WO2018113517A1 - Alkali metal niobate micro-nanowire material and preparation method therefor - Google Patents

Abstract

Provided are an alkali metal niobate micro-nanowire material and a preparation method therefor: Na₂CO₃, K₂CO₃, BaCO₃, Nb₂O₅, Bi₂O₃ and Li₂CO₃, and Sb₂O₃ are used as raw materials, and batching is carried out according to the chemical formula (1-x)K_yNa_1-yNbO₃-xBaBiO₃ or (0.94-z)K_rNa(_1-r)NbO₃-zBaBiO₃-0.06LiSbO₃, wherein 0.015≤x≤0.07, 0.4≤y≤0.6, 0.016≤z≤0.080, and 0.4≤r≤0.6. The preparation method comprises: 1) drying all of the raw materials in an oven before weighing and batching; 2) batching according to the chemical formula, and ball milling by using anhydrous ethanol as a medium; 3) a ball milled product being extracted, dried and pre-fired; 4) carrying out secondary ball milling by using anhydrous ethanol as the medium; 5) powder material which has been secondary ball milled being extracted, dried, sieved, and pressed into a round billet; 6) solid phase sintering the pressed round billet, and obtaining an alkali metal niobate micro-nanowire from a sintered body. The alkali metal niobate micro-nanowire obtained by the method using a traditional solid phase approach may grow on a ceramic substrate in an oriented arrangement, wherein the length thereof may reach up to the centimeter scale. The method is simple and low cost, while a template and catalyst are not required, and the product is pure.

Description

Alkali metal silicate micro/nano wire material and preparation method thereof Technical field

The invention relates to the field of micro-nano materials, in particular to an alkali metal citrate micro-nanowire material and a preparation method thereof.

Background technique

As an important emerging technology field in the 21st century, nanotechnology is experiencing rapid development in theory and practice. A large number of new nanomaterials and devices have been continuously developed, and in electronic communication, biomedicine, photocatalysis, environmental protection, national defense and daily life. The various fields of life show unprecedented application prospects. Nano-generators have only been an idea, and they hope to directly supply power to other microelectronic devices. For example, in biosensors, biomedical monitoring and bio-in vivo detection, in order to keep the nano-systems tiny and in vivo, the small-scale power supply system must not be less. Since Wang Zhonglin successfully prepared a well-arranged ZnO nanowire array and invented a nano-piezoelectric generator, this idea is gradually becoming a reality, and the core component of the operation of the nano-generator is piezoelectric material. For this, Science There are special reports in magazines such as "Advanced materials". In fact, the miniaturization of piezoelectric materials is not only in the fabrication of nano-piezoelectric generators, but also in terahertz wave radiation communication based on piezoelectric effects, nano-motors, piezoelectric nano-ultrasonic radars, and the like.

At present, the preparation methods of the alkali metal silicate micro/nano wires mainly include a template growth method, a hydrothermal method, a sol-gel method, a molten salt method, and an electrospinning method. Although each method has its own advantages, there are also some problems.

The template growth method can adopt AAO, carbon nanotubes, molecular sieves and silicon nanowires and other templates for auxiliary growth, and has the advantages of controllable nanowire alignment and less restriction on material structure, but the prepared nanowires are usually polycrystalline and difficult to be formed. A single crystal is obtained, and the technical problem of introducing impurities into the product due to the presence of the template is obtained.

The liquid phase methods such as hydrothermal method and sol-gel method have the advantages of low temperature and low cost, high yield and good uniformity, but the products have relatively long diameter, large size, complicated process and low product purity. technical problem. In addition, hydrothermal processes have technical problems that can only be used to prepare compounds that are insensitive to water or solvents.

In addition, if the liquid phase method is not used in combination with the template growth method, the grown nanowires are disorderly arranged.

So far, there has been no report on the solid phase preparation technology of alkali metal citrate micro/nanowire materials.

Summary of the invention

It is an object of the present invention to provide an alkali metal silicate micro/nanowire material and a process for the preparation thereof. In view of the technical problems existing in the prior art, the present invention adopts a conventional solid phase sintering method to realize controlled growth of alkali metal citrate micro/nano wires without additional supply of a gas phase, a template and a catalyst, so as to synthesize The alkali metal citrate micro-nano wire grows directly from the ceramic matrix without introducing external impurities to achieve purity of the product. In addition, on the basis of the foregoing, the synthesis temperature of the alkali metal niobate micro-nanowire is reduced by 20 to 40 ° C by co-doping lithium and antimony elements, thereby reducing energy consumption and thereby reducing Cost of production.

In order to achieve the above object, the technical solution adopted by the present invention is:

An alkali metal silicate micro/nano wire material is prepared by using Na ₂ CO ₃ , K ₂ CO ₃ , BaCO ₃ , Nb ₂ O ₅ and Bi ₂ O ₃ according to the chemical formula (1-x)K _y Na _{1 -y} NbO ₃ -xBaBiO ₃ is a compound, wherein 0.015 ≤ x ≤ 0.07, 0.4 ≤ y ≤ 0.6, a micro/nano wire material fired by a conventional ceramic solid phase sintering process.

The preparation method of the above alkali metal silicate micro/nanowire material comprises the following steps:

Step 1) All raw materials Na ₂ CO ₃ , K ₂ CO ₃ , BaCO ₃ , Nb ₂ O ₅ , and Bi ₂ O ₃ are placed in an oven at 120-300 ° C before being weighed;

Step 2) Weigh the raw material according to the chemical mass ratio of (1-x)K _y Na _1-y NbO ₃ -xBaBiO ₃ , wherein 0.015≤x≤0.07, 0.4≤y≤0.6, and put it into the ball mill bottle to Water ethanol is ball milled for 24 to 48 hours;

Step 3) taking out the powder after ball milling, drying, preheating at a heating rate of 1 to 5 ° C / min, calcining at 700-900 ° C, and calcining at 3 to 9 h. ;

Step 4) Then, the calcined powder is subjected to a second ball milling for 12 to 24 hours using anhydrous ethanol as a ball milling medium;

Step 5) taking out the second ball milled powder and drying it, and passing the second ball milled powder through a 100 mesh sieve, and then pressing it to a diameter of 14 to 25 mm and a thickness of 1-3 mm under a pressure of 100 MPa. Billet

Step 6) The pressed round billet is subjected to solid phase sintering at a temperature of 1080-1140 ° C and a holding time of 10 to 36 h during sintering, and an alkali metal niobate micro/nanowire material is obtained in the sintered body.

An alkali metal silicate micro/nano wire material is prepared by using Na ₂ CO ₃ , K ₂ CO ₃ , BaCO ₃ , Nb ₂ O ₅ , Bi ₂ O ₃ as raw materials, wherein the raw materials further include Li ₂ CO ₃ and Sb ₂ O ₃ , according to the chemical formula (0.94-z) K _r Na _(1-r) NbO ₃ -zBaBiO ₃ -0.06LiSbO ₃ , wherein 0.016 ≤ z ≤ 0.080, 0.4 ≤ r ≤ 0.6, by the traditional ceramic solid phase sintering process Micro-nano wire material fired.

The preparation method of the above alkali metal silicate micro/nanowire material comprises the following steps:

Step 1) All raw materials K ₂ CO ₃ , Na ₂ CO ₃ , BaCO ₃ , Nb ₂ O ₅ , Bi ₂ O ₃ and Li ₂ CO ₃ , Sb ₂ O ₃ are placed in an oven before weighing the ingredients at 120 Drying at -300 ° C;

Step 2) Weigh the raw material according to the chemical mass ratio (0.94-z) K _r Na _(1-r) NbO ₃ -zBaBiO ₃ -0.06LiSbO ₃ , wherein 0.016 ≤ z ≤ 0.080, 0.4 ≤ _r ≤ 0.6 In the ball mill bottle, the ball is ground for 24 to 48 hours with anhydrous ethanol as the medium;

Step 3) taking out the powder after ball milling, drying, preheating at a heating rate of 1 to 5 ° C / min, calcining at 700-900 ° C, and calcining at 3 to 9 h. ;

Step 4) Then, the calcined powder is subjected to a second ball milling for 12 to 24 hours using anhydrous ethanol as a ball milling medium;

Step 5) taking out the second ball milled powder and drying it, and passing the second ball milled powder through a 100 mesh sieve, and then pressing it to a diameter of 14 to 25 mm and a thickness of 1-3 mm under a pressure of 100 MPa. Billet

Step 6) The pressed round billet is subjected to solid phase sintering at a temperature of 1080-1140 ° C and a holding time of 10 to 36 h during sintering, and an alkali metal niobate micro/nanowire material is obtained in the sintered body.

The alkali metal citrate micro-nanowire material of the invention is confirmed to be a micro-nanowire structure by SEM electron microscopy.

Compared with the prior art, the invention has the following advantages:

(1) using a conventional solid phase sintering method to achieve controlled growth of alkali metal citrate micro/nanowires without the need to additionally provide a gas phase;

(2) The synthesized alkali metal citrate micro-nano wire is directly grown from the ceramic matrix, does not require a template and a catalyst, does not introduce external impurities, and the product is pure;

(3) The grown alkali metal citrate micro-nanowire has a textured structure, which is an ideal structure of the micro-nanowire material, which is unmatched by other methods;

(4) On the basis of the preparation of the method, the aspect ratio of the alkali metal silicate micro/nanowires can be continuously controlled by the subsequent liquid phase, hydrothermal or gas phase assisted growth by chemical topography.

(5) By synthesizing lithium and lanthanum elements to synthesize alkali metal citrate micro-nanowires, the preparation temperature is further reduced by 20 to 40 ° C, and energy consumption is reduced, thereby reducing production costs.

(6) The obtained alkali metal silicate micro/nano wire has a length of up to the order of centimeters.

(7) The obtained alkali metal silicate micro/nano wires are oriented and arranged on the ceramic substrate.

In addition, experimental studies have shown that the key to the technology of the present invention is the precise control of factors such as chemical composition, sintering process (especially sintering temperature) and experimental environment. Through regulation, the preparation of alkali metal silicate micro/nanowire materials of several tens of nanometers to several tens of micrometers can be realized. Further synthesizing lithium or lanthanum-doped alkali metal silicate micro/nano wire materials can impart new properties or functions, thereby expanding the application range of alkali metal silicate micro-nano wires, and therefore, the invention has broad application prospects. .

DRAWINGS

1 is an SEM image of an alkali metal citrate micro-nanowire prepared in Example 1;

2 is an SEM image of an alkali metal citrate micro-nanowire prepared in Example 2;

3 is an SEM image of a lithium and lanthanum-doped alkali metal silicate micro/nanowire prepared in Example 3;

4 is an SEM image of a lithium, lanthanum-doped alkali metal silicate micro/nanowire prepared in Example 4.

Detailed ways

The present invention is further described in detail with reference to the accompanying drawings, but not by limitation.

Example 1:

Preparation method of alkali metal silicate micro/nano wire material:

Step 1) All raw materials Na ₂ CO ₃ , K ₂ CO ₃ , BaCO ₃ , Nb ₂ O ₅ , and Bi ₂ O ₃ are dried in an oven at 120 ° C before weighing the ingredients;

Step 2) according to the formula (1-x)K _y Na _1-y NbO ₃ -xBaBiO ₃ , wherein x = 0.032, y = 0.5, loaded into a ball mill bottle, ball milled with anhydrous ethanol for 24h;

Step 3) The ball milled product is taken out, dried, and pre-fired at 750 ° C, the heating rate is 1 ° C / min for 6 h;

Step 4) and then ball milling with anhydrous ethanol for 24 hours and drying;

Step 5) After passing the dried powder through a 100 mesh sieve, it is pressed into a round blank having a diameter of 14 mm and a thickness of 2 mm under a pressure of 100 MPa;

Step 6) The pressed round billet is solid-phase sintered at 1100 ° C for 24 h, and an alkali metal niobate micro-nanowire material is obtained in the sintered body.

The results of SEM electron microscopy showed that the obtained alkali metal citrate micro/nanowires were micron-line structures as shown in FIG.

Example 2:

Preparation method of alkali metal silicate micro/nano wire material:

Step 1) All raw materials Na ₂ CO ₃ , K ₂ CO ₃ , BaCO ₃ , Nb ₂ O ₅ , and Bi ₂ O ₃ are dried in an oven at 120 ° C before weighing the ingredients;

Step 2) according to the formula (1-x)K _y Na _1-y NbO ₃ -xBaBiO ₃ , wherein x = 0.016, y = 0.5, loaded into a ball mill bottle, ball milled with anhydrous ethanol for 24h;

Step 3) The ball milled product is taken out, dried, and pre-fired at 750 ° C, the heating rate is 1 ° C / min for 6 h;

Step 4) and then ball milling with anhydrous ethanol for 24 hours and drying;

Step 5) After passing the dried powder through a 100 mesh sieve, it is pressed into a round blank having a diameter of 14 mm and a thickness of 2 mm under a pressure of 100 MPa;

Step 6) The pressed round billet is solid-phase sintered at 1140 ° C for 21 h, and an alkali metal niobate micro-nanowire material is obtained in the sintered body.

The results of SEM electron microscopy showed that the obtained alkali metal silicate micro/nanowires were micron-line structures as shown in FIG.

Example 3

Preparation method of lithium and cerium doped alkali metal silicate micro/nano wire material:

Step 1) All raw materials K ₂ CO ₃ , Na ₂ CO ₃ , Nb ₂ O ₅ , BaCO ₃ , Li ₂ CO ₃ , Sb ₂ O ₃ , Bi ₂ O ₃ are placed in an oven at 120 ° C before weighing. Dry to remove moisture from the raw materials;

Step 2) According to the formula (0.94-x)K _y Na _(1-y) NbO ₃ -xBaBiO ₃ -0.06LiSbO ₃ , where x=0.032, y=0.5, and then put into a nylon ball mill jar to Ethanol and zirconia balls were ball milled for 24 h;

Step 3) taking out the powder after ball milling, drying, pre-burning, pre-baking temperature is 900 ° C, calcination time is 6 h, pre-burning heating rate is 2 ° C / min;

Step 4) Then, the calcined powder is again loaded into a ball mill bottle, and the ethanol and zirconia balls are used as a ball milling medium for a second ball milling for 12 hours;

Step 5) taking the powder after the second ball milling, drying, passing through a 100 mesh sieve, and then pressing into a round blank having a diameter of 14 mm and a thickness of 2 mm under a pressure of 100 MPa;

Step 6) The pressed round blank is placed in an electric furnace and kept at a temperature of 1080 ° C for 30 hours to obtain a lithium or cerium doped alkali metal silicate micro/nano wire material.

The obtained lithium and cerium doped alkali metal silicate micro/nano wires were examined by SEM as shown in FIG.

Example 4

Preparation method of lithium and cerium doped alkali metal silicate micro/nano wire material:

The procedure not specifically described was the same as that of Example 3 except that the calcination temperature of the step 3) was 700 ° C; and the temperature in the step 6) was 1085 ° C.

The obtained lithium and cerium doped alkali metal silicate micro/nanowire materials were examined by SEM electron microscopy.

Claims (8)

1. An alkali metal niobate micro/nanowire material, characterized in that the alkali metal niobate micro/nanowire material is Na ₂ CO ₃ , K ₂ CO ₃ , BaCO ₃ , Nb ₂ O ₅ , Bi ₂ O ₃ is a raw material, and is compounded according to the formula (1-x)K _y Na _1-y NbO ₃ -xBaBiO ₃ , wherein 0.015 ≤ x ≤ 0.07, 0.4 _{≤ y ≤} 0.6, which is fired by a conventional ceramic solid phase sintering process. Micro-nano wire material.
2. The method for preparing an alkali metal silicate micro/nanowire material according to claim 1, comprising the steps of:

   Step 1) All raw materials Na ₂ CO ₃ , K ₂ CO ₃ , BaCO ₃ , Nb ₂ O ₅ and Bi ₂ O ₃ are placed in an oven for drying before weighing the ingredients;

   Step 2) Weigh the raw material according to the chemical mass ratio of (1-x)K _y Na _1-y NbO ₃ -xBaBiO ₃ , wherein 0.015≤x≤0.07, 0.4≤y≤0.6, and put it into the ball mill bottle to Water ethanol is ball milled for 24 to 48 hours;

   Step 3) taking out the powder after ball milling, drying, and pre-burning under certain conditions;

   Step 4) Then, the calcined powder is subjected to a second ball milling for 12 to 24 hours using anhydrous ethanol as a ball milling medium;

   Step 5) taking out the second ball milled powder, drying it, and pressing it into a round billet under certain conditions;

   Step 6) The solid phase of the pressed round billet is sintered, and an alkali metal niobate micro/nanowire material is obtained in the sintered body.
3. The alkali metal silicate micro/nanowire material according to claim 1, wherein the raw material further comprises Li ₂ CO ₃ and Sb ₂ O ₃ according to a chemical formula (0.94-z) K _r Na _{(1-r )} NbO _{3 -zBaBiO 3 -0.06LiSbO 3,} wherein the component mass ratio 0.016≤z≤0.080,0.4≤r≤0.6 weighed raw materials, the conventional firing process of ceramic solid phase micro nanowire material sintering.
4. The method for preparing an alkali metal silicate micro/nanowire material according to claim 3, comprising the steps of:

   Step 1) All raw materials K ₂ CO ₃ , Na ₂ CO ₃ , Nb ₂ O ₅ , BaCO ₃ , Bi ₂ O ₃ and Li ₂ CO ₃ , Sb ₂ O ₃ are placed in an oven for drying before weighing the ingredients;

   Step 2) Weigh the raw material according to the chemical mass ratio (0.94-z) K _r Na _(1-r) NbO ₃ -zBaBiO ₃ -0.06LiSbO ₃ , wherein 0.016 ≤ z ≤ 0.080, 0.4 ≤ _r ≤ 0.6 In the ball mill bottle, the ball is ground for 24 to 48 hours with anhydrous ethanol as the medium;

   Step 3) taking out the powder after ball milling, drying, and pre-burning under certain conditions;

   Step 4) Then, the calcined powder is subjected to a second ball milling for 12 to 24 hours using anhydrous ethanol as a ball milling medium;

   Step 5) taking out the second ball milled powder, drying it, and pressing it into a round billet under certain conditions;

   Step 6) The solid phase of the pressed round billet is sintered, and an alkali metal niobate micro/nanowire material is obtained in the sintered body.
5. The preparation method according to any one of claims 2 or 4, wherein the step 1) is dried at a temperature of 120 to 300 °C.
6. The preparation method according to any one of claims 2 or 4, wherein the step 3) pre-sintering temperature is 700-900 ° C, the calcination time is 3-9 h, and the calcination heating rate is 1 to 5 ° C. /min.
7. The preparation method according to any one of claims 2 or 4, wherein the step 5) is pressed into a round billet by first passing the second ball milled powder through a 100 mesh sieve and then at a pressure of 100 MPa. It is pressed into a round blank having a diameter of 14 to 25 mm and a thickness of 1-3 mm.
8. The preparation method according to any one of claims 2 or 4, wherein the step 6) is sintered at a temperature of 1080 to 1140 ° C, and the holding time during sintering is 10 to 36 hours.

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