Basalt Flake Reinforced Wear-Resistant PEEK 3D Printing Filament Based on Geometric Constraint Spreading and its Preparation Method

Abstract

This invention discloses a geometrically constrained, spread-arranged basalt flake-reinforced wear-resistant PEEK 3D printing filament and its preparation method. The 3D printing filament comprises a PEEK matrix and basalt flakes, wherein the median lateral dimension d of the basalt flakes is... 50 The thickness ranges from 10 to 80 μm, with a median thickness t. 50 The thickness is 0.5–5 μm; during printing, the layer height h, nozzle diameter D, and flake size must satisfy 0.05 ≤ d. 50 / h ≤ 0.60, 0.005 ≤ t 50 / h ≤ 0.08, 3 ≤ D / d 50 ≤ 20; Through this geometric matching, the scales are confined to a single-layer space during nozzle extrusion and deposition compaction, and are laid out along the layer to form a continuous layered wear-resistant barrier; the basalt scale surface has a gradient interface structure, which improves the interface stability between the scales and the matrix; the wear rate of the filament material of this invention is reduced, the wear resistance is significantly improved, and it has a clear critical change characteristic.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials and 3D printing technology, specifically to a basalt flake-reinforced wear-resistant PEEK 3D printing filament based on geometrically constrained spreading arrangement and its preparation method. Background Technology

[0002] Polyetheretherketone (PEEK) is widely used in aerospace, medical devices, and the automotive industry due to its excellent thermal stability, chemical stability, and mechanical properties. The development of fused deposition modeling (FDM) 3D printing technology has made the rapid fabrication of complex PEEK structural parts possible. However, the limited wear resistance of PEEK materials under sliding friction conditions restricts its application in wear-resistant components.

[0003] Currently, the main methods for reinforcing and modifying PEEK materials in FDM 3D printing include: continuous fiber reinforcement, chopped fiber filling, particulate filler reinforcement, lubricating filler modification, and sheet filler modification. Existing research on wear-resistant PEEK printing materials usually focuses on "adding a certain hard filler" or "adding a certain lubricating filler," emphasizing the type of filler, filler content, and overall mechanical properties of the composite material, while rarely designing the spatial arrangement of the filler within the printed layer during the FDM layer-by-layer deposition process.

[0004] For sheet-like or non-spherical fillers, while existing technologies generally acknowledge that they will exhibit a certain orientation under the influence of melt flow and nozzle shearing, most only address the general physical phenomenon of "flow-induced orientation" and do not propose a clear geometric constraint implementation path for the PEEK FDM high-temperature printing process. Specifically, existing technologies have not systematically solved the following problems: within what lateral dimension range can two-dimensional flakes enter the nozzle and pass through stably; within what thickness range can they be completely covered by PEEK melt without causing in-layer protrusions; what relationship should exist between the lateral dimension and the printed layer height to preferentially spread along the layer direction; what proportional relationship should exist between the nozzle diameter and the lateral dimension of the flakes to balance passability and spreading arrangement; and how to prevent flat-laid flakes from being pulled out or detached due to insufficient interfacial bonding.

[0005] Therefore, developing a PEEK 3D printing filament that can achieve stable spread and arrangement of scales within the printing layer through geometric parameter design and has excellent wear resistance has significant application value. Summary of the Invention

[0006] To address the shortcomings of the existing technologies, this invention aims to provide a geometrically constrained basalt flake-reinforced wear-resistant PEEK 3D printing filament and its preparation method. This invention does not simply add basalt flakes as filler to PEEK; instead, it limits the lateral dimensions and thickness of the basalt flakes and designs them to match the printing layer height and nozzle diameter during the FDM printing process. This allows the basalt flakes to be geometrically constrained under the combined effects of nozzle extrusion, deposition compaction, and single-layer height boundaries, preferentially accommodating them in a flat-lay manner within the printing layer, thus forming a continuous or semi-continuous layered wear-resistant structure. By constructing a gradient interface structure of inorganic anchoring layer-aromatic bridging layer-PEEK compatible outer layer, the interfacial bonding stability between the basalt flakes and the PEEK matrix is ​​improved.

[0007] To solve the above problems, the present invention adopts the following technical solution: On one hand, the present invention provides a basalt flake-reinforced wear-resistant PEEK 3D printing filament based on geometrically constrained spreading arrangement, comprising: PEEK matrix, and basalt flakes dispersed in the PEEK matrix; Wherein, the median lateral dimension d of the basalt flakes 50 The thickness ranges from 10 to 80 μm, with a median thickness t. 50 The thickness is 0.5–5 μm; In fused deposition modeling 3D printing, the printed layer height h, nozzle diameter D, and the geometric parameters of the basalt flakes satisfy the following relationship: 0.05 ≤ d 50 / h ≤ 0.60, 0.005 ≤ t 50 / h ≤ 0.08, 3 ≤ D / d 50 ≤ 20; The basalt flakes are arranged in a flat pattern within the printing layer during fused deposition modeling 3D printing.

[0008] As one possible implementation, the content of the PEEK matrix is ​​80-95 wt%, and the content of the basalt flakes is 5-20 wt%.

[0009] As one possible implementation method, the d 50 / h satisfies: 0.08 ≤ d 50 / h≤ 0.40; and / or, the t 50 / h satisfies: 0.01 ≤ t 50 / h≤ 0.05.

[0010] As one possible implementation, the printing layer height h, nozzle diameter D, and the geometric parameters of the basalt flakes satisfy any of the following matching methods: (A), d 50 10–30 μm, t 50 The thickness is 0.5–2 μm, h is 0.10–0.15 mm, and D is 0.20–0.40 mm; (B), d 50 30–50 μm, t 50 The diameter is 1–3 μm, h is 0.15–0.20 mm, and D is 0.40 mm; (C), d 50 50–80 μm, t 50 The diameter is 2–5 μm, h is 0.20–0.30 mm, and D is 0.40–0.60 mm.

[0011] As one possible implementation, the basalt flakes have a gradient interface structure on their surface, the gradient interface structure comprising, from the inside out: An inorganic anchoring layer comprising a phosphorus anchoring component and a silane condensation component; An aromatic bridging layer comprising aromatic structural units selected from aromatic ethers, aromatic ketones, imides, biphenyls, or benzene ring structures; The PEEK compatible outer layer comprises an aromatic polymer selected from polyetherimide, polyethersulfone and / or polyaryletherketone oligomers.

[0012] On the other hand, the present invention provides a method for preparing a basalt flake-reinforced wear-resistant PEEK 3D printing filament based on geometrically constrained spreading arrangement, comprising the following steps: Step S1: Use PEEK matrix and basalt flakes as printing materials, wherein the median lateral dimension d of the basalt flakes is... 50 The thickness ranges from 10 to 80 μm, with a median thickness t. 50 The thickness is 0.5–5 μm; Step S2: Melt-blend the PEEK resin and basalt flakes, then granulate to obtain composite particles; Step S3: Extrude the composite particles to obtain a basalt flake-reinforced wear-resistant PEEK 3D printing filament based on geometrically constrained spread arrangement; The extrusion molding of the composite particles includes fused deposition modeling (FDM) 3D printing, wherein the printing layer height h, nozzle diameter D, and the geometric parameters of the basalt flakes satisfy the following relationship: 0.05 ≤ d 50 / h ≤ 0.60, 0.005 ≤ t 50 / h ≤ 0.08, 3 ≤ D / d 50 ≤ 20; The basalt flakes are arranged in a flat pattern within the printing layer during fused deposition modeling 3D printing.

[0013] As one possible implementation, in step S1, the basalt flakes undergo surface treatment to form a gradient interface structure on their surface. The method for constructing the gradient interface structure includes: The basalt flakes were cleaned and their surface activated. An inorganic anchoring layer was constructed, and the surface-activated basalt flakes were treated with phosphorus-containing anchoring components and silane condensation components. Aromatic bridging layers were constructed by treating basalt flakes with inorganic anchoring layers using an organic treatment liquid containing aromatic structural units. A PEEK-compatible outer layer was constructed by coating basalt flakes with an aromatic bridging layer with a high-temperature resistant aromatic polymer solution selected from polyetherimide, polyethersulfone, or polyaryletherketone oligomers.

[0014] As one possible implementation, the phosphorus-containing anchoring component is selected from one or more of phytic acid, aminotrimethylene phosphonic acid, and hydroxyethylidene diphosphonic acid, or one or more compounds containing phosphate groups, phosphonic acid groups, and pyrophosphate groups; The silane condensation component is selected from one or more of KH550, KH560, and phenyltriethoxysilane; The organic treatment liquid containing aromatic structural units is a polyamic acid precursor solution or a high-temperature resistant aromatic oligomer containing aromatic ethers, aromatic ketones, imides, biphenyls, or benzene ring structures.

[0015] As one possible implementation, the basalt flake-reinforced wear-resistant PEEK 3D printing filament, which is arranged based on geometric constraints, is used as the surface layer of the printed part. The internal structural layer of the printed part is formed by pure PEEK or reinforced PEEK filament. The thickness of the surface layer is 0.2 to 2 mm, or the number of layers of the surface layer is 3 to 10.

[0016] As one possible implementation, in printing where a defined friction direction exists, the deposition path of the outermost surface layer is printed parallel to or at an angle of 0°-30° to the main friction direction; in printing where a defined friction direction does not exist, an interlaced path between adjacent layers or a ring path is used as the deposition path.

[0017] The beneficial effects of this invention are as follows: (1) d is clearly defined 50 / h、t 50 / h and D / d 50 Three scaling parameters enable basalt flakes to simultaneously meet the requirements of passability, spreadability, encapsulationability, and wear resistance during FDM printing, rather than relying solely on the accidental orientation caused by nozzle shearing.

[0018] (2) When the scale size and the printing layer height are in a suitable matching range, the scale is confined within the single-layer deposition space and tends to spread along the layer to form a continuous or semi-continuous layered barrier, which prolongs the abrasive cutting path, reduces the wear depth, and disperses the contact stress.

[0019] (3) The defined parameter range corresponds to the transition interval of the scale arrangement state (d 50 When / h is below 0.05, it is difficult to form an effective barrier; when it is above 0.60, it is prone to lifting, curling, or clogging. 50 / h above 0.08 causes intralayer protrusions and interlayer defects; D / d 50 (When the value is below 3, it is prone to blockage; when it is above 20, the constraints are insufficient), rather than ordinary continuous optimization.

[0020] (4) The spread hard scales can extend the abrasive penetration path, reduce the plowing depth, and disperse contact stress during sliding friction. Experiments show that the wear rate of the matched scale group is reduced by about 75.6% compared with pure PEEK and by about 67.2% compared with basalt particle group.

[0021] (5) Through the multi-layer transition design of inorganic anchoring layer-aromatic bridging layer-PEEK compatible outer layer, the interfacial shear strength can reach 19.8 MPa (about 94% higher than conventional KH550 treatment), the wear rate is further reduced, and the proportion of scale pull-out area is significantly reduced. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the directional arrangement of basalt flakes during the fused deposition modeling (FDM) 3D printing process.

[0023] Figure 2 SEM images of basalt flakes in the PEEK printing layer under different parameter conditions are shown. Among them, (a) is the SEM image of sample N-5 with D / d50=23.8; (b) is the SEM image of sample D-2 with d50 / h=0.055; (c) is the SEM image of sample D-6 with d50 / h=0.62; and (d) is the SEM image of sample D-4 with d50 / h=0.28, t50 / h=0.0167, and D / d50=9.5. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to specific embodiments.

[0025] It should be noted that these embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Simple improvements to the method under the premise of the present invention are all within the scope of protection claimed by the present invention.

[0026] A geometrically constrained, spread-arranged basalt flake-reinforced, wear-resistant PEEK 3D printing filament comprises the following components: The PEEK matrix is ​​80–95 wt%, and the basalt flake filler is 5–20 wt%. Preferably, the PEEK matrix is ​​85–92 wt%, and the basalt flake filler is 8–15 wt%; further, the PEEK matrix is ​​90 wt%, and the basalt flake filler is 10 wt%.

[0027] The median lateral dimension d50 of the basalt flakes is 10–80 μm, and the median thickness t50 is 0.5–5 μm. During actual printing, the printing layer height h, nozzle diameter D, and the d50 and t50 of the basalt flakes are selected as a set of matching parameters. These parameters simultaneously satisfy 0.05 ≤ d50 / h ≤ 0.60, 0.005 ≤ t50 / h ≤ 0.08, and 3 ≤ D / d50 ≤ 20. Through this geometric matching, the flakes are confined to a single-layer space during nozzle extrusion and deposition compaction, spreading out along the layer to form a continuous, layered wear-resistant barrier.

[0028] Preferably, the following preferred matching methods are provided: Matching method A: Small scale size, low layer height: d 50 : 10~30μm; t 50 : 0.5~2μm; h: 0.10~0.15 mm; D: 0.20~0.40 mm.

[0029] This approach is suitable for creating a more finely distributed and uniformly surfaced wear-resistant layer, and is well-suited for fine surfaces or printing conditions with smaller nozzles.

[0030] Matching method B: Medium-sized scales, medium floor height: d 50 30~50μm; t 50 : 1~3μm; h: 0.15~0.20 mm; D: 0.40 mm.

[0031] This solution is suitable for achieving a good balance between printing stability, scale spreading continuity, and abrasion resistance.

[0032] Matching method C: Larger scale size, higher floor height: d 50 50~80μm; t 50 : 2~5μm; h: 0.20~0.30 mm; D: 0.40~0.60 mm.

[0033] This approach is suitable for situations where a more pronounced layered barrier structure is required, but further increases in scale size should be avoided to prevent discontinuous deposition, warping, or nozzle clogging.

[0034] The three proportional parameters mentioned above together define the permeability, spreadability, encapsulation and wear resistance of basalt flakes in the PEEK FDM deposition space.

[0035] This invention performs gradient interface treatment on basalt flakes. The gradient interface structure, from the inside out, includes: (1) an inorganic anchoring layer; (2) an aromatic bridging layer; and (3) a PEEK compatible outer layer. The inorganic anchoring layer enhances the bonding with the flake surface; the aromatic bridging layer improves thermal stability and rigidity matching under high-temperature processing conditions; and the PEEK compatible outer layer improves compatibility and coating stability with the PEEK melt.

[0036] The process of creating a geometrically constrained, spread-out basalt flake-reinforced, wear-resistant PEEK 3D printing filament includes the following steps: Step 1: Raw material pretreatment and basalt flake gradient interface construction.

[0037] The PEEK resin was placed in a vacuum drying oven and dried at 140–160 °C for 3–6 h, preferably at 150 °C for 4 h, until its moisture content was reduced to below 0.05 wt%.

[0038] Basalt flakes were dried at 100–120 °C for 2–4 h, preferably at 110 °C for 3 h, to remove surface adsorbed water.

[0039] The basalt flakes were treated using the following gradient interface steps: a. Cleaning and surface activation: Basalt flakes were added to an ethanol / deionized water mixture (volume ratio 8:2), ultrasonically dispersed for 20 min, and then mechanically stirred at 500 rpm for 30 min to remove floating dust, weakly adsorbed impurities, and agglomerated particles from the flake surface.

[0040] Filter and wash with deionized water 2-3 times.

[0041] Then add it to a weakly acidic aqueous solution with a pH of 3-5 (the weakly acidic aqueous solution can be selected from acetic acid, citric acid, dilute hydrochloric acid or dilute nitric acid solution), with a solid-liquid ratio of 1:30 g / mL, and stir at 40 ℃ for 20 min to form more hydroxyl or metal oxide active sites on the scale surface.

[0042] After treatment, the solution was filtered, washed with deionized water until the pH of the filtrate was close to neutral, and dried at 110 °C for 3 h to obtain activated basalt flakes.

[0043] b. Construction of the inorganic anchoring layer: 100 g of activated basalt flakes were added to 3000 mL of ethanol / deionized water mixed medium, with a volume ratio of ethanol to deionized water of 8:2.

[0044] A phosphorus-anchoring component (such as phytic acid, aminotrimethylene phosphonic acid, hydroxyethylidene diphosphonic acid, or other compounds containing phosphate, phosphonic acid, or pyrophosphate groups, 1.0 g of phosphorus-anchoring component / 100 g of scales) and a silane condensation component (such as KH550, KH560, phenyltriethoxysilane, or combinations thereof, 1.5 g of silane condensation component / 100 g of scales) are added to the mixture. The pH is adjusted to 4.0–5.5, preferably 4.5, using acetic acid. The mixture is then reacted at 50–60 °C for 1–3 h, preferably 2 h.

[0045] In this process, phosphorus-containing groups preferentially adsorb, coordinate, or bond with metal oxide sites such as Fe, Al, Ca, and Mg on the surface of basalt flakes; silane components undergo hydrolysis and condensation to form Si-O-Si or Si-OM structures, thereby forming a phosphorus-containing / silicon-containing composite inorganic anchoring layer on the flake surface.

[0046] After the reaction is complete, filter the solution, wash with an ethanol / water mixture, then wash with deionized water, and then dry at 100–120 °C for 2–4 h, preferably at 110 °C for 3 h.

[0047] c. Construction of aromatic bridging layer: Basalt flakes with inorganic anchoring layers are added to an organic treatment solution containing aromatic structural units for secondary treatment.

[0048] For example, basalt flakes with an inorganic anchoring layer were added to a 1.0 wt% polyamic acid precursor solution, with N-methylpyrrolidone as the solvent, and the solid-liquid ratio was 1 g:20 mL.

[0049] The polyamic acid precursor can be prepared from pyromellitic dianhydride and 4,4'-diaminodiphenyl ether, or it can be replaced by a high-temperature resistant aromatic oligomer containing aromatic ethers, aromatic ketones, imides, biphenyls or benzene ring structures.

[0050] Stir at room temperature for 0.5–3 h, preferably 1 h, to allow aromatic precursors to be fully adsorbed or deposited on the inorganic anchoring layer of the scale surface.

[0051] The mixture is then filtered and dried at 80–120 °C for 1–3 h, preferably at 100 °C for 2 h, to remove the solvent. It is then heat-treated at 150–220 °C for 0.5–2 h, preferably at 200 °C for 1 h, to form a bridging layer with an aromatic rigid structure.

[0052] This aromatic bridging layer is used to reduce the interface abrupt change between the inorganic surface of basalt flakes and the PEEK aromatic polymer matrix, thereby improving the heat resistance, rigidity matching, and tribological service stability of the interface layer.

[0053] d. Construction of PEEK-compatible outer layer: Basalt flakes that have undergone aromatic bridging treatment are added to a 0.1–3 wt% solution of a high-temperature resistant aromatic polymer. The high-temperature resistant aromatic polymer is preferably polyetherimide, polyethersulfone, polyaryletherketone oligomers, or a combination thereof.

[0054] For example, basalt flakes that have undergone aromatic bridging treatment are added to a 1.0 wt% solution of polyetherimide or polyethersulfone, with N-methylpyrrolidone as the solvent and a solid-liquid ratio of 1 g:20 mL. The mixture is stirred at 60 °C for 1 h to allow the high-temperature resistant aromatic polymer to form a thin layer coating on the flake surface.

[0055] The mixture is then filtered, dried at 100–140 °C for 2–4 h, preferably at 120 °C for 3 h, and then heat-treated at 180–280 °C for 0.5–2 h, preferably at 260 °C for 1 h, so that the outer layer is stably attached to the surface of the aromatic bridging layer.

[0056] The surface of the obtained basalt flakes forms a gradient interface structure from the inside out, consisting of an inorganic anchoring layer, an aromatic bridging layer, and a PEEK compatible outer layer.

[0057] The PEEK compatible outer layer does not need to be exactly the same as PEEK, but it is required to have characteristics such as high temperature resistance, aromatic main chain structure and good compatibility with PEEK melt.

[0058] Step 2: Melt blending and granulation.

[0059] Weigh PEEK resin and treated basalt flakes according to the set mass ratio, add them to a high-speed mixer and premix for 5-15 minutes, preferably 10 minutes.

[0060] The premixed material is then added to a twin-screw extruder for melt blending. The temperature of the twin-screw extruder is controlled between 360 and 400°C, with the preferred temperatures for each zone being 360°C, 370°C, 380°C, 390°C, and 395°C, and the die head temperature being 390°C.

[0061] The screw speed is preferably 50–200 rpm, more preferably 80 rpm. The material residence time is preferably 1–5 min, more preferably 2–3 min.

[0062] During the melt blending process, the shear strength of the twin-screw extruder should be controlled to avoid excessive breakage of the basalt flakes, which would cause the lateral dimensions of the flakes to deviate from the d50 range defined in this invention. In this invention, the conditions for moderate shear are: a twin-screw speed of 50–150 rpm, preferably 80–120 rpm; a material residence time of 1–5 min, preferably 2–3 min; a screw length-to-diameter ratio (L / D) of 32–44; a total kneading block length accounting for 10%–25% of the effective screw length; a kneading block misalignment angle preferably 30°–45°; and a d50 retention rate of the basalt flakes after melt blending of not less than 70%, preferably not less than 80%. The d50 retention rate is calculated as d50 of the flakes after melt blending / d50 of the flakes before melt blending × 100%. In this invention, excessive shear conditions refer to processing conditions where the twin-screw rotation speed exceeds 200 rpm, the material residence time exceeds 6 minutes, or the total length of the kneaded block exceeds 30% of the effective screw length, resulting in a d50 retention rate of less than 70% for the basalt flakes after melt blending. Using the aforementioned moderate shear conditions can ensure uniform flake dispersion while reducing flake breakage and dimensional drift.

[0063] The extrudate is cooled and pelletized to obtain basalt flake-reinforced PEEK composite particles.

[0064] Step 3: Extrusion and fiber formation.

[0065] The obtained composite particles were dried at 140–160 °C for 3–6 h, preferably at 150 °C for 4 h.

[0066] The composite particles are then fed into a single-screw extruder for secondary extrusion to produce printing filaments with uniform diameter.

[0067] The preferred filament forming temperature is 380–400 ℃. The filament diameter is controlled by traction speed, cooling distance, and online diameter measurement feedback.

[0068] The preferred wire diameter is 1.75 mm or 2.85 mm.

[0069] More preferably, the diameter of the 1.75 mm wire is controlled within the range of 1.75 ± 0.05 mm, and the roundness deviation does not exceed 0.05 mm.

[0070] Step 4: FDM printing.

[0071] Based on the d of the basalt flakes used 50 and t 50 Select a matching nozzle diameter D and printing layer height h to satisfy the aforementioned relationship. The nozzle temperature is set to 380–420 ℃, the heated bed temperature is set to 140–180 ℃, the forming cavity temperature is set to 80–140 ℃, and the printing speed is set to 20–80 mm / s.

[0072] Preferably, the nozzle temperature is 405 ℃, the heated bed temperature is 160 ℃, the forming cavity temperature is 100 ℃, the printing speed is 30 mm / s, and the fill rate is 100%.

[0073] See Figure 1 During the printing process, basalt flakes are geometrically constrained by the combined effects of nozzle flow, deposition compaction, and layer height boundaries, spreading and arranging themselves along the printed layer. PEEK cools and solidifies after deposition, thus preserving the spread structure within the layer.

[0074] In printed parts requiring improved wear resistance on specific surfaces, basalt flake-reinforced PEEK filaments satisfying the geometric matching relationship of this invention can be used only in several layers on the surface of the printed part. The internal structural layers of the printed part are formed using pure PEEK or reinforced PEEK filaments. The reinforced PEEK filaments include one or more of carbon fiber reinforced PEEK, glass fiber reinforced PEEK, chopped basalt fiber reinforced PEEK, carbon nanotube reinforced PEEK, graphite modified PEEK, molybdenum disulfide modified PEEK, and polytetrafluoroethylene modified PEEK. The thickness of the surface layer is 0.2 to 2 mm, or the number of surface layers is 3 to 10.

[0075] In printing where a defined friction direction exists, the angle between the deposition path of the outermost layer and the main friction direction is 0° to 30°, preferably 0° to 15°; in printing where a defined friction direction does not exist, an interlaced path or a ring path of adjacent layers is used as the deposition path.

[0076] In applications where the friction direction is not defined, staggered paths between adjacent layers can be used, such as 0° / 90°, ±45°, or circular paths, so that the flat scales form a multi-directional wear-resistant network on the surface.

[0077] Unless otherwise specified, the same grade of PEEK resin was used as the matrix material in all the following embodiments. The PEEK resin used was VICTREX 450G unfilled semi-crystalline PEEK granules, which are natural-colored granules suitable for melt extrusion and injection molding. The basalt flakes were commercially available basalt flake powder purchased from Zhongke Huakun (Beijing) Technology Co., Ltd. The PEEK resin was vacuum dried at 150 °C for 4 h; the basalt filler was dried at 110 °C for 3 h.

[0078] The composite material was melt-blended and granulated using a twin-screw extruder, and then extruded using a single-screw extruder to prepare 1.75 mm printing filaments. The temperatures of each zone of the twin-screw extruder were 360 ​​℃, 370 ℃, 380 ℃, 390 ℃, and 395 ℃, respectively, with a die head temperature of 390 ℃, a screw speed of 80 rpm, and a material residence time of approximately 2.5 min. The filament forming temperature was 385–400 ℃, and the diameter of the resulting filaments was controlled at 1.75 ± 0.05 mm.

[0079] During FDM printing, the nozzle temperature is 405 ℃, the heated bed temperature is 160 ℃, the forming cavity temperature is 100 ℃, the printing speed is 30 mm / s, and the fill rate is 100%.

[0080] Friction and wear tests were conducted under dry friction conditions using a pin-disc type, with a load of 20 N, a sliding speed of 0.15 m / s, and a friction distance of 1000 m. At least three samples were tested per group, and the average value and standard deviation were taken. The wear rate was calculated as the ratio of volumetric wear to load and sliding distance.

[0081] Example 1 Weigh 900 g of PEEK resin and 100 g of basalt flakes after complete gradient interface treatment. (Basalt flakes d) 50 42μm, t 50 It is 2.5μm.

[0082] After premixing PEEK and basalt flakes for 10 min, they were added to a twin-screw extruder for melt blending, cooled, and pelletized.

[0083] After the composite particles were dried at 150 °C for 4 h, 1.75 mm printing filaments were prepared by a single screw extruder.

[0084] FDM printing was performed using a 0.40 mm nozzle, with a layer height of 0.15 mm. At this point, d 50 / h = 0.28, t 50 / h = 0.0167, D / d 50 = 9.5, all within the range. After friction and wear testing, the average coefficient of friction of the printed sample was 0.26 ± 0.01, and the wear rate was 2.1 × 10⁻⁶. -5 mm 3 ·N -1 ·m -1 .

[0085] Example 2 Pure PEEK printing sample: Except for the absence of basalt flakes, the drying, filament making, and printing conditions were the same as in Example 1. The resulting pure PEEK sample had an average coefficient of friction of 0.43 ± 0.03 and an abrasion rate of 8.6 × 10⁻⁶. -5 mm3 ·N -1 ·m -1 .

[0086] Example 3 Basalt particle-reinforced PEEK printing sample: Weigh out 900 g of PEEK resin and 100 g of basalt particles. The basalt particles were obtained by ball milling and sieving of basalt raw materials, with a median particle size of 40 μm.

[0087] Except for the change of filler from flakes to granules, the blending, filamentation, and printing conditions were the same as in Example 1.

[0088] The average friction coefficient of the obtained samples was 0.37 ± 0.02, and the wear rate was 6.4 × 10⁻⁶. -5 mm 3 ·N -1 ·m -1 .

[0089] These results indicate that while particulate fillers can improve local hardness, they are difficult to form a continuous layered wear-resistant barrier. The technical effect of this invention does not solely derive from basalt materials.

[0090] Example 4: Low d50 / h mismatched scale print sample: Weigh out 900 g of PEEK resin and 100 g of basalt flakes. The basalt flakes have a d50 of 12 μm and a t... 50 It is 2.0 μm.

[0091] A 0.20 mm nozzle was used, the printing layer height was 0.30 mm, and all other conditions were the same as in Example 1. At this time, d 50 / h is 0.04, which is lower than the lower limit defined in this invention.

[0092] The average friction coefficient of the obtained samples was 0.35 ± 0.03, and the wear rate was 5.8 × 10⁻⁶. -5 mm 3 ·N -1 ·m -1 .

[0093] This result indicates that when the lateral dimension of the scales is too small relative to the layer height, the layer height boundary is difficult to provide effective geometric constraints on the scales.

[0094] Example 5 high d 50 / h Non-matching scale print sample: Weigh out 900 g of PEEK resin and 100 g of basalt flakes. The basalt flakes have a d50 of 93 μm and a t... 50 It is 4.0 μm.

[0095] A 0.50 mm nozzle was used, the printing layer height was 0.15 mm, and all other conditions were the same as in Example 1. At this time, d 50 / h is 0.62, which is higher than the upper limit specified in this invention.

[0096] The average friction coefficient of the obtained samples was 0.46 ± 0.05, and the wear rate was 7.1 × 10⁻⁶. -5 mm 3 ·N -1 ·m -1 .

[0097] This result indicates that when the lateral size of the scales exceeds the stable capacity of the single-layer deposition space, the scales transform from a wear-resistant barrier into a defect source.

[0098] Example 6 Based on the results of the comparative examples of Examples 1-5, as summarized in Table 1, the wear rate of the matched flake group was reduced by approximately 75.6% compared to pure PEEK, by approximately 67.2% compared to the basalt particle group, and by approximately 63.8% compared to the unmatched small flake group.

[0099] Therefore, the technical effect of the present invention is not produced by the basalt filler or the flaky morphology alone, but by the combination of the lateral dimensions and thickness of the basalt flakes with the printing layer height and nozzle diameter.

[0100] Table 1 Summary of Basic Comparative Scale Results

[0101] Example 7 To further demonstrate the d defined in this invention 50 / h、t 50 / h and D / d 50 The range is not simply finding the optimal point in conventional experiments, but corresponds to the critical interval where the scale arrangement changes from disordered or unstable to a stable flat state. Nearest neighbor gradient experiments are set up around the boundary values ​​of the three proportional parameters.

[0102] (1)d 50 / h Critical Interval Verification As shown in Table 2, from D-1 to D-2, it can be seen that when d50 / h increases from 0.035 to 0.055, the wear rate increases from 5.6 × 10⁻⁶. -5 mm 3 ·N -1 ·m -1 It suddenly dropped to 3.7 × 10 -5 mm 3 N -1 ·m -1 The decrease was approximately 33.9%, from Figure 2As shown in (b), the scales show initial orientation, but the continuity of the layered barrier is still somewhat insufficient.

[0103] This change is not a slow, continuous optimization, but rather occurs close to d. 50 A significant performance jump occurs around / h=0.05.

[0104] As can be seen from D-5 to D-6, when d 50 When the wear rate increases from 0.55 to 0.62 per hour, the wear rate increases from 2.6 × 10⁻⁶. -5 mm 3 · N -1 ·m -1 It suddenly increased to 6.8×10 -5 mm 3 ·N -1 ·m -1 The increase was approximately 161.5%.

[0105] Therefore, d 50 The lower limit of 0.05 and the upper limit of 0.60 for / h correspond to two different types of critical transitions: below 0.05, the flakes are difficult to form an effective layered barrier; above 0.60, the flakes are difficult to stably encapsulate within the printed layer, such as... Figure 2 As shown in (c), the scales appear tilted, rolled up, or partially protruding. For example... Figure 2 As shown in (d), this is a SEM image of sample D-4 under matching conditions. The scales are laid out flat along the printed layer, proving that the aforementioned problems can be overcome under matching conditions.

[0106] Table 2 d 50 / h Critical Interval Verification Results Table

[0107] (2) t 50 / h Critical Interval Verification As shown in Table 3, from T-1 to T-2, it can be seen that when t 50 When the wear rate is increased from 0.0027 to 0.0053 per hour, the wear rate increases from 4.8 × 10⁻⁶. -5 mm 3 ·N -1 ·m -1 Reduced to 3.3×10 -5 mm 3 ·N -1 ·m -1 This indicates that when the scale thickness is less than 0.5% of the layer height, although the scales can easily pass through the nozzle and can be oriented to a certain extent, their ability to bear the load and block abrasive particles from penetrating the friction contact area is insufficient.

[0108] As can be seen from T-5 to T-6, when t50 / h increases from 0.0500 to 0.0853, the wear rate increases from 2.8 × 10⁻⁶. -5 mm 3 ·N -1 ·m -1 It suddenly increased to 6.2×10 -5 mm 3 ·N -1 ·m -1 .

[0109] Therefore, t 50 The range of 0.005 to 0.08 / h is not arbitrarily selected, but rather a critical range that simultaneously satisfies the scale load-bearing capacity and the stability of the in-layer encapsulation.

[0110] Table 3 t 50 / h Critical Interval Verification Results Table

[0111] (3) D / d 50 Critical interval verification As shown in Table 4, from N-1 to N-2, it can be seen that when D / d 50 When the efficiency was increased from 2.4 to 3.8, the printing process changed from intermittent clogging to stable extrusion, and the wear rate decreased from 7.5 × 10⁻⁶. -5 mm 3 ·N -1 ·m -1 Reduced to 3.4×10 -5 mm 3 ·N -1 ·m -1 This explains when D / d 50 When the value is below 3, the scales are too large relative to the nozzle channel, making them prone to bridging, agglomeration, and intermittent extrusion within the nozzle.

[0112] From N-4 to N-5, it can be seen that when D / d 50 When the value was increased from 19.0 to 23.8, printing could still proceed, but the wear rate increased from 2.9 × 10⁻⁶. -5 mm 3 ·N -1 ·m -1 Increased to 5.3 × 10 -5 mm 3 ·N -1 ·m -1 .Depend on Figure 2 As shown in (a), the scales in sample N-5 are oriented and dispersed and locally randomly aggregated, resulting in poor continuity of the layered barrier.

[0113] Therefore, D / d 50 =3~20 corresponds to an effective range that balances accessibility and scalability.

[0114] Table 4 D / d 50 Critical Interval Verification Results Table

[0115] Example 8 To demonstrate that the preferred inorganic anchoring layer-aromatic bridging layer-PEEK compatible outer layer gradient interface structure of this invention is not an equivalent replacement for ordinary silane coupling agent treatment, but has higher interface stability under PEEK high-temperature processing and friction wear conditions, the following interface treatment comparative example is further set up.

[0116] All groups used the same PEEK matrix, the same basalt flake geometry, and the same printing parameters. (Basalt flake d) 50 42μm, t 50 The thickness is 2.5 μm, the filler mass fraction is 10 wt%, the printed layer height is 0.15 mm, and the nozzle diameter is 0.40 mm, satisfying d 50 / h=0.28、t 50 / h=0.0167、D / d 50 =9.5, and the results of the gradient interface structure comparison and verification are shown in Table 5.

[0117] Table 5. Comparison and Verification Results of Gradient Interface Structure

[0118] As shown in I-0 and I-1, conventional silane treatment with KH550 can improve the interfacial bonding between basalt flakes and the PEEK matrix to a certain extent, increasing the interfacial shear strength from 6.8 MPa to 10.2 MPa and the wear rate from 3.8 × 10⁻⁶ MPa. -5 mm 3 ·N -1 ·m -1 Reduced to 3.1×10 -5 mm 3 ·N -1 ·m -1 .

[0119] However, due to the high processing temperature of PEEK and the fact that the PEEK molecular chain is an aromatic rigid structure, conventional KH550 treated layers are still prone to interface debonding and scale pull-out under the repeated action of high-temperature melt blending and friction loads.

[0120] After adopting a complete gradient interface structure, the interfacial shear strength of I-6 increased to 19.8 MPa, an improvement of approximately 94.1% compared to the conventional KH550 treatment; the wear rate decreased to 1.9 × 10⁻⁶. -5 mm 3 ·N -1 ·m -1Compared to the conventional KH550 treatment, the yield was reduced by approximately 38.7%; the percentage of scales pulled out from the cross-section decreased from 18% in the KH550 treatment to 5%.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described with reference to preferred embodiments, those skilled in the art should understand that various changes in form and detail can be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A basalt flake-reinforced wear-resistant PEEK 3D printing filament based on geometrically constrained spreading arrangement, characterized in that, include: PEEK matrix, and basalt flakes dispersed in the PEEK matrix; Wherein, the median lateral dimension d of the basalt flakes 50 The thickness ranges from 10 to 80 μm, with a median thickness t. 50 The thickness is 0.5–5 μm; In fused deposition modeling 3D printing, the printed layer height h, nozzle diameter D, and the geometric parameters of the basalt flakes satisfy the following relationship: 0.05 ≤ d 50 / h ≤ 0.60,0.005 ≤ t 50 / h ≤ 0.08,3 ≤ D / d 50 ≤ 20; The basalt flakes are arranged in a flat pattern within the printing layer during fused deposition modeling 3D printing.

2. The 3D printing filament according to claim 1, characterized in that, The content of the PEEK matrix is ​​80-95 wt%, and the content of the basalt flakes is 5-20 wt%.

3. The 3D printing filament according to claim 1 or 2, characterized in that, The d 50 / h satisfies: 0.08 ≤ d 50 / h≤ 0.40; And / or, the t 50 / h satisfies: 0.01 ≤ t 50 / h≤ 0.

05.

4. The 3D printing filament according to claim 3, characterized in that, The printing layer height h, nozzle diameter D, and geometric parameters of the basalt flakes satisfy any of the following matching methods: (A), d 50 10–30 μm, t 50 The thickness is 0.5–2 μm, h is 0.10–0.15 mm, and D is 0.20–0.40 mm; (B), d 50 30–50 μm, t 50 The diameter is 1–3 μm, h is 0.15–0.20 mm, and D is 0.40 mm; (C), d 50 50–80 μm, t 50 The diameter is 2–5 μm, h is 0.20–0.30 mm, and D is 0.40–0.60 mm.

5. The 3D printing filament according to any one of claims 1-4, characterized in that, The basalt flakes have a gradient interface structure on their surface, which, from the inside out, includes the following: An inorganic anchoring layer comprising a phosphorus anchoring component and a silane condensation component; An aromatic bridging layer comprising aromatic structural units selected from aromatic ethers, aromatic ketones, imides, biphenyls, or benzene ring structures; The PEEK compatible outer layer comprises an aromatic polymer selected from polyetherimide, polyethersulfone and / or polyaryletherketone oligomers.

6. A method for preparing basalt flake-reinforced wear-resistant PEEK 3D printing filaments based on geometrically constrained spreading arrangement, characterized in that, Includes the following steps: Step S1: Use PEEK matrix and basalt flakes as printing materials, wherein the median lateral dimension d of the basalt flakes is... 50 The thickness ranges from 10 to 80 μm, with a median thickness t. 50 The thickness is 0.5–5 μm; Step S2: Melt-blend the PEEK resin and basalt flakes, then granulate to obtain composite particles; Step S3: Extrude the composite particles to obtain a basalt flake-reinforced wear-resistant PEEK 3D printing filament based on geometrically constrained spread arrangement; The extrusion molding of the composite particles includes fused deposition modeling (FDM) 3D printing, wherein the printing layer height h, nozzle diameter D, and the geometric parameters of the basalt flakes satisfy the following relationship: 0.05 ≤ d 50 / h ≤ 0.60,0.005 ≤ t 50 / h ≤ 0.08,3 ≤ D / d 50 ≤ 20; The basalt flakes are arranged in a flat pattern within the printing layer during fused deposition modeling 3D printing.

7. The preparation method according to claim 6, characterized in that, In step S1, the basalt flakes undergo surface treatment to form a gradient interface structure on their surface. The method for constructing the gradient interface structure includes: The basalt flakes were cleaned and their surface activated. An inorganic anchoring layer was constructed, and the surface-activated basalt flakes were treated with phosphorus-containing anchoring components and silane condensation components. Aromatic bridging layers were constructed by treating basalt flakes with inorganic anchoring layers using an organic treatment liquid containing aromatic structural units. A PEEK-compatible outer layer was constructed by coating basalt flakes with an aromatic bridging layer with a high-temperature resistant aromatic polymer solution selected from polyetherimide, polyethersulfone, or polyaryletherketone oligomers.

8. The preparation method according to claim 7, characterized in that, The phosphorus-containing anchoring component is selected from one or more of phytic acid, aminotrimethylene phosphonic acid, and hydroxyethylidene diphosphonic acid, or one or more compounds containing phosphate groups, phosphonic acid groups, and pyrophosphate groups. The silane condensation component is selected from one or more of KH550, KH560, and phenyltriethoxysilane; The organic treatment liquid containing aromatic structural units is a polyamic acid precursor solution or a high-temperature resistant aromatic oligomer containing aromatic ethers, aromatic ketones, imides, biphenyls, or benzene ring structures.

9. The method according to claim 8, characterized in that, The basalt flake-reinforced wear-resistant PEEK 3D printing filament, arranged based on geometric constraints, serves as the surface layer of the printed part. The internal structural layers of the printed part are formed using pure PEEK or reinforced PEEK filament. The thickness of the surface layer is 0.2–2 mm, or the number of surface layers is 3–10.

10. The method according to claim 9, characterized in that, In printing with a defined friction direction, the deposition path of the outermost surface layer is made parallel to or at an angle of 0°-30° to the main friction direction; in printing without a defined friction direction, an alternating path between adjacent layers or a ring path is used as the deposition path.

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