CN112341299A

CN112341299A - Preparation of nano core-shell Al @ KIO by spray coprecipitation method4Thermite method

Info

Publication number: CN112341299A
Application number: CN202011222943.0A
Authority: CN
Inventors: 朱顺官; 李晨; 张琳; 李燕; 易镇鑫; 陈世勇; 万早雁
Original assignee: Nanjing University of Science and Technology
Current assignee: Nanjing University of Science and Technology
Priority date: 2020-11-05
Filing date: 2020-11-05
Publication date: 2021-02-09
Anticipated expiration: 2040-11-05
Also published as: CN112341299B

Abstract

The invention discloses a method for preparing nano core-shell Al @ KIO by a spray coprecipitation method₄Thermite method. The method adopts a spray coprecipitation method, takes an aqueous solution of periodate as a conveying liquid, takes an aqueous solution of sylvite or an ethanol solution as a receiving liquid, adds nano aluminum powder into the conveying liquid, disperses the conveying liquid into suspension drops containing the aluminum powder through spraying, sprays the suspension drops into the receiving liquid, replaces the periodate with potassium periodate to obtain nano nuclear shell Al @ KIO₄Thermite. The thermite prepared by the invention is a core-shell type thermite with nano potassium periodate coating nano aluminum, greatly increases the contact area among components, improves the combustion rate and the heat release performance, has the current yield of 30g/h, and can be used in semiconductor bridges, bridge wires, laser ignition and detonation sequences.

Description

Preparation of nano core-shell Al @ KIO by spray coprecipitation method4Thermite method

Technical Field

The invention relates to a method for preparing nano core-shell Al @ KIO by a spray coprecipitation method₄A method of thermite, belonging to the technical field of energetic material preparation.

Background

The nano thermite is a metastable intermolecular composite material consisting of nano-scale fuel (usually nano aluminum) and oxidant. The nanometer thermite has the characteristics of high energy density, low toxicity and the like, so that the nanometer thermite has wide interest of researchers, and makes great progress in many aspects. In one aspect, the oxidizing agent is increasing in species, including oxides (Fe)₂O₃、MoO₃、CuO、Bi₂O₃、I₂O₅) Salts of oxyacids (e.g. KMnO)₄、NaIO₄、CuSO₄·5H₂O), fluorides (e.g. FeF)₃PTTE), etc., greatly enriching the components of the thermite. On the other hand, various nanostructures, such as hollow nanospheres, nanowires, core/shell nanoarrays and assembled nanoparticles, increase the contact area between the components, greatly increasing the energy release rate. These studies show that the properties of the nano thermite can be regulated and controlled by selecting proper components and designing proper structures, and the application field of the nano thermite is further widened.

At present, a series of processes taking a spraying method as a core are applied to the preparation of a nano core-shell structure. Such as spray drying, spray pyrolysis, and the like. The spray crystallization method is a means for realizing substance crystallization in tiny liquid drops formed by spraying, and the production process is safe, rapid and environment-friendly. Michael R.Zachariah et Al prepared Al @ KIO by spray drying₄、Al@NaIO₄Core-shell thermite, the combustion mechanism (Jianan G, Feng J, Jacob RJ, equivalent. super-reactive Nanoenergetic gases generated on periodic Salts [ J]Angewandte Chemie International Edition,2013,52(37): 9743.). Preparing Al @ NaIO by Wanzao goose and the like by using spray drying method₄Core shell thermite and its use as a primer in detonator charges (Wan Z, Cruz ATM, Li Y, equivalent. factor production of NaIO4-encapsulated nanoAl microspherum as green primary expose)ve and its thermodynamic research[J]CHEM ENG J,2019,360: 778). However, since the concentration of the potassium periodate solution is very low (0.65g/100g water, 40 ℃), the yield is greatly limited, which prevents its use.

Disclosure of Invention

The invention aims to provide a method for preparing nano core-shell Al @ KIO by using a spray coprecipitation method₄Method of thermite application, the method utilizing KIO₄And NaIO₄The Al @ KIO is safely and quickly prepared at normal temperature by adopting a spray coprecipitation method₄A core-shell material.

The technical solution for realizing the invention is as follows:

preparation of nano core-shell Al @ KIO by spray coprecipitation method₄A method of thermite comprising the steps of:

adopting a spray coprecipitation method, taking an aqueous solution of periodate as a conveying liquid, taking an aqueous solution of sylvite or an ethanol solution as a receiving liquid, adding nano aluminum powder into the conveying liquid, carrying out ultrasonic treatment or stirring until the mixture is uniformly mixed, dispersing the conveying liquid into suspension liquid drops containing the aluminum powder by spraying under the conditions of normal temperature and stirring, spraying into the receiving liquid, replacing the periodate with potassium periodate to form a core-shell structure, carrying out suction filtration, washing, dehydrating and drying to obtain the nano core-shell Al @ KIO₄Thermite.

Preferably, the time of the ultrasonic treatment or the stirring is 10-20 min.

Preferably, an adhesive is further added to the conveying liquid and/or the receiving liquid. The adhesive is an adhesive conventionally used in the field, and can be polyvinyl alcohol, hydroxymethyl propyl cellulose, rosin gum, shellac, celluloid, nitrocellulose, tannic acid or phenolic resin.

Preferably, the periodate salt is selected from sodium periodate, ammonium periodate or potassium periodate. The concentration of the periodate is 2-15 wt.%.

Preferably, the potassium salt is selected from potassium chloride, potassium nitrate, potassium sulfate, potassium acetate or potassium ethoxide. The concentration of potassium salt is 2 wt.% to 15 wt.%.

Preferably, the concentration of the nano aluminum powder is 0.5 wt.% to 10 wt.%.

Preferably, the spraying conditions are: the temperature is 10-40 ℃, the feeding rate is 2-20 ml/min, the gas is nitrogen or air, and the gas flow rate is 2-30L/min.

Preferably, the nano core-shell Al @ KIO₄In the thermite, the content of each component is as follows: 60-90% of potassium periodate, 10-40% of nano aluminum and 0-10% of adhesive.

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

(1) the invention adopts a spray coprecipitation method, utilizes the spray-formed micro liquid drops, maintains the whole reaction process at normal temperature, has simple process, safe and environment-friendly preparation process, is convenient for industrialized expanded production, and can improve the performance of the thermite by adding an adhesive and the like in the system.

(2) Since the solubility of potassium periodate at room temperature (40 ℃) is only 0.65g, Al @ KIO prepared by a spray drying method₄The output of the core-shell thermite is lower and is only 2g/h, and the spray coprecipitation method skillfully utilizes KIO₄And NaIO₄The Al @ KIO is safely and quickly prepared by the solubility difference₄The core-shell thermite has the current yield of 30 g/h.

(3) The nanometer core-shell Al @ KIO prepared by the method₄The thermite has a unique microstructure, the particle size of the thermite is 100-500 nm, the two components are both in nanoscale, the thermite is in close contact, the thermite has excellent performance and good ignition and initiation performance, and can be used for semiconductor bridges, bridge wires, laser ignition and initiation sequences.

Drawings

Table 1 shows Al @ KIO prepared in example 1 and comparative example 1₄Infrared temperature measurement data of thermite.

Table 2 shows Al @ KIO prepared in example 2₄The thermite has different pulse firing sensitivities of the transducer elements.

FIG. 1 is the Al @ KIO prepared in examples 1 and 2₄Scanning electron microscope image of thermite.

FIG. 2 is Al @ KIO prepared in examples 1 and 2₄High resolution transmission electron microscopy images of thermite.

FIG. 3 is Al @ KIO prepared in example 3₄Scanning electron microscope image of thermite.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

Example 1

Respectively dissolving 5.6g of sodium periodate in 100ml of deionized water, dissolving 4g of potassium chloride in 50ml of deionized water, weighing 2.4g of nano-Al, dispersing the nano-Al in the sodium periodate solution, carrying out ultrasonic treatment for 10min, and then spraying the suspension into the potassium chloride solution through a spray head (spraying condition: N₂Flow rate 15L/min, feed rate: 10ml/min, rotation speed 800 r/min). Filtering, and drying at 60 ℃ for 24 h.

Example 2

5.6g of sodium periodate and 3.85g of potassium acetate were dissolved in 100ml of deionized water and 50ml of industrial alcohol, respectively, 2.4g of gnano-Al was weighed and dispersed in the sodium periodate solution, and ultrasonic treatment was carried out for 10 minutes, and then the suspension was transferred to the potassium acetate solution by an atomizer (spraying conditions: N;)₂Flow rate 15L/min, feed rate: 10ml/min, rotation speed 800 r/min). Filtering, and drying at 60 ℃ for 24 h.

Example 3

Respectively dissolving 1.4g of sodium periodate in 100ml of deionized water, dissolving 1g of potassium acetate in 50ml of industrial alcohol, weighing 0.6g of nano-Al, dispersing the nano-Al in the sodium periodate solution, weighing 10mg of rosin-shellac (the mass ratio is 1:1, the content of the product gum is 1%) to be dissolved in the potassium acetate solution, carrying out ultrasonic treatment for 10min, and then conveying the suspension into the potassium acetate solution through an atomizer (spraying condition: N)₂Flow rate 15L/min, feed rate: 10ml/min, rotation speed 800 r/min). Filtering, and drying at 60 ℃ for 24 h.

Comparative example 1

1.4g of sodium periodate and 1g of potassium acetate in 50ml of deionized water and 100ml of industrial alcohol, respectively, 0.6g of nano-Al was weighed and dispersed in the potassium acetate solution, sonicated for 10min, and then the suspension was transferred to the sodium periodate solution by an atomizer (spraying conditions: N: M)₂Flow rate 15L/min, feed rate: 10ml/min, rotation speed 800 r/min). Filtering, and drying at 60 ℃ for 24 h.

TABLE 1

TABLE 2

Table 1 shows the preparation of nano Al @ KIO by the spray coprecipitation method₄In the thermite process, different experimental conditions (feeding mode, feeding amount, mother solution KCl concentration and feeding rate) influence the performance of the sample, and the performance of the sample is evaluated according to an infrared temperature measurement result, so that the finally optimized process condition is determined, as shown in example 1.

Table 2 shows the impulse ignition performance of the prepared sample for the transducer elements such as semiconductor bridge, carbon film bridge, bridge wire, etc., and experiments show that 50% of the impulse ignition voltage of the sample prepared in example 2 is 10-15V, which meets the actual application requirements of the existing electric initiating explosive device and has a great application value.

FIGS. 1-3 are SEM images of prepared samples showing nano core-shell Al @ KIO₄Thermite has a unique microstructure, KIO₄The nano particles are densely distributed on the nano-Al surface in a dotted manner, and both the nano particles and the nano-Al surface are in nano scale and are in close contact, so that the excellent ignition performance of the nano-Al surface is facilitated.

Claims

1. Preparation of nano core-shell Al @ KIO by spray coprecipitation method₄The thermite method is characterized by comprising the following steps:

adopting a spray coprecipitation method, taking an aqueous solution of periodate as a conveying liquid, taking an aqueous solution of sylvite or an ethanol solution as a receiving liquid, adding nano aluminum powder into the conveying liquid, carrying out ultrasonic treatment or stirring until the mixture is uniformly mixed, dispersing the conveying liquid into suspension liquid drops containing the aluminum powder by spraying under the conditions of normal temperature and stirring, spraying into the receiving liquid, replacing the periodate with potassium periodate to form a core-shell structure, carrying out suction filtration, washing, dehydrating and drying to obtain the nano core-shell Al @ KIO₄Aluminothermic processAnd (3) preparing.

2. The method according to claim 1, wherein the time for the ultrasonic treatment or the stirring is 10-20 min.

3. The method of claim 1, wherein an adhesive is further added to the transport and/or receiving fluids.

4. The method as claimed in claim 3, wherein the adhesive is selected from polyvinyl alcohol, hydroxymethyl propyl cellulose, rosin size, shellac, celluloid, nitrocellulose, tannic acid or phenolic resin.

5. The method of claim 1, wherein said periodate salt is selected from the group consisting of sodium periodate, ammonium periodate, and potassium periodate.

6. The method of claim 1, wherein the potassium salt is selected from the group consisting of potassium chloride, potassium nitrate, potassium sulfate, potassium acetate, and potassium ethoxide.

7. The method according to claim 1, wherein the periodate is present in a concentration of 2 wt.% to 15 wt.% and the potassium salt is present in a concentration of 2 wt.% to 15 wt.%.

8. The method according to claim 1, wherein the concentration of the nano aluminum powder is 0.5 wt.% to 10 wt.%.

9. The method of claim 1, wherein the spraying conditions are: the temperature is 10-40 ℃, the feeding rate is 2-20 ml/min, the gas is nitrogen or air, and the gas flow rate is 2-30L/min.

10. The method of claim 1, wherein the nano core-shell Al @ KIO is present in a solid form₄In the thermite, the content of each component is as follows:60-90% of potassium periodate, 10-40% of nano aluminum and 0-10% of adhesive.