JP2001277180A - Zirconia cutter member and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems that a cutter made of a zirconia sintered body has high strength and toughness, but intends to degrade cutting performance of the cutting edge due to not falling but abrasion because of low hardness and the high toughness, and the tip related to the performance of the cutter is hardly machined sharply even if zirconia has high toughness as ceramic. SOLUTION: The composite zirconia sintered body for the zirconia cutter member contains zirconia ceramics components and at least one kind of ceramics components selected from not more than 50 wt.% of WC, AlN, Al2O3, and SiC. The zirconia ceramics components contain at least one kind of oxides selected from Y2O3, MgO, CaO, and CeO2 in zirconia, and has a part including 5-30 vol.% of single crystal in a part with 3 μm from the tip of the cutting edge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blade, and more particularly to an industrial or consumer blade member made of a sintered body containing zirconia as a main component.

[0002]

2. Description of the Related Art Various types of knives, whether for industrial or consumer use, have good sharpness, have a minimal decrease in sharpness, have corrosion resistance, have abrasion resistance, and have high mechanical strength and durability. There is a demand for such characteristics.
Further, in many cases, properties such as good cleaning properties and chemical resistance are required for repeated use.

Conventionally, most of industrial blades are made of so-called metal such as carbon steel, high-speed steel, and alloy. These metal industrial knives have a drawback that cutting is difficult due to the tendency to generate burrs at the time of cutting, but the chipping of the cutting edge is small due to the extensibility of the metal, and the initial sharpness is generally good. However, metals have low hardness, and sharpness is significantly reduced due to a tempering effect peculiar to metals due to a rise in temperature during use. Further, there is a problem in durability because of low hardness. Further, in general, there is a problem that metals are easily corroded by any of water, acid and alkali.

[0004] On the other hand, most of conventional consumer blades are conventionally made of carbon steel or stainless steel, and the characteristics required for consumer blades are not as severe as those required for industrial blades. However, because they are metal, these consumer knives also have the same disadvantages, albeit to varying degrees, as the industrial knives described above. Of course, stainless steel does not have to worry about rusting, but its sharpness and durability are significantly inferior to those of carbon steel.

[0005] Therefore, in order to improve various characteristics, application of various ceramics has been attempted, and Japanese Patent Application Laid-Open No. 58-71095 does not substantially include a monoclinic crystal structure.
A high strength zirconia knife is disclosed.

[0006]

However, the cutting edge made of a zirconia sintered body having these compositions is excellent in strength and toughness, but has low hardness and high toughness. There is a drawback that tends to cause a decrease in Further, it is difficult to sharply shape the tip which affects the performance of the blade even with zirconia having high toughness as ceramics.

[0007]

In order to solve the above-mentioned problems, the present invention has been studied in detail on the mechanism for reducing the sharpness of a member used for a blade and the material properties of the member. In the body, it has been found that a member having a specific crystal structure, a micromechanism, and mechanical properties with a cutting edge exhibits excellent properties, and the present invention has been completed.

That is, the present invention provides the following blade member.

A composite zirconia-based sintered body comprising a zirconia ceramic component and at least 50% by weight or less of a ceramic component selected from WC, AlN, Al ₂ O ₃ and SiC, wherein the zirconia ceramic component is Adds zirconia to Y ₂ O ₃ , MgO, CaO and Ce
It contains at least one oxide selected from O ₂ , and at a portion within 3 μm from the tip of the cutting edge,
A zirconia blade member having a portion where 5 to 30% by volume of a monoclinic crystal is generated.

Further, as a method of manufacturing the blade member, Y
Zirconia powder containing at least one oxide selected from ₂ O ₃ , MgO, CaO and CeO _{2 is} added with at least 0.1 wt% or more and 50 wt% or less of WC, Al
A mixed powder to which at least one type of ceramic powder selected from N, Al ₂ O ₃ and SiC is added is wet-mixed and pulverized so that the 90% cumulative distribution particle diameter is 2 to 6 μm and the average particle diameter is 2 μm or less. Specific surface area by BET method is 3 to 2
A slurry of fine powder of 0 m ² / g, drying the slurry, shaping the obtained powder, and cutting the surface of the sintered zirconia blade member by grinding. .

[0011] Alternatively, a chloride solution obtained by adding at least 0.1% by weight to 50% by weight of Al in terms of oxide to a chloride solution of at least one metal selected from Y, Mg, Ca and Ce and Zr. Is wet-milled to obtain a powder having a 90% cumulative distribution particle diameter of 2 to 6 μm and an average particle diameter of 2 μm.
In the following, a slurry of fine powder having a specific surface area of 3 to ²⁰ m ² / g by the BET method is formed, the slurry is dried, the obtained powder is formed, and the surface of the sintered zirconia blade member is cut by grinding. It is characterized by being attached.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION For a blade member of the present invention, it is essential to use a sintered body having ZrO ₂ as a main raw material and having the following requirements.

In the present invention, ZrO ₂ is Y ₂ O ₃ , Mg
A material containing at least one of O, CaO and CeO ₂ is used. ZrO ₂ not containing these elements
The crystal structure at high temperature is tetragonal or cubic, or a mixed phase of tetragonal and cubic, and upon cooling, the tetragonal transforms to monoclinic, but at the same time, the ceramic is destroyed due to volume expansion. I do. To avoid this, pure ZrO ₂ is converted to Y ₂
Oxides such as O ₃ , MgO, CaO and CeO ₂ are contained for stabilization. As a result, the crystal structure of ZrO ₂ after sintering becomes tetragonal, a mixed phase of tetragonal and cubic, or cubic, and the material must be basically a structure that does not contain monoclinic, It is essential to include a stabilizer.

As for the mechanism of micro-destruction of ZrO ₂ , stress-induced transformation occurs due to external force or the like, and as a result, monoclinic crystals are generated. Transformation of tetragonal and cubic crystals to monoclinic as described above causes volume expansion, so fine cracks are generated around the monoclinic, and friction, impact, stress due to cutting force, etc. Micro-destruction occurs from the crack as a starting point, and wear and chipping increase, which is not preferable. Therefore, it has been considered that a material that does not cause transformation is preferable for the zirconia blades. Therefore, as a result of diligent studies, a minute chipping generated at the cutting edge is sharp, and a method of making the sharp chipping into a minute cutting edge has been found. In other words, by proactively causing monoclinic formation at the cutting edge, which has been regarded as a weak point, the cutting edge is prevented from becoming dull due to wear,
The sharpness can be maintained for a long time. The material condition for satisfying this condition is that the monoclinic crystal has a crystal structure basically containing no monoclinic crystal, but the monoclinic crystal has a range of 5 to 30% by volume in a portion within 3 μm from the cutting edge processed by lapping or polishing. I found that a material that had naturally occurring parts was good. If it is less than 5% by volume, micro-destruction is less likely to occur and wear of the cutting edge is prioritized, so that the cutting life is short. If it exceeds 30% by volume, the speed of micro-fracture is fast, so the falling off of the cutting edge is faster and the cutting life is longer. Be shorter. Preferably it is in the range of 5 to 25% by volume.

The measurement of the crystal phase was performed using a laser Raman microprobe. The laser Raman microprobe is provided with an optical microscope in place of a micro sample chamber of a typical laser Raman spectroscope, and by using this, it is possible to measure a crystal phase of a minute portion of about 1 to several μm.

[0016] In the measurement, of the blade member after the processing of the blade edge is completed
The frequency ν₀When irradiated with laser light
Twisting frequency ν₀Of the Raman scattered light of ± ν, Sto
The frequency ν called the kes line₀Irradiation light with -ν intensity on the vertical axis
From the horizontal axis (Raman shift)
In the Mann spectrum, the Raman shift is 148 / cm ^-1
Of tetragon, 181 / cm^-1, 192 / cm^-1To monoclinic
Raman band intensity peak height I_t ¹⁴⁸, I_m ¹⁸¹,
I_m ¹⁹²From these, and the following equation C_m(%) = ｛0.5 (I_m ¹⁸¹+ I_m ¹⁹²)｝ / ｛K ・ I_t
¹⁴⁸+0.5 (I_m ¹⁸¹+ I_m ¹⁹²)｝ Means monoclinic C_m(%) Was calculated.

Here, k is a correction value of the absolute intensity of the monoclinic and tetragonal Raman bands, and Y ₂ O ₃ is 2.0 mol
%, Y ₂ O ₃ 2.5 mol%, Y ₂ O ₃ 4.0 mol%
Since k = 2.2 ± 0.2 was obtained for the sample No., the calculation was performed with k = 2.2.

WC, Al which is one of the essential requirements of the present invention
The purpose of containing N, Al ₂ O ₃ and SiC is that the blade member is required to have various characteristics depending on the material used and the material to be cut. Films with pigment coated on the surface, etc., are subject to rapid
It is effective to increase the hardness by adding ₂ O ₃ or SiC to zirconia. In addition, since the frictional heat is likely to be generated when the object to be cut is hard and thick, zirconia with a low thermal conductivity is easy to store heat, so the blade is likely to become high temperature, which deteriorates due to transformation of zirconia and affects the quality of the object to be cut. When there is a concern, it is effective to include a material having high thermal conductivity such as WC and AlN. The content and number of these components vary depending on the material and conditions of the object to be cut, but if it exceeds 50% by weight, the original strength and toughness of zirconia decrease significantly, which is not preferable as a blade member. The preferred range is 40% by weight or less, more preferably 3% by weight.
0% by weight or less.

In the present invention, ZrO ₂ is Y ₂ O ₃ , Mg
At least one of O, CaO and CeO ₂ is used as a stabilizer, and it is preferable to use Y ₂ O ₃ or CeO ₂ . It is sufficient that Y ₂ O ₃ is solid-solved at about 1 to 5 mol%, and if it is less than 1 mol%, transformation to monoclinic crystal is likely to occur during cooling, and the strength is unfavorably reduced. Also 5
If it exceeds mol%, transformation due to stress is unlikely to occur, so that the strength also decreases, which is not preferable as a blade member. More preferably, it is in the range of 1.5 to 3.5 mol%.

The micro-fracture at the cutting edge causes micro-fracture starting from a fine crack generated by transformation of the particle at the tip into a monoclinic crystal, and falls off. Microfractures occur continuously because the falling particles affect the next particle. The inventors have also found that the fracture surface created by this microfracture is sharp and effective as a cutting blade, and that it can maintain good sharpness by continuously raising. However, when the rate of development of the microfracture is low, the cutting edge becomes dull due to abrasion and the sharpness is reduced. On the other hand, when the rate of development is too high, the wear of the cutting edge is accelerated, so that the life is shortened. The microfracture at the tip of the cutting edge basically propagates along the grain boundary,
In particular, if internal stress or hair cracks generated during sintering due to non-uniformity during molding remain, micro-destruction progresses significantly, so it is necessary to eliminate non-uniformity during molding. I found it important. That is, if the particle size of the ceramic powder, which influences the moldability in the manufacturing method, is too large, large gaps are likely to be formed between the particles, and the sintering temperature needs to be increased to lower the sinterability. There is a possibility that the monoclinic crystal will increase due to sintering and the strength will decrease. Conversely, if the particle size of the ceramic powder is small, the sinterability is good, but the agglomeration of the powder tends to occur before molding and the pores, which are the fracture starting points, are easily formed during molding, so the falling speed of the cutting edge may be too fast There is. The specific surface area by the BET method described in JIS-R1626 “Method of measuring specific surface area by gas adsorption BET method of fine ceramic powder” is 3 to ²⁰ m ² / g. The 90% cumulative particle diameter was found to be 2 to 6 μm, and the average particle diameter was 2 μm or less. Preferably, the specific surface area by the BET method is 7 to
The particle size is 15 m ² / g, the 90% cumulative particle size measured by laser scattering particle size distribution measurement is 3 to 5 μm, and the average particle size is 1.5 μm or less.

It is clear that a very small portion of the blade member, a few μm from the cutting edge, greatly affects the performance, and how few defects are present in this portion determines the sharpness and life of the blade. Is one of the factors. In order to reduce the defects in the cutting edge portion, it is impossible to enhance the physical properties of only the cutting edge portion, and the entire member must have few defects, that is, be dense and have few pores. Therefore, the porosity of the sintered body is preferably as small as possible, and the preferable porosity is 5% or less. If it exceeds 5%, there is a high danger that the cutting edge of the blade will be cut by pores or the like. More preferably, it is in the range of 3% or less.

The porosity P (%) can be calculated by the following equation P = (1−ρ / ρ ₀ ) × 100 based on the theoretical density ρ ₀ and the actual density ρ.

The blade member of the present invention can be manufactured by various methods. Among them, an example of a preferable method will be described. First, by a method such as hydrolysis and coprecipitation, ZrO ₂ powder preparation was produced by Y ₂ O ₃ of 1.5 to 3.5 mol% prescribed amount of Al ₂ O ₃ in ZrO ₂ powder containing Add the powder and mix well to make a mixed powder.
The mixing operation may be wet or dry. The mixed powder is dried, if necessary, then coarsely pulverized, sieved or granulated. As a method for producing this mixed powder, Y, Mg, C
at least one metal selected from a and Ce and Zr
It is also possible to produce a chloride solution obtained by adding 50% by weight or less of Al in terms of oxide to the chloride solution by coprecipitation and thermal decomposition.

Next, the mixed powder is formed into a desired blade shape by various molding methods, for example, a mold molding method or a rubber press molding method, and then the molded body is heated at 20 to 100 ° C./hr.
After heating from 1400 ° C. to 1650 ° C. at a heating rate and holding at this temperature for several hours, sintering
It is gradually cooled to 800 ° C. at a rate of ° C./hr and further cooled to room temperature to obtain a sintered body.

The surface of the sintered body having a desired shape obtained as described above is ground, and the blade is sharpened by honing or lapping.

In the above, depending on the use of the blade, a thin sheet may be formed from raw material powder, and the sheet may be stamped and sintered. Also, a so-called hot isostatic sintering method is employed in which a molded body is sintered at 1300 to 1600 ° C, which is slightly lower than the above temperature conditions, and then sintered at 1200 to 1550 ° C under a pressure of 500 to 3000 kg / cm ^2. When used, the crystal can be made denser and the performance of the blade can be improved.

[0027]

Embodiments will be described below. The measurement and evaluation of the physical properties of the examples were performed as follows. (1) Average particle size, 90% Cumulative particle size 200 g of water and 60 g of powder were placed in a 300 cc beaker and stirred well, and then a 30% by weight slurry was prepared in an ultrasonic generator for 10 minutes. This slurry was prepared using a Nikkiso Co., Ltd. Microtrac particle size distribution analyzer model 7995-
10SRA was used. The particle size distribution of the adjusted slurry was measured, and the so-called median diameter corresponding to a cumulative distribution of 50% was defined as the average particle diameter, and the particle diameter corresponding to the cumulative distribution of 90% was calculated from the smaller particle diameter. The particle size was used. (2) Specific surface area “Monosoap” MS-17 manufactured by Yuasa Ionics Co., Ltd.
Was used to measure the specific surface area of the powder. Measurement is JIS-R
1626 "Gas adsorption BET of fine ceramic powder
Method for Measuring the Specific Surface Area ”by the BET one-point method. (3) Measurement of crystalline phase The powder was subjected to rubber press molding at a molding pressure of 1 ton / cm ² ,
The sintered sintered material is processed with a surface grinder to a size of 18 mm wide x 39 mm long x 0.3 mm thick, and the cross section of the 0.3 mm thick edge has a tip angle of 30 degrees. A sample finished by grinding with a diamond wheel of 600 mesh and further lapping with diamond abrasive grains of 1 μm or less so that the angle of the cross section of the tip becomes 40 degrees was used. The measuring instrument is Jobin Yv
Using "Ramanor" U-1000-I manufactured by On Co., Ltd., the peak height of the Raman band was measured at three points with a laser Raman microprobe at a distance of 1 μm from the tip of the blade, and the monoclinic fraction was calculated.

Example 1 A ZrO ₂ powder containing 2.5 mol% of Y ₂ O ₃ as a stabilizer and having an average particle size of 1.0 μm was added to a ZrO ₂ powder having an average particle size of 0.3 μm.
20 wt% of Al ₂ O ₃ powder having a purity of 99.9%
And then wet-mixed for 24 hours in a ball mill, dried and coarsely pulverized to obtain a mixed powder. The specific surface area of this mixed powder was 11 m ² / g, and the 90% cumulative particle size was 4.0.
μm, and the average particle size was 0.9 μm. This powder is granulated with a spray drier and the molding pressure is 1 ton / cm ²
, And sintered at 1350 ° C. Further, the sintered body was further subjected to 1500 kg under a pressure of 1000 kg / cm ^2.
C. Sintering hot isostatic sintering was performed.

The sintered body was 18 mm wide by a surface grinder.
We process to size of 39mm in length X 0.3mm in thickness,
After grinding with a 600-mesh diamond wheel so that the cross section of the 0.3 mm thick edge has a tip angle of 30 degrees, diamond diamond of 1 μm or less so that the tip cross section angle becomes 40 degrees. Finished by wrapping with grains.

Using the wrapped edge as a blade, the peak height of the Raman band was measured with a laser Raman microprobe at the cutting edge, and the monoclinic fraction was calculated. When three points were measured at a distance of 1 μm from the tip of the blade, the monoclinic fraction was 8.5% by volume, 6.1% by volume,
6.0% by volume, and 5 μm or more from the tip of the blade (5 μm, 10 μm, 50 μm, 200 μm, 50 μm
0 μm) was 0.5% by volume or less.

Thickness 2 deposited with aluminum using this blade
A polyester film of 0 μm is cut at a cutting speed of 200 m /
When used for min, a life of 150 hours or more was confirmed.

The same measurement was carried out on a blade whose tip had grown due to chipping, and the monoclinic fraction at a distance of 1 μm from the tip of the blade was 3.2% by volume, 7.5% by volume, and 4% by volume. .
8% by volume, and the point of 5 μm or more from the cutting edge is also 0.1%.
It was 5% by volume or less. When the cutting edge of this blade was sharpened again, the monoclinic ratio showed the same value,
Even when the same cutting test was performed, the life was still 150 hours or more.

Comparative Example 1 When the material was processed in Example 1 with the average particle diameter of 3 μm, the monoclinic crystal ratio of the cutting edge was 35% by volume, and the same cutting test was performed. Was.

Example 2 A ZrO ₂ powder containing 2.5 mol% of Y ₂ O ₃ as a stabilizer and having an average particle size of 1.0 μm was added to a ZrO ₂ powder having an average particle size of 0.3 μm.
The Al ₂ O ₃ powder having a purity of 99.9% is 0.1 wt.
%, And wet-mixed in a ball mill for 24 hours, then dried and coarsely pulverized to obtain a mixed powder. The specific surface area of this mixed powder is 10 m ² / g, and the 90% cumulative particle size is 3.
The average particle size was 5 μm, and the average particle size was 1.0 μm. This powder is granulated with a spray dryer, and the molding pressure is 1 ton / cm.
Rubber pressing was performed at ² , and sintering was performed at 1500 ° C.

This sintered body was processed into a size of 18 mm in width × 39 mm in length × 0.3 mm in thickness in the same manner as in Example 1 using a surface grinder. After grinding with a 600-mesh diamond wheel so that the angle of the tip is 30 degrees, lapping was further performed with diamond abrasive grains of 1 μm or less so that the angle of the cross section of the tip was 40 degrees. .

The peak height of the Raman band of the cutting edge was measured using a laser Raman microprobe, and the monoclinic crystal ratio was calculated. When three points were measured at a distance of 1 μm from the tip of the blade, the monoclinic crystal ratio was 9.0% by volume, 7.4% by volume, and 6.8% by volume, and a point of 5 μm or more from the tip of the blade ( 5 μm, 10 μm, 50 μm, 200 μm,
500 μm) was 0.5% by volume or less.

The sintered material was cut with scissors having a tip angle of 60 ° with a diamond grindstone of # 230.
When a cutting test was performed with 100 polyester yarns, 100
It could be cut more than 000 times.

Comparative Example 2 A ZrO ₂ powder containing 2.5 mol% of Y ₂ O ₃ as a stabilizer and having an average particle diameter of 1.0 μm was added with no ceramic component such as Al ₂ O ₃ , and the specific surface area was determined by the BET method. 25m ² / g
The monoclinic crystal ratio at the tip of the raw material was measured by the same method as in Example 1 and found to be 35% by volume. When this material was subjected to a cutting test using scissors in the same manner as in Example 2, the material was not cut after 10,000 times or less.

[0039]

As a result of a detailed study of the mechanism of reducing the sharpness of the member used for the cutting tool and the material properties of the member, the sintered body mainly composed of zirconia has a specific crystal structure, a fine mechanism and a mechanical characteristic of the cutting edge. Have excellent characteristics.

Continuing on the front page F term (reference) 3C027 AA11 AA17 AA18 3C046 FF33 FF42 FF47 FF49 FF51 FF52 FF55 FF57 3C058 AA04 AA09 CA01 CB10 DB02 4G031 AA03 AA04 AA07 AA08 AA12 AA29 GA0319

Claims (3)

[Claims] 1. A composite zirconia-based sintered body comprising a zirconia ceramic component and at least one ceramic component selected from WC, AlN, Al ₂ O ₃ and SiC at 50% by weight or less. The ceramic component is zirconia with Y ₂ O ₃ , MgO, CaO and C
are those containing at least one oxide selected from eO _2, and the portion within 3μm from the tip of the cutting edge, and wherein a portion of monoclinic is generated 5-30 vol% Zirconia knife member. 2. A zirconia powder containing at least one oxide selected from the group consisting of Y ₂ O ₃ , MgO, CaO and CeO ₂ , wherein at least 0.1% by weight to 50% by weight of WC, AlN, Al A mixed powder to which at least one type of ceramic powder selected from ₂ O ₃ and SiC is added is wet-mixed and pulverized to have a 90% cumulative distribution particle diameter of 2 to 6 μm.
m, an average particle diameter of 2 μm or less, and a slurry of fine powder having a specific surface area of 3 to ²⁰ m ² / g by a BET method. The slurry is dried, and the obtained powder is formed into a sintered zirconia. A method for manufacturing a zirconia blade, wherein the surface of the blade member is sharpened by grinding. 3. A chloride obtained by adding at least 0.1% by weight to 50% by weight of Al in terms of oxide to a chloride solution of at least one metal selected from Y, Mg, Ca and Ce and Zr. The solution is coprecipitated, and the powder produced by the thermal decomposition oxide production method is wet-pulverized to have a 90% cumulative distribution particle diameter of 2 to 6 μm, an average particle diameter of 2 μm or less, and a specific surface area by the BET method. Zirconia characterized in that a slurry of fine powder of 3 to ²⁰ m ² / g is formed, the slurry is dried, the obtained powder is formed, and the surface of the sintered zirconia blade member is ground by grinding. Manufacturing method of knife.