A method for constructing a ceramic-based self-lubricating, high-wear-resistant and strong-corrosion-resistant coating based on thermal spraying technology and application

Abstract

The application belongs to the technical field of surface modification, and discloses a method for constructing a ceramic-based self-lubricating, high-wear-resistant and strong-corrosion-resistant coating based on thermal spraying technology and application. The method uses a thermal sprayed ceramic coating as a template, introduces a solid-liquid reversible lubricating phase, and after being heated and melted, the solid-liquid reversible lubricating phase is penetrated into inherent pores and micro / nano cracks in the ceramic coating through a vacuum impregnation process, and is solidified and retained in the defects after cooling, so that a new ceramic-based self-lubricating and strong-corrosion-resistant composite coating is finally obtained. The preparation method is simple, fast and efficient, and does not affect the mechanical properties of the ceramic coating, and the ceramic-based self-lubricating and strong-corrosion-resistant composite coating has low friction coefficient and excellent wear resistance and corrosion resistance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of surface modification, and particularly relates to a method for constructing a ceramic-based self-lubricating, high-wear-resistant and strong-corrosion-resistant coating based on thermal spraying technology and application. BACKGROUND

[0002] All mechanical moving parts involve friction, wear and lubrication, and friction consumes 1 / 3 to 1 / 2 of the world's primary energy. About 60% of mechanical parts fail or fail due to wear or poor lubrication caused by friction. Good lubrication is one of the key technologies to prolong the service life of moving parts and improve their operation reliability. At present, in engineering practice, moving mechanisms mostly use simple solid lubrication or grease lubrication. Solid lubrication materials have high friction noise and limited service life. Liquid lubricants mostly have problems such as easy volatilization, easy degradation at high temperature, creeping, and the need for sealing during use, and are poor in carrying capacity and stability. In addition to adding lubricants, coating preparation technology is also an effective way to improve the tribological properties of materials. Among them, thermal spraying technology has become one of the most important means for preparing lubricating, wear-resistant and protective coatings on the surface of metal parts due to its economy, high efficiency, wide range of sprayable materials and other advantages. The ceramic coating prepared by atmospheric plasma spraying technology has high hardness, high strength, high rigidity, and is resistant to high temperature, corrosion, low density, wear, pollution-free and other characteristics, and is widely used in aerospace mechanisms, engine seals, high-speed cutting tools and other fields. It has become one of the most recognized hard coatings, used in industries requiring high toughness and high wear resistance.

[0003] However, due to the characteristics of the preparation process, the plasma sprayed ceramic coating inevitably contains pores and microcracks. This porous microstructure reduces the service stability and crack resistance of the ceramic coating, thereby affecting the tribological performance. In addition, these defects also provide a channel for the corrosion medium, accelerating the corrosion of the ceramic coating and the substrate. Finally, the ceramic coating usually does not have lubricating function, so its damage to the friction pair material is more serious. In the aspect of reducing friction, introducing solid lubricant into the sprayed powder to prepare ceramic matrix composite coating is a research hotspot in recent years. Chinese patent publication CN111575636 A discloses a method for improving the self-lubricating performance of thermal sprayed ceramic coating. The synthesis method utilizes the inherent pores and microcracks of the thermal sprayed ceramic coating and synthesizes carbon and molybdenum disulfide lubricants in the coating in two steps. However, the in-situ synthesis process is complex, and the defects cannot be completely filled with solid lubricant, and the anticorrosion effect is not good. In the aspect of corrosion resistance, the traditional thermal sprayed ceramic coating can seal the surface defects by brushing paraffin as a sealing agent to block the corrosion medium and prevent the corrosion of the coating and the substrate. However, the sealing effect of the brushing process is poor, it is difficult to completely seal the small defects, and the sealing depth is insufficient, and the corrosion resistance is general. Therefore, it is urgent to simplify the process and develop a simple, fast and efficient method to improve the friction reduction, wear resistance and corrosion resistance of the ceramic coating. SUMMARY

[0004] In order to overcome the shortcomings and deficiencies of the prior art, the primary purpose of the present application is to provide a method for constructing a ceramic-based self-lubricating, high-wear-resistant and strong-corrosion-resistant coating based on thermal spraying technology. The thermal sprayed ceramic coating is used as a template, and a solid-liquid reversible lubricating phase is introduced. After heating and melting, it penetrates into the inherent pores and micro / nano cracks in the ceramic coating through a vacuum impregnation process, and solidifies in the defects after cooling. Finally, a new type of ceramic-based self-lubricating and strong-corrosion-resistant composite coating is obtained. The preparation method is simple, fast and efficient, and does not affect the mechanical properties of the ceramic coating, with low friction coefficient and excellent wear resistance and corrosion resistance.

[0005] Another purpose of the present application is to provide a ceramic-based self-lubricating, high-wear-resistant and strong-corrosion-resistant coating constructed based on thermal spraying technology prepared by the above method. The phase composition, microstructure, tribological performance and lubrication mechanism of the coating are studied in depth. The research results show that a well-covered lubricating film is formed on the wear trace of the composite coating, and the structure of the amorphous phase surrounding the nanocrystals provides excellent lubrication performance and bearing capacity for the coating. The solid-liquid reversible lubricating phase can penetrate into the nanoscale defects of the coating through vacuum impregnation, and continuously overflow to supplement the lubricating film during friction, ensuring long-term effective lubrication of the coating. In addition, the neutral salt spray test results of the composite coating show that the composite coating has excellent corrosion resistance.

[0006] The application further provides application of the ceramic-based self-lubricating, high-wear-resistant and strong-corrosion-resistant coating constructed based on the thermal spraying technology in friction reduction, wear resistance and corrosion resistance.

[0007] The application achieves the above-mentioned purposes by the following scheme.

[0008] The application provides a method for constructing a ceramic-based self-lubricating, high-wear-resistant and strong-corrosion-resistant coating based on a thermal spraying technology, which comprises the following steps.

[0009] S1: spraying a ceramic coating with a thickness of 100-300 microns on a metal substrate by using a thermal spraying process;

[0010] S2: heating a lubricating phase to melting;

[0011] S3: placing the sample prepared in step S1 into the melted liquid in step S2, removing the excessive lubricating phase on the surface after vacuum impregnation, cooling and solidification, and thus obtaining a self-lubricating strong-corrosion-resistant composite coating.

[0012] The thermal spraying process in step S1 comprises any one of a low-pressure plasma spraying, an atmospheric plasma spraying, a supersonic plasma spraying and a supersonic flame spraying.

[0013] Preferably, the thermal spraying process in step S1 is the atmospheric plasma spraying, and the conditions of the atmospheric plasma spraying comprise a plasma spraying gun current of 450-650 A, an argon gas flow of 30-45 L / min, a hydrogen gas flow of 4-12 L / min, a spraying distance of 90-140 mm, a powder feeding rate of 20-60 g / min, and a prepared coating thickness of 100-300 microns.

[0014] The ceramic coating in step S1 can be any one of an oxide ceramic coating, a carbide ceramic coating or a nitride ceramic coating; preferably, the coating in step S1 is the oxide ceramic coating.

[0015] After the ceramic coating is prepared in step S1, the surface of the sample is preferably polished, ultrasonically treated and dried, and then the operation in step S3 is performed; the polishing is for the preparation of a subsequent friction experiment and also for the roughness close to that of the workpiece in use; and the ultrasonic treatment and drying are for avoiding the blockage of the impregnation channel by the floating powder in the spraying and the polishing debris.

[0016] The lubricating phase in step S2 can be any one of a palm wax, a microcrystalline wax, stearic acid, boron oxide and other lubricating phases; preferably, the lubricating phase is the palm wax.

[0017] The heating and melting temperature in step S2 is 80-550 DEG C.

[0018] The vacuum impregnation condition in step S3 is that the pressure is -0.040 to -0.085 Mpa, and the impregnation time is 40 to 60 min.

[0019] A ceramic-based self-lubricating, high-wear-resistant and strong-corrosion-resistant coating constructed by the thermal spraying technology is prepared by the method.

[0020] The ceramic-based self-lubricating, high-wear-resistant and strong-corrosion-resistant coating constructed by the thermal spraying technology is applied in the aspects of friction reduction, wear resistance and corrosion resistance.

[0021] Compared with the prior art, the application has the following advantages and beneficial effects:

[0022] (1) The application uses a thermal spraying ceramic coating as a template, introduces a solid-liquid reversible lubricating phase, and after being heated and melted, the solid-liquid reversible lubricating phase penetrates into inherent pores and micro / nano cracks in the ceramic coating through a vacuum impregnation process, and is solidified and retained in the defects after cooling, so that a new ceramic-based self-lubricating strong-corrosion-resistant composite coating is finally obtained. The preparation method is simple, fast and efficient, can realize the self-adaptive lubricating ability of the ceramic coating without affecting the comprehensive mechanical properties of the ceramic coating, and can improve the corrosion resistance of the coating by sealing the defects of the traditional thermal spraying ceramic coating, so that the structure, mechanical properties, tribological properties and corrosion resistance of the thermal spraying ceramic coating are unified.

[0023] (2) By adjusting the thermal spraying parameters, including voltage, current, spraying distance, and adjusting the heating temperature, time and vacuum degree during the vacuum impregnation of the solid-liquid lubricant, the microstructure, mechanical properties, tribological properties and corrosion resistance of the coating can be controlled.

[0024] (3) When the composite coating prepared by the application is applied to a friction condition, a friction film with low shear strength, high hardness, high elastic modulus and strong plastic deformation resistance can be formed on the friction surface, so that the friction coefficient is reduced and the wear is reduced.

[0025] (4) The solid-liquid reversible lubricating phase can penetrate into the nano-scale defects of the coating through vacuum impregnation, continuously overflow to supplement the lubricating film during the friction process, and ensure the long-term effective lubrication of the coating, and the sealing effect is remarkable, and the corrosion resistance of the composite coating is improved. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The preparation flowchart of the palm wax / alumina-titanium oxide composite coating of Example 1 of the application is shown in the figure.

[0027] Figure 2Scanning electron micrographs of the cross-section of the alumina-titania coating of the inventive comparative example 1 (a, c), the palm wax / alumina-titania composite coating of example 1 (b, d, e) and the elemental distribution map (f) thereof;

[0028] Figure 3 Scanning electron micrographs of the cross-section of the liquid paraffin / alumina-titania coating prepared by the conventional brush coating process of the inventive comparative example 2 (a) and the C element distribution map (b) thereof;

[0029] Figure 4 TEM images of the palm wax / Al2O3-TiO2 composite coating of the inventive example 1 (a, b, d, e), the inset shows the corresponding electron diffraction pattern; the corresponding elemental distribution maps (c, f); high resolution TEM image of the white box of (b) and the IFFT image attached (g); high resolution TEM image of the white box of (e) (h); 3D AOGF mapping (i).

[0030] Figure 5 Friction coefficients of the coatings prepared in the inventive examples 1-4 and comparative examples 1-2 (tested according to the standard ASTM G133-22, sliding speed of 9 cm / s, load of 9 N);

[0031] Figure 6 Tribological performance diagrams of the alumina-titania coating and the palm wax / alumina-titania composite coating of the inventive example 1 and comparative example 1; friction coefficients of the two coatings at a sliding speed of 9 cm / s and a normal load of 9 N (a); friction coefficients of the two coatings at different loads (sliding speed of 9 cm / s, cycle number of 32400) (b); friction coefficients of the two coatings at different sliding speeds (load of 9 N, cycle number of 32400) (c); volume loss of the two coatings at different sliding cycles (sliding speed of 9 cm / s, load of 9 N) (d); weight loss of the two coatings at different sliding cycles (sliding speed of 9 cm / s, load of 9 N) (e); optical micrographs showing the wear damage on the surface of the ZrO2 ball when sliding with the AT3 coating (I) after 8100 cycles (II) and with the AT3-CW composite coating (III) after 8100 cycles (IV) and 16200 cycles (f).

[0032] Figure 7 Salt spray test results of the palm wax / alumina-titania composite coating of the inventive example 1. DETAILED DESCRIPTION

[0033] The present application will be described in further detail below with reference to examples and drawings, but embodiments of the present application are not limited thereto. In the examples, unless specific conditions are noted, they are carried out under conventional conditions or conditions recommended by the manufacturer. Unless the manufacturer of the reagent or instrument is noted, it is a conventional product that can be obtained by purchase on the market.

[0034] In the examples, the prepared coating was characterized for tribological performance according to the ASTM G133-22 standard using a Retc multifunctional friction and wear tester, with the characterization conditions being: mode: ball-on-disc, with a 5 mm diameter zirconia ball as the counter-ball, the test using a sliding speed of 9 cm / s, an amplitude of 2.5 mm, and 32,400 cycles, and the tribological performance being studied at different loads (1 N, 3 N, 5 N, 7 N, 9 N) and different sliding speeds (3 cm / s, 6 cm / s, 9 cm / s, 12 cm / s, 15 cm / s) due to changes in the contact pressure and friction frequency under the use conditions. Long-time (100,000 cycles) friction experiments were performed, and the weight loss and volume loss of the coating were analyzed. All tests were carried out at room temperature of 25±2℃ and relative humidity of 40±5%.

[0035] In the examples, salt spray testing was carried out under a neutral salt spray atmosphere according to the GB / T 10125-2021 standard.

[0036] Example 1

[0037] 1) An alumina-3wt.% titania coating (commercially available Al2O3-3wt.% TiO2 powder (particle size of 22-45 μm), purchased from Sweden Ltd) was prepared on the surface of an aluminum alloy substrate using an atmospheric plasma spraying process, with a thickness of 300 μm.

[0038] 2) The sprayed alumina-titania coating was carefully polished to a roughness of 0.2 μm, and ultrasonic cleaning was performed to remove contamination and swarf caused by the polishing process.

[0039] 3) The solid-liquid reversible lubricant palm wax (purchased from Shanghai Aldrin Biochemical Technology Co., Ltd., brand C104041) was heated and melted, and the polished alumina-titania coating was immersed in the melted palm wax, and was kept at a pressure of -0.08 MPa for 40 minutes.

[0040] 4) The prepared composite coating was taken out and cooled to room temperature. Subsequently, we removed the excess palm wax on the surface of the alumina-titania coating. The palm wax / alumina-titania ceramic-based composite coating was obtained, and was named as AT3-CW coating.

[0041] The scanning electron microscope image of the cross section of the palm wax / aluminum oxide-titanium oxide composite coating of Example 1 and its element distribution map are shown as follows: Figure 2 As shown in (b), (d), (e) and (f).

[0042] The TEM image of the palm wax / Al2O3-TiO2 composite coating of Example 1 is as follows: Figure 4 (a), (b), (d), and (e) are shown in the figure, and the inset shows the corresponding electron diffraction pattern; the corresponding element distribution diagram is shown in Figure 4 (c), (f); the high-resolution TEM image of the white frame in (b) and the IFFT image are shown in Figure 4 (g) is shown; the high-resolution TEM image of the white box in (e) is shown Figure 4 As shown in (h); 3D AOGF mapping is as follows Figure 4 As shown in (i).

[0043] from Figure 2 and Figure 4 It can be seen that through the vacuum impregnation process, the solid-liquid reversible lubrication phase can penetrate into the inherent pores and micro / nanocracks inside the ceramic coating.

[0044] The palm wax / aluminum oxide-titania ceramic-based composite coating prepared in Example 1 was tested according to ASTM G133-22 standard. When the sliding speed was 9 cm / s and the load was 9 N, the friction coefficient was as follows: Figure 5 As shown, from Figure 5 It can be seen that the friction coefficient of AT3-CW coating is reduced by 80% to below 0.15.

[0045] The tribological properties of the palm wax / aluminum oxide-titania ceramic-based composite coating prepared in Example 1 were tested according to ASTM G133-22. Figure 6 As shown, from Figure 6 It can be seen that the wear resistance is improved, and the volume loss is reduced from 35.16×10 -2 mm 3 Reduced to 1.0×10 -2 mm 3 The weight loss was from 12.40×10 -4 g is reduced to 1.0×10 -4 g or less.

[0046] The salt spray test results of the palm wax / aluminum oxide-titanium oxide ceramic-based composite coating prepared in Example 1 are as follows: Figure 7 As shown, from Figure 7 It can be seen that the corrosion resistance is significantly improved. After 3000h of neutral salt spray test, there is no obvious corrosion mark on the surface of the sample.

[0047] Example 2:

[0048] 1) A layer of alumina-3wt.% titania coating with thickness of 300 μm was prepared on the surface of aluminum alloy substrate by atmospheric plasma spraying process.

[0049] 2) The sprayed alumina-titania coating was carefully polished to a roughness of 0.2 μm and ultrasonic cleaned to remove the contamination and swarf caused by the polishing process.

[0050] 3) The solid-liquid reversible lubricant stearic acid (purchased from Shanghai Aldrin Biochemical Technology Co., Ltd., brand S108289) was heated and melted, and the polished alumina-titania coating was immersed in the melted stearic acid under a pressure of -0.08 MPa for 40 minutes.

[0051] 4) The prepared composite coating was taken out and cooled to room temperature. Then we removed the excess stearic acid on the surface of the alumina-titania coating. The stearic acid / alumina-titania ceramic-based composite coating was obtained, named AT3-YZ coating.

[0052] The friction coefficient of the stearic acid / alumina-titania ceramic-based composite coating prepared in Example 2 is shown in Figure 5 As can be seen from the figure, the friction coefficient of the AT3-YZ coating is reduced to below 0.16.

[0053] Example 3:

[0054] 1) A layer of alumina-3wt.% titania coating with thickness of 300 μm was prepared on the surface of aluminum alloy substrate by atmospheric plasma spraying process.

[0055] 2) The sprayed alumina-titania coating was carefully polished to a roughness of 0.2 μm and ultrasonic cleaned to remove the contamination and swarf caused by the polishing process.

[0056] 3) The solid-liquid reversible lubricant microcrystalline wax (purchased from Shanghai Aldrin Biochemical Technology Co., Ltd., brand C304667) was heated and melted, and the polished alumina-titania coating was immersed in the melted microcrystalline wax under a pressure of -0.08 MPa for 40 minutes.

[0057] 4) The prepared composite coating was taken out and cooled to room temperature. Then we removed the excess microcrystalline wax on the surface of the alumina-titania coating. The microcrystalline wax / alumina-titania ceramic-based composite coating was obtained, named AT3-WJ coating.

[0058] The friction coefficient of the microcrystalline wax / alumina-titania ceramic-based composite coating prepared in Example 3 is shown in Figure 5As shown in the figure, the friction coefficient of the AT3-WJ coating is reduced to below 0.16.

[0059] Example 4:

[0060] 1) A layer of chromium oxide coating was prepared on the surface of an aluminum alloy substrate by atmospheric plasma spraying process (commercially available Cr203powder (particle size 22-45 pm), purchased from Sweden Ltd), with a thickness of 300 pm.

[0061] 2) The sprayed chromium oxide coating was carefully polished to a roughness of 0.2 pm, and ultrasonic cleaning was performed to remove the pollution and swarf caused by the polishing process.

[0062] 3) The solid-liquid reversible lubricant palm wax (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., brand C104041) was heated to above 140°C in a vacuum drying oven, and the polished chromium oxide coating was immersed in the melted palm wax under a pressure of -0.08 MPa for 40 minutes.

[0063] 4) The prepared composite coating was taken out and cooled to room temperature. Then we removed the excess palm wax on the surface of the chromium oxide coating. The palm wax / chromium oxide ceramic-based composite coating was obtained. It was named CR-CW coating.

[0064] The friction coefficient of the palm wax / chromium oxide ceramic-based composite coating prepared in Example 4 is shown in Figure 5 As shown in the figure, the friction coefficient of the CR-CW coating is below 0.23. (Sliding speed is 9 cm / s, load is 9 N)

[0065] Comparative Example 1:

[0066] The difference between this comparative example and Example 1 is that only steps 1) and 2) are performed to obtain an aluminum oxide-3Wt.% titanium oxide coating, which is named AT3 coating.

[0067] The scanning electron microscope image of the cross section of the aluminum oxide-titanium oxide coating of Comparative Example 1 is shown in Figure 2 (a), (c).

[0068] The friction coefficient of the aluminum oxide-3Wt.% titanium oxide coating prepared in Comparative Example 1 is shown in Figure 5 As shown in the figure, the friction coefficient of the AT3 coating is about 0.6.

[0069] Comparative Example 2:

[0070] The difference between this comparative example and Example 1 is that after performing steps 1) and 2) to obtain an aluminum oxide-3wt.% titanium oxide coating, liquid paraffin (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., brand P104801) is brushed on the surface of the coating. The coating is brushed 2-3 times to ensure uniform and full coverage of the surface. After standing at room temperature for 24 hours, the excess liquid paraffin on the surface is removed to obtain a composite coating, which is named AT3-MF coating.

[0071] The scanning electron microscope image of the cross section of the liquid paraffin / alumina-titanium oxide coating prepared by the conventional brush coating process in comparative example 2 of the present invention and the C element distribution diagram are shown as follows: Figure 3 As shown in (a) and (b), it can be seen from the figure that the brush-coating process of liquid paraffin cannot introduce liquid paraffin into the interior of the AT3 coating, and only fills the surface and shallow pores.

[0072] The friction coefficient of the aluminum oxide-3wt.% titanium oxide coating prepared in Comparative Example 2 is as follows: Figure 5 As shown in the figure, it can be seen that the friction coefficient of the AT3-MF coating is about 0.15, but it gradually fails after the number of cycles reaches 12450 and loses its lubrication ability.

[0073] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for constructing a ceramic-based self-lubricating, high-wear-resistant, strong-corrosion-resistant coating based on thermal spraying technology, characterized in that It comprises the following steps: S1: using thermal spraying process, spraying a composite ceramic coating with a thickness of 100-300 μm on a metal substrate; S2: heating the lubricating phase to melting; S3: placing the sample prepared in step S1 into the molten liquid in step S2, removing the excess lubricating phase on the surface after vacuum impregnation, cooling and solidification, to obtain a self-lubricating strong corrosion-resistant composite coating; In step S1, the composite ceramic coating is an alumina-titania coating, the thermal spraying process is atmospheric plasma spraying, and the conditions of atmospheric plasma spraying include: plasma gun current is 450-650 A, argon flow rate is 30-45 L / min, hydrogen flow rate is 4-12 L / min, spraying distance is 90-140 mm, powder feeding rate is 20-60 g / min, and a coating with a thickness of 100-300 μm is prepared. After the preparation of the composite ceramic coating, the surface of the sample is polished; The lubricating phase in step S2 is a solid-liquid reversible lubricating phase, which includes any one of palm wax, microcrystalline wax, stearic acid and boron oxide; The vacuum impregnation conditions in step S3 are: pressure is -0.040~-0.085 MPa, and impregnation time is 40-60 min; The self-lubricating strong corrosion-resistant composite coating in step S3 includes a composite ceramic coating and a solid-liquid reversible lubricating phase distributed in the inherent pores and micro / nano cracks of the composite ceramic coating; The self-lubricating strong corrosion-resistant composite coating is tested according to ASTM G133-22 standard, and the friction coefficient is reduced to below 0.16 when the sliding speed is 9 cm / s and the load is 9 N; The self-lubricating strong corrosion-resistant composite coating has a volume loss of 1.0 x 10 -2 mm 3 The weight loss is 1.0 x 10 -4 g or less.

2. The method for constructing a ceramic-based self-lubricating, high-wear-resistant and strong corrosion-resistant coating based on thermal spraying technology according to claim 1, characterized in that: After polishing the ceramic coating prepared in step S1, the surface of the sample is subjected to ultrasonic and drying treatment.

3. The method for constructing a ceramic-based self-lubricating, high-wear-resistant and strong corrosion-resistant coating based on thermal spraying technology according to claim 1, characterized in that: The lubricating phase in step S2 is palm wax.

4. The method for constructing a ceramic-based self-lubricating, high-wear-resistant and strong corrosion-resistant coating based on thermal spraying technology according to claim 1, characterized in that: The heating and melting temperature in step S2 is 80-550℃.

5. A ceramic-based self-lubricating, high-wear-resistant and strong corrosion-resistant coating constructed based on thermal spraying technology, prepared by the method according to any one of claims 1-4.

6. Application of the ceramic-based self-lubricating, high-wear-resistant and strong corrosion-resistant coating constructed based on thermal spraying technology according to claim 5 in reducing friction, wear resistance and corrosion resistance.

Images