阅读说明：本技术 基于激光辐照的dlc-纳米金刚石复合涂层制备方法 (DLC-nano diamond composite coating preparation method based on laser irradiation ) 是由 崔雨潇 郭平 马家豪 戚厚军 于 2020-11-30 设计创作，主要内容包括：一种基于激光辐照的DLC-纳米金刚石复合涂层制备方法,包括：对纳米金刚石涂层表面进行预处理；将飞秒激光光束聚焦在预处理后的纳米金刚石涂层表面晶粒顶端,进行飞秒激光刻蚀扫描处理,将纳米金刚石涂层表层纳米金刚石团簇原位诱变为类金刚石；3)对类金刚石-纳米金刚石复合涂层进行后处理。本发明不仅能够在纳米金刚石涂层表面制备类金刚石薄膜,同时大幅改善类金刚石-纳米金刚石复合涂层的表面粗糙度,具有显著增益效果。本发明获得的类金刚石-纳米金刚石复合涂层的表面粗糙度大幅降低,在摩擦过程中可显著降低摩擦副的摩擦系数和对磨面的磨损量。本发明的制备方法工艺简单,成本低廉,非常适合于干摩擦及水润滑工况。(A DLC-nano diamond composite coating preparation method based on laser irradiation comprises the following steps: pretreating the surface of the nano diamond coating; focusing a femtosecond laser beam on the top end of the crystal grains on the surface of the pretreated nano-diamond coating, performing femtosecond laser etching scanning treatment, and carrying out in-situ mutagenesis on nano-diamond clusters on the surface of the nano-diamond coating to obtain diamond-like carbon; 3) and carrying out post-treatment on the diamond-like carbon-nano diamond composite coating. The invention not only can prepare the diamond-like film on the surface of the nano diamond coating, but also greatly improves the surface roughness of the diamond-like-nano diamond composite coating, and has obvious gain effect. The surface roughness of the diamond-like carbon-nano diamond composite coating obtained by the invention is greatly reduced, and the friction coefficient of a friction pair and the abrasion loss of a grinding surface can be obviously reduced in the friction process. The preparation method has simple process and low cost, and is very suitable for dry friction and water lubrication working conditions.)

1. A DLC-nano diamond composite coating preparation method based on laser irradiation is characterized by comprising the following steps:

1) pretreating the surface of the nano diamond coating;

2) focusing a femtosecond laser beam on the top end of the crystal grains on the surface of the pretreated nano-diamond coating, performing femtosecond laser etching scanning treatment, and carrying out in-situ mutagenesis on nano-diamond clusters on the surface of the nano-diamond coating to obtain diamond-like carbon;

3) and carrying out post-treatment on the diamond-like carbon-nano diamond composite coating.

2. The preparation method of the diamond-like carbon-nano diamond composite coating based on femtosecond laser irradiation in-situ mutagenesis according to claim 1, wherein the grain diameter of the nano diamond coating crystal grains on the surface of the nano diamond coating in the step 1) is 50-100 nm.

3. The preparation method of the diamond-like carbon-nano diamond composite coating based on femtosecond laser irradiation in-situ mutagenesis according to claim 1, wherein the surface roughness of the nano diamond coating in the step 1) is Ra 70-100 nm.

4. The preparation method of the diamond-like carbon-nano diamond composite coating based on femtosecond laser irradiation in-situ mutagenesis according to the claim 1, characterized in that the pretreatment of the step 1) is to immerse the nano diamond coating into a suspension prepared by diamond micro powder and glycerol for ultrasonic grinding for 5min, wherein the grain diameter of the diamond micro powder is 2-5 μm, then immerse the nano diamond coating into absolute ethyl alcohol for ultrasonic cleaning for 5min, and then dry the diamond coating.

5. The preparation method of the diamond-like carbon-nano diamond composite coating based on femtosecond laser irradiation in-situ mutagenesis as claimed in claim 4, wherein the ratio of the diamond micro powder to the glycerol in the suspension prepared from the diamond micro powder and the glycerol is 1: 1.

6. The method for preparing the diamond-like carbon-nano diamond composite coating based on femtosecond laser irradiation in-situ mutagenesis according to claim 1, wherein the energy density of the femtosecond laser in the step 2) is 0.34-0.68J/cm²The pulse width was 200fs, the repetition frequency was 50MHz, and the spot diameter was 10 μm.

7. The preparation method of the diamond-like carbon-nano diamond composite coating based on femtosecond laser irradiation in-situ mutagenesis according to claim 1, wherein the etching scanning interval of the femtosecond laser in the step 2) is 3-5 μm.

8. The method for preparing a diamond-like carbon-nano diamond composite coating based on femtosecond laser irradiation in-situ mutagenesis according to claim 1, wherein the post-treatment in the step 3) is to place the diamond-like carbon-nano diamond coating in absolute ethyl alcohol for ultrasonic treatment for 5min to remove impurities remained on the surface of the diamond-like carbon-nano diamond composite coating after the femtosecond laser irradiation.

9. The preparation method of the diamond-like carbon-nano diamond composite coating based on femtosecond laser irradiation in-situ mutagenesis according to claim 1, wherein after the post-treatment in the step 3), the surface roughness of the finished diamond-like carbon-nano diamond composite coating is Ra 15-30 nm, and the thickness of the diamond-like carbon film on the surface layer is 50-100 nm.

Technical Field

The invention relates to a preparation method of a composite coating. In particular to a preparation method of DLC-nano diamond composite coating based on laser irradiation.

Background

The nano diamond coating has excellent mechanical properties and physical properties such as high hardness, high elastic modulus, extremely low friction coefficient, good self-lubricating property, extremely high thermal conductivity and chemical stability, small dielectric constant, wide band gap and the like, and has wide application prospect in the fields of wear-resistant and anti-friction devices and biological implantation devices. However, the surface roughness of the nano-diamond coating prepared by the chemical vapor deposition process is relatively high, and it is not generally directly applicable to the above-mentioned fields. Furthermore, the high surface roughness of the nanodiamond coating tends to result in a relatively high coefficient of friction during rubbing and high wear on the abraded surface.

However, the diamond material has extremely high hardness, the efficiency of the traditional mechanical polishing process is low, curved surfaces are difficult to polish, scratches are easily generated on the surface of the diamond coating, the application of the diamond coating in the field is influenced, and the diamond material is difficult to be directly applied to the precise polishing of the CVD diamond coating. Some researchers have proposed chemical polishing of diamond coatings by utilizing the characteristic that diamond is converted into graphite under certain conditions, but these polishing methods often require the use of special polishing solutions and finally bring about the problem of environmental pollution.

In addition to polishing, the application of solid lubricants to the diamond coated surface is another way to reduce the coefficient of friction of the diamond coating and its amount of wear on the abraded surface. DLC (Diamond-like carbon) film is a film having sp²And sp³The amorphous carbon film has excellent self-lubricating property. The nano-diamond film is simultaneously polished and the diamond-like film is expected to further improve the frictional wear performance of the nano-diamond coating, however, the conventional polishing and diamond-like film preparation composite process is very complicated and has high cost.

Disclosure of Invention

The invention aims to solve the technical problem of providing a DLC-nano diamond composite coating preparation method based on laser irradiation, which can greatly improve the surface roughness of the diamond-like carbon-nano diamond composite coating.

The technical scheme adopted by the invention is as follows: a DLC-nano diamond composite coating preparation method based on laser irradiation comprises the following steps:

1) pretreating the surface of the nano diamond coating;

2) focusing a femtosecond laser beam on the top end of the crystal grains on the surface of the pretreated nano-diamond coating, performing femtosecond laser etching scanning treatment, and carrying out in-situ mutagenesis on nano-diamond clusters on the surface of the nano-diamond coating to obtain diamond-like carbon;

3) and carrying out post-treatment on the diamond-like carbon-nano diamond composite coating.

The grain size of the nano diamond coating grains on the surface of the nano diamond coating in the step 1) is 50-100 nm.

The surface roughness of the nano diamond coating in the step 1) is Ra 70-100 nm.

The pretreatment of the step 1) is to immerse the nano diamond coating into a suspension prepared from diamond micro powder and glycerol, perform ultrasonic grinding for 5min, wherein the particle size of the diamond micro powder is 2-5 mu m, then immerse the nano diamond coating into absolute ethyl alcohol, perform ultrasonic cleaning for 5min, and then dry the nano diamond coating.

The ratio of the diamond micro powder to the glycerin in the suspension prepared from the diamond micro powder and the glycerin is 1: 1.

The energy density of the femtosecond laser in the step 2) is 0.34-0.68J/cm²The pulse width was 200fs, the repetition frequency was 50MHz, and the spot diameter was 10 μm.

And 2) the etching scanning interval of the femtosecond laser is 3-5 mu m.

And 3) performing post-treatment, namely placing the diamond-like carbon-nano diamond coating in absolute ethyl alcohol for ultrasonic treatment for 5min, and removing impurities remained on the surface of the diamond-like carbon-nano diamond composite coating after femtosecond laser irradiation.

And 3) after post-treatment, the surface roughness of the finished diamond-like carbon-nano diamond composite coating is Ra 15-30 nm, and the thickness of the surface diamond-like carbon film is 50-100 nm.

The method for preparing the DLC-nano diamond composite coating based on laser irradiation not only can prepare the diamond-like film on the surface of the nano diamond coating, but also greatly improves the surface roughness of the diamond-like film-nano diamond composite coating, and has obvious gain effect. According to the invention, a femtosecond laser irradiation method is adopted to induce the diamond component on the surface layer of the nano-diamond coating into the diamond-like component in situ, so that the surface roughness of the obtained diamond-like-nano-diamond composite coating is greatly reduced compared with the nano-diamond coating which is not subjected to femtosecond laser irradiation, and the friction coefficient of a friction pair and the abrasion loss to a grinding surface can be obviously reduced in the friction process. The preparation method has simple process and low cost, and is very suitable for dry friction and water lubrication working conditions.

Drawings

FIG. 1 is a polishing flow chart of the laser irradiation-based DLC-nanodiamond composite coating preparation method of the present invention;

fig. 2 is an SEM picture of the surface topography of an example prepared diamond-like-nanodiamond composite coating;

figure 3 is an SEM picture of the cross-sectional morphology of the diamond-like-nanodiamond composite coating prepared in example 1;

FIG. 4 is an XPS spectrum of a diamond-like-nanodiamond composite coating prepared in example 1;

figure 5 is an SEM picture of the surface topography of the diamond-like-nanodiamond composite coating prepared in example 2;

figure 6 is an SEM picture of the cross-sectional morphology of the diamond-like-nanodiamond composite coating prepared in example 2.

Detailed Description

The method for preparing DLC-nanodiamond composite coating layer based on laser irradiation according to the present invention will be described in detail with reference to the following examples and accompanying drawings.

As shown in FIG. 1, the preparation method of the DLC-nanodiamond composite coating based on laser irradiation comprises the following steps:

1) pretreating the surface of the nano diamond coating; wherein the content of the first and second substances,

the grain size of the nano diamond coating grains on the surface of the nano diamond coating is 50-100 nm. The surface roughness of the nano diamond coating is Ra 70-100 nm.

And the pretreatment comprises the steps of immersing the nano diamond coating into turbid liquid prepared from diamond micro powder and glycerol, carrying out ultrasonic grinding for 5min, immersing the diamond micro powder with the particle size of 2-5 mu m into absolute ethyl alcohol, carrying out ultrasonic cleaning for 5min, and drying. The ratio of the diamond micro powder to the glycerin in the suspension prepared from the diamond micro powder and the glycerin is 1: 1.

2) Focusing a femtosecond laser beam on the top end of the crystal grain on the surface of the pretreated nano-diamond coating, performing femtosecond laser etching scanning treatment, and carrying out in-situ mutagenesis on the nano-diamond cluster on the surface of the nano-diamond coating to obtain diamond-like carbon (DLC); wherein the content of the first and second substances,

the energy density of the femtosecond laser is 0.34-0.68J/cm²The pulse width was 200fs, the repetition frequency was 50MHz, and the spot diameter was 10 μm. The etching scanning interval of the femtosecond laser is 3-5 mu m.

3) Carrying out post-treatment on the diamond-like carbon-nano diamond composite coating; wherein the content of the first and second substances,

the post-treatment is to place the diamond-like carbon-nano diamond coating in absolute ethyl alcohol for ultrasonic treatment for 5min to remove impurities remained on the surface of the diamond-like carbon-nano diamond composite coating after femtosecond laser irradiation.

After post-treatment, the surface roughness of the finished diamond-like carbon-nano diamond composite coating is Ra 15-30 nm, and the thickness of the diamond-like carbon film on the surface layer is 50-100 nm.

The method for preparing the laser irradiation-based DLC-nanodiamond composite coating according to the present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

Example 1:

the nano diamond coating with the grain size of 50nm and the surface roughness Ra 70nm is taken as an object to carry out femtosecond laser irradiation. Firstly, preprocessing the surface of a nano diamond coating, immersing the nano diamond coating into turbid liquid prepared from diamond micro powder and glycerol, carrying out ultrasonic grinding for 5min, wherein the particle size of the diamond micro powder is 2 mu m, then immersing the nano diamond coating into absolute ethyl alcohol, carrying out ultrasonic cleaning for 5min, and then drying.

The pulse width is 200fs, and the energy density is 0.34J/cm²And the femtosecond laser with the repetition frequency of 50MHz and the spot diameter of 10 μm focuses the femtosecond laser beam on the surface of the micron diamond coating, and performs femtosecond laser irradiation scanning treatment with the scanning interval of 3 μm. And (3) carrying out in-situ mutagenesis on the nano-diamond component on the nano-diamond surface layer into the diamond-like component by femtosecond laser irradiation.

And (3) placing the diamond-like carbon-nano diamond composite coating in absolute ethyl alcohol for ultrasonic treatment for 5min, and removing impurities remained on the surface of the diamond-like carbon-nano diamond composite coating after femtosecond laser irradiation.

The thickness of the diamond-like carbon film on the surface layer of the prepared diamond-like carbon-nano diamond composite coating is 50nm, and the surface roughness is reduced from Ra 70nm to 30 nm.

Fig. 2 is an SEM picture of the surface topography of the diamond-like-nano diamond composite coating prepared in this example. Fig. 3 is an SEM picture of the cross-sectional morphology of the diamond-like-nano diamond composite coating prepared in this example. Fig. 4 is an XPS spectrum of the diamond-like-nanodiamond composite coating prepared in this example.

Example 2:

the nano diamond coating with the grain size of 100nm and the surface roughness Ra 100nm is taken as an object to carry out femtosecond laser irradiation. Firstly, preprocessing the surface of a nano diamond coating, immersing the nano diamond coating into turbid liquid prepared from diamond micro powder and glycerol, carrying out ultrasonic grinding for 5min, wherein the particle size of the diamond micro powder is 5 mu m, then immersing the nano diamond coating into absolute ethyl alcohol, carrying out ultrasonic cleaning for 5min, and then drying.

The pulse width is 200fs, and the energy density is 0.68J/cm²A femtosecond laser with repetition frequency of 50MHz and spot diameter of 10 μmThe femtosecond laser beam is focused on the surface of the micron diamond coating, and the femtosecond laser irradiation scanning treatment is carried out, wherein the scanning distance is 5 mu m. And (3) carrying out in-situ mutagenesis on the nano-diamond component on the nano-diamond surface layer into the diamond-like component by femtosecond laser irradiation.

And (3) placing the diamond-like carbon-nano diamond composite coating in absolute ethyl alcohol for ultrasonic treatment for 5min, and removing impurities remained on the surface of the diamond-like carbon-nano diamond composite coating after femtosecond laser irradiation.

The thickness of the diamond-like film on the surface layer of the prepared diamond-like-nano diamond composite coating is 100nm, and the surface roughness is reduced from Ra 100nm to 15 nm.

Fig. 5 is an SEM picture of the surface topography of the diamond-like-nanodiamond composite coating prepared in this example. Fig. 6 is an SEM picture of the cross-sectional morphology of the diamond-like-nano diamond composite coating prepared in this example.

Example 3:

the nano diamond coating with the grain size of 50nm and the surface roughness Ra 80nm is taken as an object to carry out femtosecond laser irradiation. Firstly, preprocessing the surface of a nano diamond coating, immersing the nano diamond coating into turbid liquid prepared from diamond micro powder and glycerol, carrying out ultrasonic grinding for 5min, wherein the particle size of the diamond micro powder is 3.5 mu m, then immersing the nano diamond coating into absolute ethyl alcohol, carrying out ultrasonic cleaning for 5min, and then drying.

The pulse width is 200fs, and the energy density is 0.5J/cm²And the femtosecond laser with the repetition frequency of 50MHz and the spot diameter of 10 μm focuses the femtosecond laser beam on the surface of the micron diamond coating, and performs femtosecond laser irradiation scanning treatment with the scanning interval of 4 μm. And (3) carrying out in-situ mutagenesis on the nano-diamond component on the nano-diamond surface layer into the diamond-like component by femtosecond laser irradiation.

And (3) placing the diamond-like carbon-nano diamond composite coating in absolute ethyl alcohol for ultrasonic treatment for 5min, and removing impurities remained on the surface of the diamond-like carbon-nano diamond composite coating after femtosecond laser irradiation.

The thickness of the diamond-like film on the surface layer of the prepared diamond-like-nano diamond composite coating is 100nm, and the surface roughness is reduced from Ra 80nm to 30 nm.