TWI626317B - Method for manufacturing magnesium vibration plate for sound and magnesium vibration plate for sound - Google Patents

Abstract

The present invention provides a method for producing an acoustic vibrating plate for acoustic use and a magnesium vibrating plate for acoustic use, which are capable of efficiently producing an acoustic magnesium vibrating plate having excellent rust preventive performance and having excellent acoustic characteristics.

The rust-preventing treatment step of forming the hydroxide layer (2) on the surface of the magnesium substrate (1) in a sealed container under a high pressure of about 1.1 atm and below 350 MPa can be formed on the magnesium group. The hydroxide layer (2) on the surface of the material (1) is dense and has a high hardness. Therefore, since the magnesium base material (1) is formed thin and the hardness is increased depending on the rust-preventing treatment, the increase in weight can be suppressed, so that it is possible to manufacture an acoustic characteristic by improving light weight and surface hardness. Magnesium vibrating plate for sound.

Description

Method for manufacturing magnesium vibration plate for sound and magnesium vibration plate for sound

The present invention relates to a method for producing a magnesium diaphragm for acoustic use and a magnesium diaphragm for acoustic use, which are capable of producing lightweight and high surface hardness, and excellent in acoustic characteristics and rust resistance. Magnesium vibrating plate for sound.

As a material for the acoustic diaphragm, various materials such as aluminum, titanium, magnesium, paper, and plastic can be used. As a practical metal material among these materials, magnesium has the lightest and moderate hardness and has excellent characteristics of high vibration damping property. Therefore, a magnesium base material composed of a magnesium or magnesium-based alloy is preferably used as a material for an acoustic diaphragm. When a material composed of a magnesium base material is used, an acoustic vibrating plate having characteristics of exhibiting excellent acoustic characteristics to a high sound range can be obtained. By forming the material thinner, the quality of the acoustic vibrating plate is reduced and the acoustic characteristics are improved, so that a means for forming a thinner magnesium substrate is required.

However, on the other hand, on the other side of the magnesium substrate, there is a tolerance. The disadvantage of easy rust. Therefore, when it is used as a material for an acoustic diaphragm, it is necessary to apply a rustproof treatment to the surface of the magnesium substrate. Conventionally, as the rust-preventing treatment, an anodic oxidation, an electrodeposition coating after a chemical conversion treatment, a coating depending on a coating, and the like can be used alone or in combination of a plurality of them. . As a rust-preventing treatment in which a plurality of combinations are combined, for example, a high voltage can be applied to a ceramic-based solvent, and plasma anodizing treatment can be performed to form a ceramic layer, and a resin can be applied from above.

As an example of the rustproofing treatment, Patent Document 1 describes a method of forming a hydroxide layer on the surface of a magnesium substrate.

Further, Patent Document 2 describes a method of forming an electrodeposition coating film containing an acrylic resin as a main component on the surface of a magnesium substrate.

In Patent Document 3, a method of forming a hydroxide layer by plasma anodization has been described.

[Previous Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Patent No. 4734035.

Patent Document 2: Japanese Patent No. 4307172.

Patent Document 3: Japanese Patent No. 5345155.

In the rust-preventing treatment described in Patent Document 1, there is a problem in that the surface treatment layer (hydroxide layer) containing magnesium hydroxide formed on the surface of the magnesium substrate as a main component is thin and non- Dense, so rust prevention is not sufficient. Further, since the hardness of the hydroxide layer formed on the surface of the magnesium substrate is low, the speed of sound propagation is not sufficient.

Since the method described in Patent Document 2 covers the surface of the magnesium substrate with a resin, the surface hardness is lowered. Therefore, there is a problem that the speed of sound propagation in the surface of the acoustic vibrating plate is slow.

The methods described in Patent Document 2 and Patent Document 3 require a contact for electrically conducting the acoustic vibrating plate. Therefore, it is necessary to perform a trimming step after the surface is subjected to rustproof treatment. When the trimming step is performed, the cut surface of the magnesium substrate is exposed, and a portion where the rustproof treatment is not completed is formed. When the exposed portion of the magnesium substrate is kept in the original state, there is a fear that a point of rust (rusting point) will occur thereafter, and therefore, in order to prevent the magnesium substrate exposed during the trimming step from becoming a rust point, There is a problem that the rust-preventing treatment is required after the trimming step, which causes a decrease in manufacturing efficiency.

The present invention has been made to solve the above problems, and an object of the invention is to provide a method for producing an acoustic magnesium vibration plate having excellent acoustic characteristics and an acoustic system which is lightweight and has a high surface hardness. Use a magnesium diaphragm.

The present invention provided to solve the above problems is as follows.

(1) A method for producing an acoustic vibrating plate for acoustic use, comprising: a rust-preventing treatment step of immersing a surface of a magnesium substrate in an alkaline aqueous solution under a high pressure condition higher than a one atmosphere A hydroxide is formed.

(2) The method for producing an acoustic magnesium vibration plate according to the above (1), wherein the rust-preventing treatment step is performed in a sealed container.

(3) The method for producing an acoustic magnesium vibration plate according to the above aspect, wherein the reaction temperature in the rustproof treatment step is in a range of 50 ° C or more and 300 ° C or less, and the pressure is 1.1 or more and 350 ° C. Within the scope below.

The method for producing an acoustic magnesium vibration plate according to any one of the above aspects, wherein the magnesium substrate before the treatment in the rust-preventing treatment step has a thickness of 1 mm or less. .

The method for producing an acoustic magnesium vibration plate according to any one of the above aspects, wherein the rust-preventing treatment step has a thickness of 0.01 μm or more and 20 μm or less on the surface of the magnesium base material. The aforementioned hydroxide layer within the range.

The method for producing an acoustic magnesium vibration plate according to any one of the above aspects of the present invention, characterized in that, before the rust-preventing treatment step, magnesium is formed from a magnesium or magnesium-based alloy. The step of cutting the magnesium substrate from the formed sheet of the substrate.

(7) The method for producing an acoustic magnesium vibration plate according to any one of the above aspects, wherein the rust-preventing treatment step is provided with magnesium composed of a magnesium or magnesium-based alloy. The step of cutting the magnesium substrate from the formed sheet of the substrate.

(8) The method for producing an acoustic magnesium vibration plate according to any one of the above aspects, wherein the rust-preventing treatment step forms the hydroxide layer on a surface of the magnesium substrate, and A hydroxide layer is formed inside the magnesium substrate.

(9) A magnesium diaphragm for acoustics in which a hydroxide layer is formed on a surface of a magnesium substrate, and the hydroxide layer is formed inside the magnesium substrate.

According to the present invention, a dense and stable hydroxide layer can be formed on the surface of the magnesium substrate by performing the rust-preventing treatment step under a higher pressure than normal pressure. By forming a film of a hydroxide layer having a high hardness after ceramics on the surface of the magnesium substrate, an acoustic magnesium vibration plate excellent in rust resistance and excellent in acoustic characteristics can be obtained.

In the case where the rust-preventing treatment step is performed after the trimming step, since the hydroxide layer can be formed on the entire surface including the end surface of the magnesium substrate cut in the trimming step, End face treatment after the anti-rust treatment step is required. Therefore, the manufacturing efficiency of the acoustic magnesium diaphragm can be greatly improved more than the method of performing the rust-preventing treatment step before the trimming step.

In the formation of the rust-preventing treatment step before the trimming step In this case, by performing the rust-preventing treatment step, the hardness of the magnesium foil can be improved, and deformation or the like can be prevented. Therefore, even if a thin magnesium foil is used as the magnesium substrate, the trimming step can be performed with high precision. Therefore, it is possible to manufacture an acoustic magnesium vibration plate which is made of a very thin magnesium foil and which is lightweight and has excellent acoustic characteristics.

1‧‧‧Magnesium substrate

2, 2A, 2B‧‧‧ hydroxide layer

10‧‧‧Formed products

20‧‧‧ Pressing members

30‧‧‧stage

Fig. 1 is a cross-sectional view schematically showing a surface structure of an acoustic magnesium vibration plate manufactured by the method for producing an acoustic magnesium vibration plate of the present invention.

Fig. 2 is a drawing substitute photograph showing a method of compression test of Examples and Comparative Examples of the present invention.

Fig. 3 is a photograph showing a substitute of the state of each sample before and after the salt spray test of each of the samples of Example 1 and Comparative Examples 1 to 3 after the salt spray test.

Fig. 4 is a graph showing the results of the compression test as a result of the hardness test depending on the amount of pressing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a view schematically showing an acoustic magnesium vibration plate manufactured by the method for producing an acoustic magnesium vibration plate of the present embodiment (hereinafter, referred to as a "method for manufacturing a vibration plate" as appropriate) (hereinafter, appropriately referred to as A cross-sectional view of the structure of the "magnesium vibrating plate".

As shown in FIG. 1, the hydroxide layer 2A can be formed on the surface of the magnesium substrate 1 by performing the rust-preventing treatment step under a higher pressure than the normal pressure, and the reaction proceeds to the magnesium substrate 1. The hydroxide layer 2B is formed inside. By carrying out the reaction of the rust-preventing treatment step under high pressure conditions, it is possible to form a dense and stable hydroxide layer 2 (2A, 2B) which is dense and harder than when the reaction is carried out under normal pressure conditions. In the description of the present embodiment, when the hydroxide layers 2A and 2B are not distinguished, the hydroxide layer 2 is described.

The hydroxide layer 2 is a surface treatment layer of a hydroxide containing magnesium hydroxide as a main component formed on the surface of the magnesium substrate 1, and has a very high hardness. When the rust-preventing treatment step is carried out under a high pressure condition for a sufficient period of time, the magnesium substrate 1 is entirely a slurry of hydroxide. According to this, it is understood that the hydroxide layer 2A on the surface of the magnesium substrate 1 is formed by the rust-preventing treatment step, and the reaction proceeds to the inside of the magnesium substrate 1 to form the hydroxide layer 2B. .

Generally, the thickness of the inner hydroxide layer 2B is still much smaller than the thickness of the surface hydroxide layer 2A. Therefore, the difference between the thickness of the magnesium substrate 1 before the rust-preventing treatment step and the thickness of the magnesium substrate 1 including the hydroxide layer 2 after the rust-preventing treatment step can be evaluated as the thickness of the hydroxide layer 2. .

The rust-preventing treatment step is to immerse the magnesium substrate 1 in the treatment solution described later in the container, and to control an appropriate pressure condition (high-pressure condition) higher than the normal pressure, and to maintain the temperature inside the container appropriately as described later. The temperature is carried out. In order to easily carry out the rust-preventing treatment step under high pressure conditions, it is preferred to carry out the rust-preventing treatment step in a closed container. The magnesium substrate 1 is impregnated in the treatment solution described later, and the sealed container is subjected to a reaction under high pressure or at a suitable temperature to carry out a reaction on the surface of the magnesium substrate 1, and a hydroxide layer 2 is formed.

The time of the rust-preventing treatment step may be set to a time sufficient to confirm the hydroxide layer 2 having a desired thickness while confirming the state of the hydroxide 2 formed on the surface of the magnesium substrate 1. Although sufficient time varies depending on the thickness of the produced hydroxide 2 and the reaction conditions such as temperature, pressure, solution concentration, and solution capacity, it usually takes about 0.5 to 20 hours.

The reaction temperature in the rust-preventing treatment step is preferably in the range of 50 ° C or more and 500 ° C or less, more preferably 100 ° C or more and 400 from the viewpoint of forming the dense and stable hardness of the hydroxide layer 2 . The range below °C is preferably 150 ° C or more and 300 ° C or less.

Similarly to the reaction temperature, the pressure in the rust-preventing treatment step is preferably 1.1 or more and 350 or less, more preferably 1.5 or more, from the viewpoint of forming a dense and stable hydroxide layer 2 having a high hardness. And 200 Below the air pressure, it is preferably 5 or more and 100 or less.

The thickness of the magnesium base material 1 before the treatment in the rust-preventing treatment step is preferably 1 mm or less from the viewpoint of imparting good vibration characteristics to the acoustic magnesium vibration plate produced using the magnesium substrate. It is preferably 0.1 mm (1000 μm) or less, and more preferably 0.01 mm (100 μm) or less. Since the hardness of the magnesium base material 1 is increased by performing the rustproof treatment step before the trimming step, the precision of the trimming step can be improved. Therefore, even if a very thin magnesium substrate 1 is used, the acoustic vibrating plate for sound can be produced with high precision. For example, a magnesium foil material having a thickness of 60 μm or less, 50 μm or less, and 30 μm or less can be used as the magnesium base material 1.

By performing the rust-preventing treatment step, the surface hardness of the magnesium substrate can be improved. Therefore, it is possible to produce an acoustic magnesium vibration plate having sufficient strength by using a material having a thinner thickness than conventional ones. Therefore, the acoustic vibrating plate for acoustics can be made lighter and the acoustic characteristics can be improved.

The thickness of the hydroxide layer 2 formed on the surface and inside of the magnesium substrate 1 by the rust-preventing treatment step is preferably 0.01 in terms of achieving good rust resistance and the thickness of the magnesium substrate 1. Μm or more and 20 μm or less. Further, the thickness of the oxide layer 2 was evaluated by the difference in thickness of the plate including the magnesium substrate 1 before and after the rust-preventing treatment step.

[Magnesium substrate]

As the magnesium substrate, a pure magnesium or magnesium-based alloy having a purity of 99% can be used. Examples of the magnesium-based alloy include a Mg (magnesium)-Al (aluminum)-Zn (zinc)-based alloy, a Mg-Zn-Zr (zirconium)-based alloy, a Mg-Al-based alloy, and a Mg-rare earth element-based alloy.

Specific examples of the Mg-Al-Zn-based alloy include AZ31A, AZ31B, AZ31C, AZ61A, AZ80A, and AZ91. Specific examples of the Mg-Zn-Zr-based alloy include ZK51A, ZK61A, ZK60, M6, M5, and M4. Specific examples of the Mg-Al alloy include AM100A and the like.

As the Mg-rare earth element-based alloy, specifically, EZ33A, ZE41A, QE22A, etc., by adding a rare earth element (RE: Ce (铈) or / and Nd (鐠) is mainly used as a misch metal or In the case of a didymium, MgRE can be crystallized into a pure magnesium substrate in the grain boundary, and the creep resistance is particularly improved. Moreover, by the addition of Ag (silver) or Y (钇), the yield strength can be remarkably improved.

[treatment solution]

The treatment solution used for forming the hydroxide layer on the entire surface of the magnesium substrate is preferably an alkaline aqueous solution from the viewpoint of early reaction time. Examples of the alkaline component include sodium hydroxide, potassium hydroxide, and the like. The concentration of the alkaline component contained in the aqueous solution is preferably from 1% by mass to 50% by mass, more preferably from 5% by mass to 30% by mass, even more preferably from 8% by mass to 20% by mass.

Even if pure water containing no alkaline component is used as the treatment solution, hydroxide can be formed on the surface of the magnesium substrate. However, in this case, it takes a long time to form a hydroxide more than an alkaline aqueous solution.

In the case where an alkaline aqueous solution is used as the above treatment solution, the magnesium substrate is taken out from the above treatment solution, and the surface is washed with water after the rustproof treatment step to remove the alkaline aqueous solution on the surface.

The method for producing an acoustic magnesium vibration plate according to the present embodiment is performed before or after the rust-preventing treatment step described above, and is performed by cutting off the acoustic sheet from a molded sheet of a magnesium base material composed of magnesium or a magnesium-based alloy. A trimming step of a magnesium substrate for a magnesium vibrating plate. Here, the term "molded sheet" means a magnesium substrate which is subjected to press forming or the like and which is in a state of forming a predetermined shape such as a dome shape.

When the rust-preventing treatment step is performed after the trimming step, the hydroxide layer may be entirely formed on the entire surface of the magnesium substrate including the end surface of the magnesium substrate cut after the correction step. Since the rust-preventing treatment step is performed after the trimming step, the end surface treatment step for preventing rust from occurring from the end surface is not required, so that the manufacturing efficiency can be greatly improved.

In the case where the rust-preventing treatment step is performed before the trimming step, the harder hydroxide layer 2 can be formed on the surface of the magnesium substrate. By imparting sufficient hardness to the magnesium substrate 1 in advance in the rust-preventing treatment step before the trimming step To prevent the magnesium substrate 1 from being deformed in the trimming step. That is, from the viewpoint of deformation prevention, there is an advantage that the rustproof treatment step is performed before the trimming step. A very thin foil material can be used as the magnesium substrate 1 by performing the rust-preventing treatment step before the trimming step, and the acoustic magnesium vibration plate produced by thinning the magnesium substrate 1 can be formed lightly. .

In the method for producing an acoustic magnesium vibration plate according to the present embodiment, after the rust-preventing treatment step described above, electrodeposition may be used on the surface of the magnesium substrate on which the hydroxide layer is formed from the viewpoint of improving the artistic properties. Coloring by coating or spraying.

[Examples]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

[Example 1]

A sample of a magnesium substrate having a dome-shaped diaphragm shape formed into a diameter of 25 mm was produced using a plate having a thickness of 45 μm (0.045 mm).

The sample was subjected to a rust-preventing treatment step in a sealed container under the following conditions, and a hydroxide layer was formed on the surface of the magnesium substrate. In the first embodiment, a magnesium substrate in which a hydroxide layer having a thickness of 3 μm was formed on both surfaces thereof was obtained.

(Reaction conditions)

Reaction element: 10% by mass aqueous sodium hydroxide solution.

Reaction temperature: 150 °C.

Reaction pressure: 10 atmospheres (high pressure conditions).

Reaction time: 5 hours.

Reaction device: a closed container made of stainless steel.

The thickness of the magnesium base material before the rust preventive treatment step was 45 μm (0.045 mm), and the thickness of the magnesium base material after the rust preventive treatment step was 51 μm. The total thickness of the hydroxide layer formed on both sides of the magnesium substrate by the rust-preventing treatment step was evaluated to be 6 μm (single-sided 3 μm) based on the difference in thickness between the rust-preventing treatment step. Since a magnesium substrate having a hydroxide layer firmly adhered to its surface has been obtained, it is understood that a hydroxide layer is also formed inside.

[Comparative Example 1]

Using the same sample as in Example 1, and using the following conditions, a magnesium substrate obtained by anodizing the surface thereof and forming an anodized film was produced.

[Comparative Example 2]

The same sample as in Example 1 was used, and the reaction was carried out under normal pressure in a stainless steel open vessel instead of the reaction under high pressure in a sealed container made of stainless steel, except that the same procedure as in Example 1 was carried out. Conditions A magnesium substrate having a hydroxide layer formed on its surface was produced.

[Comparative Example 3]

A sample of the magnesium substrate on which the surface before the rust-preventing treatment step of Example 1 was not subjected to rust-preventing treatment was used.

[evaluation method]

In order to evaluate the rust resistance and hardness of the above Example 1 and Comparative Examples 1 to 3, the following test methods were used.

1. Salt spray test (continuous spray test)

(1) Test method: The JIS Z 2371 salt spray test method was used as a standard.

(2) Test conditions: neutral salt spray (pH 6.5~7.2), spray chamber temperature 35±2°C, water temperature in air-saturated container 47±2°C, salt spray time 48 hours.

(3) Test apparatus: manufactured by SUGA test machine (share), salt spray test machine STP-90V2.

2. Hardness test (depending on the hardness of the press-in, Vickers hardness)

(1) Test method: The measurement depends on the hardness of the press-in.

(2) Test conditions: test force 10 mN, test force increased by 20 seconds, creeping force of 5 seconds, and test force reduced by 20 seconds.

(3) Test apparatus: A film hardness tester HM500 was manufactured by Fischer Instruments.

3. Hardness test (compression test) depending on the amount of press-in

(1) Test method: The test piece was compressed using a flat platen.

Figure 2 is a photograph of a substitute of the figure showing the state of the compression test. As shown in the figure, the molded article 10 of the magnesium base material of Example 1 and Comparative Examples 1 to 3 is placed above the stage 30 in a dome shape, and the pressing member 20 is moved in the vertical downward direction. The test force has become a point of 0.1 N as the position of the displacement of 0 mm, and the test force at the position where the displacement is 1.2 mm is read, that is, from The magnitude of the force applied to the pressing member 20 in the vertical direction of the molded article 10 is obtained. The test speed at which the pressing member 20 was moved in the vertical downward direction was set to 1 mm/min.

The results of evaluation of the rust preventive properties and hardness of the magnesium base materials of Example 1 and Comparative Examples 1 to 3 using the test methods of the above 1 to 3 are shown in Table 1.

※※ The test force (N) at a position of 1.2 mm.

Salt spray

Fig. 3 is a photograph showing a substitute of the state after the salt spray test of each of the samples of Example 1 and Comparative Examples 1 to 3 before and after the salt spray test. In Example 1 and Comparative Example 3, a salt spray test was performed on three magnesium substrates, and Comparative Examples 1 and 2 were subjected to a salt spray test on four magnesium substrates.

As shown in FIG. 3, the magnesium base materials of Comparative Example 1 and Comparative Example 2 were all rust-like in the same manner as the magnesium base material of Comparative Example 3 to which no surface treatment was applied. On the other hand, the magnesium base material of Example 1 did not rust even after the salt spray test, and the appearance before and after the salt spray test hardly changed. From this result, it is understood that the rust-preventing property of the hydroxide layer on the surface is improved by performing the rust-preventing treatment step under high pressure conditions, and the corrosion resistance (rust resistance) of the magnesium substrate is improved.

2. Hardness test (depending on the hardness test of the press-in)

The results of measuring the hardness of Example 1 and Comparative Examples 1 to 3 by the above method are shown in Table 1. The values in Table 1 are the average values of the results of each of the three samples.

According to the results shown in Table 1, Example 1 in which a hydroxide layer was formed on the surface of a magnesium substrate under high pressure conditions, and Comparative Example 3 (untreated magnesium substrate) on which the surface was not subjected to rust prevention treatment In comparison, the hardness is increased by nearly three times.

In contrast, a comparative example of the surface of the magnesium substrate treated by anodizing 1. The hardness is lower than that of Comparative Example 3. Further, Comparative Example 2 in which a hydroxide layer was formed on the surface of a magnesium substrate under normal pressure under normal pressure conditions was not used, and the hardness was the same as that of Comparative Example 3 (untreated magnesium substrate).

3. Hardness test (compression test) depending on the amount of press-in

Fig. 4 is a graph showing the results of the compression test, in which the horizontal axis shows the amount of depression and the vertical axis shows the test force at that point in time. The test force read in the position of 1.2 mm (displacement 1.2 mm) of Fig. 4 is shown in Table 1.

From the results of the compression test, it is understood that Example 1 in which the hydroxide layer is formed on the surface of the magnesium substrate in the rust-preventing treatment step is the hardest. Although Comparative Examples 1 and 2, which were not subjected to surface treatment under high pressure conditions but under normal pressure conditions, were harder than Comparative Example 3 which was not subjected to surface treatment, but when compared with Example 1, The increase in the test force is small. Specifically, in Example 1, the test force was increased by 1.1 N as compared with Comparative Example 3, whereas in Comparative Examples 1 and 2, only 0.3 N and 0.4 N were increased.

According to the results of Example 1 and Comparative Examples 1 to 3, it is understood that the magnesium substrate having the hydroxide layer formed on the surface (Example 1) can be used to produce an acoustic magnesium having the following properties by using the production method of the present invention. Vibrating plate.

(1) As a result of the specified salt spray test, since the magnesium substrate having the hydroxide layer formed on the surface (Example 1) did not show rust at the time of 48 hours, it was high. Rust resistance (corrosion resistance).

(2) Since the surface hardness of the magnesium substrate (Example 1) having the hydroxide layer formed on the surface is higher than that of the untreated magnesium substrate (Comparative Example 3), it can be improved as a vibrating body. Required characteristics.

(3) By having a high hardness, the magnesium base material can be thinned and the acoustic vibrating plate can be formed lightly. Thereby, improvement in acoustic characteristics can be expected.

(industrial availability)

According to the method for producing an acoustic magnesium vibration plate of the present invention, the rust prevention property can be improved, and the magnesium base material itself used for the acoustic magnesium vibration plate can be formed thin by the strength of the magnesium base material. Lightweight.

Further, by performing the rustproof treatment after the trimming step, the end surface treatment step can be saved, and the productivity of the production of the acoustic magnesium diaphragm can be greatly improved.

Claims (9)

A method for producing an acoustic vibrating plate for acoustic use includes a rust-preventing treatment step of forming a hydroxide on a surface of a magnesium substrate immersed in an alkaline aqueous solution under a high pressure condition higher than a normal pressure. The method for producing an acoustic magnesium vibration plate according to claim 1, wherein the rust-preventing treatment step is performed in a sealed container. The method for producing an acoustic magnesium vibration plate according to claim 2, wherein the reaction temperature in the rust-preventing treatment step is in a range of from 50 ° C to 300 ° C, and the pressure is in a range of from 1.1 to 350 . The method for producing an acoustic magnesium vibration plate according to any one of claims 1 to 3, wherein the magnesium substrate before the treatment in the rust-preventing treatment step has a thickness of 1 mm or less. The method for producing an acoustic magnesium vibration plate according to any one of claims 1 to 3, wherein the rust-preventing treatment step is to form the oxidized hydroxide in a range of 0.01 μm or more and 20 μm or less in thickness on the surface of the magnesium base material. Layer of matter. The method for producing an acoustic magnesium vibration plate according to any one of claims 1 to 3, wherein the rust-preventing treatment step is provided with a molded sheet of a magnesium base material composed of a magnesium or magnesium-based alloy. The step of cutting the edge of the magnesium substrate. The method for producing an acoustic magnesium vibration plate according to any one of claims 1 to 3, wherein after the rust-preventing treatment step, there is provided Or a step of cutting the magnesium substrate from the formed sheet of the magnesium substrate composed of the magnesium-based alloy. The method for producing an acoustic magnesium vibration plate according to any one of claims 1 to 3, wherein the rust-preventing treatment step forms the hydroxide layer on a surface of the magnesium substrate, and the magnesium substrate is A hydroxide layer is formed inside. A sound magnesium plate for acoustic use has a hydroxide layer formed on a surface of a magnesium base material, and the hydroxide layer is formed inside the magnesium base material.