and the coefficient of friction of each test piece were measured by the same test.

As apparent from the characteristics of the test pieces 11A to 11C in Table 1, the improvement of the hydrophilicity and the frictional characteristics was not recognized in the ceramic sliding member according to the present embodiment.

(Example 12)

Eight kinds of molded articles were prepared in which the amount of zinc oxide (ZnO) powder was changed using alumina powder as a main raw material. The molded body was baked in an air at a temperature of 1500 ° C. for 3 hours to obtain a sintered body. The test piece (4A-4H) of diameter 35mm and thickness 5mm was produced with this sintered compact, and the plane of the test piece was smoothed by the lap finishing of Rmax or less. Tap water was dropped on the surface of these test pieces 4A-4H, and the contact angle was measured. Moreover, two test pieces (4A-4H) were piled up, the sliding test was carried out in the hot water of 80 degrees C, and the friction coefficient was measured.

[Table 2]

Test piece Al ₂ O ₃ added amount (wt%) TiO ₂ added amount (wt%) ZnO addition amount (wt%) Contact angle (。) Coefficient of friction Strength (MPa) 4A4B4C4D4E4F4G4H 10097959080757060 00000000 0351020253040 50271510891011 0.580.280.190.110.080.130.420.45 32031531031027025512570 5A5B5C5D5E5F5G5H 9592908575706555 55555555 0351020253040 533118988910 0.590.310.180.10.070.140.360.45 33031531030528527012580 6A6B6C6D6E6F6G6H 9087858070656050 1010101010101010 0351020253040 58321510991010 0.620.330.210.120.10.170.420.43 33032031531027526012575 12A12B12C 856545 151515 02040 603821 0.70.40.41 33519555

As is apparent from the characteristics of the test pieces 4A to 4H shown in Table 2, the ceramic sliding member according to the present embodiment has a high hydrophilicity and low friction due to a decrease in contact angle and friction coefficient by adding zinc oxide to alumina (Al ₂ O ₃ ). It was confirmed that However, when the amount of zinc oxide (ZnO) added to the alumina (Al ₂ O ₃ ) exceeds 30wt%, the sinterability of the molded body was significantly deteriorated and the strength also dropped sharply. It was found that when the sinterability of the molded body deteriorated, the sintered particles of the sintered body dropped in the sliding member and the friction coefficient increased.

(Specific Example 13)

Eight kinds of molded articles were prepared by using alumina (Al ₂ O ₃ ) powder as a main raw material, adding 5 wt% of titania (TiO ₂ ) powder, and changing the amount of zinc oxide (ZnO) powder to 0 to 40 wt%. The molded body was sintered under the same conditions as in Example 4, the same test pieces 5A to 5H were made of the sintered body, and the contact angles and the friction coefficients of the test pieces 5A to 5H were measured by the same test.

As apparent from the characteristics of the test pieces 5A to 5H shown in Table 2, the ceramic sliding member according to the present embodiment had a contact angle and a friction coefficient lowered by adding zinc oxide (ZnO) to alumina (Al ₂ O ₃ ), It was confirmed that it exhibits high hydrophilicity and low friction. However, when the amount of zinc oxide (ZnO) added to alumina (Al ₂ O ₃ ) exceeded 30 wt%, the sinterability of the molded body was remarkably deteriorated and the strength also dropped sharply. It was found that when the sinterability of the molded body deteriorated, crystal grains of the sintered body dropped during the sliding test, and the friction coefficient increased. Further, the addition of titania (TiO ₂₎ to alumina (Al ₂ O ₃₎ found that the densification of the sintered body is promoted alumina (Al ₂ O ₃₎ than the titania sintered without addition of the (TiO ₂₎ is increased in intensity.

(Specific Example 14)

Eight kinds of molded articles were prepared, in which 10 wt% of titania (TiO ₂ ) powder was added using alumina (Al ₂ O ₃ ) powder as the main raw material, and the amount of zinc oxide (ZnO) powder was changed to 0 to 40 wt%. The molded body was sintered under the same conditions as in the practical example 4, the same test pieces 6A to 6H were produced from the sintered body, and the contact angles and the friction coefficients of the test pieces 6A to 6H were measured by the same test.

The ceramic sliding member according to the present embodiment was found to be able to improve hydrophilicity and friction characteristics without impairing strength by adding an appropriate amount of zinc oxide (ZnO) to alumina (Al ₂ O ₃ ).

In Comparative Examples 12A to 12C, 15 wt% of titania (TiO ₂ ) powder was added using alumina (Al ₂ O ₃ ) powder as a main raw material, and a molded article in which the addition amount of zinc oxide (ZnO) powder was changed to 0, 20, and 40 wt% was again obtained. Produced. The molded body was sintered under the same conditions as in Example 4 to produce the same test pieces 12A to 12C from the sintered body, and the contact angles and the friction coefficients of the test pieces 12A to 12C were measured by the same test.

As apparent from the characteristics of the test pieces 12A to 12C of Table 2, the improvement of the hydrophilicity and the frictional characteristics was not recognized in the ceramic sliding member according to the present embodiment.

In the present invention, as described above, the composite oxide particles containing ZnAl ₂ O ₄ as a main component are uniformly dispersed as a solid solution or a compound inside the mother phase of α-alumina (α-Al ₂ O ₃ ), and titanium (Ti) Since at least one of the compound particles of Ti) and the compound particles of iron (Fe) is present, the alumina-based ceramic sliding member has high mechanical strength and high hydrophilicity, and exhibits low friction and low wear in water.

As described above, the present invention is a composite of anhydrous aluminate (MAl ₂ O ₄ ) spinel crystal structure of the same particle size as alumina (Al ₂ O ₃ ) inside the mother phase of α alumina (α-Al ₂ O ₃ ) Since the oxide particles are uniformly dispersed as a solid solution or a compound, they have high hydrophilicity as an alumina-based ceramic sliding member, and exhibit low friction and low wear in water.

As described above, since the present invention uniformly disperses acicular and / or plate-shaped composite oxide particles mainly composed of zinc (Zn) and aluminum (Al) on the mother layer of α-alumina (α-Al ₂ O ₃ ). , Alumina-based ceramic sliding member has high hydrophilicity and exhibits low friction and low wear in water.

In the present invention, as described above, a composite oxide composed of aluminum (Al) and niobium (Nb) containing AlNbO ₄ as a main component in a mother phase made of alumina (Al ₂ O ₃ ) as a ceramic sliding member is dispersed as a compound or a solid solution, or alumina A composite oxide composed of aluminum (Al) and zinc (Zn) mainly composed of ZnAl ₂ O ₄ as a main phase in (Al ₂ O ₃ ) is dispersed as a compound or a solid solution, and alumina (Al ₂ O ₃ ) is a main component Since the main component is AlNbO ₄ containing niobium (Nb) or ZnAl ₂ O ₄ containing zinc (Zn), which has high mechanical strength, is excellent in durability, and generates a strong electric field, it has high hydrophilicity and Demonstrates low friction and low wear.

Claims (18)

Anhydrous aluminate (MAl ₂ O ₄ ) (M is a metal element) spinel having the same particle size as that of alumina (Al ₂ O ₃ ) in the mother phase of the α alumina (α-Al ₂ O ₃ ) A high hydrophilic low friction ceramic sliding member, wherein composite oxide particles having a type crystal structure are uniformly dispersed as a solid solution or a compound. The method of claim 1, wherein the anhydrous aluminate (MAl ₂ O ₄ ) is magnesium (Mg), zinc (Zn), cobalt (Co), nickel (Ni), copper (Cu), manganese (Mn), iron ( A high hydrophilic low friction ceramic sliding member composed of one of Fe). The high hydrophilic low friction ceramic sliding member according to claim 1, wherein the content of the anhydrous aluminate (MAl ₂ O ₄ ) is 5 to 50 wt%. High hydrophilic low friction characterized by uniformly dispersing acicular and / or plate-shaped composite oxide particles mainly composed of zinc (Zn) and aluminum (Al) in a mother phase of α-alumina (α-Al ₂ O ₃ ) Ceramic sliding members. 5. The method of claim 4, wherein the needle-shaped and plate-shaped composite oxide particles have a high composition ratio (ZnO: Al ₂ O ₃ ) of 1: 3 or more when the zinc (Zn) and aluminum (Al) of the main component are converted into oxides. Hydrophilic low friction ceramic sliding member. 6. The high hydrophilic low friction ceramic sliding member according to claim 5, wherein an aspect ratio of said acicular composite oxide particles is three or more. in the interior of the matrix of α-alumina (α-Al ₂ O ₃₎ aluminate, zinc (ZnAl ₂ O ₄₎ a and the compound oxide particle as a main component is uniformly dispersed as solid solution or compound, the α-alumina (α-Al ₂ O ₃ ) and at least one of titanium (Ti) compound particles and iron (Fe) compound particles are present at the grain boundaries of the composite oxide particles. 8. The high hydrophilic low friction ceramic sliding member according to claim 7, wherein the content of the compound of zinc (Zn) is 3 to 25 wt%. 8. A compound according to claim 7, wherein the blending ratio of the raw material powder is 3 to 25 wt% of zinc (Zn) compound, 0.15 to 5 wt% of titanium (Ti) oxide, 0.1 to 3 wt% of iron (Fe) oxide, A high hydrophilic low friction ceramic sliding member composed of alumina (Al ₂ O ₃ ) in the remaining portion. A needle-like and / or plate-like composite oxide particle mainly composed of zinc (Zn) and aluminum (Al) in the mother phase of α-alumina (α-Al ₂ O ₃ ) and a spinel crystal structure of ZnAl ₂ O ₄ A high hydrophilic low friction ceramic sliding member characterized by uniformly dispersing composite oxide particles. The high hydrophilic low friction ceramic sliding member according to claim 10, wherein the content of the composite oxide particles having the spinel crystal structure of ZnAl ₂ O ₄ is 30 wt% or less. Alumina (Al ₂ O ₃ ) is a main component, and as an additive, at least 3 to 25 wt% of a compound of niobium (Nb) or zinc (Zn) is converted into niobium oxide (Nb ₂ O ₅ ) and zinc oxide (ZnO), respectively. The composition is composed of a composite oxide composed of aluminum (Al) and niobium (Nb) containing AlNbO ₄ as a main component in a mother phase composed of alumina (Al ₂ O ₃ ) or dispersed as a compound or a solid solution, or alumina (Al ₂ O _3). A high hydrophilic low friction ceramic sliding member comprising a composite oxide composed of aluminum (Al) and zinc (Zn) mainly composed of ZnAl ₂ O ₄ as a compound or solid solution. It contains alumina (Al ₂ O ₃ ) as a main component and contains at least 3 to 25 wt% of niobium (Nb) compound and 3 to 10 wt% of oxide of titanium (Ti) as an additive, and its composition is alumina (Al ₂ O 3). ₃ ) A high hydrophilic low friction ceramic sliding member comprising a composite oxide composed of aluminum (Al) and niop (Nb) mainly composed of AlNbO ₄ as a compound or a solid solution. It contains alumina (Al ₂ O ₃ ) as a main component and contains 3 to 25 wt% of a compound of zinc (Zn) and 3 to 10 wt% of an oxide of titanium (Ti) as an additive, and its composition is alumina (Al ₂ O _3). A high hydrophilic low friction ceramic sliding member comprising a composite oxide composed of aluminum (Al) and zinc (Zn) mainly composed of ZnAl ₂ O ₄ as a compound or solid solution. The high hydrophilicity according to any one of claims 12 to 14, wherein the counterpart of the ceramic sliding member is one of alumina (Al ₂ O ₃ ), silicon carbide (Si ₃ C ₄ ), and silicon nitride (Si ₃ N ₄ ). Low friction ceramics sliding member. Seventh, the tenth, the twelfth to fourteenth according to any one of claims, wherein the particle size of the α-alumina (α-Al ₂ O ₃₎ is 6㎛ average, particle size of the ZnAl ₂ O ₄ is the average 6㎛ High hydrophilic low friction ceramic sliding member. 15. The high hydrophilic low friction ceramic sliding member according to any one of claims 1, 4, 7, 10, 12 and 14, wherein the ceramic sliding member is used in water. 15. The high hydrophilic low friction ceramic sliding according to any one of claims 1, 4, 7, 10, and 12 to 14, wherein the ceramic sliding member is a sliding member of the mixing valve. absence.