JPS63190756A - Manufacture of high density diamond mass - 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 [Industrial Application Field] The present invention relates to a method for manufacturing diamond enrichment used in various tools such as cutting tools, excavating tools, dressers, and the like.

[Prior Art] Currently, sintered bodies in which diamond particles are bonded to each other with a diamond-containing skewer of 70% or more are sold, and are used for cutting non-ferrous metals, plastics, ceramics, dressers, etc.
Used as drill bits and wire drawing dies.

For example, Japanese Patent Publication No. 52-12126 discloses a method for manufacturing this type of sintered body. There, diamond powder is placed in contact with a compact or sintered body of WC-Co cemented carbide, and sintering is performed at a temperature higher than the temperature at which the liquid phase of the cemented carbide occurs and under ultra-high pressure. At this time, a part of the CO in the cemented carbide penetrates into the diamond powder layer and acts as a bonding metal. The diamond sintered body made by the method disclosed in this prior art is about 10 to
Contains 15% CO by volume.

Although this sintered body has sufficient practical performance as a cutting tool for non-ferrous metals, it has the disadvantage of poor heat resistance. For example, when this sintered body is heated to 750°C or higher, a decrease in wear resistance and strength is observed;
If the temperature exceeds ℃, the sintered body will be destroyed. The reason for this is thought to be that graphitization of the diamond occurs at the interface between the diamond particles and the binder CO, and thermal stress due to the difference in coefficient of thermal expansion when the two are heated.

Furthermore, it is known that when a sintered body using CO as a binder is treated with an acid to remove most of the binding metal phase, the heat resistance of the sintered body is improved. For example, JP-A-53-1
Japanese Patent No. 14589 discloses a method for producing a diamond sintered body with improved heat resistance. However, in this case, the removed portions of the bonded metal phase become pores, which inevitably leads to a decrease in strength.

On the other hand, attempts have been made to sinter only the powder from die t7-End under ultra-high pressure, but since the diamond particles are difficult to deform, pressure is not transmitted to the gaps between the particles, resulting in graphitization. Only 1q of die A7-graphite coalescence was formed.

[Problems to be solved by the invention] When a diamond sintered body is used for a tool, especially for cutting hard rocks or ceramics, the diamond sintered body that becomes the cutting edge is high stress is applied and the temperature rises.

Therefore, in such applications, a sintered body that is heat resistant and has high strength and wear resistance is required.

However, the diamond sintered bodies according to the above-mentioned conventional techniques each have the above-mentioned drawbacks, and a sintered body with sufficient heat resistance, strength, and wear resistance cannot be obtained.

An object of the present invention is to provide a diamond carrier having sufficient heat resistance, strength, and wear resistance.

[Means for Solving the Problems] The present invention provides 0.1 to 3.0% by volume of iron group metals, Cr, Mn, Ta, and other metals by electroless plating on the surfaces of individual particles of diamond powder. Production of a high-density diamond carrier characterized by coating it with one or more of the following alloys to form a coated diamond powder, and subjecting the coated diamond powder to a sintering treatment under ultra-high pressure and high temperature conditions in which the diamond is stable. There is a method.

It should be noted that the diamond powder has an individual particle size of 0.5 to
It may be a graphitized diamond powder in which 80% by volume is graphite from the surface side. Further, by subjecting the coated diamond powder to a high temperature treatment under conditions where diamond is unstable, 0.5 to 80% by volume of each particle is phase-transformed from the surface side to graphite, and then the above-mentioned sintering treatment is performed. You can do it like this.

[Description of Means] The diamond powder which is the starting material of this invention may be either natural or synthetic. Preferably, part or all of the particle surface is graphitized, and more preferably, 0.5 to 8015 FJ% of the surface is graphitized.

There are two reasons for using diamond particles whose surfaces are graphitized as a raw material. That is, (1) the die is difficult to deform plastically, so voids remain between the individual particles even under ultra-high pressure, and the pressure applied to the diamond becomes partially unstable, resulting in a decrease in sinterability. However, if the surface is graphitized, the graphitized portion fills the voids, so no drop in effective pressure occurs. Also,
■In the reaction process of "dissolving the carbon raw material in the binder → precipitating as diamond", graphite has a lower chemical potency than diamond, so the dissolving carbon raw material has a higher ability to dissolve in the binder, High reaction speed.

In order for these effects to be noticeable, it is necessary to have a particle size of 0.5 to 0.5 b. This is because if the graphitization m is less than 0.5% by volume, the increase in packing density is insufficient and the bond between diamond particles in the synthesized sintered body becomes weak. This is because if the amount is more than 80% by volume, only a low-strength sintered body with residual graphite will be obtained.

13. Diamond powder with a graphitized surface is prepared by drying diamond powder in vacuum or in an inert gas atmosphere.
It can be easily obtained by exposing it to high temperatures of 400°C or higher.

The diamond powder is thoroughly degreased and washed in an organic solvent. This powder is immersed in a plating pretreatment solution,
Several ppm of Pd, Rh, etc. are precipitated and activated. After washing the treated powder with water, it is immersed in an electroless plating solution consisting of an iron group metal, CrSMn1Ta, and one or more of these metals. The metal or alloy is deposited on each powder in a desired container for a certain period of time, and then collected. In order to uniformly coat the powder, it is effective to stir the plating solution at high speed during the plating process. The metals or alloys to be plated are most preferably those listed above, but commercially available electroless plating solutions that contain B or P may also be used within a composition ratio that does not impair the properties of the sintered body. If so, don't use it.

The diamond powder coated with 0.41 to 3.0 volume % of iron group metals, Cr, Mn, Ta, and one or more of these alloys thus obtained is subjected to a known high-pressure process such as a belt-type device. Using a generator, the diamond is exposed to pressure and temperature conditions for several minutes under which the diamond is thermodynamically stable and the binder exhibits a catalytic action to form a die.During this time, the graphite on the surface of the raw diamond powder is transferred to the binder. By rapidly dissolving and precipitating as diamond, bonding between diamond particles progresses.

In the recovered diamond mass, the diamond particles are strongly bonded to each other, and the metal or alloy coated on the surface of the raw material Daimaru 7 is dispersed and dotted at the grain boundaries. The obtained carrier does not crack even when heated at 1100° C. in a vacuum, and has high heat resistance.

[Example 1] As a starting material, synthetic diamond powder having an average particle size of 20 μm was heat-treated at 1500° C. for 30 minutes in a vacuum (5xl Q-' torr). A constant ffi evaluation using X-ray analysis revealed that 20% by volume of each particle surface of this powder was graphite. After thoroughly washing this powder with trichlene and ethyl alcohol, it was first added to a plating pretreatment agent to reduce Rd by 3 p.
pm was precipitated. After collecting and washing with water, it was immersed in a plating solution having the composition shown in Table 1. This liquid was kept at 50°C and metal or alloy was deposited for 60 minutes.

Table 1 also shows the results of chemical analysis of the metal coating properties of the recovered powder.

(Left below) Each of these powders was sealed in a container made of Ta, and using a belt-type ultra-high pressure device, the pressure cuff was 0 Kb and the temperature was 1600°C.
It was held for 5 minutes and sintered.

As a result, a sintered body was recovered except for the No. and E powders, but sufficient sintered bodies were not obtained for the No. and E powders.

When the obtained sintered body was subjected to X-ray analysis, it was found that No.
No graphite residue was observed in the samples using powders other than NO, but a small amount of graphite remained in the samples using NO and E powders. This is considered to be because the amount of N1 coated on the No. and E powders was less than the prescribed amount of the JJ manufacturing method of the present invention, so that the conversion from graphite to diamond was not sufficiently performed.

Next, a sintered body made of NO, 8 to D was processed to make a cutting tip yJ, and an alumina sintered body with a Vickers hardness of 2000 was cut to evaluate the performance.

Table 2 shows the wear width of the tool flank using a commercially available sintered body containing about 10% CO as a comparative material. In addition, cutting speed 50m/min, depth of cut 0゜5mm, feed 0.05
Cutting was carried out under dry conditions at ++u++/rpm and cutting time of 15 minutes.

(The following is a blank space) The sintered bodies NO and C have less Co-containing skewers than the comparative materials, so their heat resistance and abrasion resistance are somewhat improved.

It can be seen that the performance of Nos., A, B, and D obtained by the method of the present invention is dramatically improved.

[Example 2] Natural Guin 17T powder with a particle size of 10 to 12 μm was used as a starting material. This was treated with Ni-C in the same manner as in Example 1.
It was processed by putting it into a plating solution of o alloy (composition ratio: 7:3 by volume). , alloying liquid 1f to the powder recovered in Table 3
Indicates fi. These powders were prepared in vacuum at <4
torr). Table 3 also shows the results of determining the diameter of the black yari-forming skewer of the powder under the conditions and treatment using X-ray analysis.

These powders are processed into 60Kb using a belt type high pressure generator.
, sintered at 1500°C for 30 minutes.

As a result, graphite remained in samples No. and I and the samples were unsintered, but the others were solid sintered bodies. Table 4 shows the results of measuring the density of these sintered bodies using the Archimedes method. Note that the sintered bodies of NO, F, H, and J are all stored in vacuum (
It showed heat resistance of 1100° C. at 2X 10-' torr), but cracks appeared in NO and G, which have a high alloy content.

[Effects of the Invention] According to the method of the present invention, excellent heat resistance and excellent heat resistance as tool materials for cutting tools, drilling tools, wire drawing dies, dressers, etc.
A diamond cleaning body having wear resistance can be obtained. In particular, the heat resistance, which was a drawback of conventional diamond sintered bodies, can be significantly improved without reducing the strength, so the range of application and performance as tool materials are dramatically improved.

Claims (3)

[Claims] (1) The surface of each individual particle of diamond powder is coated with 0.1 to 3.0 volume % of iron group metal, Cr, etc. by electroless plating method.
, Mn, Ta, and one or more of these alloys to form a coated diamond powder, and the coated diamond powder is subjected to a sintering treatment under ultra-high pressure and high temperature conditions in which the diamond is stable. A method for producing a dense diamond mass. (2) The diamond powder has an individual particle size of 0.5 to
2. The method for producing a high-density diamond mass according to claim 1, wherein the powder is graphitized diamond powder in which 80% by volume is graphite from the surface side. (3) The coated diamond powder is treated at high temperature under conditions where diamond is unstable, so that individual particles can be reduced to zero.
2. The method for producing a high-density diamond mass according to claim 1, wherein the sintering treatment is performed after 5 to 80% by volume undergoes a phase transition to graphite from the surface side.