JPS60226459A - Super hard ceramic and manufacture - 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 [Field of Industrial Application] The present invention relates to ultra-hard ceramics of B4C-TiB2-TiN having extremely high hardness and a method for producing the same.

[Conventional technology and its problems]

Since both B4C and TiB2 have high hardness, they are thought to be suitable substances for manufacturing hard materials, or both have poor sinterability and cannot be used to produce materials with high strength, so they have not been put into practical use as hard materials. The current situation is that this is not the case.

Therefore, production of B, C-Fe group metal sintered bodies and TiB2-Fe group metal sintered bodies using Fe group metals as a binder was considered, but in both cases, Fe group metal borides were generated during sintering. The sintered body has the disadvantage that the bonding metal phase is eliminated, the strength is only improved to a very small extent, and the hardness of the sintered body is greatly reduced.

In addition, in order to avoid the above-mentioned drawbacks, metal bonding agents, alloy binders, or carbide binders that do not produce borides have been investigated, but none of them has been able to improve both hardness and strength properties. 3. [Object of the Invention] Therefore, the object of the present invention is to obtain an ultra-hard sintered body with high hardness and high strength.

[Knowledge]

As a result of intensive research, the present inventors obtained the following knowledge.

(2) First, a sintered body made of two components, B4c and TiB2, was investigated, but although this material showed higher hardness than a sintered body made of each component alone, its strength was extremely low.

■Next, we produced a sintered body by adding various metals or compounds to the two components B, c and TiB2.
As in the case where Fe group metal was added to each of the above, borides of Fe group metals were generated, and the hardness of the sintered body was greatly reduced.

(2) Addition of carbide improved hardness, but did not improve strength.

(2) When a sintered body was manufactured by adding T1 nitride (hereinafter referred to as TiN) among the 3-3 nitrides to the two components of B, C and TiB2, the hardness and strength were improved.

■-4 A similar effect can be obtained by adding up to 70% by weight of TiN to Z
3, ■ The above ■-3 and ■−
When manufacturing the sintered body of No. 4, the green compact was heated to O, 1 to
By normal sintering or hot pressing in a nitrogen atmosphere of rr or higher, a sintered body with particularly high hardness and high strength was obtained.

[Matters essential to the structure of the invention] This invention:
This is an ultra-hard ceramic and a method for producing the same invented based on the above knowledge, and the ultra-hard ceramic includes 84C, TiBz, and MN (M'N: nitride of Ti.

Or, up to 70 nitrides of T1 are replaced with one or two of Zr nitride and Hf nitride)
It consists of three components, and its composition is shown in Figure 1,
In triangular coordinates, point A (B, C: 80%, T'IB2: 19%
, 1. JH: 1ch).

Point B (B, c: 80%, TiB2: 10%
, MlXI 10%).

Point c (T3.c: 60%, TiB2: 10%, M
IJ: Section 30).

Point D (B, c: 30%, TiB2:
4 0 Tsukotoi, Ml\Ding: 30%).

and point E (B4C: 30th section, TiB2: 69th section, IA
N', 1%) (the above is a weight factor), then the line AB.

It is characterized by being in the range surrounded by BC, CD, DE and EA, and has five prongs.

The manufacturing method includes B, C powder, TiB2 powder and M l-J (however,
lvi l'l: Tx nitride, or up to 70 nitrides of T1 nitride replaced with one or two of Zr nitride and Hf nitride) The powder is shown in FIG. In triangular coordinates, point A (84C: 80%, TiB 2: Ko, 9
da 6,) νIN 1%).

Point B (B, C: 80%, TiB2: lQ%,
MN: 10%).

Point C (B, C: 60 cm, TiB2: 10%, M
N: 30%).

Point D (B4C: 30%, TiB2: 40%, MN
:30%) and point E (B4C: 30%, TiB2: 69%, MN:
1%) (hereinafter, the section is the weight section), then line AB.

Blend to a composition within the range of BC, CD, DE, and EA, mix the raw material powder unblended, press mold to form a compact, and press the compact in a nitrogen atmosphere of 0.1 torr or more. 1. [Constitutional Requirements of the Invention] Next, the constitution of the present invention will be described in detail. , I) Ultra-hard ceramics (i) Component MN is Ti, N or 101 of TiN (substituted with one or two of ZrN and HfN in a proportion greater than 70%). This is because replacing TiN significantly reduces the strength of the ceramic.

(11) Composition (a) B4C B4C itself has extremely high hardness, is the main hard phase forming component of the ceramic of this invention, and has the effect of imparting high wear resistance to the ultra-hard ceramic of this invention. , If the content of F34C is less than line I)E in FIG. 1, that is, less than 30% by weight, the desired effect cannot be obtained; on the other hand,
If it exceeds the AB line in Figure 1, that is, exceeds 80% by weight, the sinterability will decrease and the strength will decrease. (that is, 30 to 80% by weight).

(b) TiB2 T I B 2 is itself 13. , C has high hardness like B and C, but when sintered together with B and C, it becomes a sintered body of extremely high hardness. It has the effect of improving the strength of hard ceramics, but if the content of TiB2 is less than the line BC in Figure 1, that is, less than 10% by weight, the desired effect cannot be obtained; That is 6
If it exceeds 9% by weight, the wear resistance and strength of the ultra-hard ceramic of the present invention will decrease and it will shatter.
2 content between the BC line and the E point (i.e. 10 to 6
9).

(c) MN MN has the effect of binding B4C and TiB2 to improve sinterability and strength, but if the MN content is less than the A to E line, that is, less than 1 weight coefficient, the desired No effect is obtained, and on the other hand, if CD and IJ are exceeded, that is, 3
If it exceeds 0% by weight, the hardness of the ultrahard ceramic of the present invention will decrease and the wear resistance will decrease.
The N content is between the AE line and the cl) line (i.e. 1~
30% by weight).

(2) Production method (1) Particle size Since TiN, ZrN, and HfN play a role as a binder phase, the finer the particle size of the nitride powder, the better, and in particular, the powder with an average particle size of 1 μm or less is preferable. B, C
The average particle size of the powder and TiB2 powder is 05~
5.0 μm and 05-5.0 μm are preferred.

(11) Mixing Mixing is carried out in a conventional manner, that is, in a ball mill in a wet manner (for example, in alcohol), for example, for 96 hours.

(iii) Forming is preferably performed at a press pressure of 10 to 30-kg/
This is done by press molding in mm.

Ov) Sintering Sintering must be carried out in a nitrogen atmosphere.

This is 1. This is to prevent iN from thermally decomposing during sintering and reducing the strength of the ultra-hard ceramic. If the pressure of nitrogen gas is less than 0.1 torr, the above desired effect cannot be obtained.

Sintering is usually carried out by sintering or hot pressing. Normal sintering is at a temperature of 1900 to 2300℃,
It is desirable to do this for 2 to 4 hours.

In the case of hot press, press pressure 100-400
kg/ffl, 05-2 at temperature 1800-2200℃
It is advisable to do it for an hour.

It is preferable to further perform hot isostatic pressing after producing ultrahard ceramics by normal sintering or hot pressing in a nitrogen atmosphere because the strength is further improved.

〔Example〕

Next, referring to Examples, the ultra-hard ceramics of the present invention and the manufacturing method thereof will be specifically explained.

Example 1 and comparative example B and C powders with an average particle size of 15 μm were used as raw material powders.

TiB2 powder of 2.0 fi m, and Q, 3
/l m of r i N powder was prepared, mixed into the composition shown in Table 1, and wet-pulverized in a ball mill for 96 hours.
After mixing and drying, the powder was press-formed at a press pressure of 20 kg/Hi to form a green compact, and the green compact was sintered under the conditions shown in Table 1, so that the composition was substantially the same as the blended composition. Ultra-hard ceramics 1 to 9 of the present invention and comparative hard ceramics 1' to 8' were produced. Note that comparatively hard ceramics are those whose compositions are outside the composition range of the present invention.

Next, the Rockwell A hardness (hereinafter referred to as HRA) and transverse rupture strength of the ultra-hard ceramic of the present invention and the comparative hard ceramic were measured, and the results are also shown in Table 1.

As is clear from Table 1, the ultra-hard ceramics of the present invention have a hardness of about 94.0-948° in HRA and a transverse rupture strength of about 67-90 kg/ma, whereas has a hardness of approximately 033 to 937° and a transverse rupture strength of approximately 4
1 to 55 kg/, j. 1. That is, it can be seen that the ultra-hard ceramic of the present invention has higher hardness and strength than comparative hard ceramics, and has extremely excellent properties. Besides the powder.

ZrN powder with an average particle size of 0.9/4 m, 0.8/4 m
l m i (f N powder was prepared, mixed into the composition shown in Table 2, and a green compact was made in the same manner as in Example 1.
This was sintered under the conditions shown in Table 2 to produce ultra-hard ceramics 20 to 31 of the present invention.

Next, the HRA and transverse rupture strength of ultra-hard ceramics 20 to 31 of the present invention were measured, and the results are also shown in Table 2.

As is clear from Table 2, up to 70% of TiN is
If one or two of rN and HfN are substituted,
The hardness is the same or slightly improved, and the strength is slightly decreased, but MN
It can be seen that the properties are almost the same as those of TiN alone.

[Uses and effects of the invention]

Reference Example From the ultra-hard ceramic flats 20 to 26 of the present invention manufactured in Example 2 and the comparative hard ceramic flats manufactured in Example 1 and Comparative Example ]' to 8', ISO standard SN
A cutting tip having a shape of P432 was cut out, and a cutting test was conducted under the following conditions.

Cutting test conditions〉 Work material:,y-s] alloy (M-12 Sj, -2,5
Steamed rice Ni -1,0%Mg -0,2%Mn -0,8%
Cu ) round bar cutting speed near 50 m/min feed: 0.12 rrun/rev.

Depth of cut: 205 Cutting time: 45 minutes Furthermore, for comparison of cutting tests, 15 μm of TiN was added to the commercially available KIO cemented carbide (called conventional alloy I), which is commonly used for cutting AQ gold alloys, and the KIO cemented carbide. Cutting was performed in the same manner using a coated cemented carbide (referred to as conventional alloy 2).

In these cutting tests, the amount of flank wear of the cutting tip and the degree of welding of the work material to the cutting edge were measured or observed, and are shown in Table 3.

As can be seen from Table 3, the ultra-hard ceramics of the present invention have extremely superior wear resistance compared to conventional alloys commonly used for cutting AQ gold alloys, and also have excellent wear resistance against cutting edges. There is almost no welding of the work material. Even compared to comparative hard ceramics whose compositions are outside the composition range of the present invention, the ultra-hard ceramics of the present invention have extremely excellent wear resistance and chipping resistance, and also have excellent welding properties on the cutting edge. There are almost no

As described above, when the ultra-hard ceramic of the present invention is applied to the cutting of A2 alloy, it exhibits particularly excellent cutting performance compared to conventional alloys, so the ultra-hard ceramic of the present invention is extremely important in practice.

[Brief explanation of drawings]

FIG. 1 shows triangular coordinates representing the composition of a ternary system of B4C, TiB2, and MN, and the range quadrupled by solid lines connecting points A, B, C, D, and E and A is the area beyond the scope of this invention. 3, which is the composition range of hard ceramics, and from point l to 1
9, points 20 to 22, 23 to 26, and 27 to 3, and points 1' to 8' correspond to the ultrahard ceramics of the present invention and the comparative hard ceramics of Example 1, Comparative Example, and Example 2, respectively. This point represents the composition of the flat surface. Applicant Mitsubishi Metals Co., Ltd. Agent Tomi 1) Kazuo and 1 other person

Claims (2)

[Claims] (1) B4C, 'riB2 and Mlri (however, ki
N: consists of three components: Tl nitride or up to 70% of T1 nitride replaced with one or two of Zr nitride and Hf nitride), and its composition is as follows:
As shown in Figure 1, in triangular coordinates, point A (s, c: so%, TiB2: 19%
,! Former section 4.1). Point B (BaC: s □%, TiB2: 10%, 1 to 4
N: 10%). Point C (B, C: 60%, TiP, 2: 10 attacks,
h4N', 30%). Point D (134c: 30chi, TiB2: 40%
, 1-4N: 30%) and point E (B, C: 30%, TiB2: 69%, MN:
1%) (hereinafter, q is weight %), line AB. An ultra-hard ceramic characterized by being in a range surrounded by BC, CD, DE, and KA. (2) B, C powder, TiB2 powder and I・1 ha (However, Mll: T1 nitride or T1 nitride 7
Powder in which up to Q% was replaced with one or both of Zr nitride and Hf nitride in the triangular coordinates shown in FIG. Point A (B4c: s○%, TiB2: 19%,
1. 1%). Point B (B, C: 80%, TiB2: 10%,
j, 41J: IQ%). Point C (B4C: 60%, TlB2: 10
%, I411: 30%). Point D (s, c: zo ratio, TiB2: 40%, Ml-1
: 30chi). and point E (B4C: 30%, TiB2 2 6
9%, 1! : 1%) (in the above, the section is the weight section), then the line AB. 13C, CD, DE, and EA, the unblended raw material powder is mixed, press-molded to form a compact, and the compact is in a nitrogen atmosphere of 0.1 torr or more. Characterized by ordinary sintering or hot pressing,
It consists of three components: B4C, TiB2 and MN, and its composition is shown on the triangular coordinates shown in Figure 1 by lines AB, BC, CD,
A method for producing ultra-hard ceramics in the range surrounded by DE and FA.