JPS6026638B2 - heat generating material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat generating material made of a mixture of a magnesium alloy and ferric oxide.

There are many types of exothermic agents known, but among them there is one called thermite, which has a large calorific value and can generate high temperatures.

This uses ferric oxide as an oxidizing agent and aluminum, magnesium, or an alloy thereof as a combustible agent. This is used as an incineration agent, heating agent, melting agent, heat transfer agent, etc., but when it is made into a high-density compression molded product to increase the calorific value per unit volume, its ignition reactivity becomes extremely poor. It has the following drawbacks. Among the heat generating materials mentioned above, those based on ferric oxide-magnesium oxide react as shown in the following formula and release a large amount of heat of about 200 ratio al/earth or more.

Therefore, if this ferric oxide-magnesium-based heat generating material can generate heat as a high-density compression molded body, the temperature during the reaction will be higher than normal ones. It is clear that the temperature will reach an extremely high temperature.

However, with the current technology, a drug with a diameter of about 5 ribs or less and compression molded at a pressure of about 30k9/min will not react even if you try to ignite it. The present inventors have conducted intensive research to overcome the above-mentioned drawbacks found in the prior art and to develop a heat generating material made of a micro-compression molded body that generates heat at high temperatures.
We have completed the present invention.

That is, according to the present invention, A fine powder of an alloy containing magnesium as a main component with a grain size of 200 mesh or less, and B a fine powder with a grain size of 200 mesh or less.
A heat generating material is provided which is made of a compression molded product of a mixture with ferric oxide in the form of a fine powder of less than mesh size. Component A, one of the heat generating material components of the present invention, is an alloy containing magnesium as a main component, and it is necessary to use it in the form of a fine powder with a particle size of 200 mesh or less, preferably 270 mesh or less.

According to the research conducted by the present inventors, alloys mainly composed of magnesium have a grain size of around 200 mesh.
When the particle size becomes smaller than that, the reactivity increases rapidly,
It has been found that when mixed with fine powder of ferric oxide, the ignition reaction occurs easily even as a compact, high-density compacted compact. In a ferric oxide-aluminum heating element, no matter how fine the aluminum powder is, its reactivity does not improve significantly, and as mentioned above, the reactivity becomes more pronounced when the particle size is reduced to 200 mesh or less. The improvement is a unique phenomenon seen in magnesium-based products. Magnesium alloys include, in addition to magnesium, one or more metals that can be alloyed with magnesium, such as nickel, manganese, zinc, iron, zirconium, calcium, aluminum, titanium, and chromium. Generally, it contains magnesium in an amount of 7% by weight or more, preferably 85% by weight or more. Further, the particle size of the ferric oxide component B is a fine powder of 200 mesh or less, preferably 320 mesh or less.

In the heat generating material of the present invention, this ferric oxide B has a weight ratio B/A of 87.5/A to the magnesium alloy component A.
It is used in a range of 12.5 to 75.0/25.0. Note that the mesh referred to in the present invention is based on the Taylor standard mesh. The heat generating material of the present invention includes various metal oxides, peroxides, chlorates, perchlorates, permanganates, sulfates, for example, oxidized steel, as long as they do not impede the purpose of the present invention. Barium peroxide, barium sulfate, potassium permanganate, perchloric acid IJ, etc. can be added.
It is also possible to add combustible agents such as silicon, zirconium, boron, magnesium, titanium, silicon iron, and the like. In the present invention, a mixture of magnesium alloy component A and ferric oxide component B is used as a compression molded body in an appropriate shape.

The shape of the hot water bowl can be arbitrary, such as a plate, a rod, or a cylinder. Compression molding is carried out by filling the mixture into an appropriately shaped mold and compressing the mixture. In this case, the pressure is usually between 10k9/ground and 500k9/ground.
In compression molding, sodium stearate, paraffin, beeswax and other binders may be used as auxiliary components to improve physical properties. The heat generating material of the present invention usually has a density of 2.0 m/m or more, preferably 2.9 m/m to 3.10 m/m.

Since the magnesium alloy used in the present invention has high extensibility, it is difficult to directly crush it into a desired particle size.

However, after reacting hydrogen with a magnesium alloy to form a hydride, this is ground into a fine powder with a particle size of 200 mesh or less, preferably 270 to 320 mesh, and then this finely ground product is heat-treated under reduced pressure to form a hydride. Dissociate hydrogen from inside. In this way, a desired finely powdered magnesium alloy can be easily obtained. In the present invention, it is advantageous to use as the heating material component a magnesium alloy containing 2 to 5% by weight of the alloy component, which has been pulverized through such a metal hydride. The heat-generating material of the present invention can be used for the same purposes as conventional heat-generating materials.
Even as a micro-compression molded product, it has extremely good ignition and reactivity, and can be used in many fields never seen before by taking advantage of its characteristics of easily achieving high temperatures. In the case of the present invention, in particular:
It is advantageously used as a rod-shaped or linear molded product with a diameter of 5 ribs or less, a plate-shaped molded product with a thickness of 3 ribs or less, and the like. For example, diameter 3
The rod-shaped molded body, which is about the same size as skin, can be used as a minute welding rod for adhering small parts of metal to each other or for melting and cutting small parts of metal by utilizing its high-temperature exothermic property. Next, the present invention will be explained in more detail with reference to Examples.

Example 1 An alloy powder consisting of 97% by weight of magnesium and 3% by weight of nickel with a particle size of approximately 100 mesh was reacted with hydrogen gas under the conditions of a temperature of 350°C and a pressure of 50k9/swift G to produce a hydride of the magnesium-nickel alloy. made.

Next, this hydride was pulverized to a particle size of 270 mesh or less, and then heated to about 200 qo under reduced pressure to obtain a fine magnesium-nickel alloy powder. Furthermore, since metallic magnesium and its alloy containing 2% by weight of nickel are very soft metals, it is difficult to reduce the particle size to 200 mesh or less as described above even if they are pulverized as they are by a normal pulverization method. In this case, the limit is pulverization to about 100 mesh. Therefore, in the case of the present invention, the powdering method using the hydride was used for pulverizing magnesium. Next, 18.6% by weight of this magnesium nickel alloy fine powder and 81.4% by weight of ferric oxide powder (particle size of 200 mesh or less) were uniformly mixed, and this mixture was heated at a pressure of 200 k9/ground to The ribs were compression molded into a rod shape with a length of 30 ribs.

When this machine-shaped molded product was placed in a metal container, sealed tightly, and electrically ignited using a resistance wire at one end, the ignition was good, and it was confirmed that the reaction progressed to the other end in an incandescent state. It was done.

In this case, the reaction temperature reaches about 3000 pm, and if air is present in the container, it will expand explosively. Since the volume of gas is proportional to the absolute temperature, in this case, the gas expands spontaneously to one pitch. In other words, the pressure increases even by one atmospheric pressure. Therefore, the compression molded product should be molded with high density and have no air bubbles. That is, it has been found that it is preferable to compress the material to a density of 2.5 kg/mass or higher, or to maintain the container under reduced pressure. For comparison, rod-shaped compression molded products were obtained in the same manner as described above using magnesium nickel alloy powder and pure magnesium metal powder with a particle size of about 100 mesh.

I tried to ignite this thing in the same way as above, but it did not react at all. Example 2 An alloy consisting of 9% by weight of metallic magnesium and 1% by weight of nickel was ground into a fine powder with a particle size of 270 mesh or less, and 19.2% by weight of this pulverized product was mixed with 80% by weight of ferric oxide with a particle size of 320 mesh or less. ．． The mother weight percent was mixed.

Next, this mixture was compression-molded in a container at a pressure of 100 k9/kg into a rod shape with a diameter of 2 ribs, which was then sealed and ignited. It was confirmed that the fuel burns evenly. Furthermore, in the above, it was confirmed that a rod shaped into a diameter 5 side under a pressure of 100 ko/ground burns at a rate of 1 ko/second in a closed metal container.

Furthermore, in the above, when the particle size of the magnesium alloy was varied, rod-shaped molded products with a diameter of 2 kites were made in the same way, and the combustion characteristics were investigated, it was found that the particle size of the magnesium alloy reached around 200 mesh, and then It has been found that when the size becomes smaller, the combustion characteristics are rapidly improved. In other words, it was found that a molded body of magnesium alloy with a particle size of 200 mesh or less is easy to ignite, and the combustion reaction proceeds at a uniform rate without interruption of the combustion reaction, whereas with a particle size larger than that, the ignition reaction is unfavorable. . In addition, since nickel in the magnesium alloy hardly reacts with ferric oxide, the higher the nickel content, the lower the calorific value of the compact.

If the nickel content exceeds 30%, the calorific value per unit weight decreases, and at the same time, the ignitability and combustibility become inferior. It is preferable to Example 3 Fe, Cr, Mm, Sn, C as magnesium alloy
Using an alloy containing various metals such as a or Zr, a heat-generating material manufactured under the same conditions as in Example 2 was made into a rod-shaped body with a diameter of 2 ribs at a pressure of 300 k9/ground, and its combustion characteristics were investigated. It was confirmed that it exhibited good combustion characteristics.

Claims (1)

[Claims] 1. A heat generating material made of a compression molded mixture of a fine powder of an alloy whose main component is A-magnesium with a grain size of 200 mesh or less and a fine powder of ferric oxide (B) with a grain size of 200 mesh or less.