阅读说明：本技术 一种五氧化三钛晶体的制备方法 (Preparation method of trititanium pentoxide crystal ) 是由 邵小兰 朱亮 于 2021-07-29 设计创作，主要内容包括：本发明公开了一种五氧化三钛晶体的制备方法,属于五氧化三钛的制备领域,本发明采用分阶段升温的方法,第一阶段：常温升至1050℃；第二阶段：1050℃升至1150℃,当温度达到1150℃时采用0.3L/min-0.8L/min的流量充入惰性保护气体；第三阶段：继续保持0.8L/min的流量充入惰性保护气体,1150℃保温1-2小时；本发明通过加大惰性保护气体的通入流量,从而加大坩埚内原料的反应速率,进而有利于五氧化三钛的合成,实现降低了加热温度、减少能源消耗的技术效果。(The invention discloses a preparation method of a trititanium pentoxide crystal, belonging to the field of preparation of trititanium pentoxide, and the invention adopts a staged heating method, wherein the first stage comprises the following steps: the temperature is raised to 1050 ℃ at normal temperature; and a second stage: 1050 ℃ is raised to 1150 ℃, and inert protective gas is filled at the flow rate of 0.3L/min-0.8L/min when the temperature reaches 1150 ℃; and a third stage: continuously keeping the flow of 0.8L/min, filling inert protective gas, and keeping the temperature at 1150 ℃ for 1-2 hours; according to the invention, the reaction rate of the raw materials in the crucible is increased by increasing the introduction flow of the inert protective gas, so that the synthesis of the titanium pentoxide is facilitated, and the technical effects of reducing the heating temperature and reducing the energy consumption are realized.)

1. A preparation method of a trititanium pentoxide crystal is characterized by comprising the following steps:

1) uniformly mixing the raw material titanium powder and the rutile type titanium dioxide powder coated by the silicon oxide according to the mass ratio of 1:9-12, granulating, and drying at the temperature of 100-;

2) putting the sintered material into a crucible, transferring the crucible into a high-temperature reduction furnace, and vacuumizing until the vacuum degree in the furnace is 10^-3-10^{- 4}pa or less;

3) and heating and sintering the whole system in stages, wherein the parameters of each stage are set as follows:

the first stage is as follows: raising the temperature to 1050 deg.C, raising the temperature at 5-7 deg.C/min, and maintaining the vacuum degree at 10 ℃^-3-10^-4pa or less;

and a second stage: 1050 ℃ is increased to 1150 ℃, the temperature increasing rate is 2-4 ℃/min, and when the temperature reaches 1150 ℃, inert protective gas is filled in at the flow rate of 0.3L/min-0.8L/min;

and a third stage: continuously keeping the flow of 0.5-0.8L/min, charging inert protective gas, keeping the temperature at 1150 ℃ for 1-2 hours, fully melting the raw materials, ensuring the temperature gradient of a solid-liquid interface for crystal growth to be within the range of 30-48 ℃/cm, ensuring the crucible descending rate to be 1.5-3.5mm/h,

4) after the crystal growth is finished, transferring the crystal into a growth furnace, preserving the heat for 10 to 24 hours, and then cooling the crystal to room temperature at a constant speed.

2. The process for preparing a trititanium pentoxide crystal according to claim 1, wherein the heating of the whole system in step 3) is electromagnetic induction heating.

3. The process for preparing a trititanium pentoxide crystal according to claim 1, wherein the crystal grown in step 4) is annealed by lowering the temperature to room temperature at a rate of 50-55 ℃/h.

4. The process for preparing a crystal of trititanium pentoxide according to claim 1, wherein the inert shielding gas charged in the second and third stages in step 3) is any one of argon, helium and helium.

Technical Field

The invention relates to preparation of titanium pentoxide, and in particular relates to a preparation method of a titanium pentoxide crystal.

Background

The titanium pentoxide is blue-black powder with metallic luster, and the oxygen content is 62.3-64.3% (atom). The trititanium pentoxide crystal has an orthorhombic structure and is produced by high-temperature sublimation crystallization, and the lattice constant α is 0.3747 nm. The density is 4.29g/cm3, the melting point is 2180 ℃, the material is used for vacuum coating, the method has the advantages of small gas release amount, high purity, no collapse point, no medicine jumping, stable refractive index and leading production technology in the same industry in China.

In the prior art, impurities are easily introduced into granular titanium pentoxide in the preparation process to form a large number of air holes, and substances with large oxygen content difference exist, so that the purity and the quality of the prepared coating layer are influenced. The existing method for preparing the titanium pentoxide coating material usually adopts a high-temperature heating method, and the high-temperature heating method has strict requirements on the insulation technology, complex process, large power consumption and high production cost.

Disclosure of Invention

The invention aims to provide a preparation method of a titanium pentoxide crystal, which reduces the heating temperature and the electric energy consumption.

The technical scheme of the invention is as follows: a preparation method of a trititanium pentoxide crystal comprises the following steps:

1) uniformly mixing the raw material titanium powder and the rutile type titanium dioxide powder coated by the silicon oxide according to the mass ratio of 1:9-12, granulating, and drying at the temperature of 100-;

2) putting the sintered material into a crucible, transferring the crucible into a high-temperature reduction furnace, and vacuumizing until the vacuum degree in the furnace is 10^-3-10^-4pa or less;

3) and heating and sintering the whole system in stages, wherein the parameters of each stage are set as follows:

the first stage is as follows: raising the temperature to 1050 deg.C, raising the temperature at 5-7 deg.C/min, and maintaining the vacuum degree at 10 ℃^-3-10^-4pa or less;

and a second stage: 1050 ℃ is increased to 1150 ℃, the temperature increasing rate is 2-4 ℃/min, and when the temperature reaches 1150 ℃, inert protective gas is filled in at the flow rate of 0.3L/min-0.8L/min;

and a third stage: continuously keeping the flow of 0.8L/min, charging inert protective gas, keeping the temperature at 1150 ℃ for 1-2 hours, fully melting the raw materials, ensuring the temperature gradient of a solid-liquid interface for crystal growth to be within the range of 30-48 ℃/cm, ensuring the descending speed of the crucible to be 1.5-3.5mm/h,

4) after the crystal growth is finished, transferring the crystal into a growth furnace, preserving the heat for 10 to 24 hours, and then cooling the crystal to room temperature at a constant speed.

According to a further technical scheme, the heating mode of the whole system in the step 3) is electromagnetic induction heating.

In the further technical scheme, the temperature is reduced to room temperature at the speed of 50-55 ℃/h in the step 4), and the grown crystal is annealed.

According to a further technical scheme, the inert protective gas filled in the second stage in the step 3) is any one of argon, helium and helium.

The invention has the beneficial effects that:

the raw material of the invention is rutile type titanium dioxide powder which is coated by silicon oxide, and the agglomeration phenomenon of the powder is serious because the nano TiO2 particles are very small and have very high specific surface area and surface energy. The rutile type titanium dioxide powder coated by silicon oxide reduces the agglomeration phenomenon of the powder, and the reaction rate of the raw materials in the crucible is increased by increasing the introduction flow of the inert protective gas in the preparation process, so that the synthesis of the trititanium pentoxide is facilitated, and the technical effects of reducing the heating temperature and reducing the energy consumption are realized.

Detailed Description

The invention will be further illustrated and understood by the following non-limiting examples.

Example 1:

a preparation method of a trititanium pentoxide crystal comprises the following steps:

1) uniformly mixing titanium powder and rutile type titanium dioxide powder coated by silicon oxide in a mass ratio of titanium to titanium dioxide of 1:9, granulating, and drying at 250 ℃ to obtain a sintered material;

2) putting the sintered material into a crucible, transferring the crucible into a high-temperature reduction furnace, and vacuumizing until the vacuum degree in the furnace is 10^-3-10^-4pa or less;

3) heating up and sintering the whole system by stages through electromagnetic induction heating, wherein the parameters of each stage are set as follows:

the first stage is as follows: raising the temperature to 1050 deg.C, raising the temperature at 5-7 deg.C/min, and maintaining the vacuum degree at 10 ℃^-3-10^-4pa or less;

and a second stage: 1050 ℃ is increased to 1150 ℃, the heating rate is 2-4 ℃/min, and when the temperature reaches 1150 ℃, argon is filled in at a flow rate of 0.3L/min;

and a third stage: argon is continuously filled at the flow rate of 0.5L/min, the temperature is kept at 1150 ℃ for 1 to 2 hours, the raw materials are fully melted, the temperature gradient of a solid-liquid interface for crystal growth is within the range of 30 to 48 ℃/cm, the descending speed of a crucible is between 1.5 and 3.5mm/h,

4) after the crystal growth is finished, transferring the crystal into a growth furnace, preserving the heat for 10 to 24 hours, and then cooling the crystal to room temperature at the speed of 50 ℃.

Example 2:

a preparation method of a trititanium pentoxide crystal comprises the following steps:

1) uniformly mixing raw material titanium powder and silicon oxide coated rutile type titanium dioxide powder according to the mass ratio of 1:10, granulating, and drying at 300 ℃ to obtain a sintered material;

2) putting the sintered material into a crucible, transferring the crucible into a high-temperature reduction furnace, and vacuumizing until the vacuum degree in the furnace is 10^-3-10^-4pa or less;

3) and heating up and sintering the whole system in stages by an electromagnetic induction heating mode, wherein the parameters of each stage are set as follows:

the first stage is as follows: raising the temperature to 1050 deg.C, raising the temperature at 5-7 deg.C/min, and maintaining the vacuum degree at 10 ℃^-3-10^-4pa or less;

and a second stage: 1050 ℃ is increased to 1150 ℃, the temperature increasing rate is 2-4 ℃/min, and helium is filled at the flow rate of 0.5L/min when the temperature reaches 1150 ℃;

and a third stage: filling helium gas at the flow rate of 0.6L/min, keeping the temperature at 1150 ℃ for 1-2 hours, fully melting the raw materials, ensuring the temperature gradient of a solid-liquid interface for crystal growth to be within the range of 30-48 ℃/cm, ensuring the descending speed of a crucible to be between 1.5-3.5mm/h,

4) after the crystal growth is finished, transferring the crystal into a growth furnace, preserving the heat for 10 to 24 hours, and then cooling the crystal to room temperature at the speed of 50 ℃.

Example 3:

a preparation method of a trititanium pentoxide crystal comprises the following steps:

1) uniformly mixing the raw material titanium powder and the rutile type titanium dioxide powder coated by the silicon oxide according to the mass ratio of 1:9-12, granulating, and drying at the temperature of 100-;

2) placing the sintered material into a crucible, transferring the crucible into a high-temperature descending furnace, and pumpingThe vacuum degree in the vacuum furnace is 10^-3-10^-4pa or less;

3) the electromagnetic induction heating heats and sinters the whole system in stages, and the parameters of each stage are set as follows:

the first stage is as follows: raising the temperature to 1050 deg.C, raising the temperature at 5-7 deg.C/min, and maintaining the vacuum degree at 10 ℃^-3-10^-4pa or less;

and a second stage: 1050 ℃ is increased to 1150 ℃, the temperature increasing rate is 2-4 ℃/min, and when the temperature reaches 1150 ℃, hydrogen is filled in at a flow rate of 0.8L/min;

and a third stage: continuously keeping the flow of 0.8L/min, charging inert hydrogen, keeping the temperature at 1150 ℃ for 1-2 hours, fully melting the raw materials, ensuring the temperature gradient of a solid-liquid interface for crystal growth to be within the range of 30-48 ℃/cm, ensuring the descending speed of a crucible to be 1.5-3.5mm/h,

4) after the crystal growth is finished, transferring the crystal into a growth furnace, preserving the heat for 10 to 24 hours, and then cooling the crystal to room temperature at the speed of 55 ℃.

The specifications of the trititanium pentoxide crystals finally prepared in the embodiments 1-3 are all within the range of 1.0-4.0mm, the prepared trititanium pentoxide crystals have small gas release amount, high purity, no collapse point and high purity and quality, and can be widely used for various antireflection films and multilayer films, and the heating temperature in the invention is 1050-.