阅读说明：本技术 一种碱法制备环保氧化锆晶体纤维的方法 (Method for preparing environment-friendly zirconia crystal fiber by alkaline process ) 是由 任克诚 夏树杨 赵显� 周小平 于 2020-07-30 设计创作，主要内容包括：本发明公开了一种碱法制备环保氧化锆晶体纤维的方法,将现有技术中的硝酸钇替换成碳酸钇,经过水体系一步合成可纺性醋酸锆胶体,进一步与碳化硅胶体,进行共混纺丝,制得氧化锆晶体纤维基体,碳酸钇的使用避免了传统工艺中硝酸钇带来的吸潮性,且在反应环境潮性较大时,仍能保持氧化锆晶体纤维生产,且在高温烧结时不再产生氮氧化物,对环境的污染更小,并在制备过程中制备一种增强液,在氧化锆晶体纤维基体与增强液进行浸泡,使得镶嵌有改性纳米金刚石的碳纳米管吸附在氧化锆晶体纤维基体表面凹槽中,进而增强了氧化锆晶体纤维的强度,大大提升了氧化锆纤维的耐冲击性。(The invention discloses a method for preparing environment-friendly zirconia crystal fiber by an alkaline method, which comprises the steps of replacing yttrium nitrate in the prior art with yttrium carbonate, further synthesizing spinnable zirconium acetate colloid through a water system, further carrying out blending spinning with silicon carbide colloid to prepare a zirconia crystal fiber matrix, wherein the use of yttrium carbonate avoids the moisture absorption caused by yttrium nitrate in the traditional process, and can still keep the production of the zirconia crystal fiber when the reaction environment has larger moisture, and does not generate nitrogen oxide during high-temperature sintering, has less pollution to the environment, prepares a reinforcing liquid in the preparation process, soaks the zirconia crystal fiber matrix and the reinforcing liquid, so that the carbon nano-tube inlaid with the modified nano-diamond is absorbed in the groove on the surface of the zirconia crystal fiber matrix, thereby enhancing the strength of the zirconia crystal fiber and greatly improving the impact resistance of the zirconia fiber.)

1. A method for preparing environment-friendly zirconia crystal fiber by an alkaline method is characterized by comprising the following steps: the method specifically comprises the following steps:

step S1: adding basic zirconium carbonate, yttrium carbonate and acetic acid into a reaction kettle, reacting at the rotation speed of 100-150r/min and the temperature of 50-60 ℃ until the viscosity of the reaction solution is 8-25Pa.s to prepare precursor zirconium acetate sol, and aging the precursor zirconium acetate sol at the temperature of 15-45 ℃ until the viscosity is 60-100Pa.s to obtain a spinnable zirconium acetate colloid;

step S2: adding the spinnable zirconium acetate colloid prepared in the step S1 into a reaction kettle, stirring and adding the silicon carbide colloid under the conditions that the rotating speed is 60-80r/min and the temperature is 320-350 ℃, stirring for 2-3h to prepare a mixed colloid, adding the mixed colloid into a high-speed centrifugal spinning machine, and spinning under the conditions that the rotating speed is 10000-13000r/min and the temperature is 20-35 ℃ to prepare gel fiber;

step S3: putting the gel fiber prepared in the step S2 into a high-temperature track kiln for heating, heating to 550 ℃ at a heating rate of 1.5-2 ℃/min, preserving heat for 1-1.5h, heating to 1050 ℃ at a heating rate of 5-10 ℃/min, preserving heat for 1-1.5h, and rapidly cooling to room temperature to prepare a zirconium oxide crystal fiber substrate with the diameter of 3-6 mu m;

step S4: adding the zirconia crystal fiber matrix prepared in the step S3 into a reinforcing liquid, soaking for 20-25h at the temperature of 25-30 ℃, taking out the zirconia crystal fiber matrix, calcining for 1-1.5h at the temperature of 300-350 ℃, calcining for 1-1.5h at the temperature of 500-550 ℃, calcining for 1-1.5h at the temperature of 700-750 ℃, calcining for 1-1.5h at the temperature of 1000-1100 ℃, and cooling to room temperature to prepare the zirconia crystal fiber.

2. The method for preparing the environmentally-friendly zirconia crystal fiber by the alkaline process according to claim 1, wherein the method comprises the following steps: the mass ratio of the basic zirconium carbonate to the yttrium carbonate in the step S1 is 5:1, and the volume ratio of the spinnable zirconium acetate colloid to the silicon carbide colloid in the step S2 is 6: 1-1.5.

3. The method for preparing the environmentally-friendly zirconia crystal fiber by the alkaline process according to claim 1, wherein the method comprises the following steps: the silicon carbide colloidal silica is prepared by the following steps:

step A1: adding polydimethylsiloxane into a reaction kettle, introducing nitrogen for protection, preserving heat for 2-2.5h under the condition that the temperature is 300-320 ℃, then, raising the temperature at the rate of 1 ℃/min to the temperature of 390-420 ℃, and preserving heat for 1.5-2h to prepare liquid polysilane;

step A2: adding divinylbenzene and the liquid polysilane prepared in the step A1 into a reaction kettle, introducing nitrogen for protection, cracking through a quartz cracking column at the temperature of 530-550 ℃, condensing and refluxing for 4-5h, and cooling to room temperature to prepare a precursor crude product;

step A3: adding the crude precursor prepared in the step A2 and xylene into a reaction kettle, stirring for 15-20min at the rotation speed of 100-150r/min and the temperature of 35-40 ℃, filtering to remove the filtrate, heating the filtrate to the temperature of 420-430 ℃ under the protection of nitrogen, preserving the heat for 1-1.5h, cooling to the temperature of 340-350 ℃, carrying out reduced pressure distillation to remove the distillate, and cooling the substrate to room temperature to prepare the precursor;

step A4: and D, adding the precursor prepared in the step A3 into a reaction kettle, and heating for 2-4h at the temperature of 320-350 ℃ to prepare the silicon carbide gel.

4. The method for preparing the environmentally-friendly zirconia crystal fiber by the alkaline process according to claim 3, wherein the method comprises the following steps: the dosage of the divinylbenzene in the step A2 is 1.5-3% of the mass of the liquid polysilane, and the dosage of the crude precursor and the xylene in the step A3 is 1g:5 mL.

5. The method for preparing the environmentally-friendly zirconia crystal fiber by the alkaline process according to claim 1, wherein the method comprises the following steps: the reinforcing liquid is prepared by the following steps:

step B1: adding a sodium hydroxide solution into a stirring kettle, stirring and adding ferric chloride under the conditions that the rotating speed is 150-;

step B2: adding the nano-diamond prepared in the step B1 and a sodium hydroxide solution into a reaction kettle, stirring for 3-5h at the rotation speed of 150-;

step B3: adding carbon nanotubes into acetone for soaking, performing ultrasonic treatment under the condition of frequency of 30-50kHz, filtering to remove acetone, washing the carbon nanotubes with deionized water for 3-5 times, washing for 20-30s each time, soaking the washed carbon nanotubes in a sodium hydroxide solution, preserving heat for 10-15min at the temperature of 80-90 ℃, filtering to remove the sodium hydroxide solution, washing the carbon nanotubes until the surface of the carbon nanotubes is neutral, adding the carbon nanotubes into a nitric acid solution, soaking for 5-10min at the temperature of 50-60 ℃, filtering to remove the nitric acid solution, and drying the carbon nanotubes to obtain modified carbon nanotubes;

step B4: and B2, adding the modified nano-diamond prepared in the step B and deionized water into a stirring kettle, stirring for 10-15min at the rotation speed of 200-300r/min, adding the modified carbon nano-tube prepared in the step B3, continuously stirring for 5-10min, and dispersing for 10-15min at the frequency of 10-15MHz to prepare the reinforcing liquid.

6. The method for preparing the environmentally-friendly zirconia crystal fiber by the alkaline process according to claim 5, wherein the method comprises the following steps: the mass fraction of the sodium hydroxide solution in the step B1 is 50-60%, and the dosage ratio of the sodium hydroxide solution to the ferric chloride is 10mL:3-5g, wherein the using amount of the carbon black is 8-10 times of that of the ferric chloride, the mass fraction of the sodium hydroxide solution in the step B2 is 10-15%, the using amount volume ratio of the gamma-aminopropyltriethoxysilane to the ethanol solution is 1:1-1.3, the mass fraction of the ethanol solution is 70-80%, the using amount of the filter cake is 30-50% of the total weight of the gamma-aminopropyltriethoxysilane and the ethanol solution, the mass fraction of the sodium hydroxide solution in the step B3 is 10-13%, the mass fraction of the nitric acid solution is 45-50%, and the using amount ratio of the modified nano-diamond, the deionized water and the modified carbon nanotube in the step B4 is 3g:10mL of: 1-1.5 g.

Technical Field

The invention belongs to the technical field of fiber preparation, and particularly relates to a method for preparing an environment-friendly zirconia crystal fiber by an alkaline method.

Background

The heat-resistant and heat-insulating performance of the zirconia fiber has the characteristics of small volume weight, low heat conductivity, high heat resistance in aerobic environment (the good fiber shape can be still kept at 2500 ℃ in the atmosphere) and the like, and the zirconia fiber has great application requirements in national defense advanced science and technology and advanced civil industry, so the development and application of the special crystal fiber are one of important development directions of modern material science and technology.

The yttrium nitrate can be used in the preparation process of the existing zirconia crystal fiber, so that the moisture absorption phenomenon can occur in the preparation process, the production is influenced, the nitrogen oxide can be generated in the preparation process, the environment is polluted, the strength of the existing zirconia crystal fiber is low, and the damage can be caused by the action of external force in the use process.

Disclosure of Invention

The invention aims to provide a method for preparing environment-friendly zirconia crystal fibers by an alkaline method.

The technical problems to be solved by the invention are as follows:

the yttrium nitrate can be used in the preparation process of the existing zirconia crystal fiber, so that the moisture absorption phenomenon can occur in the preparation process, the production is influenced, the nitrogen oxide can be generated in the preparation process, the environment is polluted, the strength of the existing zirconia crystal fiber is low, and the damage can be caused by the action of external force in the use process.

The purpose of the invention can be realized by the following technical scheme:

a method for preparing environment-friendly zirconia crystal fiber by an alkaline method specifically comprises the following steps:

step S1: adding basic zirconium carbonate, yttrium carbonate and acetic acid into a reaction kettle, reacting at the rotation speed of 100-150r/min and the temperature of 50-60 ℃ until the viscosity of the reaction solution is 8-25Pa.s to prepare precursor zirconium acetate sol, and aging the precursor zirconium acetate sol at the temperature of 15-45 ℃ until the viscosity is 60-100Pa.s to obtain a spinnable zirconium acetate colloid;

step S2: adding the spinnable zirconium acetate colloid prepared in the step S1 into a reaction kettle, stirring and adding the silicon carbide colloid under the conditions that the rotating speed is 60-80r/min and the temperature is 320-350 ℃, stirring for 2-3h to prepare a mixed colloid, adding the mixed colloid into a high-speed centrifugal spinning machine, and spinning under the conditions that the rotating speed is 10000-13000r/min and the temperature is 20-35 ℃ to prepare gel fiber;

step S3: putting the gel fiber prepared in the step S2 into a high-temperature track kiln for heating, heating to 550 ℃ at a heating rate of 1.5-2 ℃/min, preserving heat for 1-1.5h, heating to 1050 ℃ at a heating rate of 5-10 ℃/min, preserving heat for 1-1.5h, and rapidly cooling to room temperature to prepare a zirconium oxide crystal fiber substrate with the diameter of 3-6 mu m;

step S4: adding the zirconia crystal fiber matrix prepared in the step S3 into a reinforcing liquid, soaking for 20-25h at the temperature of 25-30 ℃, taking out the zirconia crystal fiber matrix, calcining for 1-1.5h at the temperature of 300-350 ℃, calcining for 1-1.5h at the temperature of 500-550 ℃, calcining for 1-1.5h at the temperature of 700-750 ℃, calcining for 1-1.5h at the temperature of 1000-1100 ℃, and cooling to room temperature to prepare the zirconia crystal fiber.

Further, the dosage mass ratio of the basic zirconium carbonate and the yttrium carbonate in the step S1 is 5:1, and the dosage volume ratio of the spinnable zirconium acetate colloid and the silicon carbide colloid in the step S2 is 6: 1-1.5.

Further, the silicon carbide colloidal silica is prepared by the following steps:

step A1: adding polydimethylsiloxane into a reaction kettle, introducing nitrogen for protection, preserving heat for 2-2.5h under the condition that the temperature is 300-320 ℃, then, raising the temperature at the rate of 1 ℃/min to the temperature of 390-420 ℃, and preserving heat for 1.5-2h to prepare liquid polysilane;

step A2: adding divinylbenzene and the liquid polysilane prepared in the step A1 into a reaction kettle, introducing nitrogen for protection, cracking through a quartz cracking column at the temperature of 530-550 ℃, condensing and refluxing for 4-5h, and cooling to room temperature to prepare a precursor crude product;

step A3: adding the crude precursor prepared in the step A2 and xylene into a reaction kettle, stirring for 15-20min at the rotation speed of 100-150r/min and the temperature of 35-40 ℃, filtering to remove the filtrate, heating the filtrate to the temperature of 420-430 ℃ under the protection of nitrogen, preserving the heat for 1-1.5h, cooling to the temperature of 340-350 ℃, carrying out reduced pressure distillation to remove the distillate, and cooling the substrate to room temperature to prepare the precursor;

step A4: and D, adding the precursor prepared in the step A3 into a reaction kettle, and heating for 2-4h at the temperature of 320-350 ℃ to prepare the silicon carbide gel.

Further, the amount of the divinylbenzene in the step A2 is 1.5-3% of the mass of the liquid polysilane, and the amount of the crude precursor and the xylene in the step A3 is 1g:5 mL.

Further, the reinforcing liquid is prepared by the following steps:

step B1: adding a sodium hydroxide solution into a stirring kettle, stirring and adding ferric chloride under the conditions that the rotating speed is 150-;

step B2: adding the nano-diamond prepared in the step B1 and a sodium hydroxide solution into a reaction kettle, stirring for 3-5h at the rotation speed of 150-;

step B3: adding carbon nanotubes into acetone for soaking, performing ultrasonic treatment under the condition of frequency of 30-50kHz, filtering to remove acetone, washing the carbon nanotubes with deionized water for 3-5 times, washing for 20-30s each time, soaking the washed carbon nanotubes in a sodium hydroxide solution, preserving heat for 10-15min at the temperature of 80-90 ℃, filtering to remove the sodium hydroxide solution, washing the carbon nanotubes until the surface of the carbon nanotubes is neutral, adding the carbon nanotubes into a nitric acid solution, soaking for 5-10min at the temperature of 50-60 ℃, filtering to remove the nitric acid solution, and drying the carbon nanotubes to obtain modified carbon nanotubes;

step B4: and B2, adding the modified nano-diamond prepared in the step B and deionized water into a stirring kettle, stirring for 10-15min at the rotation speed of 200-300r/min, adding the modified carbon nano-tube prepared in the step B3, continuously stirring for 5-10min, and dispersing for 10-15min at the frequency of 10-15MHz to prepare the reinforcing liquid.

Further, the mass fraction of the sodium hydroxide solution in the step B1 is 50-60%, and the using amount ratio of the sodium hydroxide solution to the ferric chloride is 10mL:3-5g, wherein the using amount of the carbon black is 8-10 times of that of the ferric chloride, the mass fraction of the sodium hydroxide solution in the step B2 is 10-15%, the using amount volume ratio of the gamma-aminopropyltriethoxysilane to the ethanol solution is 1:1-1.3, the mass fraction of the ethanol solution is 70-80%, the using amount of the filter cake is 30-50% of the total weight of the gamma-aminopropyltriethoxysilane and the ethanol solution, the mass fraction of the sodium hydroxide solution in the step B3 is 10-13%, the mass fraction of the nitric acid solution is 45-50%, and the using amount ratio of the modified nano-diamond, the deionized water and the modified carbon nanotube in the step B4 is 3g:10mL of: 1-1.5 g.

The invention has the beneficial effects that: in the process of preparing the zirconia crystal fiber, the invention replaces yttrium nitrate in the prior art with yttrium carbonate, a spinnable zirconium acetate colloid is further synthesized by a water system, and the spinnable zirconium acetate colloid is further blended and spun with a silicon carbide colloid to prepare a zirconia crystal fiber matrix, the use of the yttrium carbonate avoids the moisture absorption brought by the yttrium nitrate in the traditional process, the production of the zirconia crystal fiber can be still kept when the reaction environment has higher moisture, no nitrogen oxide is generated during high-temperature sintering, the environmental pollution is less, an enhancement solution is prepared in the preparation process, the carbon black is taken as a raw material to prepare the nano diamond, the surface of the nano diamond contains carboxyl and hydroxyl, the nano diamond is further treated by gamma-aminopropyltriethoxysilane, the gamma-aminopropyltriethoxysilane reacts with the surface groups of the nano diamond after hydrolysis, and a strong chemical bond is absorbed and formed on the surface of the nano diamond, and then the dispersibility of the nano-diamond is improved, the carbon nano-tube is subjected to surface treatment to enlarge gully grooves on the surface of the carbon nano-tube, so that the adsorbability of the carbon nano-tube is increased, the modified nano-diamond and the modified carbon nano-tube are treated to enable the modified nano-diamond to be inlaid on the surface of the carbon nano-tube, and then the zirconium oxide crystal fiber substrate is soaked in the reinforcing liquid, so that the carbon nano-tube inlaid with the modified nano-diamond is adsorbed in the grooves on the surface of the zirconium oxide crystal fiber substrate, so that the strength of the zirconium oxide crystal fiber is enhanced, and the impact resistance of the zirconium oxide fiber is greatly improved.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.