JPS59152267A - Manufacture of diamond sintered body - 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 The present invention relates to a method for producing a diamond sintered body suitable for cutting tools and anti-malt tools.

Conventionally, the method for manufacturing diamond sintered bodies using ultra-high pressure technology is to sinter a mixed powder of diamond powder and metal powder that dissolves diamond under high temperature and high pressure. Special Public Service as 39-2048
There are 3. In this way, when a mixed powder of diamond powder and a metal powder that dissolves the diamond is sintered under high temperature and high pressure, the finer the mixed powder becomes, especially the finer the metal powder that dissolves the diamond. The more substances that become gases at high temperatures, such as oxygen and moisture, are physically or chemically adsorbed on the surface of the powder, making it difficult to sinter under high temperature and high pressure in a sealed container, resulting in a homogeneous, high hardness product. There is a problem that it is not easy to obtain a whole sintered body.

The present invention solves the above-mentioned conventional problems and provides a manufacturing method that makes it possible to obtain a dense and highly hard diamond sintered body with ease of workability and sinterability.

The method for producing a diamond sintered body according to the present invention involves placing in a container a thin plate made of a metal or alloy in which all diamonds are melted and a diamond-containing powder green compact filled so as to be in contact with one surface of the thin plate. Pressurized heating under pressure and temperature conditions in which the diamond-containing powder compact reacts with a thin plate made of a metal or alloy that dissolves diamond within the diamond stability region or within the graphite stability region near the equilibrium line of diamond and graphite and melts. This method is followed by rapid cooling and sintering. In this way, in the method for producing a diamond sintered body, the starting material is formed into a metal or alloy metal thin plate that acts as a solvent on the diamond, and is brought into contact with a diamond-containing powder compact under ultra-high pressure and high temperature to form a thin plate. Compared to powdered metals or alloys, these metals or alloys absorb very little or almost no substances that become gaseous components such as oxygen and moisture, so the graphitization of diamond during the sintering process is completely eliminated. In addition, the sinterability is less inhibited by gas, and a thin plate made of metal or alloy is soaked in a bath and homogeneously infiltrated into the diamond-containing powder green compact, resulting in a dense and highly hard diamond sintered body. The thin plate made of metal or alloy that completely melts diamond used here is Fe, Ni, Co, etc.
, Cr, Pd.

B i, Sm, Mn, B e, Au, Ag,
, Ge, Cu.

Pr, Ba, Nd, Ce%Sr, and alloys containing these metals are considered, but Fe, Ni, CoE, and alloys containing these metals, which are effective as catalysts and solvents for diamond, are available due to price, workability, and It is also suitable from the viewpoint of ease of sintering. Thin plates made of Fe, Ni, Co and alloys of these metals are
Alloys include stainless steel and Senda 71 various alloy steels, Ni-based alloys include Inconel, Hastelloy, Permalloy, Monel, etc., CO-based alloys include Stellite, and various other brazing materials. However, these thin plates are selected depending on the use of the diamond sintered body, such as cutting tools, depending on the cutting conditions, including the rigidity of the material to be used, and wear-resistant tools, such as dies, cutting blades, cutting blades, and friction-wearing uses. It's good.

The diamond-containing powder compact as a starting material may be made of only diamond powder, but since diamond is very expensive, a sintered body made of a powder compact that contains as little diamond as possible is suitable for diamond-containing powder compacts. It is desirable that the properties be the same as those of a sintered body made of a powder green compact made only of powder, and one method for achieving this is to include graphite in an amount of 30 vol. or less relative to the diamond content of the diamond-containing powder green compact. Powder green compacts are made by melting and infiltrating thin plates made of metals or alloys, especially iron group metals or iron group metal-containing alloys, in which diamond is completely dissolved during the sintering process under high temperature and high pressure. It is converted into a highly hard and homogeneous diamond sintered body. Here, too, the thin plate made of iron group metal or iron group metal 6 negative metal-containing alloy does not adsorb substances that become gas components at high temperatures, such as oxygen or moisture, so it is easily infiltrated into the powder compact containing all graphite. At the same time, the graphite reduces the melting eccentricity of the thin plate, thereby promoting sinterability, and furthermore, the catalytic action of the thin plate made of an iron group metal or an iron group metal-containing alloy facilitates the conversion of graphite into diamond.

The graphite used here had a volume ratio of 30% or less relative to diamond, since graphite remains in the sintered body when the volume exceeds 30%, resulting in decreased hardness and increased brittleness.

As another method, the diamond content of the diamond-containing powder compact is 43% of the periodic table with a value of 70 valleys or less.
5 a y 5 carbides, nitrides, carbonitrides, borides of group A metals and their mutual solid solutions, as well as CBN, W
The powder green body selected from BN and containing all of the hard material of fct or more is a thin plate made of a metal or alloy, particularly an iron group metal or an iron group metal-containing alloy, which completely melts diamond in the sintering process under high temperature and pressure. Melting and infiltration improves wettability with the hard substance, promotes sinterability, and produces a homogeneous sintered body. In this way, a diamond sintered body containing a mixture of diamond and the above-mentioned hard substance has lower hardness and wear resistance than a diamond sintered body that does not contain a hard substance, but has improved grindability. Therefore, the production cost of the tool is reduced, and since it is covered by a diamond-gold hard substance that easily reacts with steel, it can be fully expected for some applications.

For the diamond-containing powder green compact, the thin plate made of a metal or alloy that completely melts the diamond, and the container into which the entire diamond is inserted, high-melting point metals from Groups 4a45a and 6a of the periodic table can be used, and metals from Group 4a, which have particularly good gas absorption properties, can be used. T1, Zr, and Hf are preferred.

In the method for producing a diamond sintered body of the present invention, the thermodynamic diamond stability region or the graphite stability region near the equilibrium line between diamond and graphite is preferably within the range of pressure 40 to 60 Kb and temperature 1200 to 1600°C, particularly By using a thin plate made of a metal or alloy that dissolves diamond, as in the method for producing a diamond sintered body of the present invention, pretreatment such as degassing is not necessary, and dense sintering can be achieved at lower pressure and lower temperature than conventional methods. You can get a solid body.

Next, a detailed explanation will be given according to an example.

Example 1 A cylindrical container made of Zr with an inner diameter of 11 ψ and a wall thickness of 0.15 mm was completely filled with 1.0 g of polycrystalline diamond powder of 4 to 8 μm in size, and a 00 disc of 11 ψ x 0.5 mm was brought into contact with the powder, and then a 11 ψ x 0.15 m A capsule capped with a Zr disk was placed in an ultra-high pressure device and heated to 153 Kb at a pressure of 55 Kb.
After being held at 0°C for 30 minutes, the pressure was rapidly cooled to below 1200°C while maintaining the pressure at 55 Kb, and then both the pressure and temperature were lowered to room temperature and pressure, and the sintered body was taken out. This sintered body was entirely polished to obtain a disk-shaped sintered body measuring 11ψ×2.5 mm. This sintered body has no pores or cracks, has a hardness of 6700 on the Nunib hardness, and has a structure in which diamond particles are bonded to each other, with a total volume of approximately 10 between the particles. It had a uniform structure with a CO phase of . The particle size of the diamond particles was larger than that of the starting material powder. This is Daikimo 9 before sintering
This was thought to be due to fracture of paved particles, plastic deformation, and dissolution precipitation of diamond particles during sintering.

Example 2 In the manufacturing method of Example 1, JI8Z was used instead of the 00 disc.
-3265 B? A Ni-based brazing filler metal disk 11ψXQ, 5mi corresponding to l-2 was used, and the sintering conditions were a pressure of 45Kb.

Sintering was carried out at a temperature of 1380°C and a holding time of 30 minutes, with the other conditions being the same as in Example 1. In the obtained sintered body, the diamond powder was strongly sintered, and the hardness of the diamond layer was 6600 in Knoop hardness.

Example 3 In the manufacturing method of Example 2, instead of the Ni-based brazing filler metal disk, a palladium brazing disk 11ψ×1 size corresponding to BPd-12 of JI8Z-3267, JI8Z-32660BA was used.
Gold solder disc 11φX0.3mm and A corresponding to u-3
CO-based brazing disk 11ψX0 corresponding to BCo-1 of W8
．． Sintering was performed under the same manufacturing conditions as in Example 2 using 5+gi. Each of the obtained sintered bodies was a dense sintered body in which the diamond powder was strongly sintered, and the Knoop hardness was 6500, 6400, and 660010 pages, respectively.

Example 4 In the manufacturing method of Example 1, instead of the 00 disk, a N1 disk 11ψ×0.2 size, a disk 11ψxo equivalent to 5US304 was used.
, smm, disk equivalent to No. Steroid B 11ψX 0.5
mm.

Disc 11ψX0.5a true equivalent to Inconel X-550,
Disc 11ψ×0.5 mm equivalent to hard stellite,
8 i - Disc 11 corresponding to At-containing Sendust alloy
Sintering was carried out under the same manufacturing conditions as in Example 1 using disks 11ψXQ and 5azi corresponding to S-monel alloy containing ψX0,5+m and Ni-Cu-8i, respectively. Each of the obtained sintered bodies was a dense sintered body in which the diamond powder was strongly sintered, and each exhibited a Knoop hardness of 6000 or more.

Example 5 In the manufacturing method of Example 1, instead of the 4-8 μm polycrystalline diamond powder, a mixed powder consisting of 70 volumes of 4-8 μm polycrystalline diamond powder and 30 volumes of graphite powder with an average particle size of 57 Im was used. The entire sintering process was carried out in the same manner as in Example 1, with the other manufacturing conditions being the same as in Example 1. The obtained sintered body is
Linear diffraction and 11-page inspection of the assembly showed that no graphite remained and the hardness was 6500 on the salt Knoop hardness, which was approximately the same as the sintered body of Example 1.

Example 6 Under the manufacturing conditions of Example 1, instead of the 4-8 μm polycrystalline diamond powder, 50 volumes of 4-8 μm polycrystalline diamond powder and 30 volumes of 4-8 μm CBN powder were used.
A mixed powder consisting of 20 volumes of 'fiCN powder of ~2 μm was used, and the other manufacturing conditions were the same as in Example 1.
I did it. The obtained sintered body is strongly sintered,
The Knoop hardness was also 5700'i.

Example 7 Under the production conditions of Example 1, 35 volumes of 4-8 μm polycrystalline diamond powder, 50 volumes of 4-8 μm CBN powder, and graphite powder with an average particle size of 5 μm were used in place of the 4-8 μm polycrystalline diamond powder. Sintering was carried out in the same manner as in Example 1, using a mixed powder consisting of 30 vol. The obtained sintered body is strongly sintered,
The Knoop hardness was also 5700 according to JP-A-59-152267 (4).

Claims (1)

[Scope of Claims] (11) A thin plate made of a metal or alloy capable of melting diamond and a diamond-containing powder green compact packed in contact with one surface of the thin plate are placed in a container to ensure that the diamond is within the thermodynamic diamond stability range. Alternatively, diamond is sintered by heating under pressure and then rapidly cooling within a graphite stability region near the equilibrium line of diamond and graphite and under pressure and temperature conditions where the thin plate and the powder compact react and melt. A method for producing a sintered body. (2) A method for producing a diamond sintered body according to claim 1, wherein the thin plate is made of an iron group metal or an alloy containing an iron group metal. A method for manufacturing a diamond sintered body according to claims 1 and 2, characterized in that the diamond-containing powder compact contains graphite in an amount of 30 volumes or less relative to the diamond content. 4) The diamond-containing powder green compact contains carbides, nitrides, carbonitrides, borides, and mutual solid solutions of metals of Groups 4ah, 5a, and 5a of the periodic table whose volume is 70 or less with respect to the diamond-containing lid. , as well as CBN, WB
The method for producing a diamond sintered body according to claims 1, 2, and 3, characterized in that 1ai or more selected from N is contained.