JPS6259568A - Ceramic material excellent in precise processability - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ceramic material that can be processed into a complex shape and has excellent precision workability.

[Conventional technology]

Fine ceramics are widely used as mechanical structural parts, electronic parts, etc. Alumina-based ceramics are used in such applications, but in recent years there has been a trend toward finishing parts into precise and complex shapes, and the ceramic materials used are therefore required to have excellent workability. It is becoming more and more common.

[Problems to be solved by the invention] Conventional alumina-titanium carbide ceramics are
The content is 30% by weight or less, and the toughness of alumina is not sufficiently improved, and cracks and chipping are likely to occur during precision processing. Further, this alumina-titanium carbide ceramic has a drawback of being inferior in free machinability.

The material of the present invention was devised in order to cope with the above-mentioned situation, and uses an aluminum oxide-titanium carbide composite material for cutlery,
In fields where precision loading is required such as precision jigs, we provide ceramic materials that improve machining efficiency without cracking or chipping during machining, and that can also stably manufacture products with complex shapes through electrical discharge machining. This is what I am trying to do.

[Means for solving problems]

In order to meet this objective, the present invention aims to increase the content of titanium carbide in the aluminum oxide-minilamb-titanium carbide system from 30 to 30%.
By setting the weight to 80% by weight, precision workability has been improved.

That is, the material of the present invention contains 30 to 80% by weight of titanium carbide.
By adding the following optional additive components to 100 parts of Yu, which has a basic composition of aluminum oxide and the remainder, it is possible to improve the properties according to the purpose. can.

・Magnesium, calcium, b as free machinability imparting materials
liL One or more selected from oxides of nickel, chromium, and zirconium in an amount of 0.5 to 5 fluorophores/basic composition of 0.05 to 2.0 yttrium oxide equivalent to 100 fluorine parts. Aluminum-yttrium composite oxide in weight% ・Titanium oxide or carbonate that replaces 15% by weight or less of titanium carbide in the basic composition ・Aluminum, titanium composite oxide that replaces 2% or less of aluminum oxide in the basic composition Carbides (excluding titanium carbide), nitrides, borides, and their respective composite compounds (carbonitrides, carbon Borides, boron nitrides.

One or more types of such materials (carbonitride boride) are manufactured through a sintering process after adjusting the raw material mixed powder. Sintering is preferably carried out by hot isostatic pressing or hot pressing. In the hot press method, the pressure is 50 to 350 kgf/cm" and the firing temperature is 1550 to 1800°C, while in the hot isostatic sintering method, the pressure is 500 kgf/cmz or more and the temperature is +450 to 1600.
Good results are obtained under the conditions of 'c.

The sintered body thus obtained has a theoretical density of 99% or more, almost no pores, fine grain size, and a fracture toughness value of 4.
゜5 Mpa, mI/2 or higher, no cracking or chipping occurs during processing, and excellent precision carving properties. Furthermore, since the specific resistance is 10 m·0 cm or less, it also has electrical discharge machinability.

In addition, the material sintered by the hot pressing method or hot isostatic sintering method is heated at a pressure of 0 to 10 kg/cm in a non-oxidizing atmosphere.
cm2. Distortion can be removed by heat treatment at a temperature range from 1000°C to 100°C higher than the sintering temperature. This heat-treated material does not cause cracks or fine chipping due to distortion during precision processing, so stable processing can be performed.

Here, the components of the present invention and their composition ranges will be explained in detail.

In this invention, titanium carbide is the main component of the main +A material along with aluminum oxide, and if it is less than 30% by weight, chipping tends to occur during precision processing.
It also has the disadvantage of high specific tooth resistance and poor electrical discharge machinability. On the other hand, if it exceeds 80% by weight, sintering ii! ! The aluminum oxide crystal E5 particle size becomes large, the fracture toughness is low, and chipping is likely to occur during machine processing, making it unsuitable as a ceramic or metallurgical material for precision machining. From this,! The content range of 2,000,-' was set to 30 to 80% by weight.

Among them, the content range of titanium carbide is 45 to 60%, which has a weight IQ combination of 45% to 60%. Each person has a true intention, A, and 11 skills.

In addition, if the amount of solid solution of oxygen in the final sintered body of the YrA powder or the titanium compound produced during the sintering process exceeds 15% by weight when converted to titanium oxide, the fracture toughness will decrease. This is undesirable because it tends to lower the metallurgy and cause chipping during precision machining.

However, oxygen present in titanium compounds increases the bond strength of titanium carbide components together with aluminum oxide,
This is important in obtaining a strong sintered body. Is aluminum oxide the same as titanium carbide? , is the main component of wood-based materials, and by specifying the content range of the titanium carbide component, it becomes 70 to 20% by weight.

For machining, preferably Mg,
By adding one or more kinds of various oxides of Ni, Cr, and Zr, the processability of the obtained ceramic and ceramic products is improved. Its optimum amount is 0.5-5 parts by weight. In other words, if the amount is less than 0.5 parts by weight, it is effective as a grain growth inhibitor of aluminum oxide and a dense sintered body can be obtained, but no improvement in machinability is observed. Further, if the weight is 5 or more, the bonding strength between the crystal grains of the sintered body becomes weak, which is not preferable.

Regarding zirconium oxide, unstable zirconium oxide with a particle size of 0.3 μm or less or Y2O,... 'Igo.

Zirconium oxide partially stabilized with at least one of Cab and CeO or stabilized zirconium oxide may be used (4). These zirconium oxides undergo grain growth (11
Precision machining due to the 1st effect 7 toughness tendency 1' 1 tatami effect is given. However, addition of 5 weight 1% or more: 1! :,
It has a significant (-2) negative effect on additivity.

The oxidized oxide is oxidized,
・When thorium is calculated to be less than 0.05 parts by weight, the mutual sinterability of aluminum oxide and other main ingredients will be reduced.
There is no effect, the fracture toughness value of the sintered body decreases, and chipping becomes more likely to occur during v-section processing. That is, 0.05
The effect as a sintering accelerator can be seen in the range of 2 parts by weight from 1 part by weight. In addition, as an aluminum uditorium composite oxide powder, for example, as one of the composite oxides,
It can also be used in the form of the following formula:

Y3CAI Y)z(A104):l...
1t) (Y, AI): 1A12 (Ai 04)x'
...Similar to i21, YIA12 (A10.)
Garnet or YxAl +1-XI O* (
Here, a composition represented by X<1) can also be used.

It is also possible to partially replace the titanium carbide with carbides, nitrides, borides, and composite compounds of metals from groups Na, Va, and Via of the periodic table. In that case, in order to maintain the characteristics of the aluminum oxide-titanium carbide composite material and to refine the crystal grains, the effect can only be seen by replacing 2 to 20% by weight of titanium carbide. That is, if the substitution amount is less than 2% by weight, there is no effect, and if it is more than 20% by weight, the sinterability deteriorates, and the fracture toughness of the sintered body obtained by force is low and the precision workability is poor. Therefore, the periodic table I
Va, val When replacing a part of titanium carbide with carbides (excluding titanium carbide), nitrides, borides, and the third component of the respective composite compounds of Via group metals, 2 to 20% by weight of titanium carbide. Within this range, it is possible to retain the characteristics of the alumina-titanium carbide system and still take advantage of the characteristics of the third component.

〔Example〕

Hereinafter, the method for manufacturing the ceramic material of the present invention, the machinability of fine teeth, and the free machinability will be explained using examples.

-Experiment 1- Raw material powder [α-AlzOz' average particle diameter 0.3μ] adjusted to each component composition of +1) to (25) shown in Table 1
m.

Purity 99.9χ, titanium carbide and titanium oxide: average particle size 0-5μL + Mg + Ni + Cr, Zr oxides and solid solution of titanium carbide and titanium oxide, Ittria-
Composite oxide of alumina: average particle size 0.5 μm 7 Periodicity Table Group IVa, Va, VIa metal carbides, borides: average particle size 0.8 μm)] in a graphite mold of 50 x 50 mm square and 60 III m high. Filled with
℃) and a pressure of 200 Kg/c+n2 was applied and maintained for 60 minutes. The pressure is then removed and the temperature is reduced to 50% by cooling.
A desired sintered body of x 50 x 5.5 iua was obtained. Each sintered body was cut and ground using a diamond grindstone to prepare test pieces, which were subjected to various tests.

Fracture toughness is measured from the length of the crack that occurs from the diagonal extension of the Vickers indentation.

Indentation Fracture Me
thod), the surface of the test piece was ground with a diamond wheel, and the residual stress on the surface was removed by mechanical polishing, followed by a mirror finish. All test loads are 10Kgf
The loading time was 20 seconds.

Precision workability was determined by closely observing the edges after cutting with a 500 μm diamond cutting wheel. Those with chipping on the edge portion are marked with an X, those with no chipping are marked with an O, and those with j in particular are marked with a ◎.

Regarding free-cutting properties, those that require a short cutting time to cut the same cross-sectional area are marked with a circle, and those that are long and considered unfavorable in terms of productivity are marked with an x. Fracture toughness is 4.5 MP
A value of am"" or more is indicated by a circle, and a value less than that is indicated by an X.

The electrical discharge machinability was determined by preparing a test piece of 20 x 20 x 5 mm and evaluating the results of electrical discharge machining performed using an electrode with a diameter of 1 mra. Items that can be subjected to electrical discharge machining are marked O, and items that cannot be processed at all are marked X.

The results of judgment regarding these various properties are shown in Table 1, and in particular, the effect of TiC on fracture toughness is shown in FIG.

-1 Experiment 2- Table 2 shows the results of investigating the effect of each oxide such as Mg+ Cr, N+, Zr, etc., which are free machinability imparting agents. The same method as in Experiment 1 was used to prepare test pieces and evaluate free machinability.

Experiment 3 - The results of investigating the relationship between the addition of yttrium-aluminum composite oxide as a sintering aid and precision workability are shown in Table 3. All test pieces were sintered at the same temperature. It is. The evaluation was performed using the same method as in Experiment 1.

1 Experiment 4 ~ After sintering the adjusted raw material powder used in Experiment 1 by hot pressing, the pressure was removed and the temperature was lowered to 5
Heat treatment was performed at a temperature 0°C higher. Similarly, the prepared raw material powder used in Experiment 1 was heated to a relative density of 9 by hot pressing.
Sintering to 5% and then hot isostatic pressure sintering (IIIP)
Sintering was performed at a temperature 10 (1°C) lower than the real pressing temperature.Next, heat treatment was performed at 1300°C in a non-oxidizing atmosphere.

Precision workability was evaluated using the same method as in Experiment 1. The results are shown in Table 4.

Table 3 [Effects of the Invention] The aluminum oxide-titanium carbide composite material of the present invention has excellent corrosion resistance and wear resistance like conventional aluminum oxide-titanium carbide composite materials, and has high fracture toughness, so it is easy to process. It is now possible to perform efficient machining without the occurrence of cracks or chipping. As described above, the ceramic material of the present invention has excellent precision machinability and excellent machinability as a ceramic material for slitter blades, precision jigs, and the like that require precision machining. Furthermore, by adjusting the TiC content, the specific resistance value of the resulting ceramic material can be varied over a wide range, so it can also be used as an electrical component with an appropriate resistance value depending on the purpose.

[Brief explanation of drawings]

FIG. 1 shows the influence of the content of TiC contained in the ceramic material of the present invention on the fracture toughness value.

Claims (1)

[Scope of Claims] 1. A ceramic material with excellent precision machinability characterized by having a basic composition of 30 to 80% by weight of titanium carbide and the remainder aluminum oxide. 2. Claim 1, based on 100 parts by weight of the stated basic composition, magnesium, calcium, boron, nickel,
One or two selected from oxides of chromium and zirconium
A ceramic material having excellent precision workability and containing 0.5 to 5 parts by weight of seeds or more. 3. Basic composition 100 described in claims 1 and 2.
0.05 to yttrium oxide equivalent amount per part by weight
A ceramic material containing 2.0% by weight of aluminum-yttrium composite oxide and having excellent precision workability. 4. A ceramic material with excellent precision machinability, which is obtained by replacing 15% by weight or less of titanium carbide with a titanium oxide or carbonate in the basic composition described in claims 1 to 3. 5.1 A ceramic material with excellent precision workability, which is obtained by replacing 2% by weight or less of aluminum oxide with aluminum and titanium composite oxide in the basic composition described in Claims 1 to 4. 6. In the basic composition described in Claims 1 to 5, a part of titanium carbide is contained in the periodic table IVa, Va, VIa.
Substituted with one or more of group metal carbides (excluding titanium carbide), nitrides, borides, and their respective composite compounds (carbonitride, carbonoboride, nitride boride, carbonitride boride). A ceramic material with excellent precision machinability. 7. A ceramic material with excellent precision machinability, characterized in that the material described in claims 1 to 6 is used as an electrical resistance component. 8. A ceramic material with excellent precision workability, wherein the material described in Claims 1 to 7 is manufactured by a hot pressure sintering method. 9. The hot pressure sintering method described in claim 8 is a hot isostatic pressure sintering method or a hot press method, and is heat treated after hot pressure sintering. A ceramic material with excellent precision machinability.