CN107641795A - A kind of preparation method of the anti-friction wear-resistant coating under MoDTC lubricating conditions - Google Patents

Abstract

The invention provides a method for preparing a friction-reducing and wear-resistant coating under MoDTC lubrication conditions. The Al-Mg-Ti-B-N coating was prepared by using DC magnetron sputtering, and the coating with excellent friction properties was obtained by optimizing the process parameters. In combination with practical applications, the friction reducer MoDTC was further added to the engine oil , improving the friction and wear properties of Al‑Mg‑Ti‑B‑N coatings, compared with other non-ferrous based coatings (DLC) and bearing steels, Al‑Mg‑Ti‑B‑N coatings show their excellent Excellent anti-wear performance and good compatibility with MoDTC, as shown in Figures 3, 4, and 5. The reduction of friction and wear can effectively reduce fuel consumption and energy loss, thereby reducing exhaust gas emissions and waste of resources. The steps are simple, the operation is convenient and the practicability is strong.

Description

A kind of preparation method of anti-friction and wear-resisting coating under MoDTC lubrication condition

technical field

The invention belongs to the technical field of surface engineering and wear-resistant coating materials, and in particular relates to the preparation of a friction-reducing and wear-resistant coating.

Background technique

Due to the friction and wear of mechanical components, on the one hand, it will lead to a decrease in fuel efficiency and a large amount of waste pollution. On the other hand, due to poor lubrication, the friction coefficient will be too high and the friction loss will increase. Efforts are mainly carried out in two aspects: (1) to develop wear-resistant coatings on the surface of mechanical components (2) to develop engine oil additives with better lubricating properties. Molybdenum dialkyldithiocarbamate (MoDTC) is one of the most widely used organic molybdenum friction modifier additives, which can greatly reduce the friction coefficient after being added to engine oil. Its anti-friction mechanism is to reduce the friction coefficient by self-decomposing to form MoS ₂ friction film with weak van der Waals force between layers. MoDTC decomposes through Mo-S chemical bond electron transfer to form MoDTC core unit and chain end, further MoDTC core unit forms sulfur oxide, and the chain end recombines to form thiuram disulfide (including CS chemical bond), sulfur oxide continues to decompose to form MoS ₂ and MoO ₂ , MoO ₂ is oxidized to form MoO ₃ in the presence of oxygen. Research by C. Higdon et al. showed that MoO ₃ formed by the degradation of MoDTC during the friction process has adverse effects on surface friction and wear, which will lead to increased friction coefficient and increased wear, resulting in a large amount of energy loss and resource loss.

Al-Mg-Ti-B coatings have high hardness and anti-friction and anti-wear properties, and have broad application prospects in cutting tools and automotive components. Studies have shown that in lean oil lubrication conditions, compared with DLC coatings, Al-Mg-Ti-B coatings -Mg-Ti-B coating has better tribological properties.

Contents of the invention

In order to overcome the above disadvantages, the present invention provides an Al-Mg-Ti-B-N coating with good anti-wear and anti-friction performance under the action of MoDTC anti-friction additive.

In order to achieve the above object, the present invention adopts the following technical solutions:

The invention provides the application of nitrogen doping in improving the anti-wear and anti-friction performance of Al-Mg-Ti-B coating under MoDTC lubrication condition.

In order to improve the friction and wear properties of Al-Mg-Ti-B coatings in practical applications, the present invention proposes on the basis of systematic research on the wear mechanism of Al-Mg-Ti-B coatings under MoDTC lubrication conditions and a large number of experimental explorations: Using h-BN as a solid lubricant that can reduce the friction coefficient in the process of friction and wear, the Al-Mg-Ti-B coating was modified with nitrogen, and the MoDTC lubrication under high-speed and high-load boundary lubrication conditions was studied. Friction and wear behavior of Al-Mg-Ti-BN coatings, it was accidentally found that MoO ₃ was formed at the wear scars of Al-Mg-Ti-BN coatings without nitrogen doping under MoDTC lubrication conditions, while DC magnetic field under MoDTC lubrication conditions The nitrogen-doped Al-Mg-Ti-BN coating prepared by controlled sputtering only formed the MoS ₂ friction film at the wear scar, which indicated that the synergistic effect between the nitrogen-doped Al-Mg-Ti-BN coating and MoDTC could effectively inhibit the The formation of MoO ₃ has resulted in an Al-Mg-Ti-BN coating with excellent anti-wear and anti-friction properties under high-speed and high-load MoDTC lubrication conditions.

Application of nitrogen doping to inhibit MoDTC degradation to form MoO _on Al-Mg-Ti-B coating surface during friction process.

In order to further improve the friction and wear properties of Al-Mg-Ti-B-N coatings in practical applications, the present invention studies the friction and wear behavior of Al-Mg-Ti-B-N coatings under the lubrication conditions containing MoDTC. The Al-Mg-Ti-B-N coating prepared by DC magnetron sputtering under lubricated conditions has better anti-wear and anti-friction properties.

Preferably, the MoDTC lubricating condition is that the lubricating oil is composed of base oil PAO and 1wt% antifriction additive MoDTC, the viscosity is 0.006 Pas, and the lubrication state is boundary lubrication.

The present invention also provides a method for improving the anti-wear and anti-friction properties of the Al-Mg-Ti-B coating under MoDTC lubrication conditions, including:

Nitrogen doping is carried out on the Al-Mg-Ti-B coating to obtain the Al-Mg-Ti-B-N coating.

Preferably, the Al-Mg-Ti-B-N coating is prepared by the following method:

Substrate pretreatment, backsplash cleaning;

A Ti intermediate layer is plated on the surface of the substrate by DC magnetron sputtering;

The Al-Mg-Ti-B-N coating was deposited on the Ti interlayer by magnetron sputtering.

Preferably, the base is made of bearing steel.

More preferably, the specific steps of the substrate pretreatment are:

Treat the substrate with descaling water for 6-8 hours, wash it with deionized water, and soak it in antirust water overnight. The bearing steel treated with descaling and antirust water is ultrasonically treated with acetone and ethanol for 5-10 minutes, and then use high Blow dry with pure nitrogen.

More preferably, the specific steps of backsplash cleaning are as follows: put the substrate rack on the sample tray rack of the vacuum chamber, close the chamber, vacuum the back to 7.8×10 ^-4 Pa, and then ventilate the substrate into the system. Inject 45 sccm of argon gas, keep the air pressure at ~2.3Pa, and apply a bias voltage of 700V to the substrate for backsputter cleaning for 30 minutes.

More preferably, the specific steps of coating the Ti intermediate layer are as follows: using a metal Ti target, the sputtering atmosphere is Ar, the Ar gas flow is controlled at 30-50 sccm, the sputtering pressure is 0.6Pa, the target power is ~70W, and the time is controlled In 3min.

More preferably, the specific steps of depositing the Al-Mg-Ti-BN coating are as follows: use AlMgB ₁₄ -TiB ₂ prepared by hot pressing sintering method as the target material, the sputtering atmosphere is Ar and N ₂ , and the Ar gas flow rate is Controlled at 30-50sccm, N ₂ gas flow at 10-20sccm, sputtering pressure at 0.5Pa-1Pa, target power at 120W-130W, substrate bias at 100-150V, and time at 2h.

Beneficial effects of the present invention

(1) The present invention uses the method for DC magnetron sputtering to prepare Al-Mg-Ti-BN coating, by changing the N ₂ /Ar flow rate ratio Al-Mg-Ti-B coating structure and composition are modified, An Al-Mg-Ti-BN coating with excellent friction and wear properties suitable for high-speed and high-load MoDTC lubrication conditions was obtained. Compared with the non-nitrogen-doped Al-Mg-Ti-B coating, Al-Mg-Ti-BN The coating has a lower coefficient of friction, less wear and no MoO ₃ formation is seen at the wear marks of the coating, as shown in Figures 3, 4, and 5. The reduction of friction and wear can effectively reduce fuel consumption and energy loss, thereby reducing exhaust gas emissions and waste of resources.

(2) The preparation method of the present invention is simple, the anti-friction and anti-wear effect is good, the practicability is strong, and it is easy to popularize.

Description of drawings

The accompanying drawings constituting a part of the present application are used to provide further understanding of the present application, and the schematic embodiments and descriptions of the present application are used to explain the present application, and do not constitute improper limitations to the present application.

Fig. 1 is a schematic diagram of a friction and wear test Al-Mg-Ti-B-N coating sample;

Fig. 2 is a schematic diagram of the principle of magnetron sputtering;

Figure 3 is a comparison of the friction behavior of Al-Mg-Ti-B coatings without nitrogen doping and Al-Mg-Ti-B-N coatings under high-speed and high-load MoDTC lubrication conditions;

Figure 4 is a scanning electron microscope image of the wear scars of the non-nitrogen-doped Al-Mg-Ti-B coating and the Al-Mg-Ti-B-N coating lubricated by high-speed and high-load MoDTC;

Fig. 5 is the XPS spectrum at the wear scar of the non-nitrogen-doped Al-Mg-Ti-B coating and the Al-Mg-Ti-B-N coating lubricated by MoDTC at high speed and high load.

Detailed ways

It should be pointed out that the following detailed description is exemplary and intended to provide further explanation to the present application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

Al-Mg-Ti-B-N coatings with excellent friction and wear properties under high-load and high-speed conditions were prepared by changing the substrate bias voltage, working air pressure and power optimization process parameters, and controlling the N2/Ar flow ratio. layer, in order to compare the excellent friction and wear properties of Al-Mg-Ti-B-N coating, the Al-Mg-Ti-B coating without nitrogen was used as the control group, and the UMT-3 unidirectional rotating friction and wear tester was used to scan Electron microscopy and three-dimensional white light revealed the excellent friction behavior of Al-Mg-Ti-B-N coatings. The layer friction coefficient is as low as 0.02-0.03, and the scanning electron microscope shows that there is no obvious wear at the wear marks of the coating.

Example 1

1. Coating preparation method steps

(1) Substrate cleaning

Bearing steel is used as the coating base, and the base is treated with descaling water for 6-8 hours, cleaned with deionized water and soaked in anti-rust water for one night. The bearing steel treated with de-scaling and anti-rust water uses acetone and ethanol Sonicate for 5-10min and dry with high-purity nitrogen. Put the substrate rack on the sample tray rack of the vacuum chamber, close the chamber, evacuate the back to 7.8×10 ^-4 Pa, and then pass 45 sccm argon gas into the system, keep the air pressure at ~2.3Pa. Apply a bias voltage of 700V to the chip for backsplash cleaning for 30 minutes.

(2) Ti-plated intermediate layer

A Ti intermediate layer was plated on the surface of the substrate by DC magnetron sputtering. A metal Ti target is used, the sputtering atmosphere is Ar, the Ar gas flow is controlled at 30-50 sccm, the sputtering pressure is 0.6Pa, the target power is ~70W, and the time is controlled at 3min.

(3) Al-Mg-Ti-B-N-N coating

Al-Mg-Ti-BN coatings were deposited on the Ti interlayer using the magnetron sputtering method. Use AlMgB ₁₄ -TiB ₂ prepared by hot pressing sintering method as the target material, the sputtering atmosphere is Ar and N ₂ , the Ar gas flow is controlled at 30-50 sccm, the N ₂ gas flow is controlled at 10-20 sccm, and the sputtering pressure is 0.5 Pa-1Pa, the target power is 120W-130W, the substrate bias is 100-150V, and the time is controlled at 2h.

2. Friction and wear test

The invention uses a unidirectional rotational friction motion method to study the friction and wear properties of the coating, and the unidirectional rotational motion method is mainly applicable to gears, bearings and other mechanical components with unidirectional rotational motion. This friction and wear test is carried out under high-speed and high-load boundary lubrication conditions to ensure that the friction and wear between surfaces depends on the surface properties and the characteristics of the boundary film. The load is 2N, the Hertz contact pressure is 0.58-0.68GPa, the linear velocity is 0.2m/s, the lubricating oil is composed of the base oil PAO and the antifriction additive MoDTC with a concentration of 1wt%, and the viscosity is 0.006Pa s.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, there may be various modifications and changes in the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included within the protection scope of this application.

Claims (10)

1. N doping is improving application of the Al-Mg-Ti-B coatings under MoDTC lubricating conditions in antiwear and friction reduction property.

Degrade to form MoO 2. N doping suppresses Al-Mg-Ti-B coating surfaces MoDTC in friction process₃Application.

3. application as claimed in claim 1 or 2, it is characterised in that the MoDTC lubricating conditions are lubricating oil by base oil The wear reducing additive MoDTC compositions of PAO and 1wt% concentration, viscosity 0.006Pas, lubricating status is boundary lubrication.

A kind of 4. method of raising Al-Mg-Ti-B coatings antiwear and friction reduction property under MoDTC lubricating conditions, it is characterised in that bag Include：

To carrying out N doping on Al-Mg-Ti-B coatings, Al-Mg-Ti-B-N coatings are obtained.

5. method as claimed in claim 4, it is characterised in that the preparation method of Al-Mg-Ti-B-N coatings is as follows：

Substrate pretreatment, backwash cleaning；

Using DC magnetron sputtering method in substrate surface plating Ti intermediate layers；

Using magnetically controlled sputter method on Ti intermediate layers depositing Al-Mg-Ti-B-N coatings.

6. method as claimed in claim 5, it is characterised in that

The substrate uses bearing steel.

7. method as claimed in claim 5, it is characterised in that the substrate pretreatment concretely comprises the following steps：

Using descale water process substrate 6-8h, the evening of immersion one in aqueous rust preventive is put into after being cleaned with deionized water, through deoxidation Skin and the bearing steel of antirust water process are dried up using acetone and EtOH Sonicate processing 5-10min with high pure nitrogen.

8. method as claimed in claim 5, it is characterised in that the backwash cleaning concretely comprises the following steps：Substrate frame is put into On the sample carrier plate rail of vacuum chamber, chamber is closed, back end vacuum is evacuated to 7.8 × 10^-4Pa, 45sccm is then passed through into system Argon gas, air pressure are maintained at~2.3Pa, and backwash cleaning 30min is carried out to substrate plus 700V biass.

9. method as claimed in claim 5, it is characterised in that the plating Ti intermediate layers concretely comprise the following steps：Using metal Ti Target, the control of sputtering atmosphere Ar, Ar throughput are~70W in 30-50sccm, sputtering pressure 0.6Pa, target power output, and the time is controlled System is in 3min.

10. method as claimed in claim 5, it is characterised in that the depositing Al-Mg-Ti-B-N coatings concretely comprise the following steps： Use AlMgB made from hot-pressing sintering method₁₄-TiB₂As target, sputtering atmosphere is Ar and N₂, the control of Ar throughputs is in 30- 50sccm, N₂Throughput is controlled in 10-20sccm, sputtering pressure 0.5Pa-1Pa, target power output 120W-130W, substrate bias For 100-150V, time control is in 2h.