JPS60235764A - Manufacture of boron carbide-titanium diboride two state composite superhard alloy - 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 [Technical Field] The present invention relates to a two-phase composite superstructure composed of boron carbide (hereinafter abbreviated as 84C) and titanium di-boride (hereinafter abbreviated as TiB2). The present invention relates to a method for producing hard alloys.

[Prior art]

Ceramics can be broadly divided into oxide-based and non-oxide-based. Oxide-based materials have a chemical bond structure of ionic bonds, as typified by alumina (AI□03).
Generally exhibits easy sinterability. In other words, oxide ceramics can be sintered by compressing powder and then sintering it in a pressureless sintering process called an atmospheric pressure sintering method.

On the other hand, non-oxide ceramics are difficult to sinter because they have strong covalent bonds and are called de-sintered materials.

Therefore, many non-oxide ceramics use sintering methods such as Honotopunsu (hot pressure sintering), atmospheric pressure/sintering, and HIP (hot isostatic sintering) instead of pressureless sintering. There are many. However, in the above-mentioned sintering method, the powder or molded body is placed in an excessively heat-resistant B1 (for example, a sintered alumina mold or a graphite mold) and sintered, which increases the product cost. Furthermore, it becomes difficult to create products with complex shapes.

SI3N4 and SiC are substances that have recently attracted particular attention among non-oxide ceramics.

The reason for this is, of course, that these materials have excellent mechanical properties at high temperatures, but the biggest reason is that a type of pressureless sintering method called reaction sintering method was developed. This reaction sintering method is a method in which a chemical reaction is carried out during the firing process of the compact, and for example, in the case of 513N4, 8
In this method, a S I 3N4 sintered body is obtained by nitriding and firing the powder in an atmosphere containing N2 after molding the whole powder.

Although this method is an extremely useful sintering method industrially, it has the disadvantage that the sintered body is porous and has low strength.

Among non-oxide ceramics, in addition to the above-mentioned ceramics, there is a substance K B4 that is considered to be extremely important industrially.
There are C and TlB2. These two substances are also difficult to sinter, and cannot be sintered using the reaction sintering method described above, and materials that cannot be produced into high-density sintered bodies using the pressureless sintering method. It is.

Conventionally, attempts have been made to create B,C-TiB2-based composite ceramics using a hot press method.

Both B4C and TiB2 have high hardness and excellent wear resistance, so it is extremely important industrially to achieve high density of B4C-TiB2 two-phase composite cemented carbide by pressureless sintering. .

〔the purpose〕

The purpose of the present invention is to eliminate the various drawbacks of the above-mentioned prior art and to meet the above-mentioned demands.
It is an object of the present invention to provide a manufacturing method for obtaining an IB2-based two-phase composite cemented carbide by an atmospheric pressure sintering method.

[Summary of the invention]

The manufacturing method of the boron carbide-2 titanium uride two-phase composite cemented carbide of the present invention involves pulverizing and mixing both boron carbide powder and 2#1 titanium uride powder for a predetermined period of time, and then forming them into a predetermined shape. After molding, in a vacuum or in a specified gas atmosphere, and at a temperature of I
J[Items must be sintered under normal pressure at 600°C to 2200°C.

[Embodiments of the invention]

The present invention will be explained in detail below.

(1) Manufacturing method of cemented carbide B4C powder passing through a 325 mesh and TiB2 powder passing through a 325 mesh are pulverized and mixed for 10 minutes in a ball mill made of WC-Co cemented carbide. Grinding and mixing is carried out by adding, in addition to the above-mentioned powder, an organic solvent such as toluene 1,6 rough-in and a suitable surfactant. Next, the entire dried powder was put into a mold and compression molded at a pressure of 2 tons/on.
It is molded to a predetermined size at cm2 to 4 ton/cm2.

The powder for molding may be granulated before use, and then pressureless sintering is performed on a table made of graphite or carbon in a sintered atmosphere or a gas atmosphere.

Vacuum level is 10"' 2mmHg -10-"mrnH
Although the sintering process is performed using light in g, sintering may be performed in a higher vacuum. In addition, the gas used when sintering in an atmospheric gas is Ar + co + B2 + N2
Gases containing T N2 and mixed gases of these gases't
You can use it for t.

The sintering temperature is 1600'C to 2200°C, and the most suitable sintering temperature is 21°C when sintering is carried out in vacuum.
It is 00℃. Sintering times range from addition to 2 hours.

(2) Composition of 84cmTi n2 used The composition of TlB2 for 84C is from 3 car t% to (a) weight%, for example 3
, 5.10, 20, 30, 40, 50° gloss, 70
+ 1a, 90 Mitchi [ ] composition. ,
(3) Characteristics of the cemented carbide obtained by the above-mentioned production method of the present invention (a) A two-phase multi-base type cemented carbide having a composition of 4C-(3 to 90) % T + 82 was obtained. .

(b) Structure As shown in FIG. 1 (a) to (k), the gray part is the B4C phase and the white part is the T i B 2 phase.

Addition to B4C~10) Removal % T IB 2 The black dot-like parts seen in the cemented carbide microstructure photographs (see Figure 1 (d) to (J)) are caused by polishing with diamond grains. This is the bit hole that occurred.

(c) Porosity B, 20 to 70) ji amount% T I 82
With a wide range of compositions, the porosity is 0.2% or less.

(d) Rockwell hardness (displayed on A scale) As shown in FIG. 2, K (3 to 60) and hardness q6 T + 82 composition shows 92.8 to 94.

(c) Micro Vickers hardness of BC phase (load 100g
) As shown in Figure 3, (3-701 heavy stitching%TI B2 composition shows 4200-57011 kg/mm2.

(4) Comparison with the conventional #edge method Although there is a report that the conventional B4C-Tl B2 alloy was carried out using a pot press at a temperature of 2100'C to 2400°C, the structure, porosity, Rockwell hardness No data are shown that can be compared with the rt results obtained by the manufacturing method of the present invention.

Currently, the hardest cutting tool materials include cubic boron nitride (CBN) composite sintered bodies and diamond composite sintered bodies. The alloy has approximately the same hardness and strength as these (see Figure 4).

Also, the transverse flexural strength r1 of the double mechanical cemented carbide of the present invention is approximately 82 kg/mm 8#, which is approximately the same as the two composite sintered bodies described above. Moreover, CBN and diamond have a pressure of (5 to 6) million atmospheres, +1400 to 16001'C.
In contrast, the double mechanical type cemented carbide of the present invention achieves the above-mentioned high hardness If' by the pressureless sintering method. Since it can be easily produced using a simple device, the manufacturing cost is also low.

[Effects of the present invention]

As described above, according to the present invention, the conventional B4C-TlB
In order to obtain a two-system two-phase composite cemented carbide, it was necessary to use a pressure sintering method such as a hot press method, but it is also possible to easily achieve density sintering by using a pressureless sintering method. This is advantageous in terms of manufacturing costs, and it also makes it possible to sinter large and complex shapes, which has an industrial effect. June 6, 1980 Kazuo Wakasugi, Commissioner of the Japan Patent Office1, Description of the case, Patent No. 89370 of 19892, Name of the invention: Boron carbide-2t1 titanium uride-based two-phase composite cemented carbide Manufacturing method 3, Relationship with the case of the person making the amendment Patent applicant: Department of Mechanical Engineering, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki Higashifuyama, Noda City, Chiba Prefecture [1. Detailed oath, drawings and certification - 5. Contents of the amendment ( 1) Request 4 Please write as shown in the attachment attached to t-11A (no funny content).

(2) Copy the document 111114 according to the attached document (no changes to the content).

(3) Print the drawing as per the attached attachment (no changes to the content).

(4) Add a document certifying that the claimed invention is an invention stipulated in Article (Capital) Paragraph 1 of the Patent Law as shown in the attached attachment.

Claims (1)

[Claims] The carbide t1 boron powder and the titanium carbide powder 2 are pulverized and mixed for a predetermined period of time, then molded into a predetermined shape, and then heated in a vacuum or in a predetermined gas atmosphere at a temperature of 1600°C to 220°C.
A method for producing a two-phase composite cemented carbide based on boron carbide-2#1 titanium uride, which comprises performing pressureless sintering at 0°C.