JPH09268071A - Titanium carbonitride composite silicon nitride tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a titanium carbonitride composite silicon nitride tool, excellent in abrasion resistance, especially both resistance to end cutting edge boundary wear and thermal shock resistance and in its turn suitable for high- speed cutting of cast iron, etc. SOLUTION: This titanium carbonitride composite silicon nitride tool is mainly composed of silicon carbonitride and silicon nitride and further contains 10-56wt.% Ti, 11.6-51wt.% Si and one or more of Ce, Y, Yb and Dy in 1-21wt.% total amount thereof. The tool is mainly composed of Si3 N4 excellent in both of strength and thermal shock resistance and TiCN, excellent in suppressing effects on the reactivity of the Si3 N4 with Fe and capable of manifesting a high hardness. Respective oxides of CeO2 , Y2 O3 , Yb2 O3 and Dy2 O3 are used as assistant components so as to provide the total content of the Ce, Y, Yb and Dy in the tool within the ranges. Thereby, the resistance to end cutting edge boundary wear and thermal shock resistance are improved to improve the service life thereof from that of a conventional silicon nitride cutting tool.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a titanium carbonitride composite silicon nitride tool, and more particularly to a titanium carbonitride composite silicon nitride tool having excellent wear resistance and thermal shock resistance, which is suitable for high-speed cutting of work materials such as cast iron and Inconel. It relates to a silicon nitride tool.

[0002]

2. Description of the Related Art In recent years, for example, as a tool for cutting cast iron,
A silicon nitride-based cutting tool excellent in mechanical strength and thermal shock resistance is used. On the other hand, under more severe conditions such as high-speed wet cutting with a cutting speed of over 800 m / min,
Even if a silicon nitride-based cutting tool is used, sufficient thermal shock resistance and wear resistance cannot be ensured. In such a case, C
A BN cutting tool is used. However, since the CBN cutting tool is generally manufactured using the ultra-high pressure sintering method, it is much more expensive than the silicon nitride-based cutting tool, and in order to obtain a tool that is cheaper and suitable for high speed cutting of cast iron, Various proposals have been made for silicon nitride-based cutting tools.

For example, in Japanese Patent Laid-Open No. 58-95662 and Japanese Patent Publication No. 5-7122, silicon nitride (Si
₃ N ₄₎ in the TiN are combined as a hard dispersed phase, the tool is disclosed in which by suppressing the chemical reaction between silicon nitride and Fe at elevated temperatures. Further, in Japanese Patent Publication No. 61-10416 and Japanese Patent Laid-Open No. 61-17473, it is possible to improve wear resistance by compounding silicon nitride with any one of titanium nitride, titanium carbide and titanium carbonitride as a hard dispersed phase. Proposed tools have been proposed. On the other hand, in JP-A-61-315358,
In order to suppress the generation of silicon carbide or titanium nitride and the generation of N ₂ gas that accompany the chemical reaction between titanium carbide and silicon nitride, the surface of titanium carbide particles is coated with titanium nitride, and this is used as a hard dispersed phase to form silicon nitride. Combined tools have been proposed.

The silicon nitride cutting tools disclosed in the above publications all use Al ₂ O ₃ and Mg as sintering aids.
It is manufactured by adding an oxide such as O or SiO ₂ and firing at a temperature or pressure at which silicon nitride is not decomposed.
The reason is that when silicon carbide is compounded with titanium carbide, nitride or carbonitride, the sinterability decreases as the content of these compounds increases.

[0005]

However, Al ₂ O ₃ and M, which are used as sintering aids in the prior art, are used.
Oxides such as gO and SiO ₂ react with each other during firing or react with SiO ₂ remaining on the surface of the silicon nitride surface phase to form a glass phase with a low melting point. Abrasion resistance of the cutting edge of the tool that becomes high temperature during cutting,
In particular, there is a defect that the resistance to front cutting edge boundary wear decreases.

An object of the present invention is to provide a titanium carbonitride composite silicon nitride tool which is excellent in both wear resistance, particularly resistance to front edge cutting edge wear and thermal shock resistance, and is suitable for high speed cutting of cast iron and the like. Especially.

[0007]

In order to solve the above problems, a titanium carbonitride composite silicon nitride tool (hereinafter simply referred to as a tool) of the present invention is mainly composed of titanium carbonitride and silicon nitride. It is characterized by containing 10 to 56% by weight of Ti, 11.6 to 51% by weight of Si, and 1 to 21% by weight in total of one kind or two or more kinds of Ce, Y, Yb and Dy. In the present specification, titanium carbonitride refers to a composite titanium compound (compositional formula: TiC _x N) in which carbon and nitrogen are combined at a total ratio of 1 mol per mol of titanium.
_1-x , (x> 0)).

The titanium carbonitride composite silicon nitride tool as described above contains, for example, 10 to 60% by volume of titanium carbonitride and CeO ₂ , Y ₂ O ₃ , Yb ₂ O ₃ and Dy ₂ O as sintering aid components.
0.5 to 10% by volume of one or more selected from ₃
And silicon nitride forming the balance are mixed, and the mixture is baked into a predetermined tool shape. In this case, the Ce, Y, Yb, and Dy components contained are derived from the above-mentioned sintering aid component. In that case, the oxygen content in the tool is 0.14 to 3.5% by weight.

The above tool is mainly composed of silicon nitride excellent in both strength and thermal shock resistance and titanium carbonitride excellent in the effect of suppressing the reactivity between silicon nitride and Fe and having high hardness. In addition, Ce, Y, Yb, D in the tool
By using each oxide of CeO ₂ , Y ₂ O ₃ , Yb ₂ O ₃ and Dy ₂ O ₃ as an auxiliary component so that the total content of y is within the above range, excellent wear resistance is obtained. Properties, in particular, resistance to front cutting edge boundary wear, and thermal shock resistance are improved, and their life is improved as compared with conventional silicon nitride cutting tools. As a result, the present invention can be applied to, for example, wet high-speed cutting of cast iron, which has conventionally been applied only to CBN ultra-high pressure sintered bodies, and the tool price and thus the cutting tool cost can be significantly reduced.

The reason why the wear resistance of the tool is improved is considered as follows. That is, CeO used as an auxiliary component
₂ , Y ₂ O ₃ , Yb ₂ O ₃ and Dy ₂ O ₃ have a higher melting point than conventionally used Al ₂ O ₃ , MgO, SiO _2, etc. S remaining on the surface
The reaction with iO ₂ is suppressed, and it becomes difficult to form a glass phase having a low melting point. As a result, when used as a cutting tool, for example, the cutting edge is less likely to soften even at high temperatures,
High hardness can be maintained up to a high temperature. Specifically, with the above composition setting, it is possible to realize a high-strength tool having a Vickers hardness of 16 GPa or higher at room temperature and a bending strength of 800 MPa or higher at 1000 ° C. 16 as Vickers hardness at room temperature
800 MPa or more as a bending strength at 1000 ° C. of GPa or more
By ensuring the above, it is possible to maintain sufficient wear resistance and chipping resistance, especially in the case of cutting of cast iron parts, even when there are holes and stepped portions, etc., resulting in intermittent cutting. become.

The Vickers hardness is JISR161.
It shall mean the value measured in accordance with the rule of 0.
Here, the Vickers hardness is defined as a value obtained by dividing the indentation area by the load, and has the same dimension as the area force such as pressure. In this specification, the Vickers hardness is represented by a value when the indentation area is m ² and the load is represented by N (Newton), and is also represented by Pa (Pascal) which is the SI unit in that case. Further, in this specification, the bending strength means a value measured based on a three-point bending test method defined in JISR1604 (high temperature bending strength test method for fine ceramics).

On the other hand, the fracture toughness value of the tool is JIS-R1.
Among the fracture toughness test methods described in 607 (1990), the indentation method (IF method: Indentation-Fracture).
The value measured by the method) is preferably 4.0 MPa · m ^1/2 or more. The fracture toughness value is 4.0 MPa
If it is less than m ^1/2 , it may not be possible to secure sufficient fracture resistance as a tool. The fracture toughness value is preferably 5.0 MPa · m ^1/2 or more.

The critical meaning of the range of each component will be described below. Content of Ce, Y, Yb, Dy When Ce, Y, Yb, Dy is added by an oxide, C
If the total content of e, Y, Yb, and Dy in the tool exceeds 21% by weight, the glass phase content increases, which leads to insufficient cutting performance of the tool, particularly wear resistance. Further, if the content is less than 1% by weight, the sinterability is deteriorated, and similarly, the tool performance is deteriorated. The total content is more preferably adjusted within the range of 3 to 15% by weight. The oxide may be one kind, but if two or more kinds of these oxides are added in combination, the sinterability can be further improved, and by extension, a tool that is dense, has high strength and is excellent in wear resistance. Can be obtained. Specifically, C
1% by weight of any two of e, Y, Yb and Dy
More preferably, X + Y is 3% by weight or more, and X / Y is X /%, when the content of one of the two types is X (% by weight) and the other is Y (% by weight). (X
+ Y) is preferably adjusted to fall within the range of 0.35 to 0.65.

Ti and Si contents When the Ti content is less than 10% by weight or the Si content exceeds 51% by weight, the effect of adding titanium carbonitride is to improve the hardness and wear resistance. Will not be fully achieved. Conversely, if the Ti content exceeds 56% by weight,
When the i content is less than 11.6% by weight, the relative content of silicon nitride decreases, the toughness is lost, the sinterability decreases, and the wear resistance decreases.
Therefore, the Ti content is preferably 10 to 56% by weight, and the Si content is preferably 11.6 to 51% by weight. Desirably, Ti is 19 to 41% by weight and Si is 21 to 42.
8% by weight is preferable. Thereby, the sinterability is further enhanced, and the Vickers hardness at room temperature is 17 GPa or more, 1
It is also possible to realize a high hardness and high strength tool having a bending strength of 850 MPa or more at 000 ° C. If a tool with higher hardness is required, Ti should be 41
˜56% by weight and Si in the range of 11.8 to 28.8% by weight are preferable. This makes it possible to secure a Vickers hardness of 18 GPa or more at room temperature.

The total content of Ti and Si is 48.5.
% By weight or more. If the total content is less than 48.5% by weight, the relative content of the sintering additive component will be too large and an excessive glass phase will be produced, resulting in a decrease in wear resistance and a decrease in machinability. . The total content is more preferably 51% by weight or more.

Regarding the molar contents KC and KN of C and N in titanium carbonitride, Si is the constituent of silicon nitride and C and Ti are the constituents of titanium carbonitride. Further, when it is assumed that all N is a constituent component of silicon nitride and titanium carbonitride, it is calculated based on the above molar assumptions of the respective molar contents of Ti, Si, C and N in the tool. KN / (KC + KN) is 0.5 ~
It is preferable to set 0.7, that is, slightly N rich. When KN / (KC + KN) is less than 0.5, that is, when a C-rich composition is used, free carbon is likely to be generated during firing, and the sinterability may be reduced due to the effect of CO gas generated thereby. On the other hand, KN / (KC + K
When N) exceeds 0.7, the hardness of titanium carbonitride decreases and the coefficient of linear expansion increases. For example, when the content of titanium carbonitride increases, it adversely affects the cutting performance of the tool. There are cases.

For example, Si, T determined by analysis or the like
The molar contents of i, C, and N are Nsi, NTi, and N, respectively.
Assuming C and NN, the molar amount PN of N distributed in silicon nitride is PN = (4/3) × NSi ... (1), and the remaining N is carbonitrided based on the above assumption. Considering that it is distributed to titanium, the molar amount QN of the distributed N is as follows: QN = NN-PN = NN- (4/3) * NSi (2). On the other hand, the distribution amount QC of C to titanium carbonitride
Assumes that C is all distributed to titanium carbonitride, so QC = NC (3). Therefore, KN / (KC + KN) is KN / (KC + KN) = QN / (QC + QN) = {NN- (4/3) * NSi} / {NC + NN- (4/3) * NSi} ... (4) Can be calculated as

From the composition formula of titanium carbonitride, the total amount of titanium and the carbon and nitrogen bonded thereto is equal to that of titanium carbonitride. Therefore, the distribution amount QC of C to titanium carbonitride is the molar content of titanium NTi. Can be expressed as follows: QC = NTi-QN (5) From (2), (4), and (5), KN / (KC + KN) = {NN- (4/3) × NSi} / NTi (6), and use KN / (KC + KN) with NC. It can also be calculated without.

Incidentally, Ce, Y, Yb, Dy, Ti, Si
The content of can be specified by, for example, fluorescent X-ray analysis, ICP analysis, chemical analysis, or the like.

As a method of manufacturing the above tool, a hot pressing method can be adopted. The atmosphere of the hot press is preferably, for example, an inert gas atmosphere (for example, N ₂ , Ar, etc.) at 1 to 9.8 atm, and more preferably the N ₂ atmosphere from the viewpoint of suppressing decomposition of silicon nitride during firing. The applied pressure is 200 to 300 kg / cm ² , and the firing temperature is 185.
The temperature is preferably 0 to 1900 ° C.

Further, instead of the hot pressing method, a hot isostatic pressing (HIP) method may be used. In this case, HI
As conditions for the P treatment, it is desirable that the treatment temperature be 1750 ° C. or lower and the pressure be 900 atmospheric pressure or higher. If the treatment temperature exceeds 1750 ° C., the crystal grains grow excessively during the treatment, so that the required strength cannot be secured. On the other hand, when the pressure is less than 900 atm, the material is insufficiently densified, resulting in insufficient strength. On the other hand, considering the durability of the device, the upper limit of the pressure seems to be about 2000 atm in a generally used HIP device,
A pressure higher than that may be set unless problems such as device durability occur. The processing temperature is more preferably 150
It is preferable to set in the range of 0 to 1700 ° C. The pressure is more desirably set to 1000 atm or more. Furthermore, after preforming the raw material powder,
By pre-baking at 0 to 1800 ° C. and then performing HIP treatment, it is possible to efficiently manufacture a sintered body having a desired shape. For example, when the pre-baking atmosphere is an N ₂ atmosphere of 1 atm and the pre-baking temperature is lower than 1550 ° C., open pores remain in the pre-molded body, and the effect of shrinking it by the subsequent hydrostatic pressure treatment is insufficient. May be On the other hand, when the pre-baking temperature exceeds 1800 ° C., silicon nitride is likely to be decomposed, and the strength of the material may be insufficient. However, when a pre-baking atmosphere having a pressure higher than 1 atm, for example, an N ₂ atmosphere pressurized to about 2 to 10 atm is used, decomposition of silicon nitride is less likely to occur, so the pre-baking temperature is 1800 ° C. or higher. For example, 18
It may be possible to raise the temperature up to about 50 ° C., and in some cases up to about 2000 ° C.

Next, the above-mentioned tool of the present invention includes any one or two of Al carbide, nitride, carbonitride and oxide, and Ti carbide, nitride, carbonitride and oxide. The surface can be coated with a coating layer that is mainly composed of the above solid solution, has a grain size of 0.5 μm or less, and has a film thickness of 1 to 5 μm. Thus, for example, when the reaction between silicon nitride and Fe in the work material at the time of high-speed cutting becomes a problem, the reaction can be suppressed by forming the coating, preventing the roughening of the machined surface and extending the tool life. Can be achieved.

Specific examples of the coating layer include Al ₂ O ₃ and
TiC, TiN, TiAlN, etc. can be mentioned.
Of these, the Al ₂ O ₃ coating layer improves the oxidation resistance and
The C coating layer contributes to the improvement of wear resistance by increasing the hardness. Further, the TiN coating layer is effective in reducing the processing resistance and improving the appearance color due to the reduction of the friction coefficient.
1N has an effect of improving wear resistance, like TiC. As a coating method, known methods such as various PVD methods and CVD methods can be adopted.

The particle diameter of the constituent particles of the coating layer is preferably 0.5 μm or less. By setting the particle diameter of the coating layer in the above range, the coating surface becomes smooth, the life of the coating layer is improved, and the finish of the machined surface of the work material becomes good. If the particle size exceeds 0.5 μm, the particles on the coating surface are likely to fall off during cutting, which may cause chipping or peeling. Further, the machined surface of the work material is likely to be roughened, and satisfactory cutting performance may not be obtained in some cases. In order to obtain a coating layer having a small particle size as described above, there are methods such as lowering the coating temperature, shortening the coating time, and adjusting the atmosphere.

The thickness of the coating layer is preferably 1 to 5 μm. When the film thickness is less than 1 μm, the function as the coating layer is not fulfilled, and the effect of improving the tool life due to it cannot be sufficiently obtained. On the other hand, if the film thickness exceeds 5 μm, the stress in the coating layer increases, and the coating layer is likely to peel during cutting. The thickness of the coating layer is
It is more preferable to set it in the range of 2 to 5 μm.

A plurality of coating layers may be formed. When forming a plurality of layers, it is preferable to set the total film thickness in the range of 1 to 5 μm, preferably 2 to 5 μm. In this case, the constituent materials or properties of the layers may be different from each other.

[0027]

Example 1 (Example 1) As a starting material, α having an average particle size of 0.7 μm was used.
-Si ₃ N ₄ powder, titanium carbonitride (KN / (KC + KN) = 0.5) powder with an average particle size of 1.2 μm, sintering aid powder (Yb ₂ O ₃ powder with an average particle size of 1.5 μm, average Particle size 1.0
μm CeO ₂ powder, Y ₂ O ₃ powder having an average particle size of 1.5 μm, and Dy ₂ O ₃ powder having an average particle size of 1.5 μm) were weighed so as to obtain a predetermined mixing ratio and Put the silicon nitride balls (φ12mm) and ethanol into a silicon nitride pot, and use a ball mill system for 24
Time mixing and crushing were performed. Next, the obtained slurry was put into a vacuum dryer, vacuum-sucked, and then heated to a temperature of 70 to 80 ° C. to dry the powder. The dry mixed powder is #
The particles were sieved through a 60 sieve. For comparison, a mixed powder using Al ₂ O ₃ as a sintering aid (corresponding sample is Comparative Example 6 in Table 5) was also prepared.

Next, this mixed powder was fired into a predetermined shape by using a hot pressing method. The hot press method was performed under the following conditions. First, BN powder diluted with ethanol was applied to a carbon mold as a release agent, and then a predetermined amount of powder was filled and set in an induction heating furnace. Then
The powder was 200 kg / c in a N ₂ atmosphere of 9.8 atm.
While uniaxially pressurizing with a pressure of m ^2, the temperature was raised to 1800 to 1900 ° C., and molding and sintering were performed at the same time. When the densities of the thus-obtained sintered bodies were measured by the Archimedes method, they were all densified to 99.5% or more of the theoretical density ratio. The component analysis of each sintered body was performed by a fluorescent X-ray analysis method.

Next, from each of the obtained sintered bodies, JIS R 1601 was used as a test piece for measuring physical properties described below.
The shape specified in 1 above was cut out and subjected to polishing. The cutting performance evaluation test piece was obtained by polishing the above-mentioned sintered body to give a tool shape (JIS
B4103, which was defined as SNGN120408 (Chamfer: 0.1 × 25 °)). Specifically, the cutting performance evaluation test piece 1 has a flat prismatic shape with a substantially square cross section having a thickness of about 4.76 mm and a side of about 12.7 mm, and the size of the rounded corners 1a. The radius R is about 0.8 mm. Also,
As shown in FIG. 1B, the chamfered portion formed on the edge portion 1b is formed so that the width t on the main surface 1c side is about 0.1 mm and the inclination angle θ with respect to the main surface 1c is about 25 °. did.

First, as the physical properties, the fracture toughness value (K
c), Vickers hardness and bending strength were measured. The fracture toughness value (Kc) is the IF specified in JIS R1607.
The Vickers indenter load was 30 kgf and the press-fitting time was 15 seconds according to the method. The Vickers hardness was also measured from the indentation area and the load. Also, the bending strength is
The test piece was placed in a heating furnace heated to 1000 ° C., and three-point bending was performed by the method specified in JIS R1604 as described above.

The cutting performance was evaluated under the following conditions. That is, the cylindrical work material W having the shape shown in FIG. 2A is rotated around the axis line and the outer peripheral surface of the work material W shown in FIG.
The test piece 1 shown in FIG. 2 is brought into contact with the test piece 1 as shown in FIG.
By using one of the main surfaces 1c as a rake face (hereinafter, the rake face is represented by 1c ') and the side face 1e as a flank face, the outer peripheral surface of the work material was continuously wet-cut under the following conditions. A more detailed positional relationship between the test piece 1 and the work material is shown in FIG.
As shown in FIG. In the figure, 1g indicates a lateral flank, and 1f indicates a front flank. The meanings of other symbols are shown in the drawings. Work Material: Cast Iron (JIS FC300 (Vickers Hardness: Hv = 2.2 GPa)) Work Material Shape: Outer Diameter φ240 mm, Inner Diameter φ180 mm, Length 2
00 mm Cutting speed V: 600 m / min Feed amount f: 0.1 mm / 1 revolution Cutting depth d: 0.2 mm Cutting oil: Water-soluble cutting oil W1 class 1 Z (JISK22
41 (1986); or contains 90% or more of emulsified non-volatile matter, its pH is 8.5-10.5, and non-volatile matter is 0-30.
15% by weight of fatty acid, 50-80% by weight of mineral oil, 15
~ Containing 35% surface activity)

After the cutting, the front cutting edge boundary wear amount Vn (maximum wear height in the turning direction near the boundary with the non-wear area on the front flank 1f side: see FIG. 2 (c)) of the cutting edge of the tool is measured. did. Then, the life of the test piece (tool) was determined by the cutting distance until the front cutting edge boundary wear amount Vn reached 0.1 mm. The above results are shown in Tables 1-5.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

[Table 4]

[0037]

[Table 5]

As is clear from the results, the test pieces of Examples having the compositions described in the claims of the present invention all have good cutting performance. For example, Ti of 10
In a composition containing 56% by weight of Si and 11.6 to 51% by weight of Si, the cutting distance is 15 km or more and the content of Ti is 19 to 41.
In the composition containing 20% by weight of Si and 21 to 42.8% by weight, the cutting distance is 20 km or more, and in the composition containing 41 to 56% by weight of Ti and 11.8 to 28.8% by weight of Si, the cutting distance is Values over 40 km are obtained. Also,
Boundary wear resistance of the front cutting edge is improved according to the Ti content, and the cutting distance is also extended, Ti-free product (Comparative Example 1)
It can be seen that a distance of 3 to 7 times can be processed.

The test piece of Comparative Example 3 in which the content of the sintering aid deviates from the range described in the claims of the present invention shows cutting performance which is not so good as compared with the test of each Example. . On the other hand, if the Ti content is excessive, the toughness of silicon nitride is lost, and chipping easily occurs at the cutting edge, making it unsuitable as a tool (Comparative Example 4). Also, the Vickers hardness is less than 16 GPa, and the bending strength at 1000 ° C. is 80.
It can also be seen that the test piece of less than 0 MPa is inferior in wear resistance and chipping resistance, and therefore becomes insufficient as a cutting tool.
Further, when comparing the test piece of Comparative Example 6 using Al ₂ O ₃ as a sintering aid with the samples of Examples 35 to 35 in which the contents of Ti and Si are almost similar to this, the density is almost the same level. However, it can be seen that the test pieces of the examples are superior in bending strength, fracture toughness value and cutting performance. Further, the test piece of Comparative Example 6 chipped before the wear amount of the front cutting edge reached the life value, but the test piece of the example did not chip.

(Example 2) For some compositions, the same evaluation as in Example 1 was carried out on the test pieces using the HIP method instead of the hot pressing method. The HIP was performed under the following conditions. First, the powder was press-molded into a predetermined shape, and pre-baked at 1750 ° C. for 2 hours in a N ₂ atmosphere at 1 atm. Next, the pre-baking was HIPed at 1600 ° C. for 2 hours in a N ₂ atmosphere at 1500 atm. Table 6 shows the results.

[0041]

[Table 6]

The compositions of the test pieces are shown in Table 1 as Example 1 and Table 2.
It is relatively close to that of Example 17, and it can be seen that the same physical characteristics and cutting performance as those of Example 17 are exhibited.

(Example 3) The test piece No. Using 33 (Table 3) as a base material, various coating layers were applied by the CVD method, and a cutting performance test under the same conditions as in Example 1 was performed. Table 7 shows the results.

[0044]

[Table 7]

According to this, the test pieces of the examples having the coatings satisfying the conditions described in the claims of the present invention have better cutting performance than the test pieces without coating shown in Table 3. You can see that On the other hand, it can be seen that the test pieces of Comparative Examples having a coating film outside the scope of the present invention did not show a significant improvement in cutting performance or peeling of the coating film occurred.

[Brief description of drawings]

FIG. 1 is a perspective view, a side partial sectional schematic view and a partially enlarged perspective view of a cutting performance evaluation test piece used in Examples.

FIG. 2 is an explanatory diagram showing an outline of a cutting test.

FIG. 3 is an explanatory diagram showing a positional relationship between a test piece and a work material in a cutting test.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Ninomiya 14-18 Takatsuji-cho, Mizuho-ku, Aichi Prefecture Nihon Special Ceramics Co., Ltd. 1 Kanazawa Institute of Technology

Claims (8)

[Claims] 1. Mainly composed of titanium carbonitride and silicon nitride, wherein Ti is 10 to 56% by weight and Si is 11.6 to 51.
A titanium carbonitride composite silicon nitride tool containing 1% to 21% by weight in total of 1% or more of Ce, Y, Yb and Dy. 2. The titanium carbonitride composite silicon nitride tool according to claim 1, containing one or more of Ce, Y, Yb, and Dy in a total amount of 3 to 15% by weight. 3. Vickers hardness at room temperature is 16 GPa or more and bending strength at 1000 ° C. is 800 MP.
The titanium carbonitride composite silicon nitride tool according to claim 1 or 2, which is a or more. 4. Ti: 19-41% by weight, Si: 21-
The titanium carbonitride composite silicon nitride tool according to any one of claims 1 to 3, which contains 42.8% by weight. 5. The room temperature Vickers hardness is 17 GPa or more and the bending strength at 1000 ° C. is 850 MP.
The titanium carbonitride composite silicon nitride tool according to claim 4, which is a or more. 6. Ti of 41 to 56% by weight and Si of 11.
The titanium carbonitride composite silicon nitride tool according to any one of claims 1 to 3, containing 8 to 28.8% by weight. 7. The titanium carbonitride composite silicon nitride tool according to claim 6, which has a Vickers hardness at room temperature of 18 GPa or more. 8. A main constituent is any one or two or more solid solutions of carbides, nitrides, carbonitrides and oxides of Al, and carbides, nitrides, carbonitrides and oxides of Ti. The titanium carbonitride composite according to any one of claims 1 to 7, wherein the surface of the titanium carbonitride is covered with a coating layer having a particle diameter of 0.5 µm or less and a film thickness of 1 to 5 µm. Silicon nitride tool.