A highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material and a preparation method thereof

Abstract

The present invention discloses a highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material and a preparation method thereof. The material is based on polyetheretherketone as a matrix, carbon fiber as a conductive phase, piezoelectric ceramic powder as a core functional component, and a performance control component is introduced. The material is formed by hot pressing and sintering in a precision hot molding device according to a specific temperature program and pressure, and then subjected to high-voltage polarization. The present invention uses polyetheretherketone with high strength and high wear resistance as a resin matrix, and interconnects the conductive phase and the piezoelectric ceramic powder by controlling the content and properties, forming a conductive / piezoelectric network inside the polyetheretherketone. When mechanical vibration is applied to the friction material, the electric dipole moment of the piezoelectric ceramic powder is oriented after high-temperature polarization in the composite material, and the mechanical vibration energy is converted into electrical energy through the piezoelectric effect, and then the internal micro-region conductive effect formed by the conductive phase converts the mechanical vibration energy into heat energy and dissipates it, thereby achieving the purpose of vibration reduction and noise reduction.

Description

Technical Field

[0001] The invention relates to a polymer material, in particular to a highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material and a preparation method thereof, which is mainly used for friction parts of underwater marine equipment and belongs to the field of marine engineering materials. Background Art

[0002] Many friction systems in marine engineering equipment need to serve directly in the marine environment. Low-viscosity seawater transmission often causes friction components to fail quickly due to high wear and high vibration damage. Therefore, there is an urgent need to develop a friction material that has both high wear resistance and vibration and noise reduction functions.

[0003] Traditional polymer vibration and noise reduction materials are represented by rubber. The principle is to use the viscoelasticity of the polymer itself, that is, when subjected to stress, the elastic part inside the polymer stores mechanical energy in the form of deformation like potential energy, and then returns it to the outside world; while the viscous part absorbs part of the energy and does not return it to the outside world. Since the internal friction of the material is converted into heat energy and dissipated, the vibration amplitude decays rapidly over time, thereby playing a vibration reduction role, and the noise generated is also reduced. This vibration and noise reduction mechanism based on polymer viscoelasticity determines that its scope of application depends on the glass transition of the polymer, so there are restrictions on the use temperature and vibration frequency. Piezoelectric damping materials dissipate energy by converting mechanical energy into electrical energy and then converting electrical energy into thermal energy. When the vibration energy is transmitted to the piezoelectric phase of the material, the piezoelectric phase is affected by the vibration force, and the mechanical energy is converted into electrical energy based on the piezoelectric effect, generating an AC voltage inside the material. If there is an appropriate conductive circuit inside the material, the generated electrical energy is converted into thermal energy and dissipated, and the vibration energy decays rapidly, achieving the purpose of vibration reduction. Existing piezoelectric materials are mainly monolithic ceramic materials represented by lead zirconate titanate. Damping materials based on flexible polymers are rarely reported and have not yet been applied in the engineering field.

[0004] Among all kinds of high molecular polymers, polyetheretherketone composite materials are often used as seawater lubricating materials due to their good adaptability to seawater, high strength and high wear resistance. Although as a polymer material, the viscoelasticity of polyetheretherketone enables it to have certain vibration reduction and noise reduction functions, the vibration reduction performance is highly dependent on the ambient temperature and vibration frequency: only when the temperature is at the glass transition temperature of polyetheretherketone (140-150℃), the vibration is at a specific frequency, the chain segments are in resonant motion, and the internal friction is maximum, the vibration reduction effect is obvious. To this end, the present invention uses highly wear-resistant polyetheretherketone as a resin matrix, connects the conductive fiber and the piezoelectric ceramic powder to each other, and forms a conductive / piezoelectric network inside the polymer. When mechanical vibration reaches the composite material, the piezoelectric powder converts the mechanical vibration energy into electrical energy through the piezoelectric effect, and then the internal micro-area conductive effect formed by the conductive fiber material converts the mechanical vibration energy into heat energy and dissipates it, achieving the purpose of vibration reduction and noise reduction, and solving the key wear and vibration problems of marine friction materials. Summary of the invention

[0005] The purpose of the present invention is to provide a highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material based on the piezoelectric effect, thereby breaking through the problem that the vibration-reducing and noise-reducing performance of traditional damping materials is limited by ambient temperature and vibration frequency, and having excellent wear resistance and vibration-reducing and noise-reducing performance in a wider temperature and frequency range.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] A method for preparing a polyetheretherketone-based friction material with high wear resistance and vibration and noise reduction comprises the following steps: uniformly mixing polyetheretherketone, a conductive phase, a piezoelectric ceramic powder and a performance regulating component in a mass ratio of 65-80:10-25:5-10:5-10, spreading the mixture in a steel mold, heating the mixture to 365-375°C at a rate of 3-7°C / min under a pressure of 0.1-0.5MPa / mm, sintering the mixture for 5-20min / mm, cooling and demoulding, arranging a polarizable conductive phase layer on both sides of the polyetheretherketone-based composite material obtained by sintering, polarizing the mixture at a voltage of 1-5kV / mm for 5-20min / mm at a temperature of 60-100°C, and finally removing the polarizable conductive phase layer to obtain the polyetheretherketone-based friction material with high wear resistance and vibration and noise reduction.

[0008] The mass ratio of the polyetheretherketone, the conductive phase, the piezoelectric ceramic powder and the performance regulating component is 60-85: 10-25: 5-10: 5-10, and more preferably 70-75: 15-20: 7-8: 7-8. The present invention controls the usage ratio of the polyetheretherketone, the conductive phase, the piezoelectric ceramic powder and the performance regulating component within the above range, which fully ensures that a three-dimensionally connected microscopic conductive / piezoelectric network can be formed inside the composite friction material, and avoids the composite friction material having a macroscopic conductivity, toughness and wear resistance decreased due to excessive filling.

[0009] The particle size of the polyetheretherketone is preferably 50-60 μm, more preferably 52-58 μm, and further preferably 55-56 μm. In the present invention, the melt volume flow rate of the polyetheretherketone at 380°C / 5kg is preferably 10-15 cm 3 / 10min, more preferably 11~14cm 3 / 10min, more preferably 12~13cm 3 / 10min.

[0010] The conductive phase includes one or more of conductive carbon fiber, graphite, carbon nanotube, nano copper wire and nano silver wire, and the size thereof is 8-10000nm.

[0011] The piezoelectric ceramic powder is preferably one or more of lead zirconate titanate, barium titanate, strontium titanate, sodium bismuth titanate, lead metaniobate and lead magnesium niobate. In the present invention, the particle size of the piezoelectric ceramic powder is preferably 0.50~50μm, more preferably 30~50μm. In the present invention, the piezoelectric constant (d33) of the piezoelectric ceramic powder is preferably (150~850 pC / N, more preferably 300~850 pC / N, and further preferably 700~850pC / N. In the present invention, the relative dielectric constant of the piezoelectric ceramic powder is preferably 1000~4000, more preferably 2000~4000, and further preferably 3500~4000.

[0012] The performance regulating component comprises one or more of silicon dioxide, graphene, poly(p-phenylene phenylene propanedioxazole) fiber, polytetrafluoroethylene and polyetherimide.

[0013] In the present invention, the polyetheretherketone, conductive phase, piezoelectric ceramic powder and performance regulating component are preferably dried before use, and the drying temperature is preferably 100-120°C, more preferably 110°C; the drying time is preferably 1-3h, more preferably 2h. In the present invention, the mixing method is preferably mechanical stirring mixing, and the mixing is preferably carried out in a dispersed sand mill.

[0014] In the present invention, the sintering is preferably carried out by spreading the mixed raw material obtained by mixing in a steel mold. In the present invention, the sintering pressure is preferably 0.1~0.5MPa / mm, more preferably 0.2~0.4MPa / mm, and further preferably 0.3MPa / mm; the sintering temperature is preferably 365~375℃, more preferably 368~372℃, and further preferably 370℃; the heating rate from room temperature to the sintering temperature is preferably 3~7℃ / min, more preferably 4~6℃ / min, and further preferably 5℃ / min; starting from the time when the temperature rises to the sintering temperature, the sintering holding time is preferably 5~20min / mm, more preferably 8~18min / mm, and further preferably 10~15min / mm. The present invention can ensure that the polyetheretherketone matrix fully flows during the sintering process by controlling the sintering pressure, temperature and holding time, so that the interface gap between the polyetheretherketone matrix and the multi-filler (conductive phase, piezoelectric ceramic powder and performance regulating component) is as small as possible to enhance the interface bonding force, thereby improving the mechanical strength, wear resistance, vibration and noise reduction performance and seawater adaptability of the composite friction material.

[0015] After the sintering, the present invention preferably further comprises pre-cooling, relieving pressure, cooling and demolding the sintered product in sequence to obtain a sintered material layer. The present invention has no special limitation on the pre-cooling method, and pre-cooling to a temperature ≤290°C is sufficient, more preferably 270~290°C, and further preferably 280°C. The present invention has no special limitation on the pressure relief method, and the pressure can be relieved to normal pressure by a pressure relief method well known to those skilled in the art. The present invention has no special limitation on the cooling method, and cooling to 40~60°C is sufficient, and preferably 50°C is sufficient. The present invention has no special limitation on the demolding method, and a demolding method well known to those skilled in the art can be used.

[0016] Before the polarization, the present invention preferably further comprises polarizing after arranging polarizable conductive phase layers on both sides of the polyetheretherketone-based composite material obtained by sintering, and then removing the polarizable conductive phase layers to obtain a highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material. In the present invention, the material of the polarizable conductive phase layer preferably includes a liquid polarizable conductive phase or a solid polarizable conductive phase. In the present invention, the liquid polarizable conductive phase preferably includes conductive silver glue, conductive silver paste or conductive carbon paste, more preferably conductive silver glue; the solid polarizable conductive phase is preferably a conductive tape. In the present invention, the density of the conductive silver glue is preferably 2.0~2.5g / cm 3 , more preferably 2.2 to 2.3 g / cm 3 The volume resistivity of the conductive silver paste is preferably 10 -13 ~10 -12 Ω·m, more preferably 3×10-13 ~5×10 -13 Ω·m. The present invention has no special limitation on the polarizable conductive material, and commercially available products known to those skilled in the art may be used; in an embodiment of the present invention, the conductive silver paste is preferably conductive silver paste 05001-AB; the conductive silver paste is preferably GW-03; the conductive carbon paste is preferably JW-001; the conductive tape is preferably 3J2310. In the present invention, the thickness of the polarizable conductive phase layer is preferably 0.3~2mm, more preferably 0.5~1.5mm, and further preferably 1~1.2mm. In the present invention, the setting is preferably determined according to the state of the polarizable conductive phase; when a liquid polarizable conductive phase is used, the present invention preferably coats the liquid polarizable conductive phase on the upper and lower surfaces of the sintered material layer; when a solid polarizable conductive phase is used, the present invention preferably adheres the solid polarizable conductive phase to the upper and lower surfaces of the sintered material layer. In the present invention, the polarization voltage is preferably 1-5 kV / mm, more preferably 2-4 kV / mm, and further preferably 3 kV / mm; the polarization temperature is preferably 60-100°C, more preferably 70-90°C, and further preferably 80°C; the polarization time is preferably 5-20 min / mm, more preferably 8-18 min / mm, and further preferably 10-15 min / mm; the polarization is preferably carried out in a high-voltage polarization device. In the present invention, the polarization can force the electric domains of the piezoelectric ceramic components in the composite material to be oriented along the electric field direction, so that the obtained highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material has a piezoelectric effect.

[0017] The present invention uses polyetheretherketone with high strength and high wear resistance as the resin matrix, introduces a conductive phase to construct a conductive network inside the composite material by controlling the content and properties, uses piezoelectric ceramic powder as the core functional component and introduces a performance control component, and is hot-pressed and sintered in a precision hot molding device according to a specific temperature program and pressure, and then prepared by high-voltage polarization. When mechanical vibration is applied to the friction material, the electric dipole moment of the piezoelectric ceramic powder after high-temperature polarization in the composite material is oriented, and the mechanical vibration energy is converted into electrical energy through the piezoelectric effect, and then the internal micro-area conductive effect formed by the conductive phase converts the mechanical vibration energy into heat energy and dissipates it, thereby achieving the purpose of vibration reduction and noise reduction.

[0018] The highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material provided by the present invention has wide water depth wear resistance (i.e., extremely low wear rate in the ocean depth range of 0 to 1000m), good seawater adaptability (i.e., extremely low water absorption rate in the ocean depth range of 0 to 1000m) and low-temperature vibration reduction characteristics, and can be used as underwater service friction materials for various marine engineering equipment; moreover, the highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material provided by the present invention has the characteristics of high strength, low density, self-lubrication and resistance to chemical medium erosion, and can be used as friction materials in low-viscosity fluid medium environments or dry friction conditions. As shown in the test results of the embodiment, the friction coefficient of the highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material prepared by the present invention in a normal pressure seawater environment is 0.0014 to 0.0027, and the wear rate is (2.14 to 3.79)×10 -8 mm 3 / N·m; the friction coefficient in 10MPa seawater environment is 0.0019~0.0027, and the wear rate is (2.43~4.85)×10 -8 mm 3 / N·m; tensile strength is 96~106MPa; compressive strength is 153~172MPa; flexural strength is 129~153MPa; Shore hardness is 86~88; water absorption in normal pressure seawater environment for 24h is 0.020~0.028%; water absorption in 10MPa seawater environment for 24h is 0.020~0.030%; damping factor is 0.200~0.355 at low temperature of 5℃, and damping factor tanδ is 0.20~0.355 in the temperature ≥5℃ and frequency range of 0.01~106Hz.

[0019] In summary, the preparation method provided by the present invention is simple to operate and has low production cost. By combining the multi-element / multi-scale filler component design, the composite material has wide water depth wear resistance, good seawater compatibility and low-temperature vibration reduction characteristics, and can be applied as a friction material for underwater service of various marine equipment. In addition, the friction material of the present invention also has the characteristics of high strength, low density, self-lubrication, and resistance to chemical medium erosion, and can also be applied as a friction material in other low-viscosity fluid medium environments or dry friction conditions. DETAILED DESCRIPTION

[0020] The present invention is further explained below with reference to specific embodiments.

[0021] Preparation of raw materials: The particle size of polyetheretherketone is 50~60μm, and the melt volume flow rate at 380℃ / 5kg is 10~15cm 3 / 10min; Conductive carbon fiber (type 1) resistivity 1.0×10 -3Ω·m, diameter 8~10μm; conductive carbon fiber (model 2) 1.5×10-3 Ω·m, diameter 8~10μm; piezoelectric ceramic powder particle size is 0.50~50μm, among which the piezoelectric constant d33 of lead zirconate titanate is 810 pC / N, and the relative dielectric constant is 3500; the piezoelectric constant d33 of barium titanate is 220 pC / N, and the relative dielectric constant is 1550; the piezoelectric constant d33 of strontium titanate is 210pC / N, and the relative dielectric constant is 1350; in the performance control component, the silica particle size is 50nm, and the polytetrafluoroethylene particle size is 60μm. The conductive silver paste is 05001-AB, and the density is preferably 2.0~2.5g / cm 3 The volume resistivity is preferably 10 -13 ~10 -12 Ω·m.

[0022] Example 1

[0023] Polyetheretherketone, conductive carbon fiber (model 1), lead zirconate titanate and silicon dioxide with a mass ratio of 75:10:10:5 were placed in a dispersed sand mill and mixed thoroughly and dried at 110°C for 2h, then spread in a steel mold, heated to 370°C at a rate of 5°C / min under a pressure of 7.5MPa (i.e. 0.25MPa / mm), and sintered for 300min (i.e. 10min / mm) at a temperature of 5°C / min, and the pressure was released when cooled to 290°C, and the mold was demolded when it was further cooled to 50°C to obtain a polyetheretherketone-based composite material (diameter 120mm, thickness 30mm). After the conductive silver glue 05001-AB was coated on the upper and lower surfaces of the sintered material layer, it was placed in a high-voltage polarization device and polarized at 20kV (5kV / mm) and 80°C for 30min, and the conductive silver glue was removed to obtain a highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material.

[0024] Example 2

[0025] Polyetheretherketone, conductive carbon fiber (model 2), lead zirconate titanate and silicon dioxide with a mass ratio of 75:10:10:5 were placed in a dispersed sand mill and mixed thoroughly, then dried at 110°C for 2h, and then spread in a steel mold. Under a pressure of 6MPa (i.e. 0.2MPa / mm), the temperature was raised to 366°C at a rate of 5°C / min, and then sintered for 300min (i.e. 10min / mm). The pressure was released when it was cooled to 290°C, and the mold was demolded when it was further cooled to 50°C to obtain a polyetheretherketone-based composite material (with a diameter of 120mm and a thickness of 30mm). After the conductive silver glue 05001-AB was coated on the upper and lower surfaces of the sintered material layer, it was placed in a high-voltage polarization device and polarized at 10kV and 80°C for 30min. The conductive silver glue was removed to obtain a highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material.

[0026] Example 3

[0027] Polyetheretherketone, conductive carbon fiber (model 2), lead zirconate titanate and graphene (performance control component) with a mass ratio of 80:10:5:5 were placed in a dispersed sand mill and mixed thoroughly, then dried at 110°C for 2h, and then spread in a steel mold. Under a pressure of 6MPa (i.e. 0.2MPa / mm), the temperature was raised to 366°C at a rate of 5°C / min, and then sintered for 450min (i.e. 15min / mm). The pressure was released when it was cooled to 290°C, and the mold was demolded when it was further cooled to 50°C to obtain a polyetheretherketone-based composite material (with a diameter of 120mm and a thickness of 30mm). After the conductive silver glue 05001-AB was coated on the upper and lower surfaces of the sintered material layer, it was placed in a high-voltage polarization device and polarized at 16kV and 90°C for 40min. The conductive silver glue was removed to obtain a highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material.

[0028] Example 4

[0029] Polyetheretherketone, conductive carbon fiber (model 2), barium titanate, silicon dioxide and graphene with a mass ratio of 65:20:5:5:5 were placed in a dispersed sand mill and mixed thoroughly and dried at 110°C for 2h, then spread in a steel mold, heated to 373°C at a rate of 5°C / min under a pressure of 6MPa (i.e. 0.2MPa / mm), and sintered for 300min (i.e. 10min / mm) at a temperature of 5°C / min. The pressure was released when cooled to 290°C, and the mold was demolded when it was further cooled to 50°C to obtain a polyetheretherketone-based composite material (diameter 90mm, thickness 30mm). After the conductive silver glue 05001-AB was coated on the upper and lower surfaces of the sintered material layer, it was placed in a high-voltage polarization device and polarized at 30kV and 85°C for 150min. The conductive silver glue was removed to obtain a highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material.

[0030] Example 5

[0031] Polyetheretherketone, conductive carbon fiber (model 1), strontium titanate, silicon dioxide and polytetrafluoroethylene with a mass ratio of 74:15:5:5:1 were placed in a dispersed sand mill and mixed thoroughly, then dried at 110°C for 2h, and then spread in a steel mold. Under a pressure of 6MPa (i.e. 0.2MPa / mm), the temperature was raised to 368°C at a rate of 5°C / min, and then sintered for 300min (i.e. 10min / mm). The pressure was released when it was cooled to 290°C, and the mold was demolded when it was further cooled to 50°C. The polyetheretherketone-based composite material (diameter 120mm, thickness 30mm) was obtained. After the conductive silver glue 05001-AB was coated on the upper and lower surfaces of the sintered material layer, it was placed in a high-voltage polarization device and polarized at 35kV and 90°C for 210min. The conductive silver glue was removed to obtain a highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material.

[0032] Example 6

[0033] Polyetheretherketone, conductive carbon fiber (model 1), lead zirconate titanate, silicon dioxide, polytetrafluoroethylene and carbon nanotubes with a mass ratio of 70:13:10:3:3:1 were placed in a dispersed sand mill and mixed thoroughly, then dried at 110°C for 2h, and then spread in a steel mold. Under a pressure of 6MPa (i.e. 0.2MPa / mm), the temperature was raised to 372°C at a rate of 5°C / min, and then sintered for 300min (i.e. 10min / mm). The pressure was released when it was cooled to 290°C, and the mold was demolded when it was further cooled to 50°C to obtain a polyetheretherketone-based composite material (with a diameter of 120mm and a thickness of 30mm). After the conductive silver glue 05001-AB was coated on the upper and lower surfaces of the sintered material layer, it was placed in a high-voltage polarization device and polarized for 160min at 20kV and 100°C. The conductive silver glue was removed to obtain a highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material.

[0034] Example 7

[0035] Polyetheretherketone, conductive carbon fiber (model 1), lead zirconate titanate, silicon dioxide, polyetherimide and polytetrafluoroethylene with a mass ratio of 70:13:8:3:3:2:1 were placed in a dispersed sand mill and mixed thoroughly, then dried at 110°C for 2h, and then spread in a steel mold. Under a pressure of 6MPa (i.e. 0.1MPa / mm), the temperature was raised to 368°C at a rate of 5°C / min, and then sintered for 300min (i.e. 5min / mm). The pressure was released when it was cooled to 290°C, and the mold was demolded when it was further cooled to 50°C to obtain a polyetheretherketone-based composite material (diameter 90mm, thickness 60mm). After the conductive silver glue 05001-AB was coated on the upper and lower surfaces of the sintered material layer, it was placed in a high-voltage polarization device and polarized for 300min at 60kV and 80°C. The conductive silver glue was removed to obtain a highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material.

[0036] Comparative Example 1

[0037] Polyetheretherketone, carbon fiber and silicon dioxide with a mass ratio of 75:20:5 were placed in a dispersed sand mill and mixed thoroughly, then dried at 110°C for 2h, and then spread in a steel mold. Under a pressure of 6MPa (i.e. 0.2MPa / mm), the temperature was raised to 370°C at a rate of 5°C / min, and then sintered for 300min (i.e. 10min / mm). The pressure was released when it was cooled to 290°C, and the mold was demolded when it was further cooled to 50°C to obtain a sintered material layer (with a diameter of 120mm and a thickness of 30mm). After the conductive silver glue 05001-AB was coated on the upper and lower surfaces of the sintered material layer, it was placed in a high-voltage polarization device and polarized for 300min at 60kV and 80°C, and the conductive silver glue was removed to obtain a polyetheretherketone-based composite material.

[0038] Comparative Example 2

[0039] Polyetheretherketone, glass fiber, barium titanate and graphene with a mass ratio of 75:10:10:5 were placed in a dispersed sand mill and mixed thoroughly, then dried at 110°C for 2h, and then spread in a steel mold. Under a pressure of 6MPa (i.e. 0.2MPa / mm), the temperature was raised to 370°C at a rate of 5°C / min, and then sintered for 300min (i.e. 10min / mm). The pressure was released when it was cooled to 290°C, and the mold was demolded when it was further cooled to 50°C to obtain a sintered material layer (with a diameter of 120mm and a thickness of 30mm). After the conductive silver glue 05001-AB was coated on the upper and lower surfaces of the sintered material layer, it was placed in a high-voltage polarization device and polarized for 300min at 60kV and 80°C, and the conductive silver glue was removed to obtain a polyetheretherketone-based composite material.

[0040] Comparative Example 3

[0041] Polyetheretherketone, conductive carbon fiber (model 1), barium titanate and graphene with a mass ratio of 75:10:10:5 were placed in a disperser sand mill and fully mixed, then dried at 110°C for 2h, and then spread in a steel mold. Under a pressure of 6MPa (i.e. 0.2MPa / mm), the temperature was increased to 370°C at a rate of 5°C / min, and then sintered for 300min (i.e. 10min / mm). The pressure was released when it was cooled to 290°C, and the mold was demolded when it was further cooled to 50°C to obtain a polyetheretherketone-based composite material (with a diameter of 120mm and a thickness of 30mm).

[0042] Performance Evaluation

[0043] (1) Friction and wear performance

[0044] Test method: Friction and wear performance test is carried out according to ASTM G99-05. The polyetheretherketone-based friction material is processed into a specimen with a size of φ4.8mm×12.7 mm, matched with a 316 stainless steel disc, and tested in a self-developed MM-GDX1 deep-sea environment friction and wear tester. The test contact stress is 9MPa (160N), the linear speed is 0.25 m / s, and the running time is 24 h. The medium used in the test is artificial seawater configured according to ASTM D1141-98. The friction coefficient is automatically recorded and output by the test machine, and the wear rate is calculated by the mass loss of the sample before and after wear.

[0045] (2) Mechanical properties test

[0046] Test method: After the polyetheretherketone-based friction material is processed into the specified size, the mechanical properties test is carried out on the DY35-2 universal testing machine. The tensile strength test is carried out in accordance with GB / T 1040.2-2006, the specimen is a dumbbell type of 80 mm×10mm×4 mm, and the tensile rate is 1 mm / min. The compression test is carried out in accordance with GB / T 1041-2008, the specimen is a square type of 10 mm×10mm×4 mm, and the compression rate is 1 mm / min. The bending test is carried out in accordance with GB / T 9341-2008, the specimen is a strip type of 80 mm×10mm×4 mm, and the bending rate is 2 mm / min. The Shore hardness test is carried out on the LX-D Shore hardness tester in accordance with GB / T 2411-2008, and the specimen size is 40 mm×10mm×4 mm.

[0047] (3) Water absorption test

[0048] Test method: Place a cylindrical water-absorbing sample with a size of φ25mm×25 mm in a deep-sea autoclave and perform a water absorption test within a hydrostatic pressure range of 0~10MPa. The test method is carried out in accordance with the national standard GB / T 1034-2008. The seawater used is artificial seawater configured in accordance with ASTM 1141-98. After the immersion time reaches 24 hours, quickly take out the sample, wipe off the surface seawater, and calculate the water absorption rate of the material at different ocean depths based on the mass change before and after water absorption.

[0049] (4) Low temperature damping factor test

[0050] Test method: A strip specimen with a size of 60 mm × 6 mm × 2 mm was placed in a Netsch 242E dynamic thermomechanical analyzer for low-temperature damping factor testing. The test method was carried out in accordance with ISO 6721. The test mode was three-point bending, with a span of 40 mm and a vibration frequency of 100 Hz. The sample chamber temperature was (5 ± 0.5) °C.

[0051] (5) Thermal expansion coefficient: A cylindrical specimen with a size of φ7 mm × 30 mm was placed in a DIL801L thermal expansion instrument and the thermal expansion coefficient was measured in the temperature range from room temperature to 100°C. The test method was carried out in accordance with DIN 53752-1980.

[0052] (6) Shore hardness D: Place a sample with a size of φ10 mm × 2 mm in a 10LX-D Shore hardness tester for Shore hardness measurement. The test method is in accordance with GB / T 2411-2008.

[0053] The performance test results of the highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction materials prepared in Examples 1 to 7 and Comparative Examples 1 to 3 are shown in Table 1:

[0054] Table 1 Performance test results of high wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction materials prepared in Examples 1 to 7 and Comparative Examples 1 to 3

[0055]

[0056] As shown in Table 1, the friction coefficient of the highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material prepared by the present invention in a normal pressure seawater environment is 0.0021-0.0027, and the wear rate is (2.14-4.10)×10 -8 mm 3 / N·m; the friction coefficient in 10MPa seawater environment is 0.0019~0.0027, and the wear rate is (2.43~4.85)×10 -8 mm 3 / N·m; tensile strength is 96~106MPa; compressive strength is 153~172MPa; flexural strength is 129~153MPa; Shore hardness is 86~88; water absorption rate in normal pressure seawater environment for 24h is 0.020~0.028%; water absorption rate in 10MPa seawater environment for 24h is 0.020~0.030%; damping factor is 0.200~0.355 at low temperature of 5℃. By comparing the embodiments and the comparative examples, it can be seen that the 5°C low-temperature damping factor of the highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material prepared in comparative example 1 is relatively low, indicating that the polyetheretherketone composite material not containing piezoelectric ceramic powder does not have piezoelectricity, and cannot achieve the vibration reduction and noise reduction function through the piezoelectric effect; the 5°C low-temperature damping factor of the highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material prepared in comparative example 2 is relatively low, indicating that although the polyetheretherketone composite material not containing conductive carbon fiber has certain piezoelectric properties, in the absence of a guiding phase component, the volume resistivity of the resin matrix is ​​relatively high and the conductivity is weak, the vibration energy cannot be effectively dissipated, and it does not have the vibration reduction and noise reduction function; the 5°C low-temperature damping factor of the highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material prepared in comparative example 3 is relatively low, indicating that even if an appropriate proportion of conductive fibers and piezoelectric ceramics are added at the same time, the polyetheretherketone composite material that has not been polarized still does not have piezoelectricity, and cannot achieve the vibration reduction and noise reduction function through the piezoelectric effect. In summary, the selection and compounding of the conductive phase, piezoelectric ceramic powder and the polarization treatment steps play an important role in achieving the vibration and noise reduction functions of polyetherketone.

[0057] In summary, the present invention uses conductive carbon fiber and piezoelectric ceramic powder to modify polyetheretherketone resin to improve the vibration reduction performance of the friction material, and has excellent vibration reduction and energy dissipation effects in low temperature environments; at the same time, it optimizes the friction and wear performance of the friction material, and has a lower friction coefficient and wear rate in a marine environment. The comprehensive performance of the friction material is optimized through the composite control technology of multi-element / multi-scale fillers.

Claims

1. A method for preparing a highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material used in friction parts of underwater marine equipment, comprising: uniformly mixing polyetheretherketone, a conductive phase, a piezoelectric ceramic powder and a performance control component in a mass ratio of 65-80:10-25:5-10:5-10, spreading the mixture in a steel mold, heating the mixture to 365-375°C at a rate of 3-7°C / min under a pressure of 0.1-0.5MPa / mm, sintering the mixture for 5-20min / mm, cooling and demoulding, arranging a polarizable conductive phase layer on both sides of the sintered polyetheretherketone-based composite material, polarizing the mixture at a voltage of 1-5kV / mm for 5-20min / mm at a temperature of 60-100°C, and finally removing the polarizable conductive phase layer to obtain a highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material; The particle size of the polyetheretherketone is 50-60 μm, and the melt volume flow rate at 380°C / 5kg is 10-15 cm 3 / 10min; The conductive phase is one or more of conductive carbon fiber, graphite, carbon nanotube, nano copper wire and nano silver wire, and has a size of 8 to 10000 nm; The polarizable conductive phase layer is one of a liquid polarizable conductive phase or a solid polarizable conductive phase, and the thickness of the polarizable conductive phase layer is 0.5-1.5 mm; the liquid polarizable conductive phase is one of a conductive silver paste, a conductive silver paste or a conductive carbon paste, and the solid polarizable conductive phase is a conductive tape; The piezoelectric ceramic powder is one or more of lead zirconate titanate, barium titanate, strontium titanate, sodium bismuth titanate, lead metaniobate and lead magnesium niobate, with a particle size of 0.5-50 μm, a piezoelectric constant of 150-850 pC / N, and a relative dielectric constant of 1000-4000; The performance regulating component is one or more of silicon dioxide, graphene, poly(p-phenylene phenylene propanedioxazole) fiber, polytetrafluoroethylene and polyetherimide.

2. A method for preparing a highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material used in friction parts of underwater marine equipment as claimed in claim 1, characterized in that: The polyetheretherketone, conductive phase, piezoelectric ceramic powder and performance regulating component are dried before use, the drying temperature is 100-120° C., and the processing time is 1-3 hours.

3. A highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material prepared by the method of claim 1.

4. Use of a highly wear-resistant, vibration-reducing and noise-reducing polyetheretherketone-based friction material prepared by the method of claim 1 in friction parts of underwater marine equipment.

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