JPH03247553A - Aluminum oxide-based ceramic having high strength and toughness and its production - Google Patents

Abstract

PURPOSE:To improve the strength of the ceramic by mixing the powder of the oxide of a specified metal or rare-earth element, the powder of the carbide, nitride and oxide of a group 4a metal and Al2O3 powder, compacting the mixture, sintering the green compact and then heat-treating the compact. CONSTITUTION:The Al2O3 powder having <=0.6mum average particle diameter, 0.05-2wt.% of the powder of the oxide of a metal consisting of >=1 kind among Y, Mg, Cr, Ni, Co and rare-earth elements and having <=1mum average particle diameter and 5-50wt.% of the powder of the carbide, nitride and oxide of a group 4a metal consisting of >=1 kind among the carbide, nitride, carbonitride, carboxide, nitrooxide and carbonitrooxide of Ti, Zr and Hf, having <=1.5mum average particle diameter and in which the content of the particles having <=0.3mum diameter is controlled to >=10% are mixed, and the mixture is compacted to obtain the green compact. The compact is sintered at 1680-1830 deg.C for 10-40min in the Ar or gaseous mixture of Ar and an inert gas kept at 0.8-5atm, and then held at 1300-1450 deg.C for 2-10hr in the Ar or gaseous mixture of Ar and an inert gas kept at 100-2000atm to obtain an Al2O3 ceramic having high strength and toughness and in which the particle diameter of the hard dispersed phase in the Al2O3 base is controlled to <=0.3mum.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention provides an oxidized material that has high strength and toughness and exhibits excellent performance when used as a cutting tool for cutting under especially severe conditions. This invention relates to aluminum (hereinafter referred to as Ag2O3)-based ceramics and a method for producing the same.

[Conventional technology]

BACKGROUND ART Conventionally, Al2O3-based ceramics and a method for producing the same are known, which are described, for example, in Japanese Patent Application Laid-open No. 118410/1983.

This Ag2O3-based ceramic has raw material powders such as Af1203 powder, Y, Mg, Cr, C
o, Ni, and rare earth element oxides (hereinafter referred to as YOMgO, Cr2O3゜23' Cod, Nip, and R2O3, respectively, TashiR: rare earth element) powders. metal oxide powder, as well as Ti and Zr.

and carbides, nitrides, carbonitrides, carbonates, nitoxides, and carbonitoxides of Hf (group 4a metal of the periodic table)
Hereafter, Mc, MN, and MCN, respectively.

Indicated by MCO, MNO, and MCN0, where M is T
Carbon-nitrogen-oxides (hereinafter referred to as M-C -N・
0) are prepared, and these raw material powders are expressed in weight% (hereinafter % indicates weight%): Metal oxide powder: 10% or less, M Red CψN-0 powder = 10 to 90%, Go to page 203 Powder: The remainder is blended into a composition consisting of, mixed under normal conditions, and formed into a green compact, and then mixed under normal conditions, for example 1.
In a nitrogen partial pressure atmosphere of 00 torr, temperature: 1580°C,
It is manufactured by hot pressing under the conditions of pressure crab 30 atm and holding time: 10 to 30 minutes, the above metal oxide constitutes the binder phase, and the above A 120 s and M-C-N- 0 has a structure constituting a dispersed phase, and has substantially the same component composition as the blended composition.

[Problem to be solved by the invention]

On the other hand, in recent years, demands for labor saving, higher performance, and higher speed have been severe in various industrial fields, and the same is true in the field of cutting machines, for example, and the conditions for using cutting tools are becoming increasingly harsh. For this reason, cutting tools are required to have even greater strength and toughness. However, the conventional Al2O3 ceramics mentioned above and many other Al2O3 ceramics have been found to be lacking in strength and toughness. The cutting edge is prone to chipping and chipping, and at present it is not possible to deal with this problem satisfactorily.

[Means to solve the problem]

Therefore, from the above-mentioned viewpoint, the present inventors
! 20 We focused on a-based ceramics and conducted research to improve their strength and toughness. As a result, we found that the raw material powder was Al1203 powder with an average particle size of 0.6 μm or less,
The above metal oxide powder with a particle size of 1 or less, and an average particle size of 1
．． 5am or less, 10% particle size is 0.3uIa or less
Using the above M-C-N.0 powder which accounts for 70.05-2% of the above metal oxide powder,
-0 powder: 5 to 50%, AlI2O3 powder: balance, and after mixing and forming into a green compact under normal conditions, apply 0.8 to 5 atm of pressure to the green compact. A of
In a mixed gas atmosphere of r or Ar and inert gas, temperature 7
When high-temperature and short-time sintering is performed under the conditions of holding at 1880-1830°C for 10-40 minutes, the above-mentioned metal oxide is completely dissolved in A1) 203 by this high-temperature sintering, and the above-mentioned metal oxide is M-C-N- with a particle size of 0.3 or less and an average particle size of 1.5 or less in a proportion of the hard dispersed phase of 10% or more of the solid dispersed A 1120a in a completely solid solution.
Al2O3 with a structure in which 0 is distributed as a hard dispersed phase
A base ceramic is formed, and this is further sintered continuously or intermittently after the high temperature short time sintering in an atmosphere of Ar or a mixed gas of Ar and an inert gas at a pressure of 100 to 2000 atm at a temperature of 1300 to 1450°C. to 2
When heat treatment is performed under the conditions of holding for ~10 hours, in this heat treatment, the metal oxide dissolved in AlIO promotes the crystal grain growth of AI 2033, and Alt 2
0 a is the fine particle size of the above M-C-N.0: 0.
Grain growth occurs while incorporating M-C-N.0 of 3 m or less into the crystal grains, and M-C-N.0 is distributed as a hard dispersed phase at the grain boundaries of the substrate made of Ail 20s.
M with a fine grain size of 0.311N or less is also present in the 2O3 crystal grains.
The resulting Ag2O3-based ceramics have a structure in which -C-N・0 is distributed, and due to the fine M-C-N・0 distributed within the Ag2O3 crystal grains, the Ag2O3-based ceramics have a structure in which -C-N・0 is distributed. They were surprised by the research results showing that it has significantly higher strength and toughness compared to other materials.

This invention was made based on the above research results, and uses AlI2O as a raw material powder with an average particle size of 0.8 m or less.
3 powder, the above-mentioned metal oxide powder of 1 or less, and the average particle size: 1.5 m or less, and the particle size of 0.3 or less is 10
Using the above M-C-N.0 powder containing % or more, these raw material powders are: the above metal oxide: 0.05 to 2%, the above M-C-N.0: 5 to 50%, Ag2O3: the remainder , mixed under normal conditions and formed into a green compact, and then heated to an A of 0.8 to 5 atm.
In a mixed gas atmosphere of r or Ar and inert gas, temperature:
1B Hold at 80-1830℃ for 10-40 minutes, sinter at high temperature for a short period of time, and then sinter continuously or intermittently in Ar or a mixed gas atmosphere of Ar and inert gas at 100-2000 atm. , Temperature: 2 to 1300-1450℃
A method for producing Ag2O3-based ceramics by carrying out an Ajl1203 grain growth heat treatment under the conditions of holding for ~10 hours, and a method in which 0.05 to 2% of the above metal oxides in the total proportion are solid solution. The above M C-N
The A 120 a-based ceramic has a structure in which A 120 is distributed as a hard dispersed phase, and the grain size of the hard dispersed phase distributed within the crystal grains is 0.3 or less.

Next, the reason why various conditions are limited as described above in the ceramics and the manufacturing method thereof of the present invention will be explained.

(a) Average grain size of Ag203 powder When the average grain size becomes larger than 0.6%, the average grain size of A 120 s crystal grains in ceramics is reduced to 0.6%.
It becomes difficult to suppress the level below 9I11a, and Ag2O
Since the strength of ceramics with 3 crystal grains exceeding 0.9 μm is markedly reduced, the average grain size was determined to be 0.6 μm or less.

(b) Blending ratio of M-C-N・0 powder M-C-N・0 is distributed as a hard dispersed phase at the Ag2O3 grain boundaries to improve the wear resistance of ceramics, and inside the Ag2O3 grains. It also has the effect of improving the strength and toughness of ceramics, but its blending ratio is 5%.
If the content is less than 5%, the desired effect cannot be obtained in the above action, while if the content exceeds 50%, the sinterability decreases, and the content in the ceramic exceeds 50%. Therefore, the blending ratio, that is, the content ratio, was set at 5 to 50%. In this case, the average particle size of the powder is 1
．． If it exceeds 5 uM, the average particle size in the ceramic will exceed 1.5 tlJm and become coarse, causing a decrease in strength, so the average particle size must be 1.5 tlJm or less. In addition, M・C−N・0 is incorporated into the A II 203 crystal grains during the A I 203 crystal grain growth heat treatment,
In order to facilitate distribution, the particle size must be 0.3aIe or less, and in this case, the particle size of 0.31ua or less should be 10% of the M-C-N.0 powder.
% or more, the incorporation of M・C−N・0 into the crystal grains during A M 20 s crystal grain growth becomes active,
Significant improvements in the strength and toughness of ceramics can now be seen.

(c) Blending ratio of metal oxide powder The metal oxide has an A i120 s during high-temperature and short-time sintering.
In addition to improving the sinterability and thereby improving the strength of ceramics, it also improves the strength of ceramics by incorporating fine M-C-N. 20a has the effect of promoting grain growth, but if its proportion is less than 0.05%, the desired effect cannot be obtained;
%, it will remain in the ceramic and reduce the hardness and strength, especially at high temperatures. Therefore, the blending ratio was set at 0.05 to 2% (this is a natural result). The content ratio in ceramics is also 0.
05-2%). In addition, when the average particle size exceeds 1 liter, solid solution in A I' 20 a becomes difficult, and it remains at the grain boundaries, causing a decrease in the strength and hardness of ceramics at high temperatures. Therefore, the average particle size was determined to be 111M or larger.

(d) High-temperature, short-time sintering conditions Satisfactory sintering cannot be achieved even if the atmospheric pressure is less than 0.8 atm, or if the temperature and holding time are less than 1680°C and less than 10 minutes, respectively, resulting in metal oxidation. Solid solution and densification of substances into Ag2O3 become insufficient,
On the other hand, if the atmospheric pressure exceeds 5 atm, gases generated during sintering will be present, making it impossible to obtain a dense sintered body, and if the temperature exceeds 1830°C, the material will decompose into powder. The sinterability deteriorates due to the gas generated by this decomposition, and if the holding time exceeds 40 minutes, especially fine particles of 0.3IIA or less of M-C-N-0. Grain growth occurs to a grain size of
~5 atm, temperature: 1eso~1830℃, holding time:
It was set as 0 to 40 minutes.

(e) Grain growth heat treatment of Ag203 This heat treatment reduces the bore in the ceramic to bring it close to the true density, and also aims to grow A 120 s grains, which are present at the Ag2O3 grain boundaries. Incorporating fine M-C-N-0 with a particle size of 0.3 wa or less from the M-C-N-0 that is produced, and distributing it within the crystal grains, thereby improving the strength and toughness of ceramics. However, if the atmospheric pressure is less than 100 atm, the removal of the bore will be insufficient, and if the temperature is 1300°C
Less than A! The growth of I2O3 crystal grains is extremely slow, making it impractical, and furthermore, if the holding time is less than 2 hours, Ag2O
3 The proportion of M-C-N-0 distributed within the crystal grains is M -C
- The proportion of N・0 cannot be more than 5%,
On the other hand, atmospheric pressure exceeding 2000 atm is technically and practically meaningless, and temperature exceeding 1450°C is Ap2
At the same time as the 03 crystal grains grow, M-C-N・0 grains grow, resulting in M-C-N・0 distributed within the Ag2O3 crystal grains.
The ratio of 0 is significantly reduced, and a holding time exceeding 10 hours is technically meaningless and causes high costs. Therefore, the conditions are as follows: atmospheric pressure = 100 to 2000 atm, temperature + 1300 to 1450. °C, holding time 2~J
It was set as O time.

In addition, in the method of this invention, the M-C-N.0 powder with an average particle size of 21.5111a or less containing 10% or more of fine particle sizes of 0.3 blood or less has an average particle size of 0.7 to 2 Blood M
-C-N.0 powder is charged into an attritor together with WCC cemented carbide balls having a diameter of 1 to 3 mm, and is prepared by grinding for 10 to 100 hours.

〔Example〕

Next, the ceramics of the present invention and the method for producing the same will be specifically explained using examples.

Various types of A shown in Table 1 were used as raw material powders.
Using D20a powder, M-C-N・0 powder, and metal oxide powder, these raw material powders were blended into the composition shown in Table 1, mixed for 72 hours in a ball mill, and dried. Back, plane: 30mm x 30mm, thickness =
Green compacts with dimensions of 10 degrees, and IS O-S
NGN1204 (1 ton for 18 cutting chip shaped green compacts)
Methods 1 to 15 of the present invention were carried out by press-forming at a pressure of on/cd, and then subjecting these compacts to high-temperature short-time sintering and Ag2O3 crystal grain growth heat treatment under the conditions also shown in Table 1. Ceramics 1 to 15 of the present invention were produced respectively.

In addition, for the purpose of comparison, the raw material powders shown in Table 1 were blended to the compositions also shown in Table 1, and further, instead of the above-mentioned high-temperature short-time sintering and A 1120 a grain growth heat treatment, Conventional methods 1 to 5 were carried out under the same conditions except that hot pressing was performed under the conditions shown in Table 1, and conventional ceramics 1 to 5 were manufactured, respectively.

Next, for the various ceramics obtained as a result, the component composition, theoretical density ratio, Rockwell hardness (A scale), transverse rupture strength, and indentation method (1M method)
The fracture toughness value was measured. In addition, work material: J l5-5UJ2 (quenched steel, hardness: H
RC61) perforated square material, cutting speed: 200 m/■in.

A wet interrupted cutting test was conducted on hardened steel under the conditions of depth of cut = 0.3 mm, feed rate of 20 mm, and 2 mm/rev, and the cutting time until chipping occurred on the cutting edge was measured. The results of these measurements are shown in Table 2.

〔Effect of the invention〕

From the results shown in Tables 1 and 2, it can be seen that methods 1 to 1 of the present invention
The ceramics 1 to 15 of the present invention manufactured by the conventional methods 1 to 15 all have a theoretical density ratio of 99% or more, are dense, and have extremely few micropores, and are superior to the conventional ceramics 1 to 5 manufactured by the conventional methods 1 to 5. It has superior strength and toughness, as well as high hardness, so it has excellent fracture resistance when used as a cutting tool for cutting under severe conditions that require these characteristics. It is clear that the material exhibits excellent cutting performance over a long period of time.

As mentioned above, according to the method of the present invention, A and Q having high strength and toughness as well as excellent wear resistance can be obtained.
20A-based ceramics can be produced, and the resulting Al2O3-based ceramics of the present invention have the excellent properties as described above, so they can be used not only in the cutting field but also in high-speed applications in other industrial technology fields. This brings about industrially useful effects such as improved performance and improved performance, and a significant contribution to labor savings.

Out wish Man 2. Mitsubishi Metals Co., Ltd. teenager Reason Man Chang Field sum husband 1 other person

Claims (2)

[Claims] (1) Y, Mg, Cr in a total proportion of 0.05 to 2% by weight
, Ni, Co, and one or more of rare earth element oxides in the crystal grains and grain boundaries of the substrate made of aluminum oxide in which one or more of oxides of rare earth elements are dissolved.
A structure in which one or more of 50% by weight of Ti, Zr, and Hf carbides, nitrides, carbonitrides, carbonates, nitrides, and carbonitrides are distributed as a hard dispersed phase. An aluminum oxide-based ceramic having high strength and high toughness, characterized in that the hard dispersed phase distributed within the crystal grains has a particle size of 0.3 μm or less. (2) As raw material powder, aluminum oxide powder with an average particle size of 0.6 μm or less, Y, Mg, Cr, with an average particle size of 1 μm or less,
One of the oxide powders of Co, Ni, and rare earth elements
Metal oxide powder consisting of a species or two or more species, and carbide powders and nitrides of Ti, Zr, and Hf with an average particle size of 1.5 μm or less and containing 10% by weight or more of particle sizes of 0.3 μm or less Prepare a carbon/nitrogen/oxide powder of a group 4a metal of the periodic table consisting of one or more of powder, carbonitride powder, carbonate powder, nitride powder, and carbonitoxide, These raw material powders, in weight percent, are: metal oxide powder: 0.05-2%, carbon/nitrogen/oxide powder of group 4a metals of the periodic table: 5-50%.
, aluminum oxide powder: the remainder, mixed under normal conditions and formed into a green compact, and then this green compact is heated with Ar or Ar inert at 0.8 to 5 atm. In a mixed gas atmosphere, temperature: 1680-1830℃
Sintering is carried out at a high temperature for a short period of time under the conditions of holding for 10 to 40 minutes, followed by continuous or intermittent sintering in an atmosphere of Ar or a mixed gas of Ar and inert gas at a pressure of 100 to 2000 atm, at a temperature of 1300 to 1450. 1. A method for producing aluminum oxide-based ceramics having high strength and toughness, which comprises subjecting aluminum oxide to grain growth heat treatment under the conditions of holding the aluminum oxide at a temperature of 2 to 10 hours.