JPH04285063A - Member for crusher - Google Patents

Abstract

PURPOSE:To obtain a member for crusher such as crushing balls having superior wear resistance, strength and fracture toughness. CONSTITUTION:A member for a crusher is made of Al2O3-based ceramics contg. 20-40wt.% ZrO2 contg. at least 50vol.% tetragonal crystals in the crystal structure, 1-5wt.% TiO2 and 0.1-1wt.% MgO. The average grain diameter of the Al2O3 is 1.5-5mum and at least 80% of the ZrO2 is present at the grain boundaries of the Al2O3.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to dry or wet grinding mill members that are required to have excellent wear resistance, strength, and fracture toughness, such as ball mill balls, containers, Lining materials for containers, containers for media stirring mills such as attrition mills, lining materials for containers, stirring screws, stirring rods, rotating disks, pins, balls, pebbles, beads, rollers for roller mills, and grinding chambers. lining materials for jet mills, crushing nozzles for jet mills, lining materials for crushing chambers, rotors for hammer mills, hammers, pins for pin mills,
Regarding rotors, rotors and blades of disk mills, and rotating disks of colloid mills.

0002

[Prior Art] Pulverizers include ball mills, media agitation mills, and roller mills that use the impact force, frictional force, and compression force generated by the kinetic energy of a grinding medium such as balls or beads to grind the material to be crushed. Roller mills use compression force to crush the material, jet mills that collide the material to be crushed against the lining material at high speed and use the impact force from that collision to crush the material, and rotors with fixed hammers, blades, pins, etc. Hammer mills, pin mills, and disc mills that use the impact force generated by the rotation of the crusher to crush materials, and colloid mills that use shearing force are widely used.

[0003] The above-mentioned components such as the crushing media and lining materials of these crushers are made of natural stone, ceramics such as alumina ceramics and zirconia ceramics, resin, and cemented carbide. Commonly used. However, members made of such materials are extremely susceptible to wear, and a large amount of abrasion powder gets mixed into the crushed material as impurities during grinding, causing damage to the crushed material and various materials made from the crushed material. There is a problem of deterioration of physical properties and quality. Particularly, when the crushed material is used for so-called advanced materials such as fine ceramic materials, magnetic materials, and electronic materials, the contamination of impurities by abrasion powder becomes a big problem.

[0004] In response to such demands, Japanese Patent Laid-Open No. 1986-1
The invention of No. 87157 contains 99.9% by weight of Al2O3.
Including the above, the average crystal grain size of Al2O3 is 2.5μm
Below, a crusher member made of alumina ceramics having a relative density of 98% or more is proposed. However, although this member has excellent wear resistance and hardness, it has a problem of low strength and fracture toughness, and is easily chipped or broken even by the slightest impact. In addition, in order to develop sufficient wear resistance and hardness, the purity of Al2O3 must be 99.9%.
It is necessary to increase the hardness considerably, and even if a small amount of impurity is mixed in during manufacturing, there is a problem that particle detachment wear occurs due to a decrease in grain boundary strength, resulting in a decrease in wear resistance.

On the other hand, the invention of Japanese Patent Publication No. 2-20587 is
Contains 2 to 4.5 mol% of 2O3, and has a crystalline phase of 10%
Including the above tetragonal ZrO2 and equiaxed ZrO2,
The authors also propose a crusher member made of zirconia ceramics that does not substantially contain monoclinic ZrO2, has an average crystal grain size of 4 μm or less, and has a bulk density of 5.8 g/cm 3 or more. This member has excellent strength and fracture toughness, and is useful when ceramics with relatively low hardness, such as SiO2 or BaTiO3, are to be crushed. However, there is a problem in that wear progresses rapidly when grinding materials with relatively high hardness such as Al2O3 or SiC, or when a lubricating medium is not present as in a dry grinder.

[0006] As described above, it is difficult to say that all conventional crusher members have the properties necessary for a crusher member, especially wear resistance, strength, and fracture toughness in a well-balanced manner. .

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of conventional pulverizer members, and to provide a pulverizer member that has excellent wear resistance, strength, and fracture toughness. is to provide.

[0008]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention contains 20 to 40% by weight of ZrO2, which contains Al2O3 as a main component and whose crystal structure is at least 50% by volume tetragonal. Included in the range, Ti
Contains O2 in the range of 1 to 5% by weight, and contains MgO in the range of 0.1 to 5% by weight.
1% by weight of ZrO3, the average crystal grain size of Al2O3 is in the range of 1.5 to 5 μm, and at least 80% of ZrO2 is present in the grain boundaries of Al2O3. Provide parts. Preferably, the average crystal grain size dz of ZrO2 is 1.5 to 3.
in the range of μm, and the ratio dA of the average crystal grain size dA of Al2O3 to the average crystal grain size dz of ZrO2
/dz is in the range of 1 to 3. Further, it is preferable that the member for a crusher of the present invention has a relative density of 95% or more. Furthermore, the thermal conductivity at 20°C is 0.02 to 0.
The temperature is preferably in the range of 0.7 cal/cm·sec·°C. Further, the crusher member of the present invention has a diameter of 10 mm.
Regarding the ball member, 200 of the ball members were placed in a nylon ball mill with an internal volume of 1000 ml, and 36% of the total weight of the ball member and 4% of SiC powder with an average particle size of 1 μm were added. and turn the ball mill for 10
The weight loss rate after 50 hours of operation at a speed of 0 rpm is less than 1%.

Now, the wear mechanism of crusher members is not necessarily clear, but for those made of ceramics, such as Al2O3, which have high hardness but low grain boundary strength, particle detachment wear due to destruction of grain boundaries is preferential. Furthermore, it is thought that wear due to friction occurs preferentially in ceramics such as ZrO2, which has high strength but relatively low hardness. From such estimation,
This invention suppresses the growth of intergranular cracks in Al2 O3 by dispersing ZrO2 in the grain boundaries of Al2 O3,
The aim is to improve wear resistance and strength by making grain boundary separation wear less likely to occur, and to improve fracture toughness by promoting crack deflection by increasing the crystal grain size of Al2O3.

[0010] The ceramic constituting the crusher member of the present invention contains Al2O3 as a main component. Its average grain size is then in the range of 1.5 to 5 μm. If the average grain size is less than 1.5 μm, crack deflection cannot be expected and fracture toughness will not improve. On the other hand, 5
If it exceeds .mu.m, the area of the grain boundaries in one Al2 O3 crystal grain becomes large, so grain boundary detachment wear tends to occur and the wear resistance decreases. A more preferable range of average crystal grain size is 1.5 to 3 μm.

Further, the ceramic used in the present invention contains ZrO2 in an amount of 20 to 40% by weight. This ZrO2 has at least 5
Such that 0% by volume is tetragonal and the remainder cubic and/or monoclinic. If ZrO2 is less than 20% by weight and ZrO2 having a tetragonal crystal structure is less than 50% by volume, the effect of improving strength due to stress-induced transformation from tetragonal to monoclinic cannot be expected. On the other hand, ZrO2
If it exceeds 40% by weight, agglomeration of ZrO2 crystal grains occurs, resulting in a decrease in strength and a decrease in wear resistance. Here, ZrO2 is 1.5-5 mol% to obtain at least 50 vol% tetragonal in crystal structure.
The tetragonal crystal contains stabilizers such as Y2 O3 and CeO2, and is in a metastable state at room temperature.

[0012] The above-mentioned ZrO2 has at least 8
0% is distributed in the grain boundaries of Al2O3, which is the main component. Even if it exists within the crystal grains of Al2O3,
That's a little. As a result, ZrO2 effectively causes stress-induced transformation in response to cracks propagating through the grain boundaries of Al2O3, suppressing the propagation of grain boundary cracks, making it difficult for intergranular detachment wear to occur, and improving wear resistance. At the same time, the strength is improved due to stress relaxation at the crack tip.

[0013] Furthermore, the ceramic constituting the crusher member of the present invention contains TiO2 in a range of 1 to 5% by weight. TiO2 is Al2 O3 during sintering.
Promotes the growth of crystal grains, coarsens them to an appropriate extent, allows crack deflection to work effectively, and improves fracture toughness. In order to expect such an effect, TiO2 must be 1% by weight.
is necessary. However, if it exceeds 5% by weight, A
The crystal grains of l2 O3 become too large.

[0014] MgO is a part of Al2 generated during sintering.
In addition to suppressing abnormal grain growth of O3 and making the crystal grain size of Al2O3 uniform, ZrO2 is added to the grain boundaries.
It has the effect of making it easier to distribute, thereby improving wear resistance and strength. In addition, when only TiO2 is contained, ZrO2 and TiO2 react during sintering to generate ZrTiO4, which undergoes abnormal grain growth during sintering to form acicular crystals, which deteriorate wear resistance and strength. However, by allowing MgO to coexist,
Such production reactions can be suppressed. In order to expect such an effect, at least 0.1% by weight of MgO is required. At less than 0.1% by weight, some Al2
O3 grows abnormally and ZrO2 is easily incorporated into the crystal grains. Furthermore, it becomes difficult to suppress the ZrTiO4 production reaction. On the other hand, if it exceeds 1% by weight, Al2
The effect of suppressing the growth of O3 crystal grains becomes too strong, making it impossible to keep the average crystal grain size within the above-mentioned range.

[0015] In the crusher member of the present invention, the average crystal grain size dz of ZrO2 is in the range of 1.5 to 3 μm, and the ratio of the average crystal grain size dA of Al2 O3 to the average crystal grain size dz of ZrO2 is When dA /dz is in the range of 1 to 3, wear resistance and strength are further improved. That is, by setting the average crystal grain size of ZrO2 and the value of dA /dz within the above range, intergranular detachment wear becomes difficult to occur even in ZrO2, and wear resistance is improved. In addition, moderate interphase stress comes to work between ZrO2 and Al2O3, and in addition to the crack deflection effect,
It is expected that a strengthening mechanism will emerge due to the branching of complex cracks.

[0016] Furthermore, when the relative density of the crusher member of the present invention is 95% or more, the wear resistance and strength are further improved. Here, the relative density is the relative value of the actual density to the theoretical density expressed as a percentage. When the relative density is 95% or more, the number of pores existing at the grain boundaries decreases, and the pores are Wear resistance and strength are improved because intergranular detachment wear, which occurs as a starting point for intergranular cracks, and cracks that lead to fracture are less likely to occur. Note that the theoretical density is determined by the following formula.

100/[0.2508・WA +0.2353・WT
+0.3868WM +WZ /(6.10+k・x
)] However, WA: weight % of Al2O3 WT:
Weight % of TiO2 WM: Weight % of MgO WZ: Weight % of ZrO2 k: -0.008 when the stabilizer of ZrO2 is Y2 O3, 0.014 when the stabilizer is CeO2 (Z
(value determined by the type of rO2 stabilizer and depends on lattice constant, molecular weight, crystal structure, etc.) rate is 0.0
It is in the range of 2 to 0.07 cal/cm・sec・℃. This is preferable when the component is a media stirring mill or the like.

In other words, in a pulverizer that agitates the pulverizing medium at high speed, such as a media agitation mill, heat may be generated due to the intense stirring motion, which may lead to deterioration of the quality of the crushed material due to the heat, or may cause heat generation due to evaporation of the lubricating medium. Grinding efficiency may decrease due to concentration changes. Therefore, in these crushers, members such as containers and lining materials are generally cooled, but in order to enhance the cooling effect, the higher the thermal conductivity of the members, the better. In this respect, the member of the present invention has a higher thermal conductivity than the above-mentioned ZrO2 ceramic member, and can provide a high cooling effect. Furthermore, in order to prevent heat accumulation, members made of ZrO2 ceramics need to be made thinner, which may result in a lack of strength as a member, but the member of this invention not only has high strength but also has high thermal conductivity. Therefore, such concerns can be reduced. As mentioned above, the higher the thermal conductivity, the better; however, the thermal conductivity of the ceramics used in this invention is 0.02 to 0.07 cal at 20°C.
/cm・sec・℃ range.

[0019] In the crusher member of the present invention, 200 ball members (approximately 450 g) are put into a nylon ball mill with an internal volume of 1000 ml, and the entire ball member is By weight, 36% water and 4% S with an average particle size of 1 μm.
After adding iC powder and operating the ball mill at a speed of 100 rpm for 50 hours, the weight loss rate is 1% or less. Such a value is not expected for an Al2O3 ceramic member or a ZrO2 ceramic member.

The crusher member of the present invention can be manufactured, for example, by the following method.

That is, predetermined amounts of ZrO2 powder, TiO2 powder, and MgO powder are added to Al2O3 powder, which is the main component, and mixed well to prepare a mixed powder. The mixing operation may be wet or dry. After drying the mixed powder, if necessary, coarsely crush it and sieve it, or
Granulate. Note that it is preferable to use Al2O3 powder having an average particle size in the range of 0.3 to 2 .mu.m because it enables dense sintering. Also, TiO2
In consideration of uniform dispersion in Al2 O3, it is preferable to use powders such as MgO, ZrO2, and ZrO2 having an average particle size of 1 μm or less. Further, the purity of each of the above-mentioned powders is preferably 99% or more in order to prevent abnormal growth of crystal grains due to impurities and further improve properties such as wear resistance, strength, and fracture toughness.

Next, the above mixed powder is subjected to a well-known molding method.
For example, it is molded into a desired shape using a molding method, a rubber press molding method, a cast molding method, or an injection molding method, and then sintered. The atmosphere during sintering is an oxidizing atmosphere such as air. In addition, the sintering temperature and time are such that the average crystal grain size of Al2O3 is in the range of 1.5 to 5 μm, and preferably Z
It is carefully controlled so that the average crystal grain size of rO2 is in the range of 1.5 to 3 μm and dA /dz is in the range of 1 to 3. In addition, in order to have at least 80% of ZrO2 exist in the grain boundaries of Al2O3, which is the main component, the temperature near the sintering temperature is to prevent rapid grain growth of Al2O3 and incorporation of ZrO2 into the grains. Raise the temperature at a slow rate of 0.5°C/min or less. On the other hand, after sintering, if the cooling rate is too slow, monoclinic ZrO2
is precipitated, and the tetragonal ZrO2 is deposited at least 50%.
Since the volume % cannot be achieved, cooling is performed at a rate of 5° C./min or more. Although the relative density can be sufficiently increased to 95% or more by general sintering such as pressureless sintering, it is possible to further increase the relative density to further improve wear resistance and strength. In order to further improve thermal conductivity by reducing pores, it is also preferable to subject the obtained ceramic to hot isostatic pressing treatment (HIP treatment).

[0023] Next, the obtained ceramic is subjected to mechanical processing such as grinding, polishing, etc., and, if necessary, pasting work is performed to obtain a desired member for a pulverizer.

[0024]

[Example] Example 1: Al2O3 powder with an average particle size of 0.5 μm and a purity of 99.8% and TiO2 powder with an average particle size of 0.7 μm and a purity of 99.99%. 1% by weight powder, average particle size 0.3μm, purity 99
．． 0.1% by weight of powder of 9% MgO and 1.5 mol% Y2O as a stabilizer, with an average particle size of 0.7 μm.
20% by weight of ZrO2 powder containing ZrO2 was wet-mixed in pure water for 24 hours using a ball mill, and then polyvinyl alcohol was added thereto and the mixture was sprayed and granulated to dry to obtain a mixed powder. Note that ZrO2 powder is ZrOCl2.
It was prepared by adding and mixing an aqueous solution of YCl3 to an aqueous solution of 8H2O, adding aqueous ammonia to coprecipitate the hydroxide, washing the coprecipitate with water, drying, and calcining at 1000°C for 60 minutes. .

Next, the above mixed powder is filled into a mold, and 1
Apply pressure of 000kgf/cm2, length 40mm
A molded body for strength testing with a width of 5 mm and a thickness of 4 mm was obtained. In addition, for wear testing, 1
A spherical molded body with a diameter of 10 mm was obtained under a pressure of 1,000 kgf/cm2.

[0026] Next, the above two types of molded bodies were sintered at 1550°C in the atmosphere for 2 hours to obtain two types of ceramics for strength testing and wear testing. At this time, the heating rate was 2°C/min up to 1000°C, 0.5°C/min above that, and the cooling rate was 5°C/min.

Regarding the thus obtained ceramics,
The average crystal grain size of Al2O3 and ZrO2, the proportion of tetragonal ZrO2, the proportion of ZrO2 existing at the grain boundaries of Al2O3, the average crystal grain size dA of Al2O3, the average crystal grain size dz of ZrO2, and The ratio dA/dz, relative density, bending strength, fracture toughness, thermal conductivity, and wear rate due to wear were determined.

The average crystal grain size was determined by polishing and etching the surface of the ceramic, determining the maximum length of the crystal grains in several directions on a micrograph of the etched surface, and simply averaging them.

The proportion of ZrO2 in the tetragonal crystal can be determined by (11
1) Integrated intensity T(111) of the surface diffraction peak and 2θ=
Integrated intensity M(111) of the diffraction peak of the (111) plane of the monoclinic crystal that appears around 28.2° and the diffraction peak of the (111-) plane of the monoclinic crystal that appears around 2θ = 31.5° From the integrated intensity M(111-) of
111-)]×100. Here, 1- represents -1.

[0030] Zr existing at grain boundaries of Al2O3
The proportion of O2 can be determined from the above-mentioned micrograph.
3, read the number Zb of ZrO2 present at the grain boundaries and the number Zi of ZrO2 present within the grains,
It was determined by the formula, [Zb / (Zb + Zi)] x 100.

The relative density is determined by the formula (Ds
/Dt)×100.

[0032] The bending strength was determined by performing a 3-point bending test based on JISR1601 on 10 test pieces of 36 mm in length, 4 mm in width, and 3 mm in thickness obtained by processing ceramics for strength testing, and calculating the simple average. It was calculated as a value. The span length was 30 mm, and the crosshead speed was 0.5 mm/min.

Fracture toughness is determined based on JIS R1607 by applying a load of 10 kgf to the longitudinal center of five test pieces similar to those used in the bending test using a Vickers hardness tester.
After that, a bending test was performed in the same manner as above, and the fracture toughness was determined by measuring the fracture load, which was determined as a simple average value.

Thermal conductivity was determined by the following formula using the well-known laser flash method. The measurement temperature was 20° C., the sample was a disk with a diameter of 10 mm and a thickness of 1 mm, the heat source was a ruby laser, and an infrared sensor was used for temperature detection.

0.1388・L・Q/(t・Tm) where L: Thickness of the sample Q: Amount of heat per unit area given by the laser pulse T
m: Maximum temperature rise of the sample t: Time required to reach half of Tm The wear rate due to abrasion is the rate at which 200 spherical ceramics for wear tests are barrel-polished to have a smooth surface. (weight:
W1) was placed in a nylon ball mill with a capacity of 1000 ml, and 20 g of SiC powder with an average particle size of 1 μm and 180 g of water were added.The ball mill was operated at 100 rpm for 50 hours, and the spherical ceramics were taken out and ultrasonically cleaned. It was dried, the weight W2 was measured, and the formula [(W1
-W2)/W1]×100.

Average particle size of Al2O3
:2.9μm ZrO2
average particle size of
:1.6μm dA/dz

:1.8 Tetragonal ZrO2 ratio
:93 volume% A
Proportion of ZrO2 existing at grain boundaries of l2 O3: 95
% relative density
:96.3%
bending strength
:75.8kgf/mm2
fracture toughness
:5.4MPa・m
1/2 thermal conductivity
:0.047
cal/cm・sec・℃ Wear rate due to wear:
0.13% Example 2: The amount of TiO2 powder was 3% by weight, the amount of MgO powder was 0.3% by weight, and ZrO
A test piece was prepared in the same manner as in Example 1, except that a powder containing 2.5 mol% Y2O3 was used as the powder.
Tested. The test results are shown below.

Average particle size of Al2O3
:3.0μm ZrO2
average particle size of
:1.7μm dA/dz

:1.8 Tetragonal ZrO2 ratio
:91 volume% A
Proportion of ZrO2 existing at grain boundaries of l2 O3: 92
% relative density
:97.5%
bending strength
:82.0kgf/mm2
fracture toughness
:5.4MPa・m
1/2 thermal conductivity
:0.045
cal/cm・sec・℃ Wear rate due to wear:
0.11% Example 3: The amount of TiO2 powder was 5% by weight, the amount of MgO powder was 1% by weight, and ZrO2
A test piece was prepared and tested in the same manner as in Example 1, except that a powder containing 5 mol % of Y2O3 was used. The test results are shown below.

Average particle size of Al2O3
:3.4μm ZrO2
average particle size of
:2.0μm dA/dz

:1.7 Tetragonal ZrO2 ratio
:85 volume% A
Proportion of ZrO2 existing at grain boundaries of l2 O3: 91
% relative density
:95.5%
bending strength
:79.3kgf/mm2
fracture toughness
:5.0MPa・m
1/2 thermal conductivity
:0.045
cal/cm・sec・℃ Wear rate due to wear:
0.13% Example 4: The amount of ZrO2 powder is 30% by weight
A test piece was prepared and tested in the same manner as in Example 1, except for the following. The test results are shown below.

Average particle size of Al2O3
:2.8μm ZrO2
average particle size of
:2.0μm dA/dz

:1.4 Tetragonal ZrO2 ratio
:81 volume% A
Proportion of ZrO2 existing at grain boundaries of l2 O3: 93
% relative density
:96.8%
bending strength
:92.4kgf/mm2
fracture toughness
:5.8MPa・m
1/2 thermal conductivity
:0.042
cal/cm・sec・℃ Wear rate due to wear:
0.23% Example 5: The amount of TiO2 powder was 3% by weight, the amount of MgO powder was 0.3% by weight, the ZrO2 powder containing 2.5 mol% Y2O3 was used, and , Example 1 except that the amount was 30% by weight.
A test piece was prepared and tested in the same manner. The test results are shown below.

[0040] Average particle size of Al2O3
:3.1μm ZrO2
average particle size of
:2.1μm dA/dz

:1.5 Tetragonal ZrO2 ratio
:80 volume% A
Proportion of ZrO2 existing at grain boundaries of l2 O3: 95
% relative density
:96.5%
bending strength
:88.3kgf/mm2
fracture toughness
:5.8MPa・m
1/2 thermal conductivity
:0.043
cal/cm・sec・℃ Wear rate due to wear:
0.25% Example 6: The amount of TiO2 powder was 3% by weight, the amount of MgO powder was 0.3% by weight, the ZrO2 powder containing 2.5 mol% Y2O3 was used, and , Example 1 except that the amount was 40% by weight.
A test piece was prepared and tested in the same manner. The test results are shown below.

Average particle size of Al2O3
:2.9μm ZrO2
average particle size of
:2.2μm dA/dz

:1.3 Proportion of tetragonal ZrO2
:73 volume% A
Proportion of ZrO2 existing at grain boundaries of l2 O3: 90
% relative density
:96.1%
bending strength
:74.2kgf/mm2
fracture toughness
:6.3MPa・m
1/2 thermal conductivity
:0.038
cal/cm・sec・℃ Wear rate due to wear:
0.28% Example 7: The amount of TiO2 powder was 5% by weight, the amount of MgO powder was 1% by weight, and the amount of ZrO2 powder containing 5 mol% Y2O3 was used. A test piece was prepared and tested in the same manner as in Example 1, except that the content was 40% by weight. The test results are shown below.

Average particle size of Al2O3
:3.0μm ZrO2
average particle size of
:2.4μm dA/dz

:1.3 Proportion of tetragonal ZrO2
:70 volume% A
Proportion of ZrO2 existing at grain boundaries of l2 O3: 89
% relative density
:95.3%
bending strength
:73.1kgf/mm2
fracture toughness
:6.0MPa・m
1/2 thermal conductivity
:0.038
cal/cm・sec・℃ Wear rate due to wear:
0.29% Example 8: The amount of TiO2 powder was 3% by weight, the amount of MgO powder was 0.3% by weight, the ZrO2 powder containing 2.5 mol% Y2O3 was used, and , After sintering at 1550℃, temperature 1350℃ and pressure 2000kgf/cm2 in an argon atmosphere.
A test piece was prepared and tested in the same manner as in Example 1, except that it was subjected to hot isostatic pressure treatment. The test results are shown below.

Average particle size of Al2O3
:3.1μm ZrO2
average particle size of
:1.8μm dA/dz

:1.7 Tetragonal ZrO2 ratio
:95 volume% A
Proportion of ZrO2 existing at grain boundaries of l2 O3: 92
% relative density
:99.8%
bending strength
:105.5kgf/mm2
fracture toughness
:6.0MPa ・
m1/2 thermal conductivity
:0.04
9cal/cm・sec・℃ Wear rate due to wear
: 0.08% Example 9: The amount of TiO2 powder was 3% by weight
, the amount of MgO powder is 0.3% by weight, and ZrO2
A powder containing 2.5 mol% of Y2O3 was used, and the amount was 30% by weight, and 155
After sintering at 0°C, the temperature was 1350°C in an argon atmosphere.
A test piece was prepared in the same manner as in Example 1, except that it was subjected to hot isostatic pressure treatment at a temperature of 2000 kgf/cm2 and a pressure of 2000 kgf/cm2.
Tested. The test results are shown below.

Average particle size of Al2O3
:3.2μm ZrO2
average particle size of
:2.1μm dA/dz

:1.5 Tetragonal ZrO2 ratio
:87 volume% A
Proportion of ZrO2 existing at grain boundaries of l2 O3: 93
% relative density
:99.7%
bending strength
:118.5kgf/mm2
fracture toughness
:6.5MPa・
m1/2 thermal conductivity
:0.04
5cal/cm・sec・℃ Wear rate due to wear
:0.12%

[0045]

[Comparative Example] Comparative Example 1: The amount of TiO2 powder was 3% by weight, the amount of MgO powder was 0.3% by weight, ZrO2 powder containing 2.5 mol% of Y2O3 was used, and A test piece was prepared and tested in the same manner as in Example 1, except that the amount was 5% by weight. The test results are shown below.

Average particle size of Al2O3
:3.8μm ZrO2
average particle size of
:1.0μm dA/dz

:3.8 Tetragonal ZrO2 ratio
:92 volume% A
Proportion of ZrO2 existing at grain boundaries of l2 O3: 81
% relative density
:93.3%
bending strength
:48.1kgf/mm2
fracture toughness
:4.1MPa・m
1/2 thermal conductivity
:0.053
cal/cm・sec・℃ Wear rate due to wear:
0.82% Comparative Example 2: The amount of TiO2 powder was 3% by weight, the amount of MgO powder was 0.3% by weight, ZrO2 powder containing 2.5 mol% Y2O3 was used, and , Example 1 except that the amount was 50% by weight.
A test piece was prepared and tested in the same manner. The test results are shown below.

Average particle size of Al2O3
:2.3μm ZrO2
average particle size of
:2.5μm dA/dz

:0.9 Tetragonal ZrO2 ratio
:64 volume% A
Proportion of ZrO2 existing at grain boundaries of l2 O3: 90
% relative density
:89.4%
bending strength
:49.3kgf/mm2
fracture toughness
:5.9MPa・m
1/2 thermal conductivity
:0.027
cal/cm・sec・℃ Wear rate due to wear:
0.55% Comparative Example 3: The amount of TiO2 powder was 3% by weight, no MgO powder was added, and 2% as ZrO2 powder was added.
．． A test piece was prepared and tested in the same manner as in Example 1, except that one containing 5 mol % of Y2O3 was used. The test results are shown below.

Average particle size of Al2O3
:6.8μm ZrO2
average particle size of
:1.3μm dA/dz

:5.2 Proportion of tetragonal ZrO2
:83 volume% A
Proportion of ZrO2 existing at grain boundaries of l2 O3: 69
% relative density
:92.0%
bending strength
:48.2kgf/mm2
fracture toughness
:4.5MPa・m
1/2 thermal conductivity
:0.041
cal/cm・sec・℃ Wear rate due to wear:
0.73% Comparative Example 4: Neither TiO2 powder nor MgO powder was used, but ZrO2 powder containing 2.5 mol% Y2O3 was used, and the sintering temperature was set to 1.
A test piece was prepared and tested in the same manner as in Example 1 except that the temperature was 600°C. The test results are shown below.

Average particle size of Al2O3
:1.0μm ZrO2
average particle size of
:0.5μm dA/dz

:2.0 Tetragonal ZrO2 ratio
:93 volume% A
Proportion of ZrO2 existing at grain boundaries of l2 O3: 85
% relative density
:98.5%
bending strength
:60.0kgf/mm2
fracture toughness
:3.9MPa・m
1/2 thermal conductivity
:0.042
cal/cm・sec・℃ Wear rate due to wear:
0.48% Comparative Example 5: TiO2 powder, MgO powder, Z
Example 1 was carried out in the same manner as in Example 1, except that no rO2 powder was used, and Al2O3 powder with an average particle size of 0.8 μm and a purity of 99.5% was used, and the sintering temperature was 1650°C. Test specimens were made and tested. The test results are shown below.

Average particle size of Al2O3
:5.3μm Relative density
:96.8% Bending strength

:38.0kgf/mm2 Fracture toughness

:3.2MPa ・m1/2 Thermal conductivity
:0.058cal/cm・se
c ・℃ Wear rate due to wear
:1.25% Comparative example 6
:Al2O3 powder, TiO2 powder, and MgO powder were not used, only ZrO2 powder containing 2.5 mol% Y2O3 with an average particle size of 0.7 μm was used, and the sintering temperature was 1450°C. A test piece was prepared and tested in the same manner as in Example 1, except for the following. The test results are shown below.

Average particle size of ZrO2
:0.4μm Tetragonal Z
rO2 percentage
:93 volume% relative density
:9
9.1% bending strength
:124.0
kgf/mm2 Fracture toughness
:7
．． 8MPa ・m1/2 Thermal conductivity

:0.007cal/cm・sec・℃
Wear rate due to wear
:2.21%

[0052]

[Effect of the invention] The crusher member of the present invention is made of Al2O
3 as a main component, contains ZrO2 whose crystal structure is at least 50% by volume tetragonal in the range of 20 to 40% by weight, contains TiO2 in the range of 1 to 5% by weight, and contains MgO of 0.1 to 1% by weight. Al2
The average crystal grain size of O3 is in the range of 1.5 to 5 μm,
and at least 80% of ZrO2 is Al2O3
Since it is made of ceramics that exist in the grain boundaries of , it has excellent wear resistance, strength, and fracture toughness, as is clear from the comparison between the examples and comparative examples. These characteristics are such that the average crystal grain size dz of ZrO2 is in the range of 1.5 to 3 μm, and the average crystal grain size dA of Al2O3 and the average crystal grain size dz of ZrO2 are in the range of 1.5 to 3 μm.
The improvement is further improved when the ratio dA/dz is in the range of 1 to 3. Moreover, when the relative density of the sintered body is 95% or more, further improvement is achieved.

Claims (5)

[Claims] Claim 1: Zr containing Al2O3 as a main component and whose crystal structure is at least 50% by volume tetragonal.
Contains O2 in a range of 20 to 40% by weight, TiO2 in a range of 1 to 5% by weight, and MgO in a range of 0.1 to 1% by weight.
The average crystal grain size of Al2O3 is 1.5.
A member for a pulverizer made of a ceramic having a diameter of 5 μm and at least 80% of ZrO2 present in the grain boundaries of Al2O3. [Claim 2] The average crystal grain size dz of ZrO2 is 1.5.
3 .mu.m, and the ratio dA /dz of the average crystal grain size dA of Al2O3 to the average crystal grain size dz of ZrO2 is in the range of 1 to 3. 3. The member for a crusher according to claim 1 or 2, having a relative density of 95% or more. Claim 4: Thermal conductivity at 20°C is 0.02 to 0.
The member for a crusher according to claim 1, 2 or 3, which has a temperature in the range of 0.7 cal/cm·sec·°C. 5. Regarding a ball member with a diameter of 10 mm, 200 of the ball members are placed in a nylon ball mill with an internal volume of 1000 ml, and further, 3 of the total weight of the ball members is
Claims 1 and 2, wherein the ball mill containing 6% water and 4% SiC powder having an average particle size of 1 μm and operating the ball mill at a speed of 100 rpm for 50 hours has a weight loss rate of 1% or less.
, 3 or 4 for a crusher.