JPS60184648A - Manufacture of sintered body of high pressure phase boron nitride - Google Patents

Abstract

PURPOSE:To manufacture a sintered body of high pressure phase BN having high strength, superior wear resistance and toughness by converting the material of the surfaces of high pressure phase BN particles into low pressure phase BN by treatment under temp. and pressure conditions under which high pressure phase BN is unstable, mixing the particles with binder powder, and sintering the mixture under temp. and pressure conditions under which high pressure phase BN is stable. CONSTITUTION:The material of the surfaces of high pressure phase BN (cubic BN) particles is converted into low pressure phase BN by treatment under temp. and pressure conditions under which high pressure phase BN is unstable, e.g., at about 1,300 deg.C under about 15kb pressure. The particles are then mixed with binder powder and sintered under temp. and pressure conditions under which high pressure phase BN is stable, e.g., at about 1,400 deg.C under about 50kb pressure. Powder of one or more kinds of components selected among alkali metals, alkaline earth metals, the nitrides and boronitrides of the metals, Pb, Sb, Sn and alloys of Pb, Sb and Sn is used as the binder powder.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical field The present invention is suitable for use as a cutting tool, etc. 1 = High strength and excellent wear resistance and toughness. -゛) This relates to a method of manufacturing a press-type boron nitride sintered body.

(b) Technical background The high-pressure phase type boron nitride is cubic type boron nitride (hereinafter referred to as C[3N
There are two types: wurtzite boron nitride (hereinafter referred to as WBN), but both of them have the highest hardness, second only to diamond, and have a higher hardness than tire nitride (reaction with iron group metals). Because of its low properties, it is extremely useful for grinding and cutting, such as shell abrasions, and is already widely used.

Particularly for cutting applications, sintered bodies in which CBN is bonded with C such as Go are partially used.

As mentioned above, BN has 13 hardness, heat resistance,
Endurance 1! There are 4 substances in wear 11. Various attempts have been made to sinter only this CBN (there are some, for example, as described in Japanese Patent Publication No. 39-8948).
Approximately 7 years old (1) -1,190 (needs to be sintered under ultra-high pressure and high temperature of 1°C or higher.

It is possible to generate this J, Unahataru 1z) 7mu, 1 strand A'1 at a temperature of 4. Device 4 humanoid/c
JJ, i, Hatake 11 The number of service life of the high temperature generation part is limited,
Not practical.

Further, as mentioned above, some sintered bodies using metals such as C as a binder are used, but when this is used as a cutting tool.

(1) Wear progresses from the metal bonding phase.

(2) The presence of the metal phase reduces the welding resistance of the entire sintered body.

A problem arises. This is due to the metallic phase due to the following factors.

Generally, when creating a CI3N sintered body, pressure is first applied and then the temperature is increased.Then, the molten metal infiltrates into the gaps between the CBN particles due to the high temperature for 1 minute.

Therefore, when pressure is applied between the CBN particles (snapping occurs and a so-called crosslinking phenomenon occurs), this gap becomes large and a large metal phase is formed in this part. This causes the melting phenomenon, which deteriorates the overall performance of the sintered body as described above.

(C) Disclosure of the Invention This invention reduces the occurrence of large binder phase segregation as described above, and further reduces surface pores of high-pressure phase type boron nitride particles.
, the bonding material td contained in the material is reduced. -Where is it?

Immediately 5, cross-linking is not photogenerated, b, and < is once generated.
, : There are some studies that consider breaking the bridge.

There are two ways to do this: .

One is to do this where there is no bond H
There is C, and the other 1) can be done after mixing with the binder.

The former converts the surface of high-pressure phase type nitrided I#I elementary particles into a low Im phase type nitrided i-cord (hereinafter referred to as 1'1l13N), and the weak strength and lubricity of IIBN generated on this surface are improved. The idea is to eliminate the occurrence of crosslinking by taking advantage of the fact that

As shown in the order of the drawings abCde, there is a method of converting the IΩΩ coarse-phase type boron nitride particle surface to IIBN in advance under iHi pressure or reduced pressure, and sintering under high temperature and high pressure. Type boron nitride unstable region exposed to 11
There are ways to convert it to BN.

In the latter method, high-pressure phase boron nitride particles are placed at 14:K with each other.
i;Xi〆l-7'1. % people-hIQ4ζ, M-A-=
two! ! A" + 4 demi jk - 1 noodle 411' 1 piece: 毫 +
The ability to obtain a sintered body with less binder phase ω is ↑1.

In any case, the final step of hot pressing is carried out in the high-pressure phase type boron nitride stable region, so that the portion converted to ``h[3N'' returns to coarse phase type mononitride again.

The alkali metals, alkaline earth metals, nitrides, boronitrides, lead, antimony, tin, or alloys thereof used as binders in this invention are made from hBN powder and are converted into CBN under high pressure and high temperature. It is known to be used as a catalyst when producing powder.

However, in J3 of the present invention, by using one or more selected from the group of substances having catalytic action as a binder, h
This is because BN acts effectively when re-drying to high-pressure phase type boron nitride, making it possible to obtain a uniform structure with few bonding phases.

This binding material ultimately remains in the sintered body, so if the amount used is large, the performance of the sintered body for use in tools etc. will deteriorate, which is undesirable. is 5
It is appropriate that the amount is less than % by volume.

In this invention, the device used to obtain the ζ sintered body is "C"
There are belt-type and girdle-type ultrahigh-pressure equipment used for diamond synthesis.

The drying process a3 and the pressure process '1' for C sintering are carried out in the stable region of high-pressure phase type boron nitride shown in the drawing. Within this range (.j > 1200°C or higher and pressure 40 k 11 or higher is preferred.

The above is a detailed explanation of the present invention using practical examples.

Example 1 After blending CBN powder with a uniform particle size of 5μ, magnesium powder, and magnesium nitride powder into the composition shown in Table 1,
Mix it, fill it into a container, and apply the ultra-high pressure L used for Gui X7 Mondo synthesis! In the 8II heating device, perform the following J.
I really enjoyed sintering.

J: Raise the J-L power to 15 kb, heat to 1300°C after Ic, hold for 5 minutes, and IC0 This region is in the CBN unstable region.

Thereafter, the temperature was slowly increased to 1400° C. and the pressure was increased to 50 kb (maintained for 10 minutes, then the temperature was increased to L'f, and the pressure was further lowered).

In the tI-treated sintered body, the binder was uniformly distributed in structure, and no hBN remained. Further, magnesium oxide was detected in all the samples, and the Vickers hardness (measured load: 10-) of each sample was as shown in Table 1.

Table 1 Regardless of the method of the present invention, when the route shown in Figure abe was taken, segregation of the binder was observed in the sintered body, and some vacancies were also observed.

Samples 1 to 4 Using sintered bodies made of J3 and commercially available 6 as binders - UFC25 at a peripheral speed of 500 +n/III
i n , depth of cut 0.3mu+, feed 0.1mm/
r(3V, cutting under dry conditions until IC8 flank wear width reaches 0, 2111n+, C life time is 'i
It is shown in Table 82.

Table 2 Example 2 3 CI3 N powder with an average particle size of 2μ was preliminarily prepared into 10 mm 1-1
) kept at 1300℃ for 10 minutes under a clean air 1. +1 GB
The surface of the N particles was converted to 118N.

This powder and the combined 4A powder of No. 3 shown in Table 1 of Example 1 were included in the composition of Table 1. M+:i used for
+ IJ': Sintered using a J-4 quenching device.

J, J'pressure! i 0 k b Raise the temperature to 1400°C and set it to 1400°C.j 1. ．． 5j-IAI 1jl L
/ /C,.

(1) The structure, structure, and performance of the sintered body were the same as those of Example 1 (1!J A: Trial 1).

/+li+lu+,'3 According to the method of Example 1, an experiment was conducted using the CBN of Example 1 as WB'N powder with an average particle size of 1 μm. However, the compositions were three types, Samples No. 1 to 3 in Table 1.

The structure of the obtained sintered body was uniform, and hBN and C were not present.

Using this sintered body and a commercially available sintered body with a binder such as Co, FC,,1) 45 was heated at a circumferential speed of 300 m/mi.
+1, depth of cut O', 3 mnt, feed 0. Inun
/ I'eV 1 When cutting under wet conditions, the life time until the flank wear width reaches 0,2 nun is:
The sintered bodies No. 1 to 3 of this invention took 42 minutes, 56 minutes, and 45 minutes, respectively, and the commercial product took 20 minutes.

Example 4 A binder such as gI juice phase type boron nitride powder having the composition shown in Table 3 was mixed and then filled into a container. (Example 1)
Sintering was performed using the same method as the saw.

Table 3: The sintered body has a structure in which the binder is uniformly divided into 4+L/tjj, and IIBN remains and is IC0. (using a sintered body) (r-025 at a circumferential speed of 5
00m/min, depth of cut 0.311Ill11 feed O
,1non/reV, dry article fli 'i('
I cut it. The Ki life time until the flank wear width reaches 0.2 mm is shown in Table 4.

Table 4 Sample No. 098 of Example 4 was sintered in the same manner as in Example 1 except that the binder shown in Table 5 was used instead of lead. The second
Table 1: The structure of the sintered body was uniform, with no residual 1l13N and no carbon. In addition, the Vickers hardness (before measurement iokg) of each was C as shown in Table 5.

[Brief explanation of drawings]

The drawing shows the F of 60, I11 pressure phase type nitrided film cable to explain the conditions for producing the sintered body in this method.
i-) The thermodynamically stable region on the J-Tsumaro phase diagram is 1
...Cubic crystal - low pressure phase type boron nitride equilibrium line A...High pressure phase type boron nitride stability region B...Low pressure phase type boron nitride stability region Patent applicant Sumitomo Electric Industries, Ltd. Agent Patent attorney Kazu 1 ) Akira

Claims (1)

[Claims] (1) High-temperature type! ,・C) If the unstable temperature and pressure range of U1 element is mixed with high pressure phase bar (nitride 11111 element) which avoids converting the 0 surface into low pressure phase type nitride 1i111 wire, child-bonded 4A powder, etc. Stable temperature of high-pressure phase type boron nitride within the pressure range (1) Manufacturing method of 1-pressure phase type boron nitride sintered body characterized by sintering. (2) Bonding + A powder and C-1 alkali metals, noflukali metals, or their nitrides, boronitrides, or 11), nonone J1. : We recommend using one or more powders selected from 11Y consisting of tin, tin, or their alloys! 14+ Q'l A method for producing a high-pressure phase type boron nitride sintered body according to claim 1. +31 1! The method for producing an iN E[In-type nitrided 1tjl element sintered body according to claim 1, wherein the M1 element is nitrided boron nitride. 4) After mixing the high-pressure phase with the boron nitride particles and the binder powder, the high-pressure phase is held at a high pressure that is within the unstable temperature and pressure range of the high-pressure phase boron nitride, and then the high-pressure phase boron nitride is mixed with the powder. A method for producing a high-pressure phase type boron nitride sintered body characterized by sintering within a stable temperature and pressure range. (5) A binder powder containing an alkali metal, an alkaline earth metal, or a nitride thereof. , boronitride, or lead, antimony, tin (one or more selected from the group consisting of these alloys) powder is used. (6) Production of a 11-pressure phase type boron nitride sintered body according to claim 111, wherein the high-pressure phase type boron nitride is a cubic nitride sintered body. Method.