JPS6236065A - Manufacture of heat-resistant antiabrasive ceramic material - 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] [Industrial Application Field] The present invention relates to a method for manufacturing a ceramic material with excellent heat resistance and wear resistance, and is particularly suitable for use as a cutting tool such as ductile cast iron or as an electrically conductive material. The present invention relates to a method for producing a ceramic material that is useful for certain ceramic applications, such as ceramic heaters and electrode materials that require wear and corrosion resistance.

[Prior Art] TiC has been known as a high-temperature material that has excellent spalling resistance because it has a high melting point and hardness, and also has low thermal expansion and does not reduce thermal conductivity at high temperatures. but,
Since TiC is a difficult-to-sinter material, a dense sintered body has been obtained only as a cermet by adding metals such as cobalt and Ni.

[Problems to be Solved by the Invention] However, since the cermet is a composite, it is dominated by the behavior of the metal phase, and the properties of TiC itself, particularly the high temperature properties, are not fully utilized.

For example, when cutting ductile cast iron, a cermet tip using the above-mentioned cermet is used for finishing cutting, but even in finishing cutting, high-speed cutting exceeding 300 m/min results in rapid wear and large crater wear. Chipping is also likely to occur. On the other hand, when the cutting speed is 1
If the speed is less than 50 to 200 m/min, welding will occur even if the chips are made of carbide, etc., and the finished surface will become rough.

[Means for Solving the Problems] The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for producing a dense ceramic material that takes advantage of the characteristics of TiC.

The first invention includes 1 to 40% by weight of Al2O3, 0.05 to 8% by weight of a sintering aid, 3 to 35% by weight of ZrO2 and/or HfO, and the following proportions (a) and (b). Ti C component consisting of components
17 to 95.95% by weight.
>The gist is to produce a heat-resistant and wear-resistant ceramic material by sintering it in a non-oxidizing atmosphere until the component metal no longer exists as a metal phase.

(a) 4 to 30% by weight of a metal consisting of one or more selected from groups 4a, 5a and 6a of the periodic table of elements (b) 70 to 96% by weight of Ti 0 The second invention is the first invention. In addition to the invention, 5 to 40% by weight of the TiC component in the formulation is composed of Zr, 1-1f, and one or more carbides selected from groups 5a and 6a of the periodic table of elements (c ) components.

Component (a) of the first and second inventions, that is, the metals of groups 4a, 5a, and 6a in the periodic table of elements, are Ti, Zr,
, Hf, V, Nb, Ta, Cr, Mo, and W.

The component (c) of the second invention, that is, Zr, @f, and the carbide of group 5a and 5a in the periodic table of elements is Zr.

It refers to carbides of Hf, V, Nb, Ta, Cr, Mo, and W, such as Zr C5Hf C, VC,
N1) C, TaC, CrC2, MOzC, WC, etc. can be mentioned.

In the present invention, the absence of metal as a metallic phase means that no metallic phase is detected at least by an X-ray diffraction device, preferably no metallic phase is detected by an optical microscope.

The non-oxidizing atmosphere includes TiC in the formulation during sintering.
There is no particular restriction as long as the atmosphere does not oxidize the metal of component (a), such as N2 or Ar.

It is possible to create an atmosphere such as H2. Furthermore, the above-mentioned compound can be sintered not only under normal pressure but also by pressure sintering method or hot isostatic pressing method, and the sintering temperature may be within the range normally used. It is necessary to sinter the material until the metal phase in it is no longer present.

[Effect] The operation of the first invention will be explained.

AΩ203 is a chemically stable substance with excellent oxidation resistance and low free energy of formation, and by dispersing it in the TtC component, the oxidation resistance and chemical stability of the ceramic material as a whole can be improved. . This adds oxidation resistance and chemical stability to the excellent properties of TiC.

In the present invention, Ag2O3 is used in an amount of 1 to 40% by weight, but if the amount of Ag2O3 is less than 1% by weight, the above effect cannot be sufficiently achieved, and if it exceeds 40% by weight, the properties of TiC itself will deteriorate.

In the present invention, the sintering aid is used together with Ag2O3 because
This is because, in addition to the above-mentioned effective effects of Ag2O3, the AQzO3 compound made up of Al2Og and the sintering aid assists the sintering of the ceramic material and improves the sinterability. In the present invention, sintering aids include MQO, Cab, Si 02, Ni
Oya, Y203, DV20g, ErzO3, HO20
Normal Ag2O3-based rare earth oxides such as No. 3 rare earth oxides, AQ 20
AQ such as 3-TiC system, Al2O3-Zr 02 system, etc.
Refers to those used for sintering zOa-based ceramics.

In the present invention, the sintering aid is used in an amount of 0.05% to 8% by weight, but if it is less than 0.05% by weight, the above effects cannot be sufficiently obtained, and if it is more than 8% by weight, a large amount As mentioned above, the Al2O3 compound deteriorates the high temperature properties of the ceramic material.

Zr 02 and/or Hf 02 are usually dispersed in the ceramic material in tetragonal form. When a large external force is applied to a ceramic material, the ceramic material undergoes a phase transition from tetragonal to monoclinic, and this phase change strengthens the ceramic material by absorbing the external force. This effect is identical to what is known as diffusionless lattice transformation.

In the present invention, Zr 02 and/or Hf 02 are
It is used in an amount of 3 to 35% by weight, but if it is less than 3% by weight, the above effects cannot be sufficiently achieved, and if it exceeds 35% by weight, the wear resistance of the sintered body will decrease.

Next, the above-mentioned metal (a>component) is contained in TiC, and this component (a) is dissolved as a solid solution in TiC during the sintering process,
It is necessary that it not be present in the ceramic material as a metallic phase. For this reason, TiC has a non-stoichiometric composition,
It can make the crystal structure incomplete and unstable. It is considered that this facilitates the sintering reaction such as solid phase reaction, and as a result, the sinterability of the ceramic material according to the present invention was improved. Also, this phenomenon is caused by Al2
This also means that the interface between O3 grains and Ti0 grains or TiC grains is strengthened. Furthermore, although it has not been fully elucidated yet, regarding the high temperature strength of TiC itself, it is thought that the strength and toughness are improved by the bond form taking on the characteristics of a metallic bond to the original covalent bond.

In the present invention, component (a) is used in an amount of 4 to 30% by weight of the TiC component in order to impart the above properties, but if the amount of component (a) is less than 4% by weight of the TiC component, the above effects will not be achieved. It is insufficient, and (a> component is 3 for Ti C component)
If it exceeds 0% by weight, component (a) may remain as a metal phase, and wear resistance will decrease in terms of cutting performance.

The operation of the second invention will be explained.

The second invention includes, in addition to the structure of the first invention, a carbide of the above-mentioned component (c) in the TiC component. This (c) component is Ti
Although TiC forms a solid solution in C, the crystal lattice of TiC is distorted because the atoms contained in TiC and component (c) have different sizes. A crystal lattice plane with such lattice distortion requires more energy for dislocations to move than a flat lattice plane in which atoms of the same size are lined up. That is, more energy is required to destroy the ceramic material, and the strength of the ceramic material is further improved by the above action.

In the second invention, in order to impart the above characteristics, the component (c) is used in an amount of 5 to 40% by weight of TiC, but if it is less than 5% by weight, the above characteristics will not be exhibited, and the same as in the first invention. turn into. On the other hand, if it exceeds 40% by weight, the excellent properties of TiC itself will deteriorate.

[Effects of the Invention] By using the method for producing a ceramic material of the present invention, the characteristics of TiC can be further utilized and precise wear resistance,
Ceramic materials with heat resistance can be produced.

The ceramic material manufactured by the method for manufacturing a ceramic material of the first invention can be used for cutting tools such as cast iron such as the above-mentioned ductile cast iron, steel, high nickel, aluminum, titanium, etc., nonmetallic cutting tools, wear resistance, corrosion resistance, and heat resistance. Useful for mechanical parts that require high performance.

Furthermore, since it is electrically conductive, it is useful for applications such as electrically conductive ceramics, such as ceramic heaters, and electrode materials that require wear resistance and corrosion resistance.

The ceramic material manufactured by the ceramic material manufacturing method of the second invention has, in addition to the effects of the ceramic material manufactured by w4i according to the first invention, Zr, Hf, 5a,
By adding Group 5a carbides, excellent properties such as toughness, hardness, heat resistance, and wear resistance can be added. However, all of these properties are not improved compared to the ceramic material according to the first invention; addition of Zr C, Hf C or VC improves hardness and wear resistance, while addition of Ta C or NbC improves heat resistance. WC, MozC,
The addition of Cr Cz improves the toughness over the respective ceramic materials of the first invention. Therefore, depending on the use etc., Zr,)-
When 1f, 5a, and 6a group carbides are selected and added, the first
It is possible to add superior properties to the excellent properties of the ceramic material according to the invention, and it is possible to obtain ceramic materials that are more useful as various materials.

(Example] Examples of the present invention will be described.

Sample No. 1 in Table 1 as an example of the first invention
-a to 1-k, and sample No. 2-a to 2-k as an example of the second invention, and pulverized with acetone in a stainless steel ball mill for 30 hours. Thereafter, acetone was volatilized in a dryer, and the powder was pulverized in a mortar until the entire amount passed through 60 meshes, to prepare a base powder. The amounts of component (a), (b), or (c) in the TiC component in Table 1 are weight % when the TiC component is taken as 100. In addition, the particle size of α-AΩ203 is 1 μm.
The following is 70%, the purity is 99.5% or more as a sintering aid, Zr 02 has an average particle size of 0.6 μm, Hf 02 has an average particle size of 1.5 μm, The above-mentioned component (a) was one that passed through a 325 mesh, and the component (b) was TiC with an average particle size of 1.1μ and a total carbon content of 19.4%. The above-mentioned component (c) used was one that passed through 325 mesh.

This base powder was sintered according to the sintering temperature and sintering method shown in Table 1. The sintering method used in this example was as follows: 1 Sintering in a graphite mold using a pressure sintering method at a pressure of 200 ko/d and a pressure sintering time of 15 minutes.
It was written. ) 2 Sintering for 1 hour under reduced pressure argon atmosphere.

(In the table, it is described as normal sintering.) 3. Primary sintering was performed for 1 hour in a reduced pressure argon atmosphere, and then sintering was performed by hot isostatic pressing under conditions of 1500° C. and 1500 atmospheric pressure holding time. (It was written as HIP in the table.)

The sintered body thus obtained was ground to 5NGN432TN with a diamond grindstone to a surface of 38 or less (according to JIS), the theoretical density and hardness were measured, and a cutting test was performed according to the cutting test conditions shown in Table 2. I did it. In addition, the work material is the first
As shown in the figure, it has a rod shape with a length of 400 m+a and a diameter of 150 mm, and six grooves each having a width of 5 mm are provided at equal intervals in the longitudinal direction. The sintered body thus obtained was roughly examined for the state of (a>component) using an X-ray diffractometer and an optical microscope.

Roughly, the compositions were adjusted to the proportions shown in Sample No. 1'', -a to 1'-1 in Table 1 as a comparative example of the first invention, and sample No. 1 in Table 1 as a comparative example of the second invention 9. .

2''-a to 2--f, respectively, and blended in the proportions shown in Examples,
The sample was sintered and molded in the same manner as above, and the theoretical density and hardness were measured. In addition, the state of component (a) was examined using an X-ray diffraction device or the like in the same manner as in the examples.

However, a commercially available TiC cermet was used.

Table 2 Sample No. 1-a to 1- in Table 1.

Comparison with 'l −-a ~]--i and sample NO, 2-
A~2- and Samples No.2--a~2-f revealed that in order to take advantage of the properties of TiC and to produce a dense ceramic material, AΩ203, a sintering aid, and Zr
02 and/or Hf 02 and (a) in the TiC component
, (b) component, in the case of the second invention (a>, (b), (c
) It is necessary to keep the amount of ingredients to a specified amount, and the above (
It has been found necessary to sinter so that component a) is no longer present as a metallic phase.

Further, when the electrical conductivity of the ceramic material manufactured by the method of manufacturing a ceramic material of the present invention was measured, it was about 50 to 100×10 −6 Ω·cm, although it varied depending on the composition. This can be said to be one of the ones with excellent electrical conductivity among conventional practical ceramic materials.

Roughly, when the effect of the second invention was measured, sample No.
, 1-h and sample No. 2-j, in the first invention (c
) It was confirmed that the ceramic material manufactured by adding WC, MO2C, or CrC2 as a component has superior toughness compared to the ceramic material according to the first invention, and therefore the number of impacts in the cutting test increases. Furthermore, it has been confirmed that when Zr C, Hf C, or VC is added as component (c) to the first invention, the hardness becomes higher than that of the ceramic material according to the first invention. In general, it was confirmed that when Ta 2 C and Nb 2 C were added as component (c) to the first invention, there was less decrease in heat resistance, that is, strength at high temperatures, compared to the ceramic material according to the first invention.

Incidentally, when sintered bodies were similarly prepared and tested for compounds having the compositions of the present invention not listed in Table 1, the number of impacts until breakage was similarly significantly increased compared to the conventional ones. It was confirmed that

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a workpiece used in an embodiment of the present invention.

Claims (1)

[Claims] 1. 31 to 40% by weight of Al_2O_, 0.05 to 8% by weight of sintering aid, 23 to 35% by weight of ZrO_2 and/or HfO, and components (a) and (b) in the following proportions. TiC component 1 consisting of
A heat-resistant and wear-resistant ceramic characterized by sintering a mixture consisting of 7 to 95.95% by weight in a non-oxidizing atmosphere until the metal of component (a) below no longer exists as a metal phase. Method of manufacturing materials. (a) 4 to 30% by weight of a metal consisting of one or more selected from groups 4a, 5a and 6a of the periodic table of elements (b) 70 to 96% by weight of TiC 2. The sintering aid is MgO , CaO, SiO_2, NiO
The method for producing a heat-resistant and wear-resistant ceramic material according to claim 1, wherein the ceramic material is one or more selected from rare earth oxides and rare earth oxides. 3. Consists of 31 to 40% by weight of Al_2O_, 0.05 to 8% by weight of sintering aid, 23 to 35% by weight of ZrO_2 and/or HfO, and components (a), (b), and (c) in the following proportions. Ti
17 to 95.95% by weight of component C is sintered in a non-oxidizing atmosphere until the metal of component (a) no longer exists as a metal phase.
Method of manufacturing wear-resistant ceramic materials. (a) 4 to 30% by weight of a metal consisting of one or more selected from groups 4a, 5a and 6a in the periodic table of elements (b) 30 to 91% by weight of TiC (c) Zr, Hf and elements 5 to 40% by weight of one or more carbides selected from Groups 5a and 6a of the periodic table. 4. Sintering aids include MgO, CaO, SiO_2, NiO
The method for producing a heat-resistant and wear-resistant ceramic material according to claim 3, wherein the ceramic material is one or more selected from rare earth oxides and rare earth oxides.