High uniformity yttrium stabilized zirconia feedstock for fiber ferrules and methods of making and using the same

Abstract

This invention discloses a highly uniform yttrium-stabilized zirconia feedstock for optical fiber sleeves, its preparation method, and its application. First, the YSZ powder undergoes surface pretreatment, followed by a two-step mixing method: In the first step, a high-melting-point main binder is coated onto the powder surface under high shear force at a lower temperature to form an "inner shell"; in the second step, a low-melting-point auxiliary binder and plasticizer system are introduced at a higher temperature to form a continuous flowing phase. This method overcomes the problems of uneven powder dispersion and poor rheological properties caused by traditional one-step mixing. The prepared feedstock exhibits extremely high uniformity, excellent rheological properties, and high green strength. After injection molding, debinding, and sintering using this feedstock, the resulting zirconia ceramic optical fiber sleeve has high density (≥99.5%), linear shrinkage deviation ≤ ±0.15%, diameter shrinkage deviation ≤ ±3 μm (based on a 2.5 mm inner hole), and length shrinkage deviation ≤ ±10 μm. The product exhibits good dimensional consistency, meeting the assembly requirements of high-precision optical fiber connectors.

Description

Technical Field

[0001] This invention belongs to the field of special ceramic material preparation technology, and particularly relates to a highly uniform yttrium-stabilized zirconia feedstock for optical fiber sleeves, its preparation method, and its application. Background Technology

[0002] Fiber optic sleeves are core precision components of fiber optic connectors, requiring sub-micron level precision in internal hole dimensions, as well as high wear resistance, high strength, and high reliability. Yttrium-stabilized zirconia (YSZ) is the preferred material due to its excellent comprehensive properties. The key to preparing small-volume YSZ sleeves using injection molding lies in the feedstock—a homogeneous mixture of YSZ ceramic powder and an organic binder system. In existing technologies, the preparation of YSZ feedstock often involves adding all components (ceramic powder, binder, plasticizer, lubricant, etc.) to a mixer in one step. This method is prone to the following problems with ultrafine YSZ powder (especially D50 < 0.5μm): uneven dispersion: the powder easily agglomerates due to van der Waals forces, making it difficult for the organic carrier to wet and coat each powder particle. This results in "hard agglomerate" cores within the feedstock, forming flow lines or defects during injection molding, and becoming stress concentration points during debinding and sintering, causing cracking or porosity in the preform. Rheological runaway: Adding a large amount of binder at once can cause premature volatilization of some low molecular weight components (such as paraffin) or local cross-linking of the binder (such as EVA) due to shear heat generation, resulting in unstable feed viscosity and poor batch repeatability. High shear forces acting directly on the agglomerated powder may cause irreversible mechanical damage to the powder crystal phase or surface modification layer, affecting the final sintering activity. Therefore, developing a feed preparation process that can achieve highly uniform dispersion of ultrafine YSZ powder with excellent rheological properties is a technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0003] This invention aims to overcome the shortcomings of the prior art and provide a high-uniformity yttrium-stabilized zirconia feedstock for optical fiber sleeves, its preparation method, and its application. By optimizing the mixing process and formula, the ultrafine YSZ powder is ensured to be perfectly coated and dispersed by the organic carrier. The resulting feedstock has excellent flow and molding capacity, high green strength, and uniform debinding shrinkage behavior, thereby sintering to obtain a highly dense, defect-free, and dimensionally accurate zirconia ceramic sleeve.

[0004] In a first aspect, the present invention provides a method for preparing a highly uniform yttrium-stabilized zirconia feedstock for optical fiber sleeves, comprising the following steps:

[0005] S1 Powder Pretreatment and Primary Mixing: Yttrium-stabilized zirconia powder is premixed with a high-polarity dispersant and a low-molecular-weight lubricant at 60-80℃ for 20-40 minutes;

[0006] S2 Step 1 Internal Mixing: Add the premixed powder obtained from S1 to the internal mixer, heat to 120-140℃, add the high melting point and high toughness main binder, and mix for 30-60 minutes.

[0007] S3 Step 2 Internal Mixing: Raise the internal mixer temperature to 140-160℃, add a low melting point, high flowability auxiliary binder and plasticizer system, and mix for 20-55 minutes;

[0008] S4 Cooling and Granulation.

[0009] In one embodiment, the high polarity dispersant in step S1 is selected from at least one of phosphate esters, titanate coupling agents, or polyethyleneimine derivatives, and its amount accounts for 30%-50% of the total mass of the binder; the low molecular weight lubricant is stearic acid, and its amount accounts for 0.5%-1.5% of the powder mass.

[0010] In one embodiment, the main adhesive in step S2 is selected from at least one of polypropylene or high-density polyethylene, and its amount accounts for 40%-60% of the total mass of the adhesive.

[0011] In one embodiment, the auxiliary binder and plasticizer system in step S3 includes paraffin wax, ethylene-vinyl acetate copolymer and phthalate plasticizer, and optionally contains at least one of microcrystalline wax or low molecular weight polypropylene, in an amount of 20%-55% of the total mass of the binder.

[0012] In one embodiment, the yttrium-stabilized zirconia powder has a Y2O3 content of 3 mol% and a powder D50 of 0.3-0.5 μm.

[0013] In one implementation, the volume solids content of the ceramic powder in the final feed is 52%-58%.

[0014] Secondly, the present invention provides a highly uniform yttrium-stabilized zirconia feedstock for optical fiber sleeves prepared by any of the above methods.

[0015] In one implementation, it is at 140°C for 1000 s -1 The apparent viscosity at the shear rate is 80-200 Pa·s.

[0016] In one embodiment, the zirconia ceramic fiber sleeve prepared therefrom, after sintering, has an inner diameter shrinkage deviation ≤ ±3 μm, a length direction shrinkage deviation ≤ ±10 μm, and a shrinkage uniformity ≤ 0.3%.

[0017] Thirdly, the present invention provides an injection molding application of the above-mentioned highly uniform yttrium-stabilized zirconia feedstock for optical fiber sleeves in the preparation of precision ceramic components for optical fiber sleeves.

[0018] Compared with the prior art, this application has at least the following beneficial effects:

[0019] Significantly improved dispersion uniformity: Through a two-step mixing process combined with powder pretreatment, the powder surface modification and the "core-shell" structure are gradually coated, effectively breaking down hard agglomerates of powder, and the dispersion effect is significantly better than the traditional one-step process.

[0020] Stable rheological properties: Polymers with different melting points and functions are introduced in stages to form a composite structure with a stable skeleton and a flowable matrix. The feedstock has moderate viscosity at the injection temperature and a significant shear thinning effect, which is beneficial for filling small mold cavities (such as inner holes below Φ2.5mm) while avoiding the problem of excessively high injection pressure and temperature sensitivity, resulting in a wide process window.

[0021] Increased green strength and reduced defects: The "core-shell" coating structure firmly supports the ceramic particles by the polymer network, increasing the green strength by about 15%-20% compared to the traditional one-step method. Taking Example 5 as an example, the green strength reached 19.2 MPa, which is 20% higher than that of Comparative Example 1 (16.0 MPa), and it is less prone to cracking or deformation during handling and the initial debinding stage.

[0022] High dimensional accuracy and good shrinkage consistency: Due to the uniform distribution of ceramic particles and the complete coating of organic carrier in the feed, the shrinkage consistency during sintering is good. The final product has an inner diameter deviation of ≤±3 μm (based on a 2.5 mm inner hole), a length deviation of ≤±10 μm, and a linear shrinkage rate deviation of ≤±0.15%, which can meet the requirements of fiber optic sleeves for submicron level inner hole accuracy. Attached Figure Description

[0023] Figure 1 The flowchart shows the two-step internal refining process.

[0024] Figure 2 This is a SEM image of the feeding section in Embodiment 1 of the present invention;

[0025] Figure 3 This is a SEM image of the feeding section in Embodiment 2 of the present invention;

[0026] Figure 4 This is a SEM image of the feeding section in Embodiment 3 of the present invention;

[0027] Figure 5 This is a SEM image of the feeding section in Embodiment 4 of the present invention;

[0028] Figure 6 This is a SEM image of the feeding section in Embodiment 5 of the present invention;

[0029] Figure 7 This is a SEM image of the feeding section of Comparative Example 1 of the present invention;

[0030] Figure 8 This is a photograph of the actual optical fiber sleeve of the present invention;

[0031] Figure 9 This is a SEM image of the cross-section of the sleeve after sintering according to the present invention. Detailed Implementation

[0032] A method for preparing a highly uniform yttrium-stabilized zirconia feedstock for optical fiber sleeves includes the following steps:

[0033] S1. Powder pretreatment and primary mixing: Yttrium-stabilized zirconia powder (Y2O3 content 3mol%, D50 0.3-0.5μm) is premixed with 30%-50% of the total mass of the binder with a highly polar dispersant (such as phosphate ester, titanate coupling agent or polyethyleneimine derivative) and a small amount (0.5%-1.5% of the powder mass) of a low molecular weight lubricant (such as stearic acid) in a high-speed mixer at 60-80℃ for 20-40 minutes, so that the dispersant and lubricant are fully adsorbed on the powder surface to form a preliminary organic coating layer.

[0034] S2. First Step Mixing (Building the "Core" Structure): Add the premixed powder obtained in S1 to a mixer and heat to the first temperature range (120-140℃). Add a high-melting-point, high-toughness main binder (such as polypropylene (PP) or high-density polyethylene (HDPE), accounting for 40%-60% of the total mass of the binder. At this temperature, the main binder begins to soften but does not completely melt. Under high shear force, it is "crushed" and tightly wrapped around the surface of the pre-treated powder particles, forming primary composite particles with ceramic powder as the "core" and a strong, tough polymer as the tight "inner shell." This process lasts 30-60 minutes.

[0035] S3. Second-stage mixing (building the "shell" structure and rheological phase): Raise the temperature of the internal mixer to the second temperature zone (140-160℃), at which point the main binder is completely melted. Add a low-melting-point, high-flowability auxiliary binder and plasticizer system (such as a combination of paraffin wax (PW), ethylene-vinyl acetate copolymer (EVA), and dioctyl phthalate (DOP)) in batches or slowly and continuously. This system accounts for 20%-55% of the total binder mass. This stage is carried out under relatively mild shear, allowing the low-melting-point components to fully melt and fill the spaces between the primary composite particles, forming a continuous "shell" and matrix phase that provides flowability. This process lasts 20-40 minutes until the feedstock forms a uniform, glossy, and well-ductile agglomerate.

[0036] S4. Cooling and Granulation: Take out the well-mixed feed agglomerate, cool it to room temperature, and then crush and granulate it through a granulator to obtain a granular feed product with uniform particle size (2-4mm).

[0037] The yttrium-stabilized zirconia feed prepared according to the above method is characterized by: the volume solid content of the ceramic powder being 52%-58%, and the feeding being carried out at 140℃ for 1000 s. -1 The apparent viscosity at the shear rate is 80-200 Pa·s, and it exhibits obvious shear thinning behavior.

[0038] The present invention will be further described in detail below with reference to specific embodiments, but the embodiments listed do not limit the scope of protection of the present invention.

[0039] The YSZ powder used in this invention is commercially available 3Y-TZP powder with D50=0.4μm and specific surface area of ​​7m² / g. All percentages are by mass unless otherwise specified.

[0040] Example 1

[0041] Formula: 100 parts of YSZ powder (Y2O3 content is 3mol%, D50 is 0.3-0.5μm); 18 parts of binder system, of which the volume solid content of ceramic powder is about 55 vol.

[0042] The binder system comprises: a highly polar dispersant (phosphate ester), a low molecular weight lubricant (stearic acid), a primary binder (polypropylene PP), and an auxiliary binder and plasticizer system (paraffin wax PW, ethylene-vinyl acetate copolymer EVA, and phthalate plasticizer DOP). The dispersant accounts for 40% of the total binder mass, and the stearic acid accounts for 1% of the powder mass. The primary binder accounts for 50% of the total binder mass; the auxiliary binder and plasticizer system accounts for 50% of the total binder mass (where the mass ratio of PW:EVA:DOP = 6:3:1).

[0043] Process: S1. Powder pretreatment and primary mixing: YSZ powder, phosphate ester, and stearic acid are premixed in a high-speed mixer at 80°C for 30 minutes.

[0044] S2. First step of internal mixing: Add the premixed powder obtained in S1 to the internal mixer, heat it to 140℃, add polypropylene, and mix for 45 minutes at a rotor speed of 60 rpm.

[0045] S3. Second step of internal mixing: Raise the temperature of the internal mixer to 150°C, add the mixture of paraffin, ethylene-vinyl acetate copolymer and dioctyl phthalate in three parts, with an interval of 5 minutes between each addition. After the addition is complete, reduce the rotor speed to 40 rpm and mix for 30 minutes until homogeneous.

[0046] S4. Cooling and Granulation: Discharge, cooling, and granulation.

[0047] Performance testing: The final feed contained 55% vol% ceramic powder by volume. The feed was subjected to a temperature of 140℃ for 1000 seconds. -1 The apparent viscosity at the shear rate is 150 Pa·s; the flexural strength of the injection-molded green body is 18.5 MPa; the density of the sintered body is 6.06 g / cm³; and the shrinkage uniformity is 0.25%.

[0048] Dimensional accuracy test: 100 fiber optic sleeve samples after injection molding, degreasing and sintering were randomly selected for measurement. The average inner diameter was 2.499 mm, the maximum deviation was ±2.5 μm, the average deviation in the length direction was ±8 μm, and the shrinkage deviation was ±0.12%.

[0049] Example 2

[0050] Formula: 100 parts of YSZ powder (Y2O3 content is 3mol%, D50 is 0.3-0.5μm); 16 parts of binder system, of which the volume solid content of ceramic powder is about 57 vol.

[0051] The binder system comprises: a high-polarity dispersant (titanium ester coupling agent) accounting for 35% of the total binder mass, and a low molecular weight lubricant (stearic acid) accounting for 0.8% of the powder mass. The main binder (high-density polyethylene, HDPE) accounts for 55% of the total binder mass; and the auxiliary binder and plasticizer system (paraffin wax PW, ethylene-vinyl acetate copolymer EVA, phthalate plasticizer DOP) accounts for 45% of the total binder mass (wherein the mass ratio of PW:EVA:microcrystalline wax:DBP = 6:2:1:1).

[0052] Process: S1. Powder pretreatment and primary mixing: YSZ powder, titanate coupling agent and stearic acid are premixed in a high-speed mixer at 75°C for 25 minutes.

[0053] S2. First step of internal mixing: Add the premixed powder obtained in S1 to the internal mixer, heat to 135°C, add high-density polyethylene, and mix for 50 minutes.

[0054] S3. Second step of internal mixing: Raise the temperature of the internal mixer to 155°C, add the mixture of paraffin wax, ethylene-vinyl acetate copolymer and phthalate plasticizer, and mix for 25 minutes until homogeneous.

[0055] S4. Cooling and granulation.

[0056] Performance testing: The final feed contained 57 vol% ceramic powder by volume. The feed was subjected to a temperature of 140℃ for 1000 seconds. -1 The apparent viscosity at the shear rate is 180 Pa·s; the green strength is 19.0 MPa; the sintering density is 6.05 g / cm³; and the shrinkage uniformity is 0.28%.

[0057] Dimensional accuracy test: 100 fiber optic sleeve samples were randomly selected for measurement. The average inner diameter was 2.498 mm, the maximum deviation was ±3.0 μm, the average deviation in the length direction was ±9 μm, and the shrinkage deviation was ±0.14%.

[0058] Example 3

[0059] Formula: 100 parts of YSZ powder (Y2O3 content is 3mol%, D50 is 0.3-0.5μm); 20 parts of binder system, of which the volume solid content of ceramic powder is about 53 vol.

[0060] The binder system comprises: a highly polar dispersant (polyethyleneimine derivative) accounting for 45% of the total binder mass, and a low molecular weight lubricant (stearic acid) accounting for 1.2% of the powder mass. The main binder (polypropylene PP) accounts for 45% of the total binder mass; the auxiliary binder and plasticizer system (paraffin wax PW, low molecular weight polypropylene, phthalate plasticizer DOP) accounts for 55% of the total binder mass (where the mass ratio of PW: low molecular weight polypropylene: DOP is 5:3:2).

[0061] Process: S1. Powder pretreatment and primary mixing: YSZ powder, polyethyleneimine derivative, and stearic acid are premixed in a high-speed mixer at 60°C for 40 minutes.

[0062] S2. First step of internal mixing: Add the premixed powder obtained in S1 to the internal mixer, heat to 125℃, add polypropylene, and mix for 40 minutes.

[0063] S3. Second step of internal mixing: Raise the temperature of the internal mixer to 145°C, add the mixture of paraffin, low molecular weight polypropylene and dioctyl phthalate, and mix for 35 minutes until homogeneous.

[0064] S4. Cooling and granulation.

[0065] Performance testing: The final feed contained 53% vol% ceramic powder by volume. The feed was subjected to a temperature of 140℃ for 1000 seconds. -1 The apparent viscosity at the shear rate is 100 Pa·s; the green strength is 17.8 MPa; the sintering density is 6.05 g / cm³; and the shrinkage uniformity is 0.30%.

[0066] Dimensional accuracy test: 100 fiber optic sleeve samples were randomly selected for measurement. The average inner diameter was 2.497 mm, the maximum deviation was ±3.0 μm, the average deviation in the length direction was ±9 μm, and the shrinkage deviation was ±0.14%.

[0067] Example 4

[0068] Formulation: 100 parts of YSZ powder (Y2O3 content 3mol%, D50 0.3-0.5μm); 19 parts of binder system. The binder system comprises: a high-polarity dispersant (phosphate ester) accounting for 40% of the total binder mass; a low-molecular-weight lubricant (stearic acid) accounting for 1% of the powder mass; a main binder (polypropylene and high-density polyethylene mixed in a 1:1 ratio) accounting for 50% of the total binder mass; and an auxiliary binder and plasticizer system (paraffin wax PW, ethylene-vinyl acetate copolymer EVA, microcrystalline wax, and phthalate plasticizer DOP) accounting for 50% of the total binder mass (wherein the mass ratio of PW:EVA:microcrystalline wax:DOP = 5:2:2:1).

[0069] Process: S1. Powder pretreatment and primary mixing: YSZ powder, phosphate ester, and stearic acid are premixed in a high-speed mixer at 80°C for 20 minutes.

[0070] S2. First step of internal mixing: Add the premixed powder obtained in S1 to the internal mixer, heat to 130°C, add the mixture of polypropylene and high-density polyethylene, and mix for 45 minutes.

[0071] S3. Second step of internal mixing: Raise the temperature of the internal mixer to 150°C, add the mixture of paraffin wax, ethylene-vinyl acetate copolymer, microcrystalline wax and dioctyl phthalate, and mix for 30 minutes until homogeneous.

[0072] S4. Cooling and granulation.

[0073] Performance testing: The final feed contained 55% vol% ceramic powder by volume. The feed was subjected to a temperature of 140℃ for 1000 seconds. -1 The apparent viscosity at the shear rate is 135 Pa·s; the green strength is 18.8 MPa; the sintering density is 6.05 g / cm³; and the shrinkage uniformity is 0.22%.

[0074] Dimensional accuracy test: 100 fiber optic sleeve samples were randomly selected for measurement. The average inner diameter was 2.499 mm, the maximum deviation was ±2.2 μm, the average deviation in the length direction was ±7 μm, and the shrinkage deviation was ±0.11%.

[0075] Example 5

[0076] Formula: 100 parts of YSZ powder (Y2O3 content is 3mol%, D50 is 0.3-0.5μm); 17 parts of binder system, of which the volume solid content of ceramic powder is about 56 vol.

[0077] The binder system comprises: a highly polar dispersant (composite type, phosphate ester and titanate ester 1:1) accounting for 38% of the total binder mass, and a low molecular weight lubricant (stearic acid) accounting for 0.9% of the powder mass. The main binder (high-density polyethylene HDPE) accounts for 60% of the total binder mass; and the auxiliary binder and plasticizer system (paraffin wax PW, ethylene-vinyl acetate copolymer EVA, phthalate plasticizer DBP) accounts for 40% of the total binder mass (wherein the mass ratio of PW:EVA:DBP = 6.5:2.5:1).

[0078] Process: S1. Powder pretreatment and primary mixing: YSZ powder, a mixture of phosphate ester and titanate, and stearic acid are premixed in a high-speed mixer at 70°C for 35 minutes.

[0079] S2. First step of internal mixing: Add the premixed powder obtained in S1 to the internal mixer, heat to 128°C, add high-density polyethylene, and mix for 55 minutes.

[0080] S3. Second step of internal mixing: Raise the temperature of the internal mixer to 158°C, add the mixture of paraffin wax, ethylene-vinyl acetate copolymer and dibutyl phthalate, and mix for 20 minutes until homogeneous.

[0081] S4. Cooling and granulation.

[0082] Performance testing: The volume solids content of the ceramic powder in the final feed was 56 vol%. The apparent viscosity of the feed at 140℃ and 1000 s⁻¹ shear rate was 165 Pa·s; the green strength was 19.2 MPa; the sintering density was 6.06 g / cm³; and the shrinkage uniformity was 0.20%.

[0083] Dimensional accuracy test: 100 fiber optic sleeve samples were randomly selected for measurement. The average inner diameter was 2.500 mm, the maximum deviation was ±2.0 μm, the average deviation in the length direction was ±6 μm, and the shrinkage deviation was ±0.10%.

[0084] Comparative Example 1 (Traditional One-Step Refining Method)

[0085] Formula: exactly the same as in Example 1.

[0086] Process: All components (YSZ powder, phosphate ester, stearic acid, polypropylene, and a mixture of paraffin wax, ethylene-vinyl acetate copolymer, and dioctyl phthalate) are added to a mixer at once, heated directly to 150°C, and mixed at 50 rpm for 90 minutes. Then, the mixture is cooled and granulated.

[0087] Performance testing: The apparent viscosity of the feed at 140℃ and 1000 s⁻¹ shear rate fluctuated between 120-250 Pa·s, which is much larger than the stability range of the examples (e.g., 150 Pa·s in Example 1), indicating poor rheological stability. The appearance showed visible fine particles. The green strength was 16.0 MPa. The injection molded parts showed a cracking rate of about 5% after degreasing. The sintered body density was 6.02 g / cm³, the shrinkage uniformity was 0.45%, and some products had micro-wrinkles in the inner pores.

[0088] Dimensional accuracy test: 100 fiber optic sleeve samples were randomly selected for measurement. The average inner diameter was 2.485 mm, with a maximum deviation of ±5.5 μm. The average deviation in the length direction was ±18 μm, and the shrinkage deviation was ±0.28%. Some samples could not be measured due to cracking, but these deviations have been included in the deviation statistics.

[0089] Comparative Example 2 (no powder pretreatment, two-step method)

[0090] Formula: exactly the same as in Example 2.

[0091] Process: Step S1 is omitted. YSZ powder is directly added to a Banbury mixer, heated to 135°C, and high-density polyethylene is added. The mixture is then Banburyed for 50 minutes. The temperature is then raised to 155°C, and a mixture of paraffin wax, ethylene-vinyl acetate copolymer, and phthalate plasticizers is added. The mixture is then Banburyed for 25 minutes. Finally, it is cooled and granulated.

[0092] Performance testing: The feed viscosity is relatively high (220 Pa·s), and the flowability is slightly poor; the green strength is 17.5 MPa; the sintered body density is 6.00 g / cm³, but scanning electron microscopy shows that there are a small number of isolated pores of 1-2 μm in the cross section (originating from initial agglomeration), and the shrinkage uniformity is 0.38%.

[0093] Dimensional accuracy test: 100 fiber optic sleeve samples were randomly selected for measurement. The average inner diameter was 2.490 mm, the maximum deviation was ±4.5 μm, the average deviation in the length direction was ±15 μm, and the shrinkage deviation was ±0.22%.

[0094] Figures 2 to 6 The images show SEM images of the feeding sections obtained in Examples 1 to 5, respectively. As can be seen from the images, the ceramic powder is uniformly distributed in the organic carrier, without obvious agglomerates or pores. The powder particles are fully coated by the organic binder, forming a dense "core-shell" structure, which proves the excellent effect of the method of the present invention in terms of powder dispersion and interfacial bonding.

[0095] Figure 7The image shows a SEM image of the feed cross-section obtained in Comparative Example 1 (traditional one-step internal mixing). Obvious powder agglomerates and uneven regions are visible in the image, along with micron-sized pores and incompletely wetted powder particles, indicating that traditional methods are insufficient to achieve uniform dispersion of ultrafine YSZ powder.

[0096] Figure 8 These are photographs of the actual fiber optic sleeve and enlarged views of its internal structure. The left side shows the external appearance of the sintered fiber optic sleeve, which is smooth, without cracks or deformation. The middle and right sides are microscopic images of the internal structure, showing that the inner hole edges are neat, without burrs or microscopic defects, and with high dimensional accuracy.

[0097] Figure 9 This is a SEM image of the cross-section of the optical fiber sleeve after sintering. The image shows that the ceramic grains are small and tightly packed, with clear grain boundaries, no abnormal growth, and very few pores, further verifying that the feedstock prepared by the method of this invention has high density and uniform shrinkage characteristics after sintering.

[0098] Table 1. Dimensional accuracy test results in the examples and comparative examples. .

[0099] As can be seen from the above embodiments and comparative examples:

[0100] Examples 1-5 employing the "powder pretreatment" + "two-step mixing" process of this invention show significantly better performance indicators than Comparative Example 1 using the traditional one-step method. The feed viscosity is stable, the green body strength and sintered body density are higher, and most importantly, the shrinkage uniformity is significantly improved (≤0.3%), which is crucial for ensuring the sub-micron level internal hole precision of the optical fiber sleeve.

[0101] Comparative Example 2 shows that even with the two-step method, the uniformity of the final product (manifested as the presence of micropores and a decrease in shrinkage uniformity) will be affected if the initial dispersion and coating steps of powder pretreatment are missing. This demonstrates that the synergistic effect of the pretreatment step and the two-step mixing is the key innovation.

[0102] By adjusting the formulation (such as adjusting the solid content in Example 3 and adjusting the main binder combination in Example 4), the rheological properties of the feed and the performance of the final product can be controlled within a certain range, indicating that the process has good flexibility and controllability.

[0103] In summary, the YSZ feedstock and its preparation process provided by this invention effectively solve the dispersion problem of ultrafine ceramic powder in injection feeding through innovative process design. The prepared feedstock has excellent performance and is particularly suitable for injection molding of precision ceramic parts such as optical fiber sleeves that have extremely high requirements for dimensional accuracy and reliability.

[0104] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a highly uniform yttrium-stabilized zirconia feedstock for optical fiber sleeves, characterized in that, Includes the following steps: S1 Powder Pretreatment and Primary Mixing: Yttrium-stabilized zirconia powder is premixed with a high-polarity dispersant and a low-molecular-weight lubricant at 60-80℃ for 20-40 minutes; S2 Step 1 Internal Mixing: Add the premixed powder obtained from S1 to the internal mixer, heat to 120-140℃, add the high melting point and high toughness main binder, and mix for 30-60 minutes. S3 Step 2 Internal Mixing: Raise the temperature of the internal mixer to 140-160℃, add a low melting point, high flowability auxiliary binder and plasticizer system, and mix for 20-40 minutes; S4 Cooling and Granulation.

2. The method for preparing highly uniform yttrium-stabilized zirconia feedstock for optical fiber sleeves according to claim 1, characterized in that, The high polarity dispersant in step S1 is selected from at least one of phosphate ester, titanate coupling agent or polyethyleneimine derivative, and its amount accounts for 30%-50% of the total mass of the binder; the low molecular weight lubricant is stearic acid, and its amount accounts for 0.5%-1.5% of the powder mass.

3. The method for preparing highly uniform yttrium-stabilized zirconia feedstock for optical fiber sleeves according to claim 1, characterized in that, The main adhesive mentioned in step S2 is selected from at least one of polypropylene or high-density polyethylene, and its amount accounts for 40%-60% of the total mass of the adhesive.

4. The method for preparing highly uniform yttrium-stabilized zirconia feedstock for optical fiber sleeves according to claim 1, characterized in that, The auxiliary binder and plasticizer system described in step S3 includes paraffin wax, ethylene-vinyl acetate copolymer and phthalate plasticizer, and optionally includes at least one of microcrystalline wax or low molecular weight polypropylene, the amount of which accounts for 20%-55% of the total mass of the binder.

5. The method for preparing highly uniform yttrium-stabilized zirconia feedstock for optical fiber sleeves according to claim 1, characterized in that, The yttrium-stabilized zirconia powder contains 3 mol% Y2O3 and has a powder D50 of 0.3-0.5 μm.

6. The method for preparing highly uniform yttrium-stabilized zirconia feedstock for optical fiber sleeves according to claim 1, characterized in that, The final feed contains 52%-58% ceramic powder by volume solids.

7. A highly uniform yttrium-stabilized zirconia feedstock for optical fiber sleeves prepared by the preparation method according to any one of claims 1-6.

8. The high-uniformity yttrium-stabilized zirconia feedstock for optical fiber sleeves according to claim 7, characterized in that, It is at 140℃ for 1000 s -1 The apparent viscosity at the shear rate is 80-200 Pa·s.

9. The high-uniformity yttrium-stabilized zirconia feedstock for optical fiber sleeves according to claim 7, characterized in that, The zirconia ceramic fiber sleeve prepared therefrom, after sintering, has an inner diameter shrinkage deviation of ≤ ±3 μm, a length direction shrinkage deviation of ≤ ±10 μm, and a shrinkage uniformity of ≤ 0.3%.

10. The application of a highly uniform yttrium-stabilized zirconia feedstock for optical fiber sleeves as described in any one of claims 8-9 in injection molding for the preparation of precision ceramic components for optical fiber sleeves.

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