CN111961938A

CN111961938A - Application of pure iron-based matrix to preparation of diamond tool bit and preparation method of diamond tool bit

Info

Publication number: CN111961938A
Application number: CN202010954348.XA
Authority: CN
Inventors: 赵景学; 毕琨; 郑一平
Original assignee: Chengdu Shijia Huanjing Technology Co ltd
Current assignee: Chengdu Shijia Huanjing Technology Co ltd
Priority date: 2020-09-11
Filing date: 2020-09-11
Publication date: 2020-11-20
Anticipated expiration: 2040-09-11
Also published as: WO2022052990A1; US20230313348A1; CN111961938B; EP4212640A1

Abstract

The invention provides application of a pure iron-based matrix to preparation of a diamond tool bit and a preparation method of the diamond tool bit. The present invention uses diamond tips made from a pure iron-based matrix made from iron powder having an average particle size of 1-25 μm in different scenarios. The invention uses the iron powder with the average grain diameter of 1-25 μm to shorten the movement distance of iron ions, so that the activity of the iron powder is greatly enhanced, the hardness and the strength of the diamond tool bit are favorably improved, and the retentivity and the wear resistance of diamond can be increased; in addition, the invention also controls the hot-pressing sintering temperature of the diamond tool bit at the temperature of 700-; thereby obtaining the diamond tool bit with excellent comprehensive performance and low price.

Description

Application of pure iron-based matrix to preparation of diamond tool bit and preparation method of diamond tool bit

Technical Field

The invention relates to the technical field of diamonds, in particular to application of a pure iron-based matrix to preparation of a diamond bit and a preparation method of the diamond bit.

Background

The diamond tool has the characteristics of high sharpness, high hardness, strong wear resistance and the like, and is widely applied to the industries of buildings, automobiles, geology, machinery, electronics, metallurgy, ceramics and the like. The diamond tool is composed of a substrate and a diamond tool bit, wherein the substrate mainly plays a supporting role, and the diamond tool bit mainly plays a cutting role. The tire body used in the diamond tool bit in the current market can be roughly divided into a Co-based tire body, a Fe-based tire body, a Cu-based tire body and a Ni-based tire body according to the main components of the tire body. The Co-based tire body has excellent red hardness, embedding capability and self-sharpening property, so the Co-based tire body has the best comprehensive performance. However, Co is a strategically scarce resource, and its use in diamond tips is greatly limited due to its high cost and large fluctuating price. In addition, elements such as Co, Ni and the like cause environmental pollution, the pollutants are also internationally limited to enter the formula of the diamond matrix, Fe and Co belong to the same group elements, have similar crystal structures and performances, but are much lower in price, and the reduction of the cost by replacing Co with iron is always the green development trend of the diamond tool bit. According to the records of 'the influence of Ni and Sn on the matrix structure and the performance of a Fe-based diamond tool' D 'by the general institute of mechanical science, 2018', due to the fact that the wear resistance of pure iron is low, the inertial thinking of research and development personnel is to add additives into the Fe-based matrix according to the problems of the Fe-based matrix and the application scenes of manufacturing diamond tool bits by the Fe-based matrix, wherein the additives can be alloying elements which react with the Fe-based matrix and can also be some wear-resistant components. For example, eutectic elements P, Zn and Sn can improve the sintering density of the sintered Fe-based matrix and improve the sintering quality; and for example, lanthanum, beryllium and the like in the strengthening components can improve the comprehensive properties of hardness, strength, wear resistance and the like of the sintered Fe-based matrix. But this approach is to improve Fe-based carcass performance at a sacrifice in cost. If the best balance between cost and performance of diamond tips could be achieved, it would be a qualitative leap forward for the development of diamond tips, but there is currently no report or literature on how to achieve this balance.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention aims to provide the application of the pure iron-based matrix with good comprehensive performance and low price for preparing the diamond tool bit.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

use of a pure iron-based matrix made of iron powder having an average particle size of 1-25 μm for the preparation of a diamond tip.

The invention also aims to provide a preparation method of the diamond tool bit, which comprises the following steps:

step S1: firstly, mechanically mixing iron powder and diamond, and fully mixing to obtain a mixture; wherein the mass fraction of the iron powder with the average grain diameter of 1-25 μm in the iron powder is more than or equal to 40 percent, and the volume of the diamond is 25-30 percent of the volume of the iron powder;

step S2: and (5) carrying out hot-pressing sintering forming on the mixture obtained in the step S1 and cooling to obtain the diamond tool bit.

Preferably, the temperature of the hot-pressing sintering is 700-²。

Preferably, in the step S1, the diamond is wetted by the wetting agent and then mechanically mixed with the iron powder; wherein the wetting agent is engine oil or paraffin wax.

Preferably, in the step S1, a binder with a mass of 1.2-2.2% of that of the iron powder is further added to be mechanically mixed with the diamond and the iron powder; wherein, the binder is polyethylene glycol or polyvinyl alcohol.

Correspondingly, the invention also provides a preparation method of the diamond tool bit, which comprises the following steps:

step C1: firstly, mechanically mixing iron powder and diamond, and fully mixing to obtain a mixture; wherein the mass fraction of the iron powder with the average grain diameter of 1-25 μm in the iron powder is more than or equal to 40 percent, and the volume of the diamond is 25-30 percent of the volume of the iron powder;

step C2: preparing the mixture obtained in step C1 to a density of 3.95-6.29g/cm³The blank of (2);

step C3: and C, pressureless sintering and forming the blank obtained in the step C2, and cooling to obtain the diamond tool bit.

Preferably, the pressureless sintering temperature in the step C3 is 900-.

Preferably, in the step C1, the diamond is wetted by the wetting agent and then mechanically mixed with the iron powder; wherein the wetting agent is engine oil or paraffin wax.

Preferably, a binder with the mass of 1.2-2.2% of the mass of the iron powder is also added in the step C1 to be mechanically mixed with the diamond and the iron powder; wherein, the binder is polyethylene glycol or polyvinyl alcohol.

Compared with the prior art, the invention has the following beneficial effects:

(1) the diamond tool bit is manufactured by selecting a pure iron-based matrix made of iron powder with the average grain diameter of 1-25 mu m. Because the iron powder with the average grain diameter of 1-25 mu m has strong activity and higher mechanical property, the movement distance of iron ions can be shortened, the hardness and the strength of the high-purity iron-based matrix can be favorably improved, and the holding power and the wear resistance of the pure iron-based matrix to diamond can be increased. The traditional thinking that some other elements are needed to be added to change the performance of the iron-based matrix in order to improve the performance of the high-purity iron-based matrix in the prior art is broken through, so that the preparation cost of the diamond tool bit is really reduced, and the market share of the diamond tool bit prepared by the method is enlarged.

(2) Because the coarse iron powder has strong affinity to carbon at high temperature (1000 ℃), iron and diamond in the iron-based matrix form FeC (cementite) in the sintering process of the diamond tool bit, but iron and graphite form carbon are partially decomposed in the cooling process, so that the surface of the diamond is graphitized, and the holding force of the pure iron-based matrix on the diamond is reduced. When the diamond tool bit is prepared by selecting the pure iron-based matrix consisting of the iron powder with the average grain diameter of 1-25 mu m, the hot-pressing sintering temperature is controlled to be 700-.

(3) The applicant finds that the cost of the diamond tool bit prepared by the pure iron-based matrix with the average grain diameter of 1-25 μm is 10-30% of the preparation cost of other diamond tool bits with the same performance (such as diamond tool bits prepared by Co-based matrix, Fe-based matrix added with other elements, Cu-based matrix or Ni-based matrix) in the market through market research and development in the early stage. The method realizes the real low-cost manufacture of the diamond tool bit and breaks the traditional rule of the industry. The invention has the advantages of ingenious and reasonable design, simple appearance, difficult realization of thinking, and really realizing the optimal balance between the technology and the cost only through deep research and combination of the characteristics of the iron-based tire body. The invention not only breaks through the limitation of the prior art, accords with the trend of scientific and technological development, realizes innovation, but also improves the preparation means of the diamond tool bit to a new height. Therefore, compared with the prior art, the invention has obvious technical progress, and has outstanding substantive characteristics and remarkable progress.

(4) The pure iron-based matrix can be used for preparing the diamond tool bit with optimal performance and low price in the application scene by selecting different preparation methods according to the application scene of the diamond tool made of the diamond tool bit, so that different requirements of the diamond tool bit on the market from low to high performance are met, and the market share of the diamond tool bit prepared by the method is increased.

Drawings

Figure 1 is an SEM image of diamond in a pure iron based matrix made of iron powder with an average particle size of 1-3 μm.

Detailed Description

Iron powder:

the iron powder described in the following examples is from Yaan Shijia micro technology, Inc., and the oxygen content in the iron powder having an average particle size of 1-25 μm in the examples of the present invention is 2000-7000 PPM. The atomized iron powder and reduced iron powder are from GKN company.

Example (b):

the technical solution of the present invention will be further clearly and completely described in the following examples and comparative examples, wherein the raw materials used in the examples of the present invention and the preparation raw materials are all commercially available.

Example 1

A preparation method of a diamond tool bit specifically comprises the following steps:

step S1: firstly, weighing diamond and iron powder according to a proportion, then wetting the iron powder by using liquid paraffin or engine oil, then filling the wetted diamond and iron powder into a storage bin, mechanically mixing for 60-90min, and fully mixing to obtain a mixture; wherein the iron powder is iron powder with average particle size of 1 μm, and the volume of the diamond is 25% of that of the iron powder.

Step S2: loading the mixture obtained in the step S1 into a graphite or steel mold, performing hot-pressing sintering at 700 ℃, and keeping the temperature for 90-120S, wherein the pressure of the hot-pressing sintering is 200-²And after sintering, cooling to obtain the diamond tool bit.

And the diamond segments prepared in example 1 were made into diamond terrace grinding blocks.

Example 2

step S1: firstly, adding iron powder, diamond and adhesive into a feed bin according to a certain proportion, rolling and mixing for 30-60min, sieving to obtain spherical particle mixture with average particle size of 60-100 meshes, then filling the spherical particle mixture into a steel die, and placing the steel die under the condition of pressure of 0.5-5.5t/cm²Cold pressing to density of 3.95-6.29g/cm³The blank of (2); wherein the iron powder is iron powder with average particle size of 1 μm, the volume of diamond is 25% of the volume of the iron powder, the binder is 1.2-2.2% of the weight of the iron powder, and the binder is PEG (polyethylene glycol) or PVA (polyvinyl alcohol).

Step S2: loading the blank obtained in the step S1 into a graphite die, carrying out hot-pressing sintering at 700 ℃, and keeping the temperature for 90-120S, wherein the pressure of the hot-pressing sintering is 200-²And after sintering, cooling to obtain the diamond tool bit.

And the diamond tips prepared in example 2 were made into coring thin wall water drill bits.

Example 3

step S1: firstly, adding iron powder, diamond and adhesive into a feed bin according to a certain proportion, rolling and mixing for 30-60min, sieving to obtain spherical particle mixture with average particle size of 60-100 meshes, then filling the spherical particle mixture into a steel die, and placing the steel die under the condition of pressure of 0.5-5.5t/cm²Cold pressing to density of 3.95-6.29g/cm³The blank of (2); wherein the iron powder is 25 μm in average particle size, the volume of the diamond is 25% of the volume of the iron powder, the binder is 1.2-2.2% of the mass of the iron powder, and the binder is PEG or PVA.

Step S2: loading the blank obtained in the step S1 into a graphite die, carrying out hot-pressing sintering at 860 ℃, and keeping the temperature for 90-120S, wherein the pressure of the hot-pressing sintering is 200-²And after sintering, cooling to obtain the diamond tool bit.

And the diamond segments prepared in example 3 were made into diamond road saw blades.

Example 4

step S1: firstly, adding iron powder, diamond and adhesive into a feed bin according to a certain proportion, rolling and mixing for 30-60min, sieving to obtain spherical particle mixture with average particle size of 60-100 meshes, then filling the spherical particle mixture into a steel die, and placing the steel die under the condition of pressure of 0.5-5.5t/cm²Cold pressing to density of 3.95-6.29g/cm³The blank of (2); wherein the iron powder is iron powder with the average grain diameter of 8 mu m, the volume of the diamond is 30 percent of the volume of the iron powder, the binder is 1.2 to 2.2 percent of the mass of the iron powder, and the binder is PEG or PVA.

Step S2: loading the blank obtained in the step S1 into a graphite die, carrying out hot-pressing sintering at 765 ℃, and keeping the temperature for 90-120S, wherein the pressure of the hot-pressing sintering is 200-²And after sintering, cooling to obtain the diamond tool bit.

And the diamond segments prepared in example 4 were made into diamond ceramic water-grinding wheels.

Example 5

step S1: firstly, adding iron powder, diamond and adhesive into a feed bin according to a certain proportion, rolling and mixing for 30-60min, sieving to obtain spherical particle mixture with average particle size of 60-100 meshes, then filling the spherical particle mixture into a steel die, and placing the steel die under the condition of pressure of 0.5-5.5t/cm²Cold pressing to density of 3.95-6.29g/cm³The blank of (2); wherein the iron powder is iron powder with average particle size of 1-3 μm, the volume of diamond is 25% of the volume of the iron powder, the binder is 1.2-2.2% of the mass of the iron powder, and the binder is PEG or PVA.

Step S2: loading the blank obtained in the step S1 into a graphite die, carrying out hot-pressing sintering at 750 ℃, and keeping the temperature for 90-120S, wherein the pressure of the hot-pressing sintering is 200-²And after sintering, cooling to obtain the diamond tool bit.

And the diamond tips prepared in example 5 were made into coring thin wall water drill bits.

Example 6

step C1: firstly, adding iron powder, diamond and adhesive into a bin according to a certain proportion, rolling and mixing for 30-60min, and sieving to obtain a spherical particle mixture with the average particle size of 60-100 meshes; wherein the iron powder is iron powder with the average grain diameter of 1-3 μm, the volume of the diamond is 30% of the volume of the iron powder, the binder is 1.2-2.2% of the mass of the iron powder, and the binder is PEG or PVA.

Step C2, the spherical particle mixture obtained in step C1 is charged into a steel mold under a pressure of 0.5 to 5.5t/cm²Cold pressing to density of 3.95-6.29g/cm³The blank of (1).

Step C3: and D, placing the blank obtained in the step C2 into a graphite boat, sintering without pressure at 920 ℃, keeping the temperature for 30-60min, and cooling after sintering to obtain the diamond tool bit.

And the diamond segments prepared in example 6 were made into diamond road saw blades.

Example 7

step S1: firstly, performing ball milling and mixing on iron powder and reduced iron powder for 30min, then proportionally filling the mixture and diamond into a storage bin, mechanically mixing for 60-90min, and fully mixing to obtain a mixture; wherein the iron powder comprises iron powder with the average particle size of 1-3 mu m and reduced iron powder with the average particle size of 150 mu m, the mass ratio of the iron powder with the average particle size of 1-3 mu m to the reduced iron powder is 50:50, the volume of the diamond is 25% of the volume of the iron powder, and the diamond needs to be wetted by liquid paraffin or engine oil before mechanical mixing.

Step S2: loading the mixture obtained in the step S1 into a graphite or steel mold, performing hot-pressing sintering at 780 ℃, and keeping the temperature for 90-120S, wherein the pressure of the hot-pressing sintering is 200-²And cooling to obtain the diamond tool bit after sintering.

And the diamond tips prepared in example 7 were made into diamond ceramic blocks.

Example 8

step S1: firstly, performing ball milling and mixing on iron powder and reduced iron powder for 30min, then proportionally filling the mixture and diamond into a storage bin, mechanically mixing for 60-90min, and fully mixing to obtain a mixture; wherein the iron powder comprises iron powder with the average particle size of 1-3 mu m and reduced iron powder with the average particle size of 48 mu m, the mass ratio of the iron powder with the average particle size of 1-3 mu m to the reduced iron powder is 70:30, the volume of the diamond is 30% of the volume of the iron powder, and the diamond needs to be wetted by liquid paraffin or engine oil before mechanical mixing.

And the diamond tips prepared in example 8 were made into diamond terrace grinding blocks.

Example 9

step S1: firstly, performing ball milling and mixing on iron powder and reduced iron powder for 30min, then proportionally filling the mixture and diamond into a storage bin, mechanically mixing for 60-90min, and fully mixing to obtain a mixture; wherein the iron powder comprises iron powder with the average grain diameter of 1-3 mu m and reduced iron powder with the average grain diameter of 75 mu m, the mass ratio of the iron powder with the average grain diameter of 1-3 mu m to the reduced iron powder is 40:60, the volume of the diamond is 25 percent of the volume of the iron powder, and the diamond needs to be wetted by liquid paraffin or engine oil before mechanical mixing.

Step S2: loading the mixture obtained in the step S1 into a graphite or steel mold, performing hot-pressing sintering at 810 ℃, and keeping the temperature for 90-120S, wherein the pressure of the hot-pressing sintering is 200-²And cooling to obtain the diamond tool bit after sintering.

And the diamond tips prepared in example 9 were made into diamond terrace abrasive blocks.

Example 10

step S1: firstly, ball-milling and mixing iron powder and reduced iron powder for 30min, then proportionally filling the mixture and diamond into a storage bin, mechanically mixing for 30-60min, fully mixing to obtain a powder mixture, then filling the obtained powder mixture into a steel die, and putting the pressure of the powder mixture into the steel die to be 0.5-5.5t/cm²Cold pressing to density of 3.95-6.29g/cm³The blank of (2); wherein the iron powder comprises iron powder with the average particle size of 1-3 mu m and reduced iron powder with the average particle size of 40-50 mu m, the mass ratio of the iron powder with the average particle size of 1-3 mu m to the reduced iron powder is 50:50, the volume of the diamond is 25% of the volume of the iron powder, and the diamond needs to be wetted by liquid paraffin or engine oil before mechanical mixing.

Step S2: loading the blank obtained in the step S1 into a graphite die, carrying out hot-pressing sintering at 780 ℃, and keeping the temperature for 90-120S, wherein the pressure of the hot-pressing sintering is 200-²And after sintering, cooling to obtain the diamond tool bit.

And the diamond tips prepared in example 10 were made into coring thin wall water drill bits.

Example 11

step C1: firstly, performing ball milling and mixing on iron powder and reduced iron powder for 30min, then proportionally filling the mixture and diamond into a storage bin, mechanically mixing for 30-60min, and fully mixing to obtain a powder mixture; wherein the iron powder comprises iron powder with the average grain diameter of 1-3 mu m and reduced iron powder with the average grain diameter of 40-50 mu m, the mass ratio of the iron powder with the average grain diameter of 1-3 mu m to the reduced iron powder is 50:50, the volume of the diamond is 30% of the volume of the iron powder, and the diamond needs to be wetted by liquid paraffin or engine oil before mechanical mixing.

Step C2, the powder mixture obtained in step C1 is put into a steel die under a pressure of 0.5-5.5t/cm²Cold pressing to obtain blank with density of 70-80%.

Step C3: and D, placing the blank obtained in the step C2 into a graphite boat, sintering without pressure at 960 ℃, preserving heat for 30-60min, and cooling after sintering to obtain the diamond tool bit.

And the diamond segments prepared in example 11 were formed into stone saw blades.

Example 12

step S1: firstly, ball-milling and mixing iron powder and atomized iron powder for 30min, then proportionally filling the mixture and diamond into a storage bin, mechanically mixing for 30-60min, fully mixing to obtain a powder mixture, then filling the obtained powder mixture into a steel die, and putting the pressure of the powder mixture into the steel die at 0.5-5.5t/cm²Cold pressing to density of 3.95-6.29g/cm³The blank of (2); wherein the iron powder comprises iron powder with the average particle size of 1-3 mu m and atomized iron powder with the average particle size of 40-50 mu m, the mass ratio of the iron powder with the average particle size of 1-3 mu m to the atomized iron powder is 50:50, the volume of the diamond is 30% of the volume of the iron powder, and the diamond needs to be wetted by liquid paraffin or engine oil before mechanical mixing.

Step S2: loading the blank obtained in the step S1 into a graphite die, carrying out hot-pressing sintering at 800 ℃, and keeping the temperature for 90-120S, wherein the pressure of the hot-pressing sintering is 200-²And after sintering, cooling to obtain the diamond tool bit.

And the diamond tips prepared in example 12 were made into coring thin wall water drill bits.

Example 13

step C1: firstly, ball-milling and mixing iron powder and atomized iron powder for 30min, then proportionally filling the mixture and diamond into a storage bin, mechanically mixing for 30-60min, and fully mixing to obtain a powder mixture; wherein the iron powder comprises iron powder with the average particle size of 1-3 mu m and atomized iron powder with the average particle size of 40-50 mu m, the mass ratio of the iron powder with the average particle size of 1-3 mu m to the atomized iron powder is 50:50, the volume of the diamond is 30% of the volume of the iron powder, and the diamond needs to be wetted by liquid paraffin or engine oil before mechanical mixing.

Step C2 filling the powder mixture obtained in step C1 in a steel mould under a pressure of 0.5-5.5t/cm²Cold pressing to density of 3.95-6.29g/cm³The blank of (1).

Step C3: and D, placing the blank obtained in the step C2 into a graphite boat, sintering under a condition of 900 ℃ without pressure, preserving heat for 30-60min, and cooling after sintering to obtain the diamond tool bit.

And the diamond tips prepared in example 13 were made into coring thin wall water drill bits.

Comparative example 1

A diamond tip was prepared according to example 5, except that the temperature for the hot press sintering was 640 ℃ and the soak time was 80 seconds.

And the diamond segments prepared in comparative example 1 were made into coring thin-wall water drill bits.

Comparative example 2

A diamond tip was prepared according to example 5, except that the temperature for the hot press sintering was 900 ℃ and the soak time was 130 seconds.

And the diamond segments prepared in comparative example 2 were made into coring thin-wall water drill bits.

Comparative example 3

A diamond tip was prepared according to example 5, except that the temperature for the hot press sintering was 900 ℃ and the soak time was 110 seconds.

And the diamond tips prepared in comparative example 3 were made into coring thin wall water drill bits.

Comparative example 4

A diamond segment was prepared according to example 6, except that the pressureless sintering temperature was 860 ℃ and the soak time was 20 min.

And the diamond segments prepared in comparative example 4 were made into diamond road saw blades.

Comparative example 5

A diamond segment was prepared according to example 6, except that the pressureless sintering temperature was 1000 ℃ and the soak time was 70 min.

And the diamond segments prepared in comparative example 5 were made into diamond road saw blades.

Comparative example 6

A diamond segment was prepared according to example 6, except that the pressureless sintering temperature was 1000 ℃ and the soak time was 50 min.

And the diamond segments prepared in comparative example 6 were made into diamond road saw blades.

And (3) testing and analyzing:

1. SEM image analysis

SEM analysis was performed on the diamond tip produced in example 5, and the result is shown in FIG. 1. As can be seen in fig. 1, the diamond is firmly encapsulated by the pure iron-based matrix.

2. Performance testing of sintered pure iron-based green bodies

The sintered pure iron-based green bodies of the above examples and comparative examples were subjected to density, hardness, bending resistance, and compactness tests, and the results are shown in table 1.

TABLE 1 EXAMPLES AND TEST TABLE FOR PERFORMANCE OF COMPARATIVE SINTERED PURE-IRON-BASED MOLDS

The performance of the coring thin-wall water drill bits made from the diamond segments prepared in examples 5 and 10 was tested and the results are shown in table 2:

TABLE 2 coring thin-walled water drill bit Performance test made with Diamond tips

As can be seen from table 2, the diamond tips made from the pure iron-based matrix wear equally or less than the diamond tips of the conventional Fe-Cu-Ni-Sn matrix on the market, breaking the conventional thinking that researchers need to add some additives in order to increase the performance of the iron-based matrix.

In summary, the present invention solves the technical deficiencies of the prior art. According to the invention, the iron powder in the pure iron-based matrix is refined, and the average particle size of the iron powder is reduced to 1-25 μm, so that the movement distance of iron ions is shortened, the activity of the iron powder is greatly enhanced, the hardness and the strength of a diamond tool bit are improved, and the holding force and the wear resistance of diamond can be increased; and meanwhile, the sintering temperature of the diamond tool bit is set to be low-temperature sintering, and the reaction speed of iron and diamond is controlled, so that the iron can be combined with the diamond by chemical bonds, and the diamond is not excessively carbonized to influence the strength of the diamond. Thereby obtaining the diamond tool bit with excellent comprehensive performance and low price in different application scenes.

The foregoing is only a partial embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. Use of a pure iron-based matrix made of iron powder having an average particle size of 1-25 μm for the preparation of a diamond tip.

2. A method of making a diamond tip according to claim 1, comprising the steps of:

3. The method for preparing a diamond segment as set forth in claim 2, wherein the temperature of the hot press sintering is 700-²。

4. The method for manufacturing a diamond segment according to claim 3, wherein the diamond is wetted with the wetting agent and then mechanically mixed with the iron powder in step S1; wherein the wetting agent is engine oil or paraffin wax.

5. The method for manufacturing a diamond tip according to claim 3, wherein a binder is further added in an amount of 1.2-2.2% by mass based on the mass of the iron powder in step S1 to be mechanically mixed with the diamond and the iron powder; wherein, the binder is polyethylene glycol or polyvinyl alcohol.

6. A method of making a diamond tip according to claim 1, comprising the steps of:

7. The method for preparing a diamond tip as set forth in claim 6, wherein the pressureless sintering temperature in the step C3 is 900-.

8. The method for manufacturing the diamond segments according to claim 7, wherein the diamond is wetted with the wetting agent and then mechanically mixed with the iron powder in the step C1; wherein the wetting agent is engine oil or paraffin wax.

9. The method for manufacturing a diamond tip according to claim 7, wherein a binder is further added in an amount of 1.2-2.2% by mass based on the mass of the iron powder in step C1 to be mechanically mixed with the diamond and the iron powder; wherein, the binder is polyethylene glycol or polyvinyl alcohol.