JP3492648B2 - TiN-Al2O3-based sintered body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] The present invention relates to TiN-Al_TwoO_ThreeSeries
It is about union. [0002] 2. Description of the Related Art Conventionally, cells having excellent hardness and abrasion properties have been developed.
Use the Lamix sintered body as a material for cutting tools and bearings.
It has been proposed to use For example, Japanese Patent Application Laid-Open No. 55-7579 discloses
Is Al_TwoO_ThreeOf raw material powder containing Ti and TiN as main components
Form a shape and control the shape to a specified temperature and pressure
A multi-stage firing method is disclosed. Further, Japanese Patent Application Laid-Open No. 63-129060 discloses
Is Al_TwoO_ThreeRaw material obtained by adding oxides such as Mn and Ti to powder
Forming a compact from powder and firing the compact in air
And then H_Two-N_TwoDisclosure of firing method under atmosphere
Have been. According to this method, firing in air
First, Al_TwoO_ThreeIs formed, followed by H_Two-N_Twoatmosphere
Al firing by firing below_TwoO_ThreeA TiN layer is formed at the grain boundaries of the crystal
Is done. [0005] SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open
In the method of JP-A-7579, TiN used as a raw material
Is expensive, resulting in high production costs.
there were. Also, with this method, Al_TwoO_ThreeGrain growth
The physical strength becomes weaker, and residue such as binder burns.
It was not very suitable, for example, it remained in the aggregate. On the other hand, Japanese Patent Application Laid-Open No. 63-129060 discloses
Method requires adjustment to a specific atmosphere during firing
Therefore, the manufacturing process becomes complicated and the manufacturing cost increases.
Problem. Also, in this method, Al_TwoO_Three
Because the main component is, the desired hardness cannot be obtained
There was also a problem. Therefore, the present inventors have conducted extensive research.
, AlN powder and TiO_TwoMix with the powder in the prescribed ratio
The raw material mixture is used as a compact, and the compact is inert atmosphere.
By firing below, a suitable sintered body is easily and
It was found that it can be obtained at low cost. Also according to the method
Is also known to provide excellent physical strength to sintered compacts.
I saw. The reason for this is that the Al_TwoO_ThreeLayer
It is presumed to be formed. And the original
The inventors have completed the present invention based on these findings.
Was. [0008] According to the present invention, there is provided:A
1N powder with an average particle size of 0.5 μm to 1.0 μm,
O ₂ Adjust the average particle size of powder to 1.0μm ~ 2.0μm
In addition,TiO for AlN powder₂The amount of powder
Weight ratio (TiO₂/ AlN) 2/3 to 1
Compound into the prescribed shapepressAfter molding, the molded body isDegreasing
AndUnder inert atmosphereAnd under pressureFiring atTiN connection
Al at the grain boundaries ₂ O ₃ LayersFormed. Under such an inert gas atmosphere,
When fired, TiO_TwoThe titanium inside is nitrided from AlN.
Aluminum in AlN
iO _TwoIs oxidized by oxygen derived from as a result,
Al at the grain boundaries of TiN crystal grains_TwoO_ThreeCrystal structure with layers formed
And the physical strength of the sintered body is improved. According to the present invention, an expensive TiN powder
About 50% cheaper TiO instead of_TwoUsing powder as raw material
Therefore, the overall cost can be reduced. Less than
Below, TiN-Al of the present invention_TwoO_ThreeMethod for manufacturing sintered compacts
And will be described in detail. In the present invention, as described above, the AlN powder
TiO_TwoThe compounding ratio of the powder is in the range of 2/3 to 1.
It is essential. Here, the compounding ratio is represented by% by weight.
Value ratio. When the compounding ratio is less than 2/3, the sintered body
The ratio of TiN in the inside is small, and the original strength of TiN
You will not be able to gain the degree. On the other hand, the compounding ratio exceeds 1
Then, TiO_TwoBecomes difficult to completely nitride.
For this reason, TiO_TwoRemains in the sintered body,
Will worsen the nature. The average particle size of the AlN powder is 0.5 μm or more.
It is preferably 1.0 μm. Also, TiO_TwoPowder
Preferably has an average particle size of 1.0 μm to 2.0 μm.
New The reason is that AlN_TwoO_ThreeEffective layers
This is because it can be formed in These powders further contain an organic binder,
And a sintering aid are mixed. The raw material mixture is
After being mixed in minutes, it is molded into a predetermined shape. Furthermore, before
The molded body is degreased under an inert atmosphere, and
Thus, the organic binder and the like are removed from the molded body. Also,
The temperature at the time of degreasing is preferably from 600 ° C to 950 ° C.
is there. Next, the molded body is made of, for example, nitrogen,
Firing with inert gas such as gon, neon, helium, etc.
It is fired in a furnace. Among these inert gases,
It is desirable to select nitrogen. The reason is T
iO_TwoNitrogen in the atmosphere also participates in the nitridation reaction of
This is because the chemical reaction is promoted as a whole. Also, Kos
This is because it is advantageous to use nitrogen in terms of temperature. In addition,
To achieve an active atmosphere, the firing furnace must be
In addition to the above method,^-FourVacuum strip below Torr
May be used. The firing of the compact is performed under pressure.
Is desirable. The reason is that the firing time of the compact is shortened.
Not only can we obtain a dense sintered body
It is. As this kind of pressure firing method, for example,
Hot pressing and hot isostatic pressing (HIP)
I can do it. In particular, 1000 atm.
It is preferred to sinter the compact under 00 atm.
The reason is that sintering is denser and has extremely high physical strength
Because you can get your body. The temperature at the time of firing the compact is 1
It is desirable that the temperature be 550 ° C to 1800 ° C. This firing
If the temperature is lower than 1550 ° C., the TiN is completely sintered.
It cannot be performed, and is not suitable. On the other hand, this firing temperature
Exceeds 1800 ° C, it takes time for temperature rise and temperature cooling.
This is not preferable in terms of process and cost. [0019] DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the present invention will be described below.
This will be described in detail. In this embodiment, first, the average particle size is 2.0
μm TiO_TwoPowder (high purity chemical, purity 99.9%)
45.0% by weight, AlN powder having an average particle size of 1.0 μm
(Manufactured by Tokuyama Soda) 50.0% by weight, sintering aid
Tria (Y_TwoO_Three) 5% by weight, as organic binder
10% by weight of krill resin and ethanol 5 as solvent
Eight milliliters were wet mixed by a ball mill. Therefore
In this embodiment, TiO with respect to AlN powder is used._TwoMixing powder
Specific TiO_Two/ AlN is 0.9. After the raw material mixture is dried and pulverized,
After molding, a predetermined shape (in this embodiment, the outer shape is 75 mm × 5
(5 mm flat plate). Next, the molded body is
It was charged in a firing furnace with nitrogen circulated, and the compact was heated to 850 ° C.
Degreased. Due to this degreasing step,
Decomposed and removed organic substances. Next, the compact is filled with H filled with nitrogen.
Load into IP baking furnace and set surface pressure to 250kg / cm^TwoSet to
Pressure sintering was performed. At that time, the firing temperature was 1550 ° C
The firing time was set to 2 hours. The TiN system manufactured by the above steps
In order to evaluate the characteristics of the sintered body,
Hardness (HV), bending strength (kg / mm²) And density (g / c
m³) Measured. SoThe measurement results are shown in Table 1 below.
You. The TiO in the raw material mixture_TwoPowder and Al
Comparative Example 1 and Example by changing only the compounding ratio with N powder
2 were manufactured. As shown in Table 1, the ratio
In Comparative Example 1, 30% by weight of AlN powder and 65% by weight of T
iO_TwoPowder and the composition ratio of TiO_Two/ AlN is 1
And 2.2. On the other hand, in Comparative Example 2, 70
Wt% AlN powder and 25 wt% TiO_TwoIncluding powder
, Its composition ratio TiO_Two/ AlN is less than 2/3
And 0.4. About each comparative example 1 and 2, an example and
Table 1 shows the results of the same measurement. [0024] [Table 1] As is clear from Table 1, in the embodiment,
Hardness, bending strength and density of sintered body from each comparative example
Was also excellent. Further, the cross section of the sintered body is treated with a molten alkali.
(After this treatment,_TwoO_ThreeWill be corroded)
The minute was observed with an electron microscope. As a result, grain boundaries are etched.
AlN at the grain boundaries of TiN_TwoO_Threelayer
It was confirmed that was formed. On the other hand, when the mixing ratio is less than 2/3,
In Example 1, the ratio of TiN in the sintered body was small.
As a result, the original strength of TiN could not be obtained. Ma
In Comparative Example 2 in which the mixing ratio exceeds 1, TiO 2_TwoTo
TiO cannot be completely nitrided_TwoIs in the sintered body
It was confirmed that a large amount remained. And the sintered body
Also tended to deteriorate physical properties. Summarizing the above results, the sintered body of the embodiment
Have better physical properties than Comparative Examples 1 and 2.
That is clear. Moreover, according to the manufacturing method of this embodiment,
Different from the conventional one, which is manufactured through complicated manufacturing processes.
To produce the desired sintered body relatively easily and reliably.
Can be. And even in this case, the raw materials used
Costs can be reduced because the cost of
It is also possible. [0029] As described in detail above, according to the present invention,
Low raw material costs and no need for complicated manufacturing processes
Despite this, the excellent physical strength of the sintered body is improved.
It has the effect.

Claims (1)

(57) [Claims 1] The average particle size of the AlN powder is 0.5 μm to 1.
0 μm, the average particle size of the TiO ₂ powder is 1.0 μm to 2.
After adjusting to 0 μm, TiO ₂
Amount of the powder weight ratio _{(TiO 2 / AlN) 2 /} 3~
After press- molding the raw material mixture of No. 1 into a predetermined shape, the compact is degreased and fired under an inert atmosphere and under pressure to form an Al ₂ O 3 layer at the grain boundaries of TiN.
-Al ₂ O ₃ system sintered body.