阅读说明：本技术 一种含氢的金属燃烧剂及其制备方法 (Hydrogen-containing metal combustion agent and preparation method thereof ) 是由 柳东明 时文涛 张明 斯庭智 李永涛 张庆安 于 2020-04-03 设计创作，主要内容包括：本发明公开了一种含氢的金属燃烧剂及其制备方法,属于固体燃烧剂技术领域。该燃烧剂由铝、镁和氢三种元素组成,其物相组成为铝和氢化镁,铝与氢化镁的摩尔比为2～4:1。其制备方法包括下述步骤：首先,按照2～4:[1/(1-x)](x为熔炼过程中镁的烧损率)的摩尔比,称取纯度不低于99.5％的金属铝和镁；然后,利用熔炼法将铝和镁熔炼成合金,并将合金机械粉碎成粒度小于300目的粉末；最后,在350～400℃和8MPa氢压下对合金粉末进行氢化处理。本发明的技术效果在于：所提供的含氢的金属燃烧剂具有低的点火温度、高的反应活性和燃烧效率,且制备工艺简单、安全可靠、价格低廉。(The invention discloses a hydrogen-containing metal combustion agent and a preparation method thereof, belonging to the technical field of solid combustion agents. The combustion agent consists of three elements of aluminum, magnesium and hydrogen, the phase composition of the combustion agent is aluminum and magnesium hydride, and the molar ratio of the aluminum to the magnesium hydride is 2-4: 1. The preparation method comprises the following steps: firstly, weighing metal aluminum and magnesium with the purity of not less than 99.5 percent according to the molar ratio of (1/(1-x)) (x is the burning loss rate of magnesium in the smelting process) of 2-4; then, smelting aluminum and magnesium into alloy by using a smelting method, and mechanically crushing the alloy into powder with the particle size of less than 300 meshes; and finally, carrying out hydrogenation treatment on the alloy powder at 350-400 ℃ and 8MPa hydrogen pressure. The invention has the technical effects that: the provided hydrogen-containing metal combustion agent has the advantages of low ignition temperature, high reaction activity and combustion efficiency, simple preparation process, safety, reliability and low price.)

1. A metal combustion agent containing hydrogen is characterized in that the element composition of the combustion agent is aluminum, magnesium and hydrogen, the phase composition is aluminum and magnesium hydride, and the molar ratio of the aluminum to the magnesium hydride is 2-4: 1;

the preparation of the combustion agent comprises the following steps:

(1) weighing metal aluminum and magnesium with the purity not lower than 99.5% according to the molar ratio of [1/(1-x) ] of 2-4; x is the burning loss rate of magnesium in the smelting process;

(2) smelting the aluminum and the magnesium in the step (1) into alloy by using a smelting method;

(3) mechanically crushing the alloy obtained in the step (2) into powder;

(4) and (4) carrying out hydrogenation treatment on the alloy powder obtained in the step (3).

2. The hydrogen-containing metal combustion agent according to claim 1, wherein the powder size after the alloy is mechanically pulverized in the step (3) is less than 300 mesh.

3. The hydrogen-containing metal combustion agent according to claim 1, wherein the step (4) of hydrotreating is: and (2) carrying out hydrogen absorption and desorption cycles twice at 350-400 ℃: absorbing hydrogen for 24h under the hydrogen pressure of 8MPa, and absorbing hydrogen for 24h under the hydrogen pressure of 8MPa after releasing hydrogen for 1h in vacuum.

Technical Field

The invention belongs to the technical field of solid combustion agents, and particularly relates to a hydrogen-containing metal combustion agent and a preparation method thereof.

Background

The metal combustion agent is an important component of modern solid propellant, which can not only improve the energy density of the propellant, but also inhibit the oscillatory combustion of metal oxide solid particles generated by combustion. The aluminum powder has high volume combustion enthalpy and energy density, is rich in resources and low in price, and is a widely applied light metal combustion agent. However, the conventional aluminum powder has disadvantages of high ignition temperature, low combustion efficiency, incomplete combustion, and easy agglomeration during combustion due to its low melting point and high boiling point.

The Combustion process of the aluminum powder is related to the particle size, nanocrystallization of the aluminum powder is one of effective methods for improving the Combustion performance of the aluminum powder, compared with micron-sized aluminum powder, the nanometer-sized aluminum powder has low ignition temperature, and single-particle Combustion is prone to occur due to the reduction of the ignition threshold, so that the Combustion efficiency is improved, and particle agglomeration is reduced [ Luohsia, Nippon, Zenhao et al, light alloy processing technology, 2007,35(10):69-72], but the high specific surface area of the nanometer-sized aluminum powder causes the oxidation to easily occur in the air, and the actual active aluminum content and Combustion heat value are greatly reduced.

Disclosure of Invention

Aiming at the defects of the prior aluminum-based metal combustion agent technology, the invention provides the hydrogen-containing metal combustion agent with excellent performance, low cost and simple preparation process and the preparation method thereof.

In order to achieve the purpose, the invention adopts the technical scheme that:

the hydrogen-containing metal combustion agent provided by the invention comprises three elements of aluminum, magnesium and hydrogen, the phase composition of the hydrogen-containing metal combustion agent is aluminum and magnesium hydride, and the molar ratio of the aluminum to the magnesium hydride is 2-4: 1.

The preparation of the combustion agent comprises the following steps:

(1) weighing metal aluminum and magnesium with the purity not lower than 99.5% according to the molar ratio of [1/(1-x) ] of 2-4; x is the burning loss rate of magnesium in the smelting process;

(2) smelting the aluminum and the magnesium in the step (1) into alloy by using a smelting method;

(3) mechanically crushing the alloy obtained in the step (2) into powder;

(4) and (4) carrying out hydrogenation treatment on the alloy powder obtained in the step (3).

As an optimization, the powder size after the alloy is mechanically crushed in the step (3) is less than 300 meshes.

As an optimization, the step (4) hydrotreating refers to: and (2) carrying out hydrogen absorption and desorption cycles twice at 350-400 ℃: absorbing hydrogen for 24h under the hydrogen pressure of 8MPa, and absorbing hydrogen for 24h under the hydrogen pressure of 8MPa after releasing hydrogen for 1h in vacuum.

The scientific principle of the invention is as follows:

the invention introduces hydrogen into the aluminum-magnesium alloy combustion agent in a solid state, so that the phase composition of the combustion agent is changed from the original Al₃Mg₂And Al phase to MgH₂And the Al phase can effectively reduce the ignition temperature and improve the activity and the combustion efficiency of the combustion agent. First, in the process of hydrotreating aluminum-magnesium alloys, the absorption and release of hydrogen causes the expansion and contraction of crystal lattices, resulting in pulverization of the aluminum-magnesium alloy and formation of a large number of crystal defects, thereby significantly increasing the combustion reaction interface and activity. Secondly, the aluminum-magnesium alloy combustion agent containing hydrogen is in the combustion processIn, MgH₂Will decompose and release hydrogen, will form a fresh surface due to the shrinkage of the crystal lattice, and will facilitate the combustion to proceed, again, hydrogen has a value of 1.43 × 10⁵The kJ/kg combustion heat value is far higher than that of any metal combustion agent, and the hydrogen-containing aluminum-magnesium alloy combustion agent can release a large amount of heat in the combustion process of hydrogen release and combustion, so that the combustion performance is improved.

Compared with the prior art, the invention has the beneficial effects that:

(1) the provided hydrogen-containing metal combustion agent has low ignition temperature, high reaction activity and high combustion efficiency.

(2) The provided hydrogen-containing metal combustion agent takes metal aluminum and magnesium as initial raw materials, and has wide sources and low price.

(3) The preparation method of the hydrogen-containing metal combustion agent has simple process, and is safe and reliable.

Drawings

FIG. 1 shows Al in example 1 of the present invention₂Hydride of Mg alloy (a), Al in example 2₃Hydride of Mg alloy (b) and Al in example 3₄X-ray diffraction pattern of Mg alloy hydride (c).

FIG. 2 shows Al in example 1 of the present invention₂Scanning electron micrographs of Mg alloy hydride.

FIG. 3 shows Al in example 1 of the present invention₂Hydride of Mg alloy and Al₂The Mg alloy heats up to a combustion temperature curve of 425 ℃.

FIG. 4 shows Al in example 1 of the present invention₂Hydride of Mg alloy and Al₂Differential scanning calorimetry curve of Mg alloy in air.

FIG. 5 shows Al in example 3 of the present invention₄Differential scanning calorimetry curve of Mg alloy hydride in air.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but the present invention is not limited to the embodiments.