CN111390181A

CN111390181A - Preparation process of diamond tool

Info

Publication number: CN111390181A
Application number: CN202010302195.0A
Authority: CN
Inventors: 高忠麟; 舒诚
Original assignee: Rongcheng Zhonglei Technology Development Co ltd
Current assignee: Rongcheng Zhonglei Technology Development Co ltd
Priority date: 2020-04-16
Filing date: 2020-04-16
Publication date: 2020-07-10
Anticipated expiration: 2040-04-16
Also published as: CN111390181B

Abstract

The invention relates to the technical field of preparation of diamond tools, in particular to a preparation process of a diamond tool. A preparation process of a diamond tool comprises the following steps: step A, mixing a water-soluble polymer binder soluble in ethanol with a water-insoluble polymer binder soluble in ethanol to prepare a binder composition which can be completely dissolved in ethanol and partially dissolved in water; b, dissolving the binder composition prepared in the step A by using ethanol to prepare a binder solution; and step C, dry-mixing the metal pre-alloy powder and the diamond particles to obtain a matrix alloy dry-mixed material. The invention aims to provide a preparation process of a diamond tool, which effectively improves the density of the prepared diamond tool, has good mechanical property and high breaking strength, improves the service performance of the diamond tool and prolongs the service life of the diamond tool.

Description

Preparation process of diamond tool

Technical Field

The invention relates to the technical field of preparation of diamond tools, in particular to a preparation process of a diamond tool.

Background

In the manufacturing process of the diamond tool, the former matrix alloy powder uses copper powder, cobalt powder and nickel powder as main components, the content of iron powder is little, the oxidation resistance of the matrix alloy powder is good, but with the sharp rise of the price of metal cobalt, the diamond tool class basically avoids using high-price cobalt resources, iron is adopted instead to replace cobalt, because the iron powder is easy to oxidize, the matrix alloy powder is easy to oxidize, and the traditional hot-pressing sintering process is used, the hydrogen reduction process is not carried out, the matrix alloy blank is in the burdening, mixing, pressing and sintering processes, when the air humidity in contact with the matrix alloy blank is larger, a layer of water can be adsorbed on the surface of the matrix alloy blank, a layer of oxidation film can be formed through air oxidation, the diamond tool after hot-pressing sintering shrinks insufficiently, the density is greatly reduced, the strength is poor, and diamond particles in the diamond tool are easy to fall off, the service life is shortened, and the diamond tool can be scrapped in severe cases and can be stopped in humid seasons.

Disclosure of Invention

The invention aims to provide a preparation process of a diamond tool, which effectively improves the density of the prepared diamond tool, has good mechanical property and high breaking strength, improves the service performance of the diamond tool and prolongs the service life of the diamond tool.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation process of a diamond tool comprises the following steps:

step A, mixing a water-soluble polymer binder soluble in ethanol with a water-insoluble polymer binder soluble in ethanol to prepare a binder composition which can be completely dissolved in ethanol and partially dissolved in water;

b, dissolving the binder composition prepared in the step A by using ethanol to prepare a binder solution;

step C, carrying out dry mixing on the metal pre-alloy powder and the diamond particles to obtain a matrix alloy dry mixture;

step D, heating and kneading the binder solution prepared in the step B and the matrix alloy dry blend prepared in the step C, and then granulating to prepare matrix alloy granules;

step E, pressing and molding the matrix alloy granulated material prepared in the step D to obtain a matrix alloy blank;

f, soaking the blank of the tire body alloy prepared in the step E in soaking water for degreasing, and then drying and pre-oxidizing;

and G, carrying out vacuum thermal degreasing and hydrogen reduction pressure sintering on the matrix alloy blank treated in the step F to obtain the diamond tool.

Preferably, the water-soluble polymer binder soluble in ethanol is polyethylene glycol, the polymerization degree of the polyethylene glycol is 1500-2500, and the water-insoluble polymer binder soluble in ethanol is polyvinyl butyral.

Preferably, in the step a, 60 to 70% of the water-soluble polymer binder soluble in ethanol and 40 to 30% of the water-insoluble polymer binder soluble in ethanol are weighed and mixed according to mass percentage to prepare the binder composition completely soluble in ethanol and partially soluble in water.

Preferably, in the step F, the dipping soaking water degreasing is to put the blank of the matrix alloy into water to be soaked for 5-10 hours at room temperature.

Preferably, in the step F, the drying and pre-oxidizing treatment is to dry and pre-oxidize the carcass alloy blank degreased by the soaking water in the air at room temperature for 6-10 hours.

Preferably, the step B specifically includes:

step B1, weighing 30% of the binder composition and 70% of the ethanol according to the mass percentage, heating the ethanol to 50 ℃ and keeping the temperature constant;

and step B2, adding the adhesive composition into the ethanol, and stirring for dissolving.

Preferably, the step D specifically includes:

step D1, adding the matrix alloy dry blend into a kneader with the heating temperature of 60 ℃;

step D2, mixing the binder solution and the matrix alloy dry blend according to the mass ratio of 1: and 20, adding the binder solution into the kneader, kneading until ethanol in the binder solution is completely volatilized, naturally cooling to room temperature, and then sieving by using a sieve with 10-30 meshes to obtain the matrix alloy granulating material.

Preferably, in the step E, the pressure of the press forming is 2.5 to 5 tons per square centimeter, and the pressure maintaining time is 30 s.

Preferably, the metal prealloying powder comprises 36% of Fe powder, 24% of Cu powder, 15% of Co powder, 9% of Ni powder, 3% of Sn powder and 13% of WC powder by mass percent;

and in the step C, weighing 92.5% of the metal pre-alloy powder and 7.5% of diamond particles according to the volume percentage, and carrying out dry mixing for 2-3 h.

Preferably, the step G specifically includes:

g1, placing the tire body alloy blank processed in the step F into a vacuum pressure sintering furnace, preserving heat for 1h under the conditions that the temperature is 300 ℃ and the vacuum degree is 1Pa, and carrying out vacuum thermal degreasing;

g2, heating the vacuum pressure sintering furnace to 500 ℃, preserving heat for 1h, introducing hydrogen, controlling the pressure in the furnace to be 0.1035MPa, and performing hydrogen deoxidation and reduction;

g3, heating the vacuum pressure sintering furnace to 900 ℃, preserving heat for 1h, introducing argon gas, controlling the pressure in the furnace to be 10MPa, and carrying out vacuum pressure sintering;

and G4, stopping the operation of the vacuum pressure sintering furnace, and cooling to room temperature to obtain the diamond tool.

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

the invention carries out granulation after heating and kneading the binder solution and the matrix alloy dry mixture, because the surface of metal pre-alloy powder particles in the matrix alloy dry mixture is wrapped with a layer of binder solution in advance, the matrix alloy blank is formed by pressing after granulation, then the matrix alloy blank is soaked with soaking water for degreasing, the water-soluble polymer binder which is soluble in ethanol in the binder solution is dissolved in water, the water-soluble polymer binder which is soluble in ethanol in the binder solution is leached by aqueous solution, so that the water is uniformly absorbed into the inner part of the matrix alloy blank, then drying and pre-oxidation treatment are carried out, and capillary gaps are left in the inner part of the matrix alloy blank due to volatilization of the aqueous solution in the drying process, providing a passage for air to enter the interior of said carcass alloy blank body, which, due to the co-action of air and moisture, so that the surface of the metal pre-alloy powder particles of the matrix alloy blank is wholly and uniformly pre-oxidized to form a metal oxide film, reducing the pre-oxidized metal oxide film into alloy particles through vacuum thermal degreasing and hydrogen reduction pressure sintering, because the alloy particles have extremely large specific surface area and extremely high sintering reaction activity, the metal pre-alloy powder of the matrix alloy blank can be promoted to be combined into an alloy body when the alloy particles are subjected to hydrogen reduction and pressure sintering, simultaneously improves the holding force of the metal pre-alloy powder to the diamond particles, effectively improves the density of the prepared diamond tool, meanwhile, the mechanical property is good, the service performance of the diamond tool is improved, and the service life of the diamond tool is prolonged.

Detailed Description

A preparation process of a diamond tool comprises the following steps:

Heating and kneading the binder solution and the matrix alloy dry mixture, granulating, wherein a layer of binder solution is wrapped on the surface of metal pre-alloy powder particles in the matrix alloy dry mixture in advance, the matrix alloy blank is formed by compression molding after granulation, then the matrix alloy blank is soaked in soaking water for degreasing, the water-soluble high polymer binder which is soluble in ethanol in the binder solution is dissolved in water by utilizing the water absorption of the binder solution wrapping the surface of the metal pre-alloy powder particles of the matrix alloy blank, the water-soluble high polymer binder which is soluble in ethanol in the binder solution is leached by an aqueous solution, so that the water is uniformly absorbed into the inside of the matrix alloy blank, then drying and pre-oxidizing treatment are carried out, and capillary gaps are left in the inside of the matrix alloy blank due to volatilization of the aqueous solution in the drying process, providing a passage for air to enter the interior of said carcass alloy blank body, which, due to the co-action of air and moisture, so that the surface of the metal pre-alloy powder particles of the matrix alloy blank is wholly and uniformly pre-oxidized to form a metal oxide film, reducing the pre-oxidized metal oxide film into alloy particles through vacuum thermal degreasing and hydrogen reduction pressure sintering, because the alloy particles have extremely large specific surface area and extremely high sintering reaction activity, the metal pre-alloy powder of the matrix alloy blank can be promoted to be combined into an alloy body when the alloy particles are subjected to hydrogen reduction and pressure sintering, simultaneously improves the holding force of the metal pre-alloy powder to the diamond particles, effectively improves the density of the prepared diamond tool, meanwhile, the mechanical property is good, the service performance of the diamond tool is improved, and the service life of the diamond tool is prolonged.

The binder solution has the main function of completely coating the metal pre-alloy powder and the diamond particles, so that the metal pre-alloy powder and the diamond particles are bonded, the metal pre-alloy powder and the diamond particles are not easily separated in the pressing and forming process, and the strength of the matrix alloy blank is improved;

polyethylene glycol (PEG) is used as the water-soluble polymer binder which is soluble in ethanol and is used as a water-soluble binder, the polyethylene glycol (PEG) can play a role of uniformly absorbing moisture into the inner part of the matrix alloy blank, when the water solution is volatilized during drying, a capillary gap is reserved in the inner part of the matrix alloy blank, a channel is provided for air to enter and pre-oxidize, when the polymerization degree of the polyethylene glycol is too small, the polyethylene glycol is liquid, when the binder solution and the matrix alloy dry blend are heated and kneaded in step D, after the ethanol is volatilized, the liquid polyethylene glycol cannot play a role of uniformly absorbing moisture into the inner part of the matrix alloy blank, when the polymerization degree of the polyethylene glycol is too large, the solubility in the water solution is small, when the matrix alloy blank is soaked in water for degreasing, the water solution is not easily leached, and the water solution is prevented from being absorbed into the inner part, thereby affecting the pre-oxidation effect;

polyvinyl butyral (PVB) is used as the water-insoluble polymer binder which is soluble in ethanol, and due to the characteristic that the PVB has strong cohesiveness, is soluble in ethanol and is basically insoluble in water, after the tire body alloy blank is soaked in water for degreasing, the water-insoluble polymer binder which is soluble in ethanol is remained, so that the effect of bonding the metal pre-alloy powder and the diamond particles can be achieved, and the strength of the tire body alloy blank is improved.

When the matrix alloy blank is soaked in water for degreasing, water solution is used for leaching the water-soluble polymer binder soluble in ethanol, so that the water is uniformly absorbed into the matrix alloy blank, when the matrix alloy blank is dried, the water solution is volatilized to enable capillary gaps to be reserved in the matrix alloy blank, a channel is provided for air to enter and preoxidize, and the residual water-insoluble polymer binder soluble in ethanol can be used for bonding the metal pre-alloy powder and diamond particles;

if the addition amount of the water-insoluble polymer binder soluble in ethanol is too small and the water-soluble polymer binder soluble in ethanol is too much, the strength of the matrix alloy blank degreased by the soaking and soaking water is poor, and the strength of the prepared diamond tool is poor;

if the addition amount of the water-insoluble polymer binder soluble in ethanol is too large and the amount of the water-soluble polymer binder soluble in ethanol is too small, in the process of degreasing by the soaking and soaking water, the amount of the water-soluble polymer binder soluble in ethanol in the binder solution leached by the aqueous solution is too small, so that the amount of moisture absorbed into the inner part of the matrix alloy blank is small, a small capillary gap is left in the inner part of the matrix alloy blank after drying, the pre-oxidation effect of metal pre-alloy powder particles in the matrix alloy blank is poor, and the compactness and the mechanical strength of the prepared diamond tool are influenced.

And (E) degreasing by using the dipping soaking water, leaching the water-soluble polymer binder which is soluble in ethanol in the binder solution by using an aqueous solution, and uniformly absorbing water into the inner part of the matrix alloy blank.

Placing the tire body alloy blank degreased by soaking water in air to carry out drying and pre-oxidation treatment at room temperature, wherein capillary gaps are reserved inside the tire body alloy blank body due to volatilization of an aqueous solution in the drying process, a channel is provided for air to enter the tire body alloy blank body, the surface of metal pre-alloy powder particles of the tire body alloy blank is wholly and uniformly pre-oxidized due to the combined action of air and moisture, and if the drying and pre-oxidation time is too short, the pre-oxidation degree of the metal pre-alloy powder particles inside the blank inside the tire body alloy blank is not enough, so that the compactness and the mechanical strength of a manufactured diamond tool are influenced.

Preferably, the step B specifically includes:

Adding the binder composition into the ethanol, stirring and dissolving, wherein under the dilution of the ethanol, the dispersion degree of the binder composition in the matrix alloy dry mixture can be increased, the mixing uniformity is increased, so that the binder composition can be uniformly dispersed in the metal prealloy powder and the diamond particles of the matrix alloy dry mixture, and the dissolution speed of the binder composition in the ethanol can be accelerated by heating the ethanol to 50 ℃ and keeping the temperature constant; the water-based binder is adopted, and water is not combusted or volatile, so that the processing process is safer and more environment-friendly, and the problem that an oil-soluble solvent is flammable and explosive when being degreased by the solvent is solved.

Preferably, the step D specifically includes:

Heating and kneading the binder solution and the matrix alloy dry blend, wherein the binder solution can bind metal pre-alloy powder and diamond particles in the matrix alloy dry blend together, after the heating and kneading, ethanol of the binder solution is completely volatilized, the mixture of the binder solution and the matrix alloy dry blend becomes powder, because part of the metal pre-alloy powder and the diamond particles are likely to be bonded and agglomerated under the action of the binder solution, and the agglomeration can be dispersed through sieving treatment, so that the dispersion uniformity of the diamond particles in the matrix alloy dry blend in the matrix alloy granulating material is improved, if the sieving mesh is too small, the particle size is too large, the agglomeration cannot be dispersed, and the diamond particles in the matrix alloy dry blend are easily dispersed in the matrix alloy granulating material unevenly, the mechanical strength of the manufactured diamond tool is affected, if the sieving mesh number is too large, the particle size is too small, and in the compression molding process of the step E, because the particles of the matrix alloy granulating material are loose, the compression effect is poor, the density of the manufactured diamond tool is poor, and the mechanical strength is poor.

The blank of the matrix alloy obtained by compression molding is high in strength and good in mechanical property, and after the blank is subjected to soaking, water degreasing, drying and pre-oxidation treatment, and then vacuum thermal degreasing and hydrogen reduction and pressure sintering, the prepared diamond tool is good in mechanical property.

It should be noted that various metal powders in the metal prealloy powder are commercially available from the existing market.

The metal pre-alloy powder has high hardness and high impact strength, and is dry-mixed with the diamond particles under the bonding action of the binder solution to obtain the matrix alloy dry-mixed material, and the diamond tool obtained through high-temperature pressure sintering has high hardness and high breaking strength.

Preferably, the step G specifically includes:

And G, placing the tire body alloy blank in a vacuum pressure sintering furnace to complete the whole process of vacuum thermal degreasing, hydrogen deoxidation and reduction and vacuum pressure sintering at one time, so that the production period and the energy consumption are reduced, the production efficiency is improved, the labor intensity and the production cost are reduced, and the energy consumption and the environmental pollution are greatly reduced.

And G1, performing vacuum thermal degreasing, improving the vapor pressure of the high polymer by utilizing the vacuum effect, promoting decomposition, reducing degreasing residues, and accelerating degreasing speed and efficiency, wherein the water-insoluble high polymer binder which can be dissolved in ethanol is remained in the matrix alloy blank degreased by the dipping soaking water and can be removed only by the thermal decomposition of the vacuum thermal degreasing.

Step G2 is to perform the hydrogen deoxidation and reduction, and to reduce the metal oxide film formed on the surface of the metal pre-alloy powder particles of the matrix alloy blank into alloy particles, because the alloy particles have a very large specific surface area and a very large sintering reaction activity, the metal pre-alloy powder particles of the matrix alloy blank can be promoted to be combined into an alloy body when being subjected to hydrogen reduction and pressure sintering, so that the holding force of the diamond particles is improved, and the density of the prepared diamond tool is improved.

Step G3 adding argon gas to carry out the vacuum pressure sintering can further improve the density and the strength of the diamond tool, improve the compactness of a sintered body and reduce air holes and crack defects in the diamond tool.

The technical solution of the present invention is further explained by the following embodiments.

Example 1

A diamond tool is prepared by the following steps:

step A, weighing 65% of polyethylene glycol (with the polymerization degree of 2000) and 35% of polyvinyl butyral according to the mass percentage, and mixing to prepare a binder composition which can be completely dissolved in ethanol and partially dissolved in water;

step B, preparing a binder solution

Step B1, weighing 30% of the binder composition prepared in the step A and 70% of ethanol according to the mass percentage, putting the weighed ethanol into a sealed beaker, heating to 50 ℃ and keeping the temperature constant, and starting a stirrer to stir the ethanol;

step B2, adding the weighed binder composition into ethanol, stirring and dissolving to prepare a binder solution;

step C, weighing 92.5% of metal pre-alloy powder (the metal pre-alloy powder is obtained by mixing 36% of Fe powder, 24% of Cu powder, 15% of Co powder, 9% of Ni powder, 3% of Sn powder and 13% of WC powder) and 7.5% of diamond particles according to the volume percentage, and placing the mixture in a roller mixer for dry mixing for 3 hours to prepare a matrix alloy dry blend;

step D, preparing a matrix alloy granulating material

Step D1, adding the matrix alloy dry blend prepared in the step C into a kneader with the heating temperature of 60 ℃;

step D2, mixing the binder solution and the matrix alloy dry blend according to the mass ratio of 1: 20, adding the binder solution prepared in the step B into a kneader for kneading until the ethanol in the binder solution is completely volatilized, enabling the mixture to become powder, naturally cooling to room temperature, taking out and sieving by a 20-mesh sieve to obtain matrix alloy granulating materials;

e, putting the carcass alloy granulating material prepared in the step D into a hopper of a 60-ton automatic press, setting the pressure of press forming to be 3 tons/square centimeter and the pressure maintaining time to be 30s, and pressing to obtain a carcass alloy blank;

step F, soaking the matrix alloy blank prepared in the step E in water at room temperature for 10 hours for soaking, soaking in water for degreasing, taking out, drying in air at room temperature, and pre-oxidizing for 10 hours;

step G, carrying out vacuum thermal degreasing and hydrogen reduction pressure sintering

Example 2

A diamond tool is prepared by the following steps:

step A, weighing 60% of polyethylene glycol (with the polymerization degree of 1500) and 40% of polyvinyl butyral according to the mass percentage, and mixing to prepare a binder composition which can be completely dissolved in ethanol and partially dissolved in water;

step B, preparing a binder solution

step C, weighing 92.5% of metal pre-alloy powder (the metal pre-alloy powder is obtained by mixing 36% of Fe powder, 24% of Cu powder, 15% of Co powder, 9% of Ni powder, 3% of Sn powder and 13% of WC powder) and 7.5% of diamond particles according to the volume percentage, and placing the mixture in a roller mixer for dry mixing for 2 hours to prepare a matrix alloy dry blend;

step D, preparing a matrix alloy granulating material

step D2, mixing the binder solution and the matrix alloy dry blend according to the mass ratio of 1: 20, adding the binder solution prepared in the step B into a kneader for kneading until the ethanol in the binder solution is completely volatilized, enabling the mixture to become powder, naturally cooling to room temperature, taking out and sieving by a 10-mesh sieve to obtain matrix alloy granulating materials;

e, putting the carcass alloy granulating material prepared in the step D into a hopper of a 60-ton automatic press, setting the pressure of press forming to be 4 tons/square centimeter and the pressure maintaining time to be 30s, and pressing to obtain a carcass alloy blank;

step F, soaking the matrix alloy blank prepared in the step E in water at room temperature for 6 hours for soaking, soaking in soaking water for degreasing, taking out, drying in air at room temperature, and pre-oxidizing for 7 hours;

Example 3

A diamond tool is prepared by the following steps:

step A, weighing 70% of polyethylene glycol (with the polymerization degree of 1500) and 30% of polyvinyl butyral according to the mass percentage, and mixing to prepare a binder composition which can be completely dissolved in ethanol and partially dissolved in water;

step B, preparing a binder solution

step D, preparing a matrix alloy granulating material

step D2, mixing the binder solution and the matrix alloy dry blend according to the mass ratio of 1: 20, adding the binder solution prepared in the step B into a kneader for kneading until the ethanol in the binder solution is completely volatilized, enabling the mixture to become powder, naturally cooling to room temperature, taking out and sieving by a 30-mesh sieve to obtain matrix alloy granulating materials;

e, putting the carcass alloy granulating material prepared in the step D into a hopper of a 60-ton automatic press, setting the pressure of press forming to be 5 tons/square centimeter and the pressure maintaining time to be 30s, and pressing to obtain a carcass alloy blank;

step F, soaking the matrix alloy blank prepared in the step E in water at room temperature for 8 hours for soaking, soaking in soaking water for degreasing, taking out, drying in air at room temperature and pre-oxidizing for 8 hours;

Comparative example 1

Example 1 was selected for comparison.

In this comparative example, the raw materials were the same as in example 1, and the preparation method comprises the step F of immersing the blank of the matrix alloy obtained in the step E in water at room temperature for 8 hours to carry out degreasing treatment with immersion water, taking out the blank to suck water, and drying the blank in a drying oven for 2 hours at a drying temperature of 50 ℃, and the remaining steps of the preparation method were the same as in example 1 to obtain a diamond tool.

Comparative example 2

Example 1 was selected for comparison.

In this comparative example, the polymerization degree of polyethylene glycol was 800, and the remaining raw material components were the same as in example 1, and a diamond tool was manufactured according to the manufacturing method of example 1.

Comparative example 3

Example 1 was selected for comparison.

In this comparative example, the polymerization degree of polyethylene glycol was 2800, and the remaining raw material components were the same as in example 1, and a diamond tool was manufactured according to the manufacturing method of example 1.

Comparative example 4

Example 1 was selected for comparison.

In this comparative example, the raw materials were identical to those of example 1, and in the preparation method, step a was carried out by weighing 80% by mass of polyethylene glycol (degree of polymerization 1500) and 20% by mass of polyvinyl butyral, mixing them to prepare a binder composition which was completely soluble in ethanol and partially soluble in water, and the other preparation method steps were identical to those of example 1 to prepare a diamond tool.

Comparative example 5

Example 1 was selected for comparison.

In this comparative example, the raw materials were identical to those of example 1, and in the preparation method, step a was carried out by weighing 50% polyethylene glycol (degree of polymerization 1500) and 50% polyvinyl butyral, mixing them by mass to prepare a binder composition that was completely soluble in ethanol and partially soluble in water, and the remaining preparation method steps were identical to those of example 1 to prepare a diamond tool.

Comparative example 6

Example 1 was selected for comparison.

In this comparative example, the raw materials were the same as in example 1, and the step F in the manufacturing method was to soak the body alloy blank obtained in step E in water at room temperature for 3 hours to carry out soaking water degreasing treatment, then to take out and place in the air to dry at room temperature and pre-oxidize for 10 hours, and the remaining manufacturing method steps were the same as in example 1 to obtain a diamond tool.

Comparative example 7

Example 1 was selected for comparison.

In this comparative example, the raw materials were the same as in example 1, and the step F in the manufacturing method was to soak the body alloy blank obtained in step E in water at room temperature for 10 hours to carry out soaking water degreasing treatment, then to take out and place in the air at room temperature for drying and pre-oxidation for 3 hours, and the remaining manufacturing method steps were the same as in example 1 to obtain a diamond tool.

Comparative example 8

Example 1 was selected for comparison.

In this comparative example, the raw materials were the same as in example 1, and step B1 of the manufacturing method was to weigh 30% of the binder composition obtained in step a and 70% of ethanol by mass, place the weighed ethanol in a sealed beaker, start a stirrer to stir the ethanol, and manufacture a diamond tool in accordance with example 1 for the remaining manufacturing method steps.

Comparative example 9

Example 1 was selected for comparison.

In this comparative example, the raw materials were the same as in example 1, and step D2 in the preparation method was performed according to the mass ratio of the binder solution to the matrix alloy dry blend being 1: and 20, adding the binder solution prepared in the step B into a kneader for kneading until ethanol in the binder solution is completely volatilized, enabling the mixture to become powder, naturally cooling to room temperature, taking out and sieving by using a 5-mesh sieve, and enabling the other preparation method steps to be consistent with those in the example 1 to prepare the diamond tool.

Comparative example 10

Example 1 was selected for comparison.

In this comparative example, the raw materials were the same as in example 1, and step D2 in the preparation method was performed according to the mass ratio of the binder solution to the matrix alloy dry blend being 1: and 20, adding the binder solution prepared in the step B into a kneader for kneading until ethanol in the binder solution is completely volatilized, enabling the mixture to become powder, naturally cooling to room temperature, taking out and sieving by a 50-mesh sieve, and enabling the steps of the other preparation methods to be consistent with those of the example 1 to prepare the diamond tool.

The diamond tools prepared in examples 1 to 3 and comparative examples 1 to 10 were subjected to a bulk density (water drainage method) and a relative theoretical density (relative theoretical density: bulk density/theoretical density of substance, theoretical density of diamond tool (matrix) was 8.48 g/cm) by a conventional metal material test method³Testing the performances of hardness (HRB steel ball indentation method) and breaking strength (three-point breaking method);

the theoretical density of the diamond tool (matrix) is calculated in the following way: because the metal prealloying powder consists of 36% of Fe powder, 24% of Cu powder, 15% of Co powder, 9% of Ni powder, 3% of Sn powder and 13% of WC powder by mass percent, the density of the Fe powder contained in the metal prealloying powder is 7.86g/cm³The densities of Cu powder, Co powder and Ni powder are all 8.9g/cm³The density of Sn powder is 6.54g/cm³The density of WC powder is 15.63g/cm³And calculating by taking 100g of the metal prealloying powder, the metal prealloying powder comprises 36g of Fe powder, 24g of Cu powder, 15g of Co powder, 9g of Ni powder, 3g of Sn powder and 13g of WC powder, and the density of the metal prealloying powder is as follows: density ρ is mass M/volume V, then: the density ρ 1 of the metal prealloyed powder is:

ρ1＝100/(36/7.86+24/8.9+15/8.9+9/8.9+3/6.54+13/15.63)＝8.88g/cm³92.5% by volume of the metal prealloyed powder is weighed and dry mixed with 7.5% by volume of diamond particlesThe density was 3.52g/cm³And performing weighting calculation to obtain the theoretical density rho 2 of the diamond tool (matrix) to be 8.88 to 0.925 to 3.52 to 0.075 to 8.48g/cm³；

The following performance test results were obtained:

TABLE 1 Performance test of examples and comparative examples

From the above test results, it can be seen that the diamond tools manufactured in examples 1 to 3 have high density and mechanical strength, because the matrix alloy blank is subjected to degreasing by soaking and soaking in water, drying and pre-oxidation treatment during the manufacturing process, the surface of the metal pre-alloy powder particles of the matrix alloy blank is uniformly pre-oxidized as a whole to form a metal oxide film, and finally the pre-oxidized metal oxide film is reduced into alloy particles through vacuum thermal degreasing and hydrogen reduction pressure sintering, because the alloy particles have a very large specific surface area and a very large sintering reaction activity, the metal pre-alloy powder of the matrix alloy blank can be promoted to be combined into an alloy body during the hydrogen reduction pressure sintering, and simultaneously the holding force of the metal pre-alloy powder on the diamond particles is also improved, the density of the manufactured diamond tools is effectively improved, and the relative theoretical density in the performance test is high, the diamond tool prepared in the embodiment 1 has the relative theoretical density of 99.9%, and meanwhile, the mechanical property is good, the hardness and the breaking strength in a performance test are high, the use performance of the diamond tool is improved, and the service life of the diamond tool is prolonged.

It can be seen from example 1 and comparative example 1 that when step F is to soak the prepared blank of the matrix alloy in water at room temperature for 8 hours to carry out soaking and soaking water degreasing treatment, then take out and suck up water, and place the blank in a drying oven for drying for 2 hours, the relative theoretical density, hardness and breaking strength of the diamond tool prepared in comparative example 1 are all lower than those of example 1 because of not carrying out pre-oxidation treatment, and the relative theoretical density, hardness and breaking strength of the diamond tool prepared from the blank of the matrix alloy subjected to pre-oxidation treatment in examples 1 to 3 are all higher than those of comparative example 1, and the diamond tool with excellent performance can be prepared by combining the pre-oxidation treatment process with vacuum thermal degreasing and hydrogen reduction pressure sintering.

As can be seen from example 1 and comparative example 2, when the polymerization degree of the polyethylene glycol is 800, the relative theoretical density, hardness and flexural strength of the prepared diamond tool are all lower than those of example 1, and since the polymerization degree of the polyethylene glycol in comparative example 2 is too small, the polyethylene glycol is in a liquid state, the polyethylene glycol is used for preparing a binder composition to prepare a binder solution, and when the binder solution is heated and kneaded with the matrix alloy dry blend in step D, after ethanol is volatilized, the liquid polyethylene glycol cannot play a role in uniformly absorbing water into the interior of the matrix alloy blank, the surface pre-oxidation of the metal pre-alloy powder particles in the interior of the matrix alloy blank is incomplete, and the compactness and mechanical strength of the diamond tool are affected.

As can be seen from example 1 and comparative example 3, when the polymerization degree of polyethylene glycol is 2800, the relative theoretical density, hardness and flexural strength of the diamond tool produced are all lower than those of example 1, and since the polymerization degree of polyethylene glycol in comparative example 3 is too large, the solubility of the polyethylene glycol with too large polymerization degree in an aqueous solution is low, the polyethylene glycol is not easy to leach when the carcass alloy blank is soaked in soaking water for degreasing, the absorption of the aqueous solution into the interior of the carcass alloy blank is influenced, the surface pre-oxidation of the metal pre-alloy powder particles in the interior of the carcass alloy blank is incomplete, and the compactness and mechanical strength of the diamond tool are influenced.

As is clear from example 1 and comparative example 4, when the amount of polyvinyl butyral added was too small, the amount of water-insoluble polymer binder added was too small, and the amount of water-soluble polymer binder soluble in ethanol was too large, and after degreasing with dipping and soaking water, the matrix alloy blank did not have sufficient water-insoluble polymer binder to bind, and the strength of the matrix alloy blank was poor, and the hardness and the flexural strength of the diamond tool obtained were significantly poor.

As can be seen from example 1 and comparative example 5, when the addition amount of the polyvinyl butyral is too large, the addition amount of the water-insoluble polymer binder is too large, the water-soluble polymer binder soluble in ethanol is too small, and during the process of soaking, soaking and degreasing the matrix alloy blank, the water-soluble polymer binder soluble in ethanol in the binder solution leached by the aqueous solution is too small, so that the amount of moisture absorbed into the interior of the matrix alloy blank is small, the capillary gaps left in the interior of the dried matrix alloy blank are small, the pre-oxidation effect of the metal pre-alloy powder particles in the matrix alloy blank is poor, and the compactness and mechanical strength of the diamond tool produced are affected.

As can be seen from example 1 and comparative example 6, when the time for degreasing the body alloy blank by soaking in the soaking water is too short, the pre-oxidation effect of the metal pre-alloy powder particles inside the body alloy blank is reduced because the aqueous solution is not easily absorbed into the inside of the body alloy blank, and the relative theoretical density, hardness and flexural strength of the diamond tool manufactured are all lower than those of example 1.

It can be seen from example 1 and comparative example 7 that the relative theoretical density, hardness and breaking strength of the diamond tool prepared in comparative example 7 are lower than those of example 1, and since the time for drying and pre-oxidation of the matrix alloy blank after degreasing treatment with soaking water is too short in example 7, the degree of pre-oxidation of the metal pre-alloy powder particles inside the blank inside the matrix alloy blank is not enough, which affects the compactness and mechanical strength of the prepared diamond tool.

As can be seen from example 1 and comparative example 8, since comparative example 8 does not heat ethanol in step B1, the binder composition is not completely dissolved in the solvent ethanol, the binder composition is easily agglomerated, the dispersibility in the matrix alloy dry mixture is poor, the performance of the diamond tool is seriously affected, and the relative theoretical density, hardness and breaking strength of the diamond tool are significantly reduced.

As can be seen from example 1 and comparative example 9, in the process of preparing the matrix alloy granulated material in step D, since the mesh number is too small, the particle size of the prepared matrix alloy granulated material is too large, and the agglomerates formed by the binder solution and the matrix alloy dry mixture cannot be dispersed, so that the diamond particles in the matrix alloy dry mixture are not uniformly dispersed in the matrix alloy granulated material, which affects the mechanical strength of the prepared diamond tool, and the hardness and the flexural strength of the diamond tool prepared in comparative example 9 are obviously lower than those of example 1.

As can be seen from example 1 and comparative example 10, the particle size of the obtained matrix alloy granulated material is too small due to too large number of sieving meshes, and when the matrix alloy granulated material is subjected to compression molding in step E, the compression effect is poor due to the small and loose particles of the matrix alloy granulated material, and the obtained diamond tool has poor compactness and poor mechanical strength.

The technical principle of the present invention is described above in connection with specific embodiments. The description is made for the purpose of illustrating the principles of the invention and should not be construed in any way as limiting the scope of the invention. Based on the explanations herein, those skilled in the art will be able to conceive of other embodiments of the present invention without inventive effort, which would fall within the scope of the present invention.

Claims

1. A process for preparing a diamond tool, comprising the steps of:

2. The process for preparing a diamond tool according to claim 1, wherein the water-soluble polymer binder soluble in ethanol is polyethylene glycol, the degree of polymerization of the polyethylene glycol is 1500 to 2500, and the water-insoluble polymer binder soluble in ethanol is polyvinyl butyral.

3. The process for preparing a diamond tool according to claim 1, wherein in the step a, 60 to 70% by weight of the water-soluble polymer binder soluble in ethanol is mixed with 40 to 30% by weight of the water-insoluble polymer binder soluble in ethanol to prepare the binder composition completely soluble in ethanol and partially soluble in water.

4. The process for preparing a diamond tool as claimed in claim 1, wherein in step F, the step of degreasing with dipping soaking water is to put the blank of the matrix alloy into water and soak the blank of the matrix alloy for 5-10 hours at room temperature.

5. The process for preparing a diamond tool as claimed in claim 1, wherein in step F, the drying and pre-oxidation treatment is to dry and pre-oxidize the blank of the matrix alloy degreased by soaking water in air at room temperature for 6-10 h.

6. The process for preparing a diamond tool according to claim 1, wherein the step B specifically comprises:

7. The process for preparing a diamond tool according to claim 1, wherein the step D specifically comprises:

8. The process for preparing a diamond tool according to claim 1, wherein in the step E, the pressure for press forming is 2.5 to 5 tons/cm, and the dwell time is 30 s.

9. The process of claim 1, wherein the metallic prealloyed powder comprises, by mass percent, 36% Fe powder, 24% Cu powder, 15% Co powder, 9% Ni powder, 3% Sn powder, and 13% WC powder;

10. The process for preparing a diamond tool according to claim 1, wherein the step G specifically comprises: