Preparation method for yttrium aluminum garnet continuous fiber

Abstract

A preparation method for an yttrium aluminum garnet continuous fiber. The method prepares a spinnable precursor sol by utilizing an Al.sub.13 colloidal particles contained alumina sol, γ-AlOOH nano-dispersion, yttria sol, glacial acetic acid and polyvinylpyrrolidone, then prepares a gel continuous fiber by adopting a dry spinning technique, and carries out a heat treatment to obtain the yttrium aluminum garnet continuous fiber.

Claims

1. A method for preparing a continuous YAG fiber comprises the following steps: (1) preparation of a spinnable sol a sol containing colloidal Al.sub.13 particles are mixed with a γ-AlOOH nanodispersion which is added into a Y.sub.2O.sub.3 sol, stirred in a water bath of 30-40° C., a glacial acetic acid is added during the stirring process, and then pH value is adjusted to 1-3 by adding dilute nitric acid; a spinning additive PVP is added, stirred and mixed evenly, an aging temperature is set to 25-80° C. until viscosity of solution is up to 400-600 Pa.Math.s to form the spinnable sol; the sol containing colloidal Al.sub.13 particles has an alumina content of 15-35 wt %, the Y.sub.2O.sub.3 sol has a solid content of 10-30 wt %, and the γ-AlOOH nanodispersion has a solid content of 8.5-15 wt %, and a molar ratio of Y.sub.2O.sub.3 to glacial acetic acid is 1:(1-2), the amount of the PVP is added in 0.5-5 wt % of total solid content; a molar ratio of Y.sub.2O.sub.3 to aluminum oxide is 1:(1-2); (2) dry-spun to prepare a YAG gel fiber the spinnable sol prepared in the step (1) is dry-spun to form the YAG gel fiber at a condition: 15-800 of spinnerets is used, and diameter of a spinneret is 0.06-0.15 mm, a wire take-up speed is 60-180 m/min, environment temperature is 18-40° C., a relative humidity (RH) is 20-70%; and (3) ceramization of the YAG gel fiber the YAG gel fiber formed in the step (2) is ceramized by being heated to 450-600° C. at a rate of 0.5-3° C./min, and incubated for 0.5-2 hours, then the temperature is increased to 900-1400° C. at the rate of 3-10° C./min and incubated for 0.5-2 hours which yields the continuous YAG fiber.

2. The method according to claim 1, wherein the mass of the colloidal Al.sub.13 particles in the sol containing the colloidal Al.sub.13 particles in the step (1) is 20-25 wt %, the solid content of the γ-AlOOH nanodispersion is 10-15 wt %, the solid content of the Y.sub.2O.sub.3 sol is 15 wt %, and the spinning additive PVP is added in an amount of 1 wt % of the total solid content.

3. The method according to claim 1, wherein the mass ratio of γ-AlOOH nanodispersion to the Al.sub.13 colloids in the sol is (3-9):1.

4. The method according to claim 1, wherein the aging temperature in the step (1) is 35-50° C., and the viscosity is 450-550 Pa.Math.s.

5. The method according to claim 1, wherein after the pH value is adjusted in the step (1), a vacuum of 0.095 MPa is applied.

6. The method according to claim 1, wherein the molar ratio of the Y.sub.2O.sub.3 to the glacial acetic acid in the step (1) is 1:(1.1-1.5).

7. The method according to claim 1, wherein the pH value is adjusted to 1.5-2.5.

8. The method according to claim 1, wherein in the process (2), the spinneret has a pore diameter of 0.06-0.10 mm, and the wire take-up speed is 80-140 m/min.

9. The method according to claim 1, wherein the environment temperature in the step (2) is 25-35° C., the RH is 30-45%.

10. The method according to claim 1, wherein the YAG gel fiber in the step (3) is heated to the temperature of 450-600° C. at the rate of 0.8-1° C./min, and incubated for 1-2 hours, then the temperature is increased to 900-1400° C. at the rate of 3-5° C./min, and incubated for 1-2 hours.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is the XRD pattern of as-formed continuous YAG gel fibers after sintered at different temperatures in Example 1 of the present invention.

(2) FIG. 2 is an optical image of a continuous YAG gel fiber in Example 1 of the present invention.

(3) FIG. 3 is a SEM image of a continuous YAG fiber in Example 1 of the present invention.

(4) FIG. 4 is a high magnification SEM image of continuous YAG fiber in Example 1 of the present invention.

(5) FIG. 5 is a SEM image showing a high magnification of a cross section of a continuous YAG fiber in Example 1 of the present invention.

DETAILED DESCRIPTION

(6) The present invention will be further described below in conjunction with the embodiments, but is not limited thereto.

(7) The spinnable sol containing colloidal Al.sub.13 particles described in the examples was prepared as follows:

(8) The aluminum powders and the aluminum salt solution are used as raw materials, and the molar ratio of the aluminum salt to the aluminum powder is 1:(1-5), and the mixed solution is heated to reflux until the aluminum powder is completely reacted, cooled, and filtered to form an alumina sol containing colloidal Al.sub.13 particles. The sol has a mass content of 20-25 wt %, the size of the colloidal particle is 5 nm, and the aluminum salt may be aluminum chloride, aluminum nitrate, or aluminum sulfate.

Example 1

(9) A method for preparing continuous YAG fiber comprises the following processes:

(10) (1) Preparation of Spinnable Sol

(11) 925.2 g of the sol containing Al.sub.13 colloidal particles (solid content: 22.04 wt %) and 419.6 g of γ-AlOOH nanodispersion (solid content: 12.15 wt %) were mixed, and stirred until to form a homogeneous mixture, according to n(Al.sub.2O.sub.3):n(Y.sub.2O.sub.3)=5:3 metering composition 2258.1 g of Y.sub.2O.sub.3 sol (solid content is 15 wt %) is added, stirring in water bath at 35° C., 450 g of glacial acetic acid is added during the stirring process, wherein the molar ratio of Y.sub.2O.sub.3 to glacial acetic acid is 1:1.25, then 173 g of dilute nitric acid is added to adjust the pH value to 2.0, 39.6 g of PVP solution is added, being stirred and mixed well.

(12) The aging temperature was set to 40° C., the aging process was carried out under the vacuum degree of 0.095 MPa, and the viscosity of the mixed sol was aged up to 500 Pa.Math.s to form a spinnable sol.

(13) (2) Dry-Spinning to Form Gel Fiber

(14) The spinnable sol prepared in the process (1) is dry-spun to form a YAG gel fiber. The preparative conditions are as follows: the spinneret has a pore diameter of 0.06 mm, the wire take-up speed is 100 m/min, and the environment temperature is 25-30° C. The relative humidity (RH) is 30-40%, as shown in FIG. 2, the fiber length can reach several kilometers.

(15) (3) The Ceramization of the YAG Gel Fiber

(16) The YAG gel fiber prepared in the process (2) is ceramized, and the preparative conditions are as follows: the temperature is raised to 500° C. at a speed of 1° C./min, kept at that temperature for 1 h, then the temperature is raised to 1200° C. at a rate of 5° C./min, and maintained at that temperature for 2 h to form continuous YAG fiber.

(17) The as-prepared continuous YAG fiber has a diameter of 7.7-8.5 μm and a fiber shrinkage of about 30% at volume. The fiber surface is smooth and the internal structure is dense. The XRD pattern show that the crystal phase of the fiber is a YAG structure, its average tensile strength is 932 MPa.

(18) In the process (3) for the ceramization of YAG gel fiber, the final sintering temperature was selected to be 700° C., 800° C., 900° C., 1000° C., and the XRD pattern of the continuous YAG fiber shown in FIG. 1, the YAG fiber sintered at 800° C. starts pomegranate, and when the sintering temperature is 1000° C., it is completely converted into a YAG structure.

(19) The SEM image of the continuous YAG fiber in this example is shown in FIG. 3. The high-magnification SEM image is shown in FIG. 4, and the SEM image of the fiber cross-section magnification is shown in FIG. 5. It can be seen from FIGS. 3, 4 and 5 that the fiber has a uniform diameter and a smooth surface. The internal structure of the fiber is dense and the number of pores between the grains is small, which is favorable for the mechanical strength of the fiber.

Comparative Example 1

(20) A method for preparing continuous YAG fiber comprises the following processes:

(21) (1) Preparation of Spinnable Sol

(22) 1156.5 g of a sol containing Al.sub.13 colloidal particles (solid content: 22.04 wt %) and 2258.1 g of Y.sub.2O.sub.3 sol (solid content: 15 wt % by weight) were mixed at a ratio of n(Al.sub.2O.sub.3):n(Y.sub.2O.sub.3)=5:3. The mixture was stirred in water bath at 35° C. During the stirring, 450 g of glacial acetic acid was added, wherein the molar ratio of Y.sub.2O.sub.3 to glacial acetic acid was 1:1.25, then 138 g of dilute nitric acid was added to adjust the pH value to 2.0, and 98.9 g of PVP solution was added, and the mixture was stirred and homogenized.

(23) The aging temperature was set to 40° C., the aging process was carried out under the vacuum degree of 0.095 MPa, and the mixed sol was aged to a viscosity of 513 Pa.Math.s to form a spinnable sol.

(24) (2) Dry-Spun to Prepare Gel Fiber

(25) The sol prepared in the process (1) is dry-spun to form a YAG gel fiber. The preparative conditions are as follows: the spinneret has a pore diameter of 0.06 mm, the wire take-up speed is 80 m/min, and the environment temperature is 25-30° C., the RH is 30-40%.

(26) Process (3) is the same as in Embodiment 1.

(27) The as-prepared continuous YAG fiber has a diameter of 9.5-10.2 μm. The gel fiber is easy to break and the diameter is coarse during the spinning process, and the fiber shrinkage rate is about 33% at volume, the fiber surface has slag balls and the internal structure is not dense, the XRD pattern show that the crystal phase of the fiber is a YAG structure, and the average tensile strength of the fiber is 494 MPa. It can be seen that the sol containing Al.sub.13 colloidal particles alone is used as the alumina source, which seriously affects the tensile strength of the continuous YAG fiber.

Example 2

(28) A method for preparing continuous YAG fiber comprises the following processes:

(29) (1) Preparation of Spinnable Sol

(30) 925.2 g of the sol containing colloidal Al.sub.13 particles (solid content: 22.04 wt %) and 419.6 g of γ-AlOOH nanodispersion (solid content: 12.15 wt %) were mixed, and stirred until to form the homogeneous mixture, according to n(Al.sub.2O.sub.3):n(Y.sub.2O.sub.3)=5:3 metering composition. 2258.1 g of Y.sub.2O.sub.3 sol (solid content 15 wt %) is added, stirred in water bath at 35° C., 450 g of glacial acetic acid was added during the stirring process, wherein the molar ratio of Y.sub.2O.sub.3 to glacial acetic acid is 1:1.25, the pH value was 3.8 after 98.9 g of PVP solution was added, the mixture was stirred and mixed uniformly.

(31) The aging temperature is set to 40° C., the aging process is carried out under the condition of vacuum degree of 0.095 MPa, and the mixed sol is aged to a viscosity of 496 Pa.Math.s to form the spinnable sol.

(32) Process (2) is the same as in example 1.

(33) Process (3) is the same as in example 1.

(34) The continuous YAG fiber has a diameter of 7.8-9.0 μm, its shrinkage is about 32%, the fiber surface is smooth, but the number of pores between the grains is large, and the XRD pattern shows that the fiber is a YAG structure. The average tensile strength of the fiber was 583 MPa.

Example 3

(35) A method for preparing continuous YAG fiber comprises the following processes:

(36) (1) Preparation of Spinnable Sol

(37) 925.2 g of the sol containing colloidal Al.sub.13 particles (solid content: 22.04 wt %) and 419.6 g of γ-AlOOH nanodispersion (solid content: 12.15 wt %) were mixed, and stirred until to form homogeneous solution, according to n(Al.sub.2O.sub.3):n(Y.sub.2O.sub.3)=5:3 metering composition. 2258.1 g of Y.sub.2O.sub.3 sol (solid content 15 wt %) is added, stirred in water bath at 35° C., 486 g of glacial acetic acid is added during the stirring process, wherein the molar ratio of Y.sub.2O.sub.3 to glacial acetic acid is 1:1.35, then 195 g of dilute nitric acid is added to adjust the pH value to 1.8, 98.9 g of PVP solution is added, stirred and mixed evenly.

(38) The aging temperature was set to 40° C., the aging process was carried out under the vacuum degree of 0.095 MPa, and the viscosity of mixed sol was up to 520 Pa.Math.s to form a spinnable sol.

(39) Process (2) is the same as in Embodiment 1.

(40) Process (3) is the same as in Embodiment 1.

(41) The as-prepared continuous YAG fiber has a diameter of 7.8-9.0 μm, its shrinkage is about 32%, the fiber surface is smooth, the internal structure is dense, and the XRD pattern showed that the fiber is a YAG structure, and the average tensile strength of the fiber is 913 MPa.

Example 4

(42) A method for preparing continuous YAG fiber comprises the following processes:

(43) (1) Preparation of Spinnable Sol

(44) 925.2 g of the sol containing colloidal Al.sub.13 particles (solid content: 22.04 wt %) and 419.6 g of γ-AlOOH nanodispersion (solid content: 12.15 wt %) were mixed, and stirred until to form homogeneous mixture according to n(Al.sub.2O.sub.3):n(Y.sub.2O.sub.3)=5:3 metering composition. 2258.1 g of Y.sub.2O.sub.3 sol (solid content 15 wt %) was added, stirred in water bath at 35° C., 720 g of glacial acetic acid was added during the stirring process, wherein the molar ratio of Y.sub.2O.sub.3 to glacial acetic acid was 1:2, then 159 g of dilute nitric acid was added to adjust the pH value to 1.8 after 98.9 g of PVP solution was added, stirred and mixed well.

(45) The aging temperature was set to 40° C., the aging process was carried out under the vacuum degree of 0.095 MPa, and the mixed sol was aged to a viscosity of 515 Pa.Math.s to form a spinnable sol.

(46) (2) Dry-Spun to Prepare Gel Fiber

(47) The sol prepared in the process (1) is dry-spun to form a YAG gel fiber. The preparative conditions are as follows: the spinneret has a pore diameter of 0.06 mm, the wire take-up speed is 80 m/min, and the environment temperature is 25-30° C., the RH is 30-40%, as shown in FIG. 2, the fiber length can reach several kilometers.

(48) Process (3) is the same as in Embodiment 1.

(49) The continuous YAG fiber has a diameter of 8.5-9.5 μm, and the gel fiber is easy to break and has a relatively large diameter during spinning, its shrinkage is about 34%, the fiber surface is smooth, and the number of pores between the grains is large, XRD pattern shows that the fiber is a YAG structure, and its average tensile strength is 700 MPa.

Example 5

(50) A method for preparing continuous YAG fiber comprises the following processes:

(51) Process (1) is the same as in Example 1.

(52) (2) Dry-Spun to Prepare Gel Fiber

(53) The sol prepared in the process (1) is dry-spun to form a YAG gel fiber. The preparative conditions are as follows: the spinneret has a pore diameter of 0.1 mm, the wire take-up speed is 120 m/min, and the environment temperature is 30-35° C., the RH is 30-40%.

(54) (3) The Ceramization of YAG Gel Fiber

(55) The YAG gel fiber prepared in the process (2) is ceramized, and the preparative conditions are as follows: the temperature is raised to 500° C. at a rate of 0.8° C./min, kept at that temperature for 1 h, and then heated to 1200° C. at a rate of 4° C./min, maintained at that temperature for 2 h to form continuous YAG fiber.

(56) The as-obtained continuous YAG fiber has a diameter of 8.5-9.8 μm and a shrinkage of about 30%. The fiber surface is smooth and the internal structure is dense. XRD pattern shows that the fiber is a YAG structure, and the average tensile strength of the fiber is 826 MPa.

Example 6

(57) A method for preparing continuous YAG fiber comprises the following processes:

(58) (1) Preparation of Spinnable Sol

(59) 809.6 g of the sol containing colloidal Al.sub.13 particles (solid content: 22.04 wt %) and 629.4 g of γ-AlOOH nanodispersion (solid content: 12.15 wt %) were mixed, and stirred to form a uniform mixture according to n(Al.sub.2O.sub.3):n(Y.sub.2O.sub.3)=5:3 metering composition. 2258.1 g of Y.sub.2O.sub.3 sol (solid content 15 wt %) is added, stirred in water bath at 35° C., 450 g of glacial acetic acid is added during the stirring process, wherein the molar ratio of Y.sub.2O.sub.3 to glacial acetic acid is 1:1.25, then 173 g of dilute nitric acid is added to adjust the pH value to 2.0, 39.6 g of PVP solution is added, stirred and mixed well.

(60) The aging temperature was set to 40° C., the aging process was carried out under the vacuum degree of 0.095 MPa, and the viscosity of solution was up to 485 Pa.Math.s to form a spinnable sol.

(61) Process (2) is the same as in Embodiment 1.

(62) Process (3) is the same as in Embodiment 1.

(63) The continuous YAG fiber has a diameter of 7.1-8.5 μm and a shrinkage of about 30%. The fiber surface is smooth and the internal structure is dense. XRD pattern shows that the fiber was a YAG structure, and the average tensile strength of the fiber is 809 MPa.

Example 7

(64) A method for preparing continuous YAG fiber comprises the following processes:

(65) (1) Preparation of Spinnable Sol

(66) 925.2 g of the sol containing colloidal Al.sub.13 particles (solid content: 22.04 wt %) and 419.6 g of γ-AlOOH nanodispersion (solid content: 12.15 wt %) were mixed, and stirred until to form a homogeneous mixture according to n(Al.sub.2O.sub.3):n(Y.sub.2O.sub.3)=5:3 metering composition. 2258.1 g of Y.sub.2O.sub.3 sol (solid content of 15 wt %) was added, then 54.9 g of zirconium acetate with a solid content of 22% was added, stirring in water bath at 35° C., 450 g of glacial acetic acid was added during the stirring process, in which the molar ratio of Y.sub.2O.sub.3 to glacial acetic acid was 1:1.25, finally 173 g of dilute nitric acid was added to adjust the pH value to 2.0, 40.4 g of PVP solution was added, stirred and mixed uniformly.

(67) The aging temperature was set to 40° C., the aging process was carried out under the condition of a vacuum degree of 0.095 MPa, and the viscosity of solution was up to 500 Pa.Math.s to form a spinnable sol.

(68) Process (2) is the same as in Embodiment 1.

(69) Process (3) is the same as in Embodiment 1.

(70) The obtained continuous YAG fiber has a diameter of 6.7-8.5 μm and a shrinkage of about 29%. The fiber surface is smooth and the internal structure is dense. XRD pattern shows that the fiber is a YAG structure, and the average tensile strength of the fiber is 950 MPa.

Example 8

(71) A method for preparing continuous YAG fiber comprises the following processes:

(72) (1) Preparation of Spinnable Sol

(73) 1184.3 g of the sol containing colloidal Al.sub.13 particles (solid content: 22.04 wt %) and 537.1 g of γ-AlOOH nanodispersion (solid content: 12.15 wt %) were mixed, and stirred to form uniform mixture according to n(Al.sub.2O.sub.3):n(Y.sub.2O.sub.3)=2:1 metering composition. 2408.6 g of Y.sub.2O.sub.3 sol (solid content was 15 wt %) was added, stirred in water bath at 35° C., 450 g of glacial acetic acid was added during stirring process, and the molar ratio of Y.sub.2O.sub.3 to glacial acetic acid was 1:1.25, then 206 g of dilute nitric acid was added to adjust the pH value to 2.0, 45.8 g of PVP solution was added, stirred and mixed well.

(74) The aging temperature was set to 40° C., the aging process was carried out under the vacuum degree of 0.095 MPa, and the solution was aged to a viscosity of 515 Pa.Math.s to form a spinnable sol.

(75) (2) Dry-Spun to Prepare Gel Fiber

(76) The sol prepared in the process (1) is dry-spun to form a YAG gel fiber. The preparative conditions are as follows: the spinneret has a pore diameter of 0.06 mm, the wire take-up speed is 100 m/min, and the environment temperature is 25-30° C., the RH is 25-35%.

(77) (3) The Ceramization of the YAG Gel Fiber

(78) YAG gel fiber is prepared in process (2).