阅读说明：本技术 一种金红石晶须的制备方法 (Preparation method of rutile crystal whisker ) 是由 刘旭东 王磊 毕孝国 孙旭东 惠宇 那兆霖 王兴安 于 2019-11-05 设计创作，主要内容包括：本发明涉及金红石晶须领域,具体公开了一种金红石晶须的制备方法,以纯度为99.99％以上、粒度为200～300目的TiO<Sub>2</Sub>微粉为原料,通过给料机构以20～60次/min的频率将粉料送入晶须生长炉的生长室中,在氢气流量为12～16L/min和氧气流量为10～14L/min时燃烧产生氢氧火焰中经过熔化、结晶等过程,在Al<Sub>2</Sub>O<Sub>3</Sub>基片上稳定生长6～8h,即得金红石晶须。与现有技术相比,本发明采用的焰熔法的制备方法,没有加入其它物质,制备得到的晶须品质非常高,可以利用其各向异性作为功能材料,尤其是作为介电材料和半导体材料进行使用,也可以利用其力学性能作为增强增韧复合材料进行使用。采用这种制备方法可以用来制备其它高温氧化物晶须。(The invention relates to the field of rutile whiskers, and particularly discloses a preparation method of rutile whiskers, which is characterized in that TiO with purity of more than 99.99% and granularity of 200-300 meshes is used 2 The micro powder is used as a raw material, the powder is fed into a growth chamber of a whisker growth furnace through a feeding mechanism at the frequency of 20-60 times/min, and is subjected to melting, crystallization and other processes in oxyhydrogen flame generated by combustion when the hydrogen flow is 12-16L/min and the oxygen flow is 10-14L/min, so that Al is formed 2 O 3 And stably growing on the substrate for 6-8 h to obtain the rutile crystal whisker. Compared with the prior art, the flame fusion method adopted by the invention has the advantages that other substances are not added, the quality of the prepared crystal whisker is very high, the anisotropy of the crystal whisker can be used as a functional material, and particularly, the crystal whisker can be used as a functional materialThe material is used as a dielectric material and a semiconductor material, and can also be used as a reinforcing and toughening composite material by utilizing the mechanical property of the material. The preparation method can be used for preparing other high-temperature oxide whiskers.)

1. A method for preparing rutile crystal whisker, use titanium dioxide micropowder as raw materials, characterized by, prepare rutile crystal whisker in the crystal whisker growing apparatus of flame fusion method, the concrete step is as follows:

(1) setting the hydrogen flow rate at 12-16L/min and the oxygen flow rate at 10-14L/min to make H₂And O₂The flow ratio of (1) is less than 2:1 to maintain the oxidizing atmosphere in the growth chamber, and ignition is carried out;

(2) slowly increasing H₂And O₂Flow, preheating the growth chamber and the furnace body for 1-1.5 h to stabilize the internal temperature of the growth chamber and the furnace body;

(3) in the preheating process of the step (2), a whisker growth substrate is arranged in the growth chamber and slowly ascends to a whisker growth interface through the lifting mechanism at the speed of 150-;

(4) starting a vibration mechanism of a feeding system, starting feeding, wherein the vibration frequency is 20-60 times/min, powder raw materials fall into a raw material bin through a screen under the action of the vibration mechanism, and are blown into a growth chamber through a nozzle under the action of oxygen, the raw material powder is heated and melted in high-temperature flame, and finally, crystallization is carried out on a crystal whisker growth substrate to obtain rutile crystal whiskers;

(5) observing the growth state of the crystal whisker through the observation hole, and setting the descending speed of the crystal whisker growth substrate to be 1-5 mm/h according to the growth state of the crystal whisker;

(6) stabilizing the growth process of the step (5) for 6-8 h to prepare rutile whiskers with the length of 5-15 mm;

(7) and simultaneously closing the flow of hydrogen and oxygen, and carrying out heat preservation treatment on the rutile whiskers in the growth chamber.

2. A method for preparing rutile crystal whisker according to claim 1, wherein in the preparation process, the rutile powder raw material is 200-300 mesh, the purity is 99.99% or more, and the crystal whisker growth substrate is Al₂O₃A material.

3. The method of claim 1, wherein the flame fusion whisker growth apparatus comprises a lifting mechanism, a substrate support rod, a furnace body, a whisker growth substrate, a growth chamber, a burner and a feeding system; the burner comprises a nozzle and a metal pipe; a hydrogen inlet is arranged on one side of the upper part of the combustor, the metal pipe is positioned in the combustor, and a nozzle is arranged at the bottom of the combustor and connected with the bottom of the metal pipe; the feeding system comprises a raw material bin, a screen and a vibration mechanism, wherein the vibration mechanism is arranged above the screen, the screen is positioned in the raw material bin, and an oxygen inlet is formed in one side of the raw material bin; the bottom of the raw material bin is communicated with the top of a metal tube in the burner, the bottom of the burner is communicated with the furnace body, the top and the bottom of the furnace body are of an open structure, a growth chamber is arranged in the furnace body, a crystal whisker growth substrate is positioned in the growth chamber, and the crystal whisker growth substrate is connected with the lifting mechanism through a substrate supporting rod.

4. The method for preparing rutile whiskers according to claim 3, wherein the growth chamber has a three-section truncated cone structure, the upper section is a gas mixing and combustion zone, the diameters of the upper bottom and the lower bottom are phi 40mm and phi 50mm respectively, and the height is 100 mm; the middle section is a crystal growth high-temperature area, the diameters of the upper bottom and the lower bottom are phi 50mm and phi 60mm respectively, and the height is 20 mm; the lower section is a crystal heat preservation area, the diameters of the upper bottom and the lower bottom are phi 60mm and phi 70mm respectively, and the height is 250 mm.

5. The method for preparing rutile whiskers according to claim 1, wherein the furnace body is provided with an observation hole, and the observation hole is communicated with a crystal growth high-temperature region of the growth chamber.

Technical Field

The invention belongs to the technical field of rutile materials, and particularly relates to a preparation method of rutile whiskers.

Background

TiO₂Is an important transition metal oxide, and has higher chemical stability, thermal stability and biological inertia; the paint is non-toxic, and has strong weather resistance and corrosion resistance; the white pigment has the best opacity, whiteness and luminosity, can reflect light with different wavelengths in natural light to the same extent, has the highest refractive index, and is generally considered to be the best white pigment in the world; the photoelectric property is good; in addition, it has strong absorption and shielding effects on ultraviolet rays. Therefore, it is widely used in the fields of pigments, paints, toothpastes, ultraviolet absorbers, cosmetics, food additives, medicines, and the like. But with the development of social economy, the improvement of science and technology and the enhancement of the environmental awareness of human beings and TiO₂The continuous improvement of TiO₂Not only in the conventional field, but also in the fields of photocatalysis, photovoltaic cells, sensors, etc., new application studies are continuously occurring and receiving more and more attention. Titanium dioxide whisker, as a novel inorganic ceramic whisker material, has the advantages of excellent physical, chemical and dielectric properties, low density, high melting point, high modulus and the like, and is widely used in the fields of photocatalytic materials, electronic ceramic materials, ultraviolet radiation resistant coatings, inorganic fillers, pigments, reinforcing agents for cosmetics and composite materials and the like.

At present, the preparation methods of inorganic whisker materials mainly comprise a gas phase method, a fluxing agent method, a hydrothermal method, a sintering method, a fluxing agent method, a gel method and the like, and research reports on titanium dioxide whiskers are relatively few. Liu ze et al was selected in 1998Titanium dioxide, KOH and the like are used as raw materials, the titanium dioxide whisker is prepared by a hydrothermal synthesis method and is obtained by washing and drying; wumengqiang et al Ti (OH) 2001₄The powder is taken as a raw material, KOH is taken as a mineralizer, ammonia water is added to the raw material and evenly mixed, the mixture is placed in a high-pressure reaction kettle, and the mixture obtained by hydrothermal treatment for a period of time at a set temperature is subjected to centrifugal separation, washing and drying to obtain titanium dioxide whiskers; in 2006, nano TiO is applied to the ocean₂And AlCl₃·6H₂O is used as raw material, and the rutile TiO is prepared by using NaCl and KCl composite molten salt system at 1200 DEG C₂Needle-shaped whiskers. The main preparation method of the titanium dioxide whisker is a low-temperature hydrothermal method, the size of the whisker prepared by the method is small, and when the titanium dioxide whisker is prepared by a high-temperature molten salt method, the purity of the titanium dioxide whisker is poor due to a plurality of varieties of raw materials.

Disclosure of Invention

Aiming at the problems in the prior art, the application provides a preparation method of rutile whiskers, which solves the problems of low temperature, small size of the whiskers, low purity and the like of the existing preparation method.

In order to achieve the purpose, the technical scheme of the application is as follows: a method for preparing rutile crystal whisker, which takes high-purity titanium dioxide micropowder as a raw material, prepares the rutile crystal whisker in a flame fusion method crystal whisker growth device (shown as figure 1), and comprises the following steps:

(1) setting the hydrogen flow rate at 12-16L/min and the oxygen flow rate at 10-14L/min to make H₂And O₂The flow ratio of (1) is less than 2:1 to maintain the oxidizing atmosphere in the growth chamber, and ignition is carried out;

(2) slowly increasing H₂And O₂Flow, preheating the growth chamber and the furnace body for 1-1.5 h to stabilize the internal temperature of the growth chamber and the furnace body;

(3) in the preheating process of the step (2), a whisker growth substrate is arranged in the growth chamber and slowly ascends to a whisker growth interface through the lifting mechanism at the speed of 150-;

(4) starting a vibration mechanism of a feeding system, starting feeding, wherein the vibration frequency is 20-60 times/min, powder raw materials fall into a raw material bin through a screen under the action of the vibration mechanism, and are blown into a growth chamber through a nozzle under the action of oxygen, the raw material powder is heated and melted in high-temperature flame, and finally, crystallization is carried out on a crystal whisker growth substrate to obtain rutile crystal whiskers;

(5) observing the growth state of the crystal whisker through the observation hole, and setting the descending speed of the crystal whisker growth substrate to be 1-5 mm/h according to the growth state of the crystal whisker;

(6) stabilizing the growth process of the step (5) for 6-8 h to prepare rutile whiskers with the length of 5-15 mm;

(7) and simultaneously closing the flow of hydrogen and oxygen, and carrying out heat preservation treatment on the rutile whiskers in the growth chamber.

Furthermore, in the preparation process, the rutile powder raw material is 200-300 meshes, the purity is more than 99.99%, and the crystal whisker growth substrate is Al₂O₃A material.

Furthermore, the flame fusion method whisker growth device comprises a lifting mechanism, a substrate supporting rod, a furnace body, a whisker growth substrate, a growth chamber, a combustor and a feeding system; the burner comprises a nozzle and a metal pipe; a hydrogen inlet is arranged on one side of the upper part of the combustor, the metal pipe is positioned in the combustor, and a nozzle is arranged at the bottom of the combustor and connected with the bottom of the metal pipe; the feeding system comprises a raw material bin, a screen and a vibration mechanism, wherein the vibration mechanism is arranged above the screen, the screen is positioned in the raw material bin, and an oxygen inlet is formed in one side of the raw material bin; the bottom of the raw material bin is communicated with the top of a metal tube in the burner, the bottom of the burner is communicated with the furnace body, the top and the bottom of the furnace body are of an open structure, a growth chamber is arranged in the furnace body, a crystal whisker growth substrate is positioned in the growth chamber, and the crystal whisker growth substrate is connected with the lifting mechanism through a substrate supporting rod.

Furthermore, the structure of the growth chamber is a three-section truncated cone structure, the upper section is a gas mixing and burning zone, the diameters of the upper bottom and the lower bottom are phi 40mm and phi 50mm respectively, and the height is 100 mm; the middle section is a crystal growth high-temperature area, the diameters of the upper bottom and the lower bottom are phi 50mm and phi 60mm respectively, and the height is 20 mm; the lower section is a crystal heat preservation area, the diameters of the upper bottom and the lower bottom are phi 60mm and phi 70mm respectively, and the height is 250 mm.

Furthermore, an observation hole is arranged on the furnace body and communicated with the crystal growth high-temperature area of the growth chamber.

Due to the adoption of the technical scheme, the invention can obtain the following technical effects:

(1) the flame melting preparation method adopted by the invention has no addition of other substances, the prepared whisker has very high quality, and the preparation method can be used for preparing other high-temperature oxide whiskers.

(2) The prepared rutile crystal whisker has the radial length of 5-15 mm, the axial diameter of 5-50 mu m and the length-diameter ratio of 100-1000, and can be used as a functional material, particularly as a dielectric material and a semiconductor material.

(3) The prepared rutile crystal whisker can be used as a reinforcing and toughening composite material by utilizing the mechanical property of the rutile crystal whisker.

Drawings

FIG. 1 is a schematic structural diagram of a whisker growth device by a flame fusion method;

figure 2 is an XRD pattern of rutile whiskers produced herein;

figure 3 is an SEM image of rutile whiskers made in the present application.

The sequence numbers in the figures illustrate: 1. a lifting mechanism; 2. a substrate support bar; 3. a furnace body; 4. a whisker growth substrate; 5. a growth chamber; 6. whisker; 7. an observation hole; 8. a flame; 9. a nozzle; 10. a raw material bin; 11. screening a screen; 12. powder raw materials; 13. a vibration mechanism; 14. a feed system; 15. a burner.

Detailed Description

The embodiments of the present invention are implemented on the premise of the technical solution of the present invention, and detailed embodiments and specific operation procedures are given, but the scope of the present invention is not limited to the following embodiments.