JPH0578776A - Cermet alloy and its production - Google Patents

Abstract

PURPOSE:To enable high density sintering by sintering under reduced pressure or atmospheric pressure and to obtain a high hardness and high toughness alloy by forming a hard phase based on MC, MN or MCN (M is a specified transition metal), a hard phase based on a W-Ni-B compd. and a binding phase based on Ni. CONSTITUTION:A powdery mixture consisting of 10-45vol.% WB, 5-25vol.% Ni and the balance one or more among MC, MN and MCN (M is a group IVa, Va or VIa transition metal of the periodic table) is compacted and sintered at 1,300-1,600 deg.C for 10-120min to obtain the objective cermet alloy having high hardness comparable to that of a ceramic tool. In this allay, a hard phase based on one or more among MC, MN and MCN consists of one or more among MC, MW and MCN and (M, W) (B, C) and/or (M, W) (B, N) and/or (M, W) (B, CN). One or more among MC, MN and MCN may form the core part of the hard phase and (M, W) (B, C) and/or (M, W) (B, N) and/or (M, W) (B, CN) may form the peripheral part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cermet alloy, and more particularly to a cermet alloy which is easy to sinter, has extremely high hardness, and has good characteristics as a tool material, and a method for producing the same.

[0002]

2. Description of the Related Art As is well known, cermet alloys are composite materials intended to combine the high hardness characteristics of carbides and nitrides with the high toughness characteristics of metals. Usually, the metal exists as a binder phase in this composite material, and the carbides, nitrides, etc. exist as hard particles.

Examples of the hard particles include carbides such as TiC (titanium carbide) and WC (tungsten carbide), nitrides such as SiN and TiN, borides such as TiB and WB, which are Ni or Co (cobalt). ) Bonded TiC-Ni, TiC-WC-Co, Ti
C-WC-Co-Ni cermet alloy and this TiC
A cermet alloy in which TiCN is replaced by TiCN is known.

[0004]

In a cermet alloy, in the usual case, the toughness of the cermet alloy decreases if the materials and blends are selected so as to increase its hardness, and conversely, the hardness decreases when trying to increase the toughness. .. For example, TiC-
In the WC-Co system, when the Co content is reduced, the hardness increases but the toughness decreases. When the Co content is low, sintering becomes difficult and sufficient densification cannot be performed. On the contrary, when Co is increased, the toughness is improved but the hardness is decreased.

Further, conventionally, in order to obtain a cermet alloy having high hardness and high density, special pressure sintering such as hot pressing or hot isostatic pressing (HIP) is required, and the manufacturing process is complicated. There is a problem.

The present invention solves the above-mentioned problems of the prior art, can increase hardness without lowering toughness, and does not require pressure sintering such as hot pressing or HIP, and can be performed under reduced pressure or normal pressure. It is an object of the present invention to provide a cermet alloy having high hardness, which is capable of high-density sintering by the above-mentioned sintering means and is comparable in hardness to a ceramic tool.

[0007]

Means for Solving the Problems As a result of various investigations to solve the above problems, the inventor of the present invention has found that WB powder,
Ni powder, and one or more kinds of MC, MN and MCN (M is one or more kinds of transition metal elements of groups 4a, 5a and 6a of the periodic table-the same in the following description) powder. The mixed and sintered cermet alloy is composed of one or more of MC, MN and MCN, a hard phase containing W-Ni-B compound as a main component, and a binder phase containing Ni as a main component. We have come to discover that they have both high toughness and hardness.

The above-mentioned WB powder, Ni powder, and M
Further investigation of a cermet alloy obtained by mixing and sintering one or more powders of C, MN and MCN,
The following was found.

That is, the hard phase mainly composed of one or more of MC, MN and MCN is MC, MN and M.
One or more of CN and (M, W) (B, C) and / or (M, W) (B, N) and / or (M, W) (B, CN), MC, MN and MC
One or two or more types of N are used for the core, and (M, W)
(B, C) and / or (M, W) (B, N) and / or (M, W) (B, CN) may be present on the outer peripheral portion to form a cored structure.

The cermet alloy of the invention of this application and the method for producing the same are based on the above findings,
According to the invention of this application, there is provided a cermet alloy comprising one or more of MC, MN and MCN, a hard phase containing W-Ni-B compound as a main component, and a bonding phase containing Ni as a main component. ..

The metallic Ni content in the binder phase is preferably 7% by weight or less. This is because if the content of metallic Ni that does not contribute to the formation of the W-Ni-B compound exceeds 7% by weight, the hardness will decrease.

According to the invention of this application, MC, MN,
And a hard phase mainly composed of one or more of MCN and a hard phase mainly composed of a W-Ni-B compound, and Ni
A sintered body consisting of a binder phase composed mainly of
The hard phase mainly composed of one or more of N and MCN is one or more of MC, MN and MCN, and (M, W) (B, C), (M, W) (B , N),
A cermet alloy composed of one or more of (M, W) (B, CN) is provided.

Further, according to the invention of this application, MC, MN
And a hard phase mainly composed of one or more of MCN and a hard phase mainly composed of a W-Ni-B compound, and Ni
A sintered body consisting of a binder phase mainly composed of W-Ni
A cermet alloy composed of NiW ₂ B ₂ is provided as the hard phase mainly containing the —B compound.

In addition, according to the invention of this application, MC, M
A hard phase mainly composed of one or more of N and MCN and a hard phase mainly composed of a W-Ni-B compound, and N
A sintered body comprising a binder phase mainly composed of i,
The hard phase mainly composed of one or more kinds of MN and MCN includes one or more kinds of MC, MN and MCN, and (M, W) (B, C), (M, W) (B , N) and (M, W) (B, CN), or a hard phase mainly composed of a W—Ni—B compound is NiW.
_A cermet alloy consisting of ₂ B ₂ is provided.

Further, according to the invention of this application, Ti
A hard body mainly composed of C, a hard phase mainly composed of a W-Ni-B compound, and a binder phase mainly composed of Ni, wherein the hard phase mainly composed of TiC is TiC and ( A cermet alloy composed of Ti, W) (B, C) is provided.

Further, according to the invention of this application, TiC
A hard phase mainly composed of a W-Ni-B compound, a hard phase mainly composed of a W-Ni-B compound, and a binder phase mainly composed of Ni, wherein the hard phase mainly composed of a W-Ni-B compound is , NiW ₂ B ₂ cermet alloys are provided.

In addition, according to the invention of this application, Ti
A hard body mainly composed of C, a hard phase mainly composed of a W-Ni-B compound, and a binder phase mainly composed of Ni, wherein the hard phase mainly composed of TiC is TiC and ( A cermet alloy composed of NiWB and NiW ₂ B ₂ is provided as a hard phase composed of Ti, W) (B, C) and mainly composed of a W—Ni—B compound.

According to the invention of this application, WC and W-
Provided is a cermet alloy comprising a hard phase mainly composed of a Ni-B compound and a binder phase mainly composed of Ni.

In addition, according to the invention of this application, in the powder state, WB is 10 to 45% by volume, Ni is 5 to 25% by volume, and the balance is M.
After mixing and molding one or more of C, MN and MCN, sintering temperature 1300 to 1600 ° C., sintering time 10
A method for producing a cermet alloy that is sintered under the condition of 120 minutes is provided.

In addition, according to the invention of this application, WB in a powder state is 15 to 45% by volume, Ni is 5 to 25% by volume, and the balance T is T.
After mixing and molding iC, sintering temperature 1300 to 1600
Provided is a method for producing a cermet alloy, which is sintered under the conditions of ℃ and a sintering time of 10 to 120 minutes.

In addition, according to the present invention, 10 to 40% by volume of WB, 5 to 20% by volume of Ni, and the balance WC are mixed and molded in the raw material powder, and then the sintering temperature is set to 1300 to 160.
Provided is a method for producing a cermet alloy which is sintered under conditions of 0 ° C. and a sintering time of 10 to 120 minutes.

In order to produce the cermet alloy of the present invention, one or more powders of MC, MN and MCN, WB and Ni powders are mixed and molded, and sintered in a non-oxidizing atmosphere. good.

One or two of MC, MN and MCN
When mixing the powders of at least one kind and the powders of WB and Ni, the mixing compounding ratio is preferably within the range of Table 1 for each component.

When WB exceeds 45% by volume in this compounding ratio, uniform sintering tends to be difficult. Further, when Ni is less than 5% by volume, strength and toughness decrease. It is presumed that this is because the W-Ni-B composite phase formed by the reaction of WB and Ni becomes difficult to form when the amount of Ni is small. Further, if the Ni content exceeds 25% by volume, the binder phase becomes excessive and the hardness of the cermet alloy decreases.

If the powder particle size is too small, the amount of oxygen in the powder increases and pores are likely to occur during sintering. Conversely, if the powder particle size increases, the activity of the powder decreases and it becomes difficult to proceed with sintering. MC, MN and M blended from the above viewpoints
The particle size of one or more powders of CN is 0.5-45.
μm, especially about 0.7-10 μm is preferable. The particle size of WB is preferably 0.8-10 μm, especially 1.0-5.0 μm. Ni may be about 10.0 μm or less.

This compact can be sintered by a pressureless sintering method. The atmosphere is preferably a non-oxidizing atmosphere such as nitrogen, argon or vacuum. Of course, it can be sintered by hot pressing or HIP, but a high-density sintered body can be obtained without using such a pressure sintering method. In the case of the non-pressure sintering method, the sintering temperature is preferably 1300-1600 ° C., particularly 1400-1500 ° C., and the sintering time is 10
-120 minutes, especially 30-90 minutes are preferred. If the sintering temperature is less than 1400 ° C, the sintering does not proceed sufficiently and pores are likely to remain if the sintering temperature is less than 1300 ° C.
If the temperature exceeds 0 ° C., the grain growth of the hard phase becomes remarkable, which is not preferable. If the sintering time is less than 10 minutes, the pores tend to remain, while if it exceeds 120 minutes, grain growth of the hard phase tends to occur, which is not preferable.

[0027]

In the present invention, Ni melts at the time of sintering, promotes the sintering to achieve densification, and becomes a composite material in which hard particles are firmly bonded to Ni. Moreover, as a result of the research of the present invention, this Ni is merely MC, MN and MCN particles and W.
-Not only filling the gaps between the B compound particles, but also a part of Ni reacts with WB and enters the inside of the WB particles, and NiW ₂
It was found to form a B ₂ phase. Such W-Ni-
Since the B-based composite phase has a higher affinity with the Ni matrix phase than the WB single phase, the cermet alloy of the invention of this application has a high bonding strength between the W-Ni-B phase and the Ni phase.

In addition, due to the above-mentioned sintering, part of WB is M
Reacts with C, MN and MCN, MC, MN and MCN
(M, W) (B, C) on at least the surface of the particle,
A composite phase of (M, W) (B, N) and (M, W) (B, CN) is formed, and MC, MN and MCN particles have a core structure having a core part and an outer skin part. This skin phase is a phase containing a larger amount of W and B than the core. Such {MC, MN and MCN- (M, W) (B, C), (M, W) (B,
N), (M, W) (B, CN)} cored structure is MC, MN
Since it has a higher affinity for Ni than the MCN phase and MC,
MN and MCN particles and Ni are bound via the (M, W) (B, C) and / or (M, W) (B, N) and / or (M, W) (B, CN) phases. The composition becomes a so-called functionally graded structure in which the composition gradually changes from the MC, MN, and MCN cores toward the Ni side, and the bond strength is high.

Further, the melting point is lowered due to the reaction melting of Ni and a part of WB during the above-mentioned sintering, so that a sufficiently dense sintered body can be formed without using the pressure sintering method. It is considered possible to

As described above, the bonding strength between the hard particles or between the hard particles and the Ni matrix phase is extremely high, so that the cermet alloy of the present invention has excellent toughness. Further, high hardness MC, MN and MCN are used as the hard particles, and a part of low hardness Ni after sintering is W-Ni-B.
Since the compound is formed, the hardness of the cermet alloy also becomes high. As a result of various studies, it was confirmed that the cermet alloy of the present invention has a high Vickers hardness Hv of 1800 or more.

In the cermet alloy of the present invention, it is possible to replace a part of Ni added as a binder phase with Co, and in this case also Co acts like Ni and has high strength and high toughness. A cermet alloy can be obtained.

[0032]

[Example] Example 1 As the MC, MN, and MCN, the particle size is 0.5 to 10μ.
m WC, and the particle size is 1.0 to 5.0 μm
B and 5 to 10 μm of Ni were mixed according to the formulation (volume%) shown in Table 1. 1,500 kgf /
Press molding was performed at a pressure of cm ² (about 147 × 10 Pa) to obtain a compact having a diameter of 10 mm and a height of 5 mm. The compact was sintered in vacuum at 1500 ° C., 1525 ° C. and 1550 ° C. for 1 hour to obtain a cermet alloy.
Table 1 shows the Vickers hardness Hv (1
500), Hv (1525) and Hv (1550) and crack resistance CR (1500), CR (152)
The values of 5) and CR (1550) are also shown. IC
P-Ni is the value of Ni in the binder phase measured by plasma emission spectrometry. That is, the sintered body was crushed to 325 mesh or less to be used as a material for analysis, only the metal phase was selectively dissolved in the acid solution, and the non-dissolved powder was removed from the solution by filtration with a filter to remove Ni in the solution. It is an analysis. Thereby, the amount of metallic Ni remaining in the binder phase of the sintered body can be analyzed.

[0033]

[Table 1]

As is clear from Table 1, the cermet alloys of the examples of the present invention have Vickers hardness of more than 1700 and crack resistance C as shown in Nos. 1-9.
It is recognized that the value of R is also large.

FIG. 1 is a view schematically showing the X-ray diffraction result of the sintered body in the example of the present invention, which is WC-30vo.
This is an example when 1% WB-10 vol% Ni is sintered at 1500 ° C. As is apparent from FIG. 1, most of Ni reacts with WB by sintering to form NiW ₂ B ₂ which is a W—Ni—B compound.

FIG. 2 is a photograph showing the microstructure of the sintered body in this example, and shows the result (magnification 2400 times) of observing the microstructure of the sintered body shown in FIG. 1 with an SEM. Further, FIG. 3 is a photograph at a higher magnification (magnification of 12,000). 2 and 3, the white phase is WC and the black phase is NiW ₂ B ₂ . Ni as the binder phase is 1 wt%
The quantity is small as follows, and it is not recognized in this visual field.

Example 2 As the MC, MN and MCN, the grain size is 0.5 to 1.0.
Using TiC, TaC, NbC, TiN, and TiCN of μm, WB of 0.8 μm and Ni and Co of 3.0 μm were mixed according to the formulation shown in Table 2. These mixtures were used in Example 1.
Molded and sintered under the same conditions as above to obtain a sintered body. , Vickers hardness Hv, and crack resistance CR were measured. The results are shown in Table 2, which shows that the cermet alloy of the present invention has high hardness and high toughness.

When the structure of the No. 1 alloy in Table 2 was observed, TiC, (Ti, W) (B, C), Ti
It was found to be a structure composed of a hard phase composed of W ₂ B ₂ and a binder phase composed of Ni.

[0039]

As described above, according to the cermet alloy of the present invention and the method for producing the same, the excellent effects of high hardness, compactness and excellent toughness are exhibited. Further, according to the cermet alloy and the method for producing the same of the present invention, there is an advantage that high-density sintering can be performed by reduced pressure or normal pressure sintering without using HIP, hot pressing or the like. Moreover, according to the cermet alloy and the manufacturing method thereof of the present invention, there is an effect that the diamond film can be surely deposited.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an X-ray diffraction result of a sintered body in Example 1 of the present invention.

FIG. 2 is an electron micrograph of a cermet alloy of an example of the present invention, taken by an electron microscope (magnification: 2400).
Times).

FIG. 3 is an electron micrograph of a metal microstructure of a cermet alloy according to an example of the present invention (magnification: 16000).
Times).

[Table 2]

Claims (16)

[Claims] 1. A MC, MN, and MCN of one or more (M is one or more of transition metal elements of Groups 4a, 5a, and 6a of the Periodic Table) and a W-Ni-B compound. A cermet alloy comprising a hard phase mainly containing Ni and a binder phase mainly containing Ni. 2. The cermet alloy according to claim 1, wherein the binder phase metal Ni is 7% by weight or less. 3. One or two of MC, MN, and MCN.
A hard phase mainly composed of at least one kind (M is one or more kinds of transition metal elements of Groups 4a, 5a and 6a of the Periodic Table) and W
A hard body mainly composed of a hard phase composed mainly of a —Ni—B compound and a binder phase composed mainly of Ni, wherein the hard phase composed mainly of one or more of MC, MN and MCN is
One or more of MC, MN and MCN, and (M, W) (B, C), (M, W) (B, N), (M,
W) A cermet alloy comprising one or more of (B, CN). 4. The hard phase mainly composed of one kind or two or more kinds of MC, MN and MCN is one of MC, MN and MCN.
Type or two or more types of cores, and (M, W) (B,
C), (M, W) (B, N) and (M, W) (B, C
The cermet alloy according to claim 3, which comprises one or more outer peripheral portions of N). 5. A hard phase mainly composed of one or more of MC, MN and MCN (M is one or more of transition metal elements of Groups 4a, 5a and 6a of the Periodic Table) and W. −
Hard phase composed mainly of Ni-B compound, and a sintered body made of a binder phase composed mainly of Ni, the hard phase composed mainly of W-Ni-B compound, in that it consists of NiW ₂ B ₂ A characteristic cermet alloy. 6. A hard phase containing at least one of MC, MN and MCN (M is one or more of transition metal elements of groups 4a, 5a and 6a of the periodic table) and W. −
A sintered body comprising a hard phase mainly composed of a Ni-B compound and a binder phase mainly composed of Ni, wherein the hard phase mainly composed of one or more of MC, MN and MCN is M
One or more of C, MN and MCN, and one of (M, W) (B, C), (M, W) (B, N) and (M, W) (B, CN) or The hard phase mainly composed of W-Ni-B compound is NiW.
A cermet alloy characterized by comprising ₂ B ₂ . 7. The hard phase mainly composed of one or more of MC, MN and MCN is one of MC, MN and MCN.
Type or two or more types of cores, and (M, W) (B,
C), (M, W) (B, N) and (M, W) (B, C
The cermet alloy according to claim 6, which comprises one or more of N). 8. A hard phase mainly composed of TiC and W-Ni
-A sintered body composed of a hard phase mainly composed of a B compound and a binder phase mainly composed of Ni, and the hard phase mainly composed of TiC is composed of TiC and (Ti, W) (B, C). A cermet alloy characterized in that 9. The cermet alloy according to claim 8, wherein the hard phase mainly composed of TiC comprises a core portion of TiC and an outer peripheral portion of (Ti, W) (B, C). 10. A hard phase mainly composed of TiC and W-N
hard phase for the i-B compound mainly, and a sintered body made of a binder phase composed mainly of Ni, the hard phase composed mainly of W-Ni-B compound, in that it consists of NiW ₂ B ₂ A characteristic cermet alloy. 11. A hard phase mainly composed of TiC and W-N
A hard body mainly composed of an i-B compound and a binder phase mainly composed of Ni, wherein the hard phase mainly composed of TiC is composed of TiC and (Ti, W) (B, C). The hard phase mainly composed of W-Ni-B compound is NiW ₂
A cermet alloy characterized by comprising B ₂ . 12. The hard phase mainly composed of TiC is TiC.
The cermet alloy according to claim 11, wherein the cermet alloy comprises a core portion of and a peripheral portion of (Ti, W) (B, C). 13. A cermet alloy comprising a hard phase containing WC and a W—Ni—B compound as a main component, and a binder phase containing Ni as a main component. 14. WB in a powder state, 10 to 45% by volume,
5 to 25% by volume of Ni, the balance MC, MN, and one or more kinds of MCN (M is periodic table 4a, 5a, 6a
After mixing and molding one or more kinds of transition metal elements of group I, sintering temperature 1300 to 1600 ° C., sintering time 10
A method for producing a cermet alloy, characterized by sintering under the condition of 120 minutes. 15. WB in the powder state in an amount of 10 to 45% by volume,
After mixing and molding 5 to 25% by volume of Ni and the balance of TiC, the sintering temperature is 1300 to 1600 ° C. and the sintering time is 10 to 1
A method for producing a cermet alloy, which comprises sintering for 20 minutes. 16. A raw material powder containing 10 to 40% by volume of WB,
After mixing and molding 5 to 20% by volume of Ni and the balance WC, the sintering temperature is 1300 to 1600 ° C. and the sintering time is 10 to 1
A method for producing a cermet alloy, which comprises sintering for 20 minutes.