阅读说明：本技术 一种无酸碱预处理的硬质合金基体金刚石涂层的制备方法 (Preparation method of hard alloy matrix diamond coating without acid-base pretreatment ) 是由 陈乃超 刘冬梅 居法松 于 2021-08-05 设计创作，主要内容包括：本发明提供一种无酸碱预处理的硬质合金基体金刚石涂层制备方法,包括如下步骤：使用金刚石微粉与砂纸相配合对硬质合金基体表面进行打磨,将处理好的基体进行超声清洗；采用湿法分散颗粒的方法将颗粒均匀的分散在基体表面放入干燥箱中进行干燥；采用热丝化学气相沉积法沉积金刚石涂层,依次经过金刚石形核和生长阶段,得到无酸碱预处理的硬质合金涂层。与现有的技术相比较,本发明的操作过程对于硬质合金造成的损伤比较小,同时获得的涂层质量与经过预处理的涂层效果相近。添加的颗粒提高金刚石涂层的沉积速率,提高了涂层的附着力和抗裂性。(The invention provides a preparation method of a hard alloy matrix diamond coating without acid-base pretreatment, which comprises the following steps: grinding the surface of a hard alloy substrate by matching diamond micro powder with sand paper, and ultrasonically cleaning the processed substrate; uniformly dispersing the particles on the surface of the matrix by adopting a wet particle dispersing method, and drying the matrix in a drying box; and depositing the diamond coating by adopting a hot wire chemical vapor deposition method, and sequentially carrying out diamond nucleation and growth stages to obtain the acid-base pretreatment-free hard alloy coating. Compared with the prior art, the damage to the hard alloy is smaller in the operation process, and the obtained coating quality is similar to the pretreated coating effect. The added particles increase the deposition rate of the diamond coating and improve the adhesion and crack resistance of the coating.)

1. A preparation method of a hard alloy matrix diamond coating without acid-base pretreatment is characterized by comprising the following steps: comprises the steps of (a) preparing a mixture of a plurality of raw materials,

treating the surface of a substrate: grinding the surface of the hard alloy matrix by using sand paper and diamond micro powder, removing the diamond micro powder and other impurities on the surface of the ground hard alloy matrix, and drying;

wet dispersion of particles: preparing solid particles and a solution, putting the solid particles into the solution, uniformly mixing the solution by a stirrer to form a mixed solution, and performing ultrasonic dispersion. Sucking the mixed solution by using a rubber head dropper, dropping the mixed solution on the surface of the substrate, and then putting the substrate into a blast drying oven for drying;

CVD diamond coating preparation: and depositing the diamond coating by adopting a hot wire chemical vapor deposition method to obtain the hard alloy diamond coating without acid-base pretreatment.

2. The method of making an acid and base pretreatment free cemented carbide substrate diamond coating of claim 1, wherein: the hard alloy matrix comprises tungsten-cobalt hard alloy, tungsten-titanium hard alloy and tungsten-titanium-tantalum (niobium) hard alloy.

3. The method of making an acid-base pretreatment free cemented carbide substrate diamond coating of claim 1 or 2, wherein: the cemented carbide substrate comprises tungsten-cobalt cemented carbide YG3, YG6, YG8 and YG 12.

4. The method of making an acid and base pretreatment free cemented carbide substrate diamond coating of claim 1, wherein: the solid particles have stronger absorption capacity of hydrocarbon groups, and the rate of absorbing the hydrocarbon groups is faster than that of Co element.

5. The method of making an acid-base pretreatment free cemented carbide substrate diamond coating of claim 1 or 4, wherein: the solid particles comprise graphene oxide particles, and the particle thickness of the solid particles is 1-3 nm.

6. The method of making an acid and base pretreatment free cemented carbide substrate diamond coating of claim 1, wherein: the solution comprises 90% ethanol solution.

7. The method of making an acid and base pretreatment free cemented carbide substrate diamond coating of claim 1, wherein: the concentration of the solid particles in the mixed solution is 0.5-2 g/L.

8. The method of making an acid and base pretreatment free cemented carbide substrate diamond coating of claim 1, wherein: the hot wire chemical vapor deposition method comprises the following steps,

depositing a diamond coating by adopting a hot filament chemical vapor deposition method, taking hydrogen and acetone as reaction gases, and respectively setting the flow rates of the hydrogen and the acetone to be 240sccm and 90 sccm; the nucleation time and the coating growth time are set to be 30min and 4h respectively in the experiment.

9. The method of making an acid-base pretreatment free cemented carbide substrate diamond coating of claim 1 or 8, wherein: the hot wire chemical vapor deposition method comprises the following steps,

the technological structure parameters are as follows: four tantalum wires with the diameter of 6mm and the interval of 20mm are uniformly distributed, the power is set to be 4.5KW, the distance between the surface of the substrate and the tantalum wires is 10mm, the pressure of a vacuum chamber in a nucleation stage is 1.5-2.0 kPa, and the pressure in a growth stage is 4.0-5.0 kPa;

in the whole deposition process, the temperature of the hot wire is kept at 2100-2300 ℃, and the surface temperature of the substrate is 800-900 ℃.

Technical Field

The invention belongs to the technical field of surface engineering, and relates to a preparation method and application of a hard alloy matrix diamond coating without acid-base pretreatment.

Background

The hard alloy is one of main application materials of the high-wear-resistance part, and the hard alloy diamond coating cutter is adopted, so that the service life of the cutter can be greatly prolonged, and the economical efficiency of processing and manufacturing is improved. However, the existence of Co element in the hard alloy binder causes graphitization in the preparation process of the diamond coating, and the diamond coating cannot be prepared on the cutter or the adhesion of the coating is poor. Thus, a pre-treatment of the cemented carbide substrate is required prior to the deposition of the diamond coating. Common pretreatment methods such as acid-base pretreatment methods remove surface Co elements by etching the surface of the cemented carbide, so as to eliminate the graphitization effect of Co.

Although the acid-base pretreatment method can effectively eliminate the influence of Co, the acid-base corrosion can cause certain damage to the hard alloy matrix. If the surface of the micro-drill made of hard alloy is damaged, the strength of the hard alloy is reduced, and the coated cutter is easy to break. Aiming at the hard alloy material, the invention provides a novel preparation method applied to the diamond coating of the non-pretreated hard alloy matrix.

Disclosure of Invention

This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.

The present invention has been made keeping in mind the above and/or other problems occurring in the prior art.

Therefore, the object of the present invention is to provide a method for preparing a diamond coating on a cemented carbide substrate without acid-base pretreatment, according to the deficiencies of the prior art.

To solve the above technical problem, according to an aspect of the present invention, the present invention provides the following technical solutions: a method for preparing a hard alloy diamond coating without acid-base pretreatment comprises the following steps,

treating the surface of a substrate: grinding the surface of the hard alloy matrix by using sand paper and diamond micro powder, removing the diamond micro powder and other impurities on the surface of the ground hard alloy matrix, and drying;

wet dispersion of particles: preparing solid particles and a solution, putting the solid particles into the solution, uniformly mixing the solution by a stirrer to form a mixed solution, and performing ultrasonic dispersion. Sucking the mixed solution by using a rubber head dropper, dropping the mixed solution on the surface of the substrate, and then putting the substrate into a blast drying oven for drying;

CVD diamond coating preparation: and depositing the diamond coating by adopting a hot wire chemical vapor deposition method to obtain the hard alloy diamond coating without acid-base pretreatment.

As a preferable embodiment of the method for preparing the acid-base pretreatment-free hard alloy matrix diamond coating, the method comprises the following steps: the hard alloy matrix comprises tungsten-cobalt hard alloy, tungsten-titanium hard alloy and tungsten-titanium-tantalum (niobium) hard alloy.

As a preferable embodiment of the method for preparing the acid-base pretreatment-free hard alloy matrix diamond coating, the method comprises the following steps: the cemented carbide substrate comprises tungsten-cobalt cemented carbide YG3, YG6, YG8 and YG 12.

As a preferable embodiment of the method for preparing the acid-base pretreatment-free hard alloy matrix diamond coating, the method comprises the following steps: the solid particles have stronger absorption capacity of hydrocarbon groups, and the rate of absorbing the hydrocarbon groups is faster than that of Co element.

As a preferable embodiment of the method for preparing the acid-base pretreatment-free hard alloy matrix diamond coating, the method comprises the following steps: the solid particles comprise graphene oxide particles, and the particle thickness of the solid particles is 1-3 nm.

As a preferable embodiment of the method for preparing the acid-base pretreatment-free hard alloy matrix diamond coating, the method comprises the following steps: the solution comprises 90% ethanol solution.

As a preferable embodiment of the method for preparing the acid-base pretreatment-free hard alloy matrix diamond coating, the method comprises the following steps: the concentration of the solid particles in the mixed solution is 0.5-2 g/L.

As a preferable embodiment of the method for preparing the acid-base pretreatment-free hard alloy matrix diamond coating, the method comprises the following steps: the hot wire chemical vapor deposition method comprises the following steps,

depositing a diamond coating by adopting a hot filament chemical vapor deposition method, taking hydrogen and acetone as reaction gases, and respectively setting the flow rates of the hydrogen and the acetone to be 240sccm and 90 sccm; the nucleation time and the coating growth time are set to be 30min and 4h respectively in the experiment.

As a preferable embodiment of the method for preparing the acid-base pretreatment-free hard alloy matrix diamond coating, the method comprises the following steps: the hot wire chemical vapor deposition method comprises the following steps,

the technological structure parameters are as follows: four tantalum wires with the diameter of 6mm and the interval of 20mm are uniformly distributed, the power is set to be 4.5KW, the distance between the surface of the substrate and the tantalum wires is 10mm, the pressure of a vacuum chamber in a nucleation stage is 1.5-2.0 kPa, and the pressure in a growth stage is 4.0-5.0 kPa;

in the whole deposition process, the temperature of the hot wire is kept at 2100-2300 ℃, and the surface temperature of the substrate is 800-900 ℃.

The invention has the beneficial effects that:

the solid particles added in the stage of wet-method particle dispersion have stronger carbon-hydrogen group suction capacity and can bear high temperature, meanwhile, the solid particles can improve the growth rate of the diamond coating, the time of Co element participating in reaction in the hard alloy matrix is reduced by a chemical competitive adsorption mode, and the influence of Co element graphitization is inhibited. The solid particles also have a hardness that provides the coating with greater adhesion and crack resistance.

Compared with the existing acid-base pretreatment method, the diamond coating generated by the invention has the effect similar to that of the coating obtained after the acid-base pretreatment. And the surface of the substrate which is not subjected to acid-base pretreatment is smoother than that of the substrate which is subjected to acid-base pretreatment. The preparation process of the invention has no acid and alkali pollution, and the preparation method is simple, convenient, economical and practical.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise. Wherein:

fig. 1 is a microstructure of an SEM of a surface of a cemented carbide substrate without acid-base pretreatment.

FIG. 2 is a microscopic topography of an SEM of a substrate surface with a dispersion of particles without acid or base treatment.

Fig. 3 is a microscopic topography of a diamond coating SEM grown without acid-base pretreatment of the surface with dispersed particles.

FIG. 4 shows the SEM microstructure of the substrate surface after acid-base pretreatment of the cemented carbide substrate.

FIG. 5 is an SEM image of the surface morphology of a diamond coating deposited and grown on a cemented carbide substrate subjected to acid-base pretreatment

Fig. 6 is a graph comparing indentation topography of a diamond coated cemented carbide substrate without acid and base pretreatment added solid particles with an acid and base pretreatment diamond coated cemented carbide substrate under a load of 100, 200 and 300N.

FIG. 7 is a graph of the morphology of a deposit-grown coating prepared according to the present invention with a particle concentration of 0.5 g/L.

FIG. 8 is a topographical map of a 2g/L deposit-generated coating with particles prepared according to the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, specific embodiments thereof are described in detail below with reference to examples of the specification.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

In the embodiment of the present invention, the cemented carbide substrate is a tungsten-cobalt cemented carbide YG6, which comprises the following components: WC 94% and Co 6%. The thickness of the solid particles of the graphene oxide used in the embodiment of the invention is 2 nm.

The other raw materials used in the present invention are commercially available unless otherwise specified.

Example 1

(1) Surface treatment of substrates

Step 1: polishing the surface of a hard alloy matrix on 1500-mesh abrasive paper by using diamond micro powder, and removing partial impurities on the surface of the matrix; and then using 200-mesh sand paper to match with the diamond micropowder to continuously grind the substrate to obtain a smooth substrate surface with a plurality of small pits.

Step 2: and continuously washing the surface of the substrate for 10 minutes by using deionized water to remove the redundant large-particle diamond micro powder and other impurities on the surface of the substrate.

And step 3: and soaking the substrate material in an acetone solution for 20 minutes of ultrasonic cleaning to remove impurities on the surface of the substrate.

And 4, step 4: and (3) putting the treated substrate into a constant-temperature air-blast drying oven to dry the surface, wherein the temperature of the constant-temperature air-blast drying oven is set to be 60 ℃.

The Scanning Electron Microscope (SEM) morphology of the treated substrate surface is shown in FIG. 1.

(2) Wet-process dispersion particles

Firstly preparing solid particle solution, weighing solid particle powder with the mass of 0.1g by using an electronic balance, weighing 100ml of 90% ethanol solution by using a measuring cylinder, and putting the solid particles into the ethanol solution. The solution is stirred evenly by a stirrer and is put into an ultrasonic machine for ultrasonic dispersion for 10 minutes. Sucking the solution by a rubber head dropper, dropping the solution on the surface of the dried clean hard alloy substrate, and stably putting the substrate into an air-blast drying oven for drying at a constant temperature of 60 ℃. The presence of solid particles on the surface of the cemented carbide substrate can be seen under SEM, as shown in figure 2.

(3) CVD diamond preparation

The invention adopts a hot wire chemical vapor deposition method, uses metal tantalum wires as hot wires, uses hydrogen and acetone as reaction gases, and uses the acetone to provide carbon-containing radicals. The hydrogen and acetone flow rates were set at 240sccm and 90sccm, respectively, with a nucleation time of 30 minutes and a coating growth time of 4 hours. The technological structure parameters are set to be that four tantalum wires with the diameter of 6mm and the interval of 20mm are uniformly distributed, the power is set to be 4.5KW, the distance between the surface of the substrate and the tantalum wires is 10mm, the pressure of a vacuum chamber in a nucleation stage is 1.5-2.0 kPa, and the pressure in a growth stage is 4.0-5.0 kPa. In the whole deposition process, the temperature of the hot wire is kept about 2200 ℃, and the surface temperature of the substrate is about 800-900 ℃.

The surface topography of the grown micron diamond coating is shown in fig. 3, and it can be seen that the diamond coating is grown on the cemented carbide substrate without acid-base pretreatment.

FIG. 4 is an SEM image of the surface morphology of a base body after acid-base pretreatment of a hard alloy base body, and FIG. 5 is an SEM image of the surface morphology of a diamond coating layer which is deposited and grown on the hard alloy base body after acid-base pretreatment. Compared with fig. 1 and 3, the diamond coating produced by the invention has the effect similar to that of the coating obtained after acid-base pretreatment.

Example 2

The adhesion of the CVD diamond coating was studied using a Rockwell C indentation experiment. In the experiment, a standard 120-degree conical Rockwell diamond indenter is used for penetrating the diamond coating, and 100N, 200N and 300N of loads perpendicular to the direction of the substrate are respectively applied to the indenter to obtain indentation marks of the diamond coating. And then, the sample surface after the Rockwell indentation experiment is characterized by using SEM, and indentation marks and the damage degree of the coating are observed. The indentation morphology of the diamond coating without acid-base pretreatment added particles prepared in example 1 under the load of 100, 200 and 300N is shown in FIG. 6.

It can be observed from fig. 6 that the maximum crack diameters of the coatings are similar at the same load. This indicates that the quality of the coating grown from the added particles did not degrade. By comparing with the indentation experiment of the coating grown after pretreatment, the effect of the coating grown by adding the particles without the acid-base pretreatment of the matrix is similar to the effect of the coating grown by pretreatment in resisting cracks.

Example 3

(1) Surface treatment of substrates

Step 1: polishing the surface of a hard alloy matrix on 1500-mesh abrasive paper by using diamond micro powder, and removing partial impurities on the surface of the matrix; and then using 200-mesh sand paper to match with the diamond micropowder to continuously grind the substrate to obtain a smooth substrate surface with a plurality of small pits.

Step 2: and continuously washing the surface of the substrate for 10 minutes by using deionized water to remove the redundant large-particle diamond micro powder and other impurities on the surface of the substrate.

And step 3: and soaking the substrate material in an acetone solution for 20 minutes of ultrasonic cleaning to remove impurities on the surface of the substrate.

And 4, step 4: and (3) putting the treated substrate into a constant-temperature air-blast drying oven to dry the surface, wherein the temperature of the constant-temperature air-blast drying oven is set to be 60 ℃.

(2) Wet-process dispersion particles

Firstly preparing solid particle solution, weighing solid particle powder with the mass of 0.05g by using an electronic balance, weighing 100mL of 90% ethanol solution by using a measuring cylinder, and putting the solid particles into the ethanol solution. The solution is stirred evenly by a stirrer and is put into an ultrasonic machine for ultrasonic dispersion for 10 minutes. Sucking the solution by a rubber head dropper, dropping the solution on the surface of the dried clean hard alloy substrate, and stably putting the substrate into an air-blast drying oven for drying at a constant temperature of 60 ℃.

(3) CVD diamond preparation

The invention adopts a hot wire chemical vapor deposition method, uses metal tantalum wires as hot wires, uses hydrogen and acetone as reaction gases, and uses the acetone to provide carbon-containing radicals. The hydrogen and acetone flow rates were set at 240sccm and 90sccm, respectively, with a nucleation time of 30 minutes and a coating growth time of 4 hours. The technological structure parameters are set to be that four tantalum wires with the diameter of 6mm and the interval of 20mm are uniformly distributed, the power is set to be 4.5KW, the distance between the surface of the substrate and the tantalum wires is 10mm, the pressure of a vacuum chamber in a nucleation stage is 1.5-2.0 kPa, and the pressure in a growth stage is 4.0-5.0 kPa. In the whole deposition process, the temperature of the hot wire is kept about 2200 ℃, and the surface temperature of the substrate is about 800-900 ℃.

The coating deposited on the cemented carbide substrate showed large areas of flaking off as shown in fig. 7. This indicates that the concentration of 0.5g/L is less particles, so that the graphitization of the coating reduces the adhesion between the coating and the cemented carbide substrate.

Example 4

(1) Surface treatment of substrates

Step 1: polishing the surface of a hard alloy matrix on 1500-mesh abrasive paper by using diamond micro powder, and removing partial impurities on the surface of the matrix; and then using 200-mesh sand paper to match with the diamond micropowder to continuously grind the substrate to obtain a smooth substrate surface with a plurality of small pits.

Step 2: and continuously washing the surface of the substrate for 10 minutes by using deionized water to remove the redundant large-particle diamond micro powder and other impurities on the surface of the substrate.

And step 3: and soaking the substrate material in an acetone solution for 20 minutes of ultrasonic cleaning to remove impurities on the surface of the substrate.

And 4, step 4: and (3) putting the treated substrate into a constant-temperature air-blast drying oven to dry the surface, wherein the temperature of the constant-temperature air-blast drying oven is set to be 60 ℃.

(2) Wet-process dispersion particles

Firstly preparing solid particle solution, weighing solid particle powder with the mass of 0.2g by using an electronic balance, weighing 100mL of 90% ethanol solution by using a measuring cylinder, and putting the solid particles into the ethanol solution. The solution is stirred evenly by a stirrer and is put into an ultrasonic machine for ultrasonic dispersion for 10 minutes. Sucking the solution by a rubber head dropper, dropping the solution on the surface of the dried clean hard alloy substrate, and stably putting the substrate into an air-blast drying oven for drying at a constant temperature of 60 ℃.

(3) CVD diamond preparation

The invention adopts a hot wire chemical vapor deposition method, uses metal tantalum wires as hot wires, uses hydrogen and acetone as reaction gases, and uses the acetone to provide carbon-containing radicals. The hydrogen and acetone flow rates were set at 240sccm and 90sccm, respectively, with a nucleation time of 30 minutes and a coating growth time of 4 hours. The technological structure parameters are set to be that four tantalum wires with the diameter of 6mm and the interval of 20mm are uniformly distributed, the power is set to be 4.5KW, the distance between the surface of the substrate and the tantalum wires is 10mm, the pressure of a vacuum chamber in a nucleation stage is 1.5-2.0 kPa, and the pressure in a growth stage is 4.0-5.0 kPa. In the whole deposition process, the temperature of the hot wire is kept about 2200 ℃, and the surface temperature of the substrate is about 800-900 ℃.

When the concentration of the particles is 2g/L, the grown diamond coating also falls off in a large area, as shown in FIG. 8. This indicates that too high a concentration of particles will also reduce the adhesion between the diamond coating and the substrate.

It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.