Low-friction phenolic-bonded solid self-lubricating coating and method for its preparation

Abstract

The present application relates to a kind of low friction phenolic adhesive type solid self-lubricating coating, the coating is made of the following mass fraction of components: 72%~96.5% phenolic resin, 1%~10% solid lubricant, 1%~10% functional nanofiller, 1%~5% hard nanoparticles, 0.5%~3% auxiliary agent.Simultaneously, the preparation method of the coating is also disclosed.The present application utilizes the synergistic effect of multielement particles containing transition metal to regulate the friction interface friction film structure, and obtains a phenolic adhesive type solid self-lubricating coating with low friction coefficient and wear rate, which can meet the use requirements in the field of moving component coating materials under harsh oil lubrication conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of engineering materials, in particular to a low-friction phenolic adhesive type solid self-lubricating coating and a preparation method thereof. BACKGROUND

[0002] With the continuous development of industrial technology, the service life of transmission components is continuously extended, and higher requirements are put forward for the mechanical and tribological properties of mechanical wear-resistant parts. Design and development of polymer coatings with excellent self-lubricating properties and reliable wear resistance have gradually become a research hotspot in various countries.

[0003] Phenolic resin (PF) is a high molecular material connected by benzene ring and methylene group and dibenzyl ether bond, which has excellent heat resistance. PF-based coating is often used to protect metal parts due to its adhesion to metal matrix. However, phenolic resin has high brittleness, poor toughness and poor wear resistance, which reduces its wear life and limits the application of lubricating coating in harsh working conditions. At present, transition metals are often introduced as lubricating oil additives to induce polyolefin oil dehydrogenation reaction, promote tribological chemical and tribological physical reaction, and thus promote the formation of friction film and improve the tribological properties, but the effect of improving wear rate is not obvious.

[0004] Therefore, in order to realize boundary lubrication in harsh working conditions and reduce wear rate, the coating material needs to meet the requirements of low friction coefficient and high wear resistance at the same time. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a low-friction phenolic adhesive type solid self-lubricating coating with high wear resistance.

[0006] Another technical problem to be solved by the present application is to provide a preparation method of the low-friction phenolic adhesive type solid self-lubricating coating.

[0007] To solve the above problems, the low-friction phenolic adhesive type solid self-lubricating coating according to the present application is characterized in that the coating is made of the following components with mass fraction: 72% to 96.5% of phenolic resin, 1% to 10% of solid lubricant, 1% to 10% of functional nano filler, 1% to 5% of hard nano particle, and 0.5% to 3% of additive.

[0008] The phenolic resin is a thermosetting liquid phenolic resin.

[0009] The solid lubricant is molybdenum disulfide powder with particle size of 0.5 to 1.5 um.

[0010] The functional nano filler is sub-micron nickel powder and its derivatives with particle size of 0.5 to 1.5 um.

[0011] The hard nano particle is titanium dioxide with particle size of 200 to 300 nm.

[0012] The auxiliary agent is composed of 0.5-1 parts by mass of wetting dispersant and 0.5-1 parts of leveling agent.

[0013] The preparation method of the low-friction phenolic adhesive type solid self-lubricating coating as described above is characterized in that: firstly, the components are weighed according to the proportions; then the functional nano-filler, hard nano-particle, solid lubricant and auxiliary agent are simultaneously added into the phenolic resin, and a modified phenolic composite material is prepared through mechanical stirring and three-roll grinding; the modified phenolic composite material is added into the mixed organic solvent at a mass fraction of 25-75%, and after stirring and mixing for 5-30 min, it is filtered to obtain the product.

[0014] The mechanical stirring condition refers to using a negative pressure high-speed stirrer to continuously stir at a speed of 1500-2000 revolutions per minute for 5-10 min at 25℃.

[0015] The three-roll grinding condition refers to using a three-roll grinder to grind twice, with the first grinding to a material fineness of 15um-30um and the second grinding to a material fineness of 5um-10um.

[0016] The mixed organic solvent refers to a mixed solution obtained by uniformly mixing methanol, anhydrous ethanol or n-butanol with toluene, ethylbenzene or NMP at a volume ratio of 1:1-5:1.

[0017] Compared with the prior art, the present application has the following advantages:

[0018] 1. Through the formula optimization of the functional nano-filler, hard nano-particle titanium dioxide and solid lubricant molybdenum disulfide, the catalytic decomposition of the functional nano-filler, the ball bearing effect of titanium dioxide and the easy-shearing lubricating characteristics of molybdenum disulfide are ingeniously utilized to synergistically promote the frictional physical and chemical effects of the phenolic resin and the filler on the friction interface, so as to generate a double-layer friction film with a carbon-based layer on the top and an organic-inorganic hybrid layer on the bottom on the surface of the mating metal, the friction film has high load-carrying capacity and self-lubricating characteristics, direct scraping of the friction pair is avoided, the friction coefficient of the coating is reduced, the wear rate of the coating is significantly reduced, and the service life is improved.

[0019] 2. The experiment proves that the phenolic adhesive type solid self-lubricating coating of the present application exhibits low friction coefficient and wear rate under harsh oil lubrication conditions. DETAILED DESCRIPTION

[0020] A low-friction phenolic adhesive type solid self-lubricating coating is prepared from the following components by mass fraction (g): 72%-96.5% phenolic resin, 1%-10% solid lubricant, 1%-10% functional nano-filler, 1%-5% hard nano-particle and 0.5%-3% auxiliary agent.

[0021] Wherein: phenolic resin is thermosetting liquid phenolic resin.

[0022] Solid lubricant is molybdenum disulfide powder with particle size of 0.5-1.5um.

[0023] Functional nanofiller is sub-micron nickel powder and its derivatives (such as: nickel oxide, nickel silicate, nickel sulfide, etc.), with particle size of 0.5-1.5um.

[0024] Hard nanoparticles are titanium dioxide with particle size of 200-300nm.

[0025] Auxiliary agent is composed of wet dispersant 0.5-1 parts and leveling agent 0.5-1 parts by mass (g). Wet dispersant is BYK330; leveling agent is BYK352.

[0026] The preparation method of the low-friction phenolic adhesive type solid self-lubricating coating:

[0027] Firstly, weigh according to the proportion; then add functional nanofiller, hard nanoparticles, solid lubricant and auxiliary agent into phenolic resin at the same time, use negative pressure high-speed stirrer, continuously stir at 25℃ with 1500-2000 revolutions / minute for 5-10 minutes, prepare premix; add the premix into three-roll mill and grind twice, the first grinding to material fineness of 15um-30um, the second grinding to material fineness of 5um-10um, prepare modified phenolic composite material. Modified phenolic composite material is added into mixed organic solvent with mass fraction of 25-75%, mixed organic solvent refers to the mixed solution obtained by uniformly mixing methanol, anhydrous ethanol or n-butanol with toluene, ethylbenzene or NMP in volume ratio (ml / ml) of 1:1-5:1. After stirring and mixing for 5-30 minutes, filter, obtain low-friction phenolic adhesive type solid self-lubricating coating.

[0028] Spray the obtained coating on the surface of substrate (such as aluminum plate), then solidify at 150℃ for 1h, prepare modified phenolic composite coating with thickness of 25-40um and surface roughness of 0.10-0.20um.

[0029] Example 1

[0030] Take 3g nickel powder, 3g titanium dioxide, 5g molybdenum disulfide, 87.5g liquid phenolic resin and 1.5g additives (1g wetting dispersant, 0.5g leveling agent) into a negative pressure high-speed mixer, continuously stir at 1500 rpm for 10 min at 25°C; the premix is added into a three-roll mill, ground to a standard fineness of 5um-10um, then transferred to a 150°C air-drying oven for 1h, to prepare a modified phenolic composite. The modified phenolic composite is added into a volume fraction of 2:1 methanol / toluene mixed solvent, stirred and mixed for 10 min, then filtered to obtain a low-friction phenolic adhesive type solid self-lubricating coating.

[0031] The obtained coating is sprayed onto the surface of a substrate, then cured at 150°C for 1h to prepare a modified phenolic composite coating with a thickness of 25-40um and a surface roughness of 0.10-0.20um, then its tribological properties are investigated.

[0032] Example 2

[0033] Select 5g nickel powder, 3g titanium dioxide, 5g molybdenum disulfide, 85.5g liquid phenolic resin and 1.5g additives (1g wetting dispersant, 0.5g leveling agent), repeat the method of Example 1 to prepare a modified phenolic composite coating, then investigate its tribological properties.

[0034] Example 3

[0035] Select 5g nickel powder, 5g titanium dioxide, 5g molybdenum disulfide, 83.5g liquid phenolic resin and 1.5g additives (1g wetting dispersant, 0.5g leveling agent), repeat the method of Example 1 to prepare a modified phenolic composite coating, then investigate its tribological properties.

[0036] Comparative Example 1

[0037] Select 98.5g liquid phenolic resin and 1.5g additives (1g wetting dispersant, 0.5g leveling agent), repeat the method of Example 1 to prepare a modified phenolic composite coating, then investigate its tribological properties.

[0038] Comparative Example 2

[0039] Select 5g molybdenum disulfide, 93.5g liquid phenolic resin and 1.5g additives (1g wetting dispersant, 0.5g leveling agent), repeat the method of Example 1 to prepare a modified phenolic composite coating, then investigate its tribological properties.

[0040] Comparative Example 3

[0041] Example 4 5g of titanium dioxide, 5g of molybdenum disulfide, 88.5g of liquid phenolic resin and 1.5g of additives (1g of wetting dispersant and 0.5g of leveling agent) were selected, and the method of Example 1 was repeated to prepare a modified phenolic composite coating, and then the tribological properties thereof were investigated.

[0042] Comparative Example 4

[0043] Example 4 5g of titanium dioxide, 5g of molybdenum disulfide, 88.5g of liquid phenolic resin and 1.5g of additives (1g of wetting dispersant and 0.5g of leveling agent) were selected, and the method of Example 1 was repeated to prepare a modified phenolic composite coating, and then the tribological properties thereof were investigated.

[0044] The above Examples 1-3 and Comparative Examples 1-4 were subjected to a friction test. A high-speed ring-block tester was used for the test. The metal with the coating was mechanically processed into a 50x10x4mm 3 The counter part was a GCr15 bearing steel. The counter part was polished with sandpaper to obtain an average surface roughness Ra=0.25.

[0045] The test conditions were as follows: test load 100N, sliding speed 0.2m / s, duration 1h, and the pair was immersed in a cavity filled with polyalphaolefin (PAO) oil. After the friction test, the width of the wear scar was measured using an optical microscope, and the wear rate was calculated using the following formula.

[0046] The formula for calculating the wear rate is as follows:

[0047]

[0048] Wherein, L' is the width of the sample (mm), R is the diameter of the counter steel ring (mm), W is the width of the wear scar (mm), F is the normal applied force (N), and L is the sliding distance (m).

[0049] The average friction coefficient and wear rate of the materials prepared in the examples and comparative examples were determined and calculated, and the results are shown in Table 1.

[0050] Table 1. Average friction coefficient and wear rate of the materials prepared in the examples and comparative examples

[0051] coefficient of friction Wear rate (10 -6 mm 3 / Nm)]]> example 1 0.0108 1.476 example 2 0.0161 2.552 example 3 0.0136 1.891 comparative example 1 0.0982 3.991 comparative example 2 0.0361 8.812 comparative example 3 0.0214 3.640 comparative example 4 0.0307 3.417

[0052] As can be seen from Table 1, the high-toughness phenolic-based composite coating obtained by the present application (Examples 1-3) has significantly reduced friction and wear properties compared to conventional wear-resistant modified composite materials (Comparative Examples 1-4), and the wear rate is greatly reduced compared to the latter.

[0053] Therefore, by reasonable formulation design, clever use of the catalytic decomposition of nickel powder, the ball bearing effect of titanium dioxide and the easy shear lubrication characteristics of molybdenum disulfide, the formation and generation of the double-layer organic-inorganic hybrid friction film with high load capacity and self-lubricating properties are synergistically promoted in the friction interface, direct scraping of the friction pair is avoided, the friction coefficient of the coating is reduced, the wear rate of the coating is significantly reduced, and the service life is improved.

Claims

1. A low-friction phenolic adhesive solid self-lubricating coating, characterized in that: The coating is made of the following components in the indicated mass fractions: 72%~96.5% phenolic resin, 1%~10% solid lubricant, 1%~10% functional nanofiller, 1%~5% hard nanoparticles, and 0.5%~3% additives; the solid lubricant is molybdenum disulfide powder with a particle size of 0.5~1.5 μm; the functional nanofiller is submicron nickel powder and its derivatives with a particle size of 0.5~1.5 μm; the hard nanoparticles are titanium dioxide with a particle size of 200~300 nm; the additives consist of 0.5~1 parts by mass of wetting and dispersing agent and 0.5~1 parts by mass of leveling agent.

2. The low-friction phenolic adhesive solid self-lubricating coating as described in claim 1, characterized in that: The phenolic resin is a thermosetting liquid phenolic resin.

3. A method for preparing a low-friction phenolic adhesive solid self-lubricating coating as described in any one of claims 1 to 2, characterized in that: First, weigh the components according to the specified ratio; then, add the functional nanofiller, hard nanoparticles, solid lubricant, and additives to the phenolic resin simultaneously, and obtain the modified phenolic composite material by mechanical stirring and three-roll milling; the modified phenolic composite material is added to a mixed organic solvent at a mass fraction of 25-75%, stirred and mixed for 5-30 minutes, and then filtered to obtain the final product.

4. The preparation method of a low-friction phenolic adhesive solid self-lubricating coating as described in claim 3, characterized in that: The mechanical stirring conditions refer to using a negative pressure high-speed mixer, stirring continuously at 1500~2000 rpm for 5~10 minutes at 25℃.

5. The preparation method of a low-friction phenolic adhesive solid self-lubricating coating as described in claim 3, characterized in that: The conditions for three-roll milling refer to using a three-roll mill and milling twice: the first milling is to mill until the material fineness is 15um~30um, and the second milling is to mill until the material fineness is 5um~10um.

6. The preparation method of a low-friction phenolic adhesive solid self-lubricating coating as described in claim 3, characterized in that: The mixed organic solvent refers to a mixed solution obtained by mixing methanol, anhydrous ethanol or n-butanol with toluene, ethylbenzene or NMP in a volume ratio of 1:1 to 5:1.

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