阅读说明：本技术 一种硼氮化钼/硫化钼纳米复合涂层及其制备方法 (Molybdenum boron nitride/molybdenum sulfide nano composite coating and preparation method thereof ) 是由 朱晓东 王大伟 李倩叶 李雁淮 宋忠孝 于 2020-06-17 设计创作，主要内容包括：本发明公开了一种硼氮化钼/硫化钼纳米复合涂层及其制备方法,采用反应磁控溅射技术阴极溅射金属Mo和B<Sub>4</Sub>C、MoS<Sub>2</Sub>复合靶,并与真空室中Ar和N<Sub>2</Sub>混合气体中的N<Sub>2</Sub>气反应,在基底表面获得了Mo-B-S-C-N五元硬质涂层,即硼氮化钼/硫化钼纳米复合涂层,通过调节复合靶中B<Sub>4</Sub>C及MoS<Sub>2</Sub>的面积,使该涂层中B和S的含量容易控制。涂层中B、C、S、Mo、N元素的原子百分比为0.5～12％、2～14％、0.5～10％、55～40％、42～24％。该方法工艺简单,易于实施。本发明克服了现有硬质镀层摩擦学性能的不足,兼备硬度高、耐磨和室温到高温低摩擦系数的特点,在高速或干切削工具上具有良好的应用前景和推广价值。(The invention discloses a boron-molybdenum nitride/molybdenum sulfide nano composite coating and a preparation method thereof, and the reactive magnetron sputtering technology is adopted to sputter metal Mo and metal B 4 C、MoS 2 Compounding the target with Ar and N in a vacuum chamber 2 N in the mixed gas 2 Gas reaction is carried out to obtain a Mo-B-S-C-N quinary hard coating on the surface of the substrate, namely a boron-molybdenum nitride/molybdenum sulfide nano composite coating, and B in the composite target is adjusted 4 C and MoS 2 The area of (a) allows easy control of the content of B and S in the coating. The atomic percentages of B, C, S, Mo and N in the coating are 0.5-12%, 2-14%, 0.5-10%, 55-40% and 42-24%. The method has simple process and is easy to implement. The invention overcomes the defects of the tribological performance of the existing hard coating, has the characteristics of high hardness, wear resistance and low friction coefficient from room temperature to high temperature, and has good application prospect and popularization value on high-speed or dry cutting tools.)

1. The boron nitride molybdenum/molybdenum sulfide nano composite coating is characterized in that: the boron-molybdenum nitride/molybdenum sulfide nano composite coating is a Mo-B-S-C-N five-element coating, wherein the atomic percent of Mo element is 55-40%, the atomic percent of N element is 42-24%, the atomic percent of B element is 0.5-12%, the atomic percent of C element is 2-14%, and the atomic percent of S element is 0.5-10%.

2. The molybdenum boron nitride/molybdenum sulfide nanocomposite coating according to claim 1, wherein: the hardness of the boron nitride molybdenum/molybdenum sulfide nano composite coating is 19-27 GPa, the friction coefficient at normal temperature is not less than 0.19, and the friction coefficient at 600 ℃ is not less than 0.15.

3. The method for preparing the boron nitride/molybdenum sulfide nano composite coating according to claim 1, comprising the following steps:

1) will consist of metal Mo and B₄C and MoS₂The formed composite target and the substrate are respectively arranged on a cathode and a sample stage in a vacuum chamber of magnetron sputtering equipment;

2) vacuumizing a vacuum chamber of a magnetron sputtering device, introducing argon gas, starting glow discharge, and applying negative bias to a substrate for sputtering cleaning;

3) introducing argon and nitrogen into a vacuum chamber of a magnetron sputtering device, carrying out magnetron sputtering on the composite target, and applying negative bias to the substrate in the deposition process to bombard by using nitrogen ions to obtain the boron-molybdenum nitride/molybdenum sulfide nano composite coating.

4. The method for preparing a molybdenum boronitride/molybdenum sulfide nanocomposite coating according to claim 3, wherein: the metal Mo and (B) in the composite target₄C and MoS₂) The area ratio is 10:1 to 7:3, wherein B₄C and MoS₂The area ratio is 5: 1-1: 5, the purity of Mo is 99.99%, B₄C and MoS₂The purity of (C) is 99.9%, and the distance between the composite target and the substrate is 80 to120mm。

5. The method for preparing a molybdenum boronitride/molybdenum sulfide nanocomposite coating according to claim 3, wherein: the substrate is a metal substrate or a ceramic substrate, wherein the metal substrate is steel, cast iron or hard alloy.

6. The method for preparing a molybdenum boronitride/molybdenum sulfide nanocomposite coating according to claim 3, wherein: in the step 2), the vacuum degree in the vacuum chamber of the magnetron sputtering equipment is pumped to be less than or equal to 5 multiplied by 10^-4And after Pa, applying negative bias of 400-800V to the substrate, and sputtering and cleaning the surface of the substrate for at least 10min by utilizing argon ions.

7. The method for preparing a molybdenum boronitride/molybdenum sulfide nanocomposite coating according to claim 3, wherein: the flow ratio of the argon to the nitrogen introduced in the step 3) is 5: 1-1: 10, and the working pressure is 0.1-2 Pa.

8. The method for preparing a molybdenum boronitride/molybdenum sulfide nanocomposite coating according to claim 3, wherein: the magnetron sputtering power in the step 3) is 100-300W, and the time is 120-240 min.

9. The method for preparing a molybdenum boronitride/molybdenum sulfide nanocomposite coating according to claim 3, wherein: and 3) in the step 3), negative bias is applied to the substrate to be 40-120V in the deposition process, and nitrogen ions are utilized to carry out auxiliary bombardment on the coating in the deposition process.

10. The method for preparing a molybdenum boronitride/molybdenum sulfide nanocomposite coating according to claim 3, wherein: and in the step 3), after the magnetron sputtering is finished, stopping introducing the argon and the nitrogen, and keeping a vacuum state until the substrate temperature is less than or equal to 60 ℃.

Technical Field

The invention belongs to the technical field of material surface coatings, and particularly relates to a boron-molybdenum nitride/molybdenum sulfide nano composite coating and a preparation method thereof.

Background

With the development of cutting technology, particularly in certain high-speed cutting and other specific processing conditions, such as deep hole processing and some complex processing environments, when the cutting fluid cannot be sufficiently lubricated and cooled, the requirements on the performance of the cutter material are higher. Under high-speed cutting conditions or when partial lubrication and cooling are insufficient, a large amount of cutting heat is generated due to friction, so that a cutter is gradually bonded and abraded to cause failure, and the processing quality of a workpiece is reduced. This means that the tool itself needs to have high hardness, good wear resistance, stable chemical properties, resistance to heat and oxidation, low friction coefficient, etc. The low-friction-coefficient hard coating with both wear-resisting and wear-resisting characteristics can reduce the friction and wear of workpieces, reduce or replace liquid lubrication and cooling, save equipment investment, avoid environmental pollution caused by cutting fluid and realize clean production, so that the cutting tool is an efficient and clean green cutting tool and has a quite wide application prospect in the modern cutting and machining industry.

The molybdenum nitride has high hardness, and the friction coefficient is far lower than that of nitride of other transition group metals such as TiN and the like. Although the friction coefficient of the molybdenum nitride coating is low at high temperature, the molybdenum nitride coating is easily oxidized to cause reduction in strength hardness and insufficient wear resistance. The oxidation resistance and the hardness of the molybdenum nitride coating are improved by an alloying method, and meanwhile, the friction coefficient of the coating is further reduced, so that the application field and the use condition of the molybdenum nitride coating can be expanded. At present, no report is found in documents for researching the Mo-B-S-C-N quinary coating.

Disclosure of Invention

The invention aims to provide a boron molybdenum nitride/molybdenum sulfide nano composite coating and a preparation method thereof.

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

a preparation method of a boron-molybdenum nitride/molybdenum sulfide nano composite coating comprises the following steps:

1) will be made of metal MoAnd B₄C and MoS₂The formed composite target and the substrate are respectively arranged on a cathode and a sample stage in a vacuum chamber of magnetron sputtering equipment;

2) vacuumizing a vacuum chamber of a magnetron sputtering device, and then sputtering and cleaning the surface of the substrate by using argon ions;

3) and introducing argon and nitrogen into a vacuum chamber of the magnetron sputtering equipment, carrying out magnetron sputtering on the composite target, and carrying out auxiliary bombardment on the coating in deposition by using nitrogen ions in the deposition process to obtain the boron-molybdenum nitride/molybdenum sulfide nano composite coating.

The metal Mo and (B) in the composite target₄C and MoS₂) The area ratio of (A) to (B) is 10:1 to 7:3, wherein B₄C and MoS₂The area ratio is 5: 1-1: 5, the purity of Mo is 99.99%, B₄C and MoS₂The purity of the composite target is 99.9%, and the distance between the composite target and the substrate is 80-120 mm.

The substrate is a metal substrate or a ceramic substrate, wherein the metal substrate is steel, cast iron or hard alloy.

In the step 2), the vacuum degree in the vacuum chamber of the magnetron sputtering equipment is pumped to be less than or equal to 5 multiplied by 10^-4And after Pa, applying negative bias of 400-800V to the substrate, and sputtering and cleaning the surface of the substrate for at least 10min by utilizing argon ions.

The flow ratio of the argon to the nitrogen introduced in the step 3) is 1: 1-1: 10, and the working pressure is 0.1-2 Pa.

The magnetron sputtering power in the step 3) is 100-300W, and the time is 120-240 min.

And 3) in the step 3), negative bias of 40-120V is applied to the substrate in the deposition process, and nitrogen ions and argon ions are utilized to carry out auxiliary bombardment on the coating in the deposition process.

And in the step 3), after the magnetron sputtering is finished, stopping introducing the argon and the nitrogen, and keeping a vacuum state until the substrate temperature is less than or equal to 60 ℃.

The molybdenum boron nitride/molybdenum sulfide nano composite coating prepared by the preparation method is a Mo-B-S-C-N quinary coating, wherein the atomic percent of Mo is 55-40%, the atomic percent of N is 42-24%, the atomic percent of B is 0.5-12%, the atomic percent of C is 2-14%, and the atomic percent of S is 0.5-10%.

The hardness of the boron nitride molybdenum/molybdenum sulfide nano composite coating is 19-27 GPa, the friction coefficient at normal temperature is not less than 0.19, and the friction coefficient at 600 ℃ is not less than 0.15.

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

the preparation method of the boron molybdenum nitride/molybdenum sulfide nano composite coating provided by the invention selects proper metal Mo and B on the basis of the molybdenum nitride coating₄C and MoS₂Composite target and corresponding sputtering technological parameters, and adopts reaction magnetron sputtering technology to sputter metal Mo and metal B at cathode₄C and MoS₂Compounding the target with Ar and N in a vacuum chamber₂N in the mixed gas₂Gas reaction is carried out to form a Mo-B-S-C-N quinary hard coating with appropriate B, C, S element content, namely a boron-molybdenum nitride/molybdenum sulfide nano composite coating on the surface of the substrate, and B in the composite target is adjusted₄C and MoS₂The occupied area of the target ensures that the content of B and S in the coating is easy to control, and the method has simple process and is easy to implement.

The boron molybdenum nitride/molybdenum sulfide nano composite coating (Mo-B-S-C-N quinary hard coating) provided by the invention is 0.5-12%, 2-14%, 0.5-10%, 55-40% and 42-24% of B, C, S, Mo and N elements respectively in atomic percentage. The coating overcomes the defects of the existing hard coating in the aspect of performance and tribology, has the characteristics of high hardness, wear resistance and low friction coefficient at room temperature and high temperature, and has good popularization and application prospects on high-speed cutting or dry cutting tools.

Further experiments show that the hardness of the boron molybdenum nitride/molybdenum sulfide nano composite coating (Mo-B-S-C-N quinary hard coating) prepared by the invention can reach 27GPa, the friction coefficient at room temperature is as low as 0.19, the friction coefficient at 600 ℃ is as low as 0.15, and the wear rate is less than 1/80 of the molybdenum nitride coating.

Drawings

FIG. 1 shows Mo and B metals used in the present invention₄C and MoS₂The structural schematic diagram of the formed composite target;

FIG. 2 is an XRD pattern of the molybdenum boron nitride/molybdenum sulfide nanocomposite coating prepared by the invention;

FIG. 3 is a graph showing the relationship between the hardness of the boron nitride/molybdenum sulfide nanocomposite coating and the content of B, S;

FIG. 4 is a graph showing the relationship between the average friction coefficient of the boron-molybdenum nitride/molybdenum sulfide nanocomposite coating prepared by the method of the invention and the content of B, S.

FIG. 5 is a graph showing the relationship between the wear rate of the boron nitride/molybdenum sulfide nanocomposite coating and the content of B, S at room temperature.

FIG. 6 is a graph showing the relationship between the average friction coefficient of the boron-molybdenum nitride/molybdenum sulfide nanocomposite coating prepared by the method of the present invention and the content of B, S at 600 ℃.

FIG. 7 is a graph showing the relationship between the wear rate of the boron nitride/molybdenum sulfide nanocomposite coating prepared by the method of the present invention and the B, S content at 600 ℃.

Detailed Description

The invention prepares the boron-molybdenum nitride/molybdenum sulfide nano composite coating (Mo-B-S-C-N quinary coating) by adopting a molybdenum target (with the purity of 99.99 percent) and B₄C target (purity 99.9%) and MoS₂The target (purity 99.9%) is made into composite target, and is deposited on the substrate of metal, hard alloy or ceramic by means of direct-current magnetron sputtering, and is obtained by utilizing nitrogen ion and argon ion to make auxiliary bombardment under the action of negative bias voltage of the substrate. The thickness of the prepared boron molybdenum nitride/molybdenum sulfide nano composite coating (Mo-B-S-C-N quinary coating) is 1-5 mu m, the hardness is 17-27 GPa, the friction coefficient at normal temperature is 0.19 at the lowest, and the friction coefficient at high temperature (600 ℃) is 0.15 at the lowest. Wherein the atomic percentage of the C element is 2-14%, the atomic percentage of the B element is 0.5-12%, the atomic percentage of the S element is 0.5-10%, the atomic percentage of the Mo element is 55-40%, and the atomic percentage of the N element is 44-24%.

By combining the friction coefficient and the wear resistance at different temperatures, the more preferable range is 3-6 atomic percent of the S element and 4-12 atomic percent of the B element.

The preparation method of the molybdenum boron nitride/molybdenum sulfide nano composite coating provided by the invention comprises the following specific steps:

1) metal (steel, cast iron or hard alloy) or ceramic is taken as a substrate, and the substrate is fixed on a rotatable workpiece frame in a vacuum chamber after deoiling, oxide removal and hot air blow drying;

2) mixing high-purity Mo and a certain quantity of B₄C and MoS₂The composite target composed of target sheets is arranged on a magnetron sputtering source; metal Mo and (B) in composite target₄C and MoS₂) The area ratio of (A) to (B) is 10:1 to 7:3, wherein B₄C and MoS₂The area ratio is 5: 1-1: 5, the purity of Mo is 99.99%, B₄C and MoS₂The purity of the composite target is 99.9%, and the distance between the composite target and the substrate is 80-120 mm;

3) then the vacuum degree in the vacuum chamber is pumped to be less than or equal to 5 multiplied by 10^-4Pa, introducing Ar with the flow rate of 20sccm, and pre-sputtering Mo/B when the air pressure of the vacuum chamber is 0.3Pa₄C, compounding a target for 5min, wherein the pre-sputtering power is 150W;

4) introducing 6sccm argon gas into an ion source, applying negative bias of 400-800V to the substrate, and sputtering and cleaning the surface of the substrate for at least 10min by using argon ions generated by glow discharge;

5) and then introducing 4-10 sccm argon and 4-40 sccm nitrogen to form a mixed atmosphere, wherein the flow ratio of the argon to the nitrogen is 1: 1-1: 10, and the working pressure is 0.1-2 Pa.

6) Sputtering Mo/B in a vacuum chamber at a power of 100-300W in an argon-nitrogen mixed atmosphere₄And C, performing the composite target for 120-240 min, applying negative bias voltage of 40 eV-120V to the substrate, and performing auxiliary bombardment on the coating in deposition by using nitrogen ions and argon ions to prepare the boron-molybdenum nitride/molybdenum sulfide nano composite coating (Mo-B-S-C-N quinary hard coating).

The present invention will be described in detail below with reference to the drawings and examples, but the present invention is not limited to the examples.