JPH1129355A - Polycrystalline magnesium oxide vacuum-deposition material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polycrystalline MgO vacuum-deposition material capable of forming a MgO film having an approximately uniform thickness substantially without generating a splash, even when subjected to a vacuum-deposition treatment by an electron beam method. SOLUTION: This polycrystalline MgO vacuum-deposition material comprises sintered pellets 11 having a MgO purity of >=99.5% and a relative density of >=96% and formed in a spherical shape. The crystal particle diameters of the pellets are 1-500 μm. Si and Al impurities are contained it the pellets 11 in element concentrations of <=200 ppm and <=200 ppm, respectively. Ca, Zn and Fe impurities are also contained in element concentrations of <=250 ppm, <=150 ppm and <=50 ppm, respectively. Cr, V and Ni impurities are also contained in element concentrations of <=10 ppm, <=10 ppm and <=10 ppm, respectively. Na, K and C impurities are more also contained in element concentrations of <=20 ppm, <=20 ppm and <=70 ppm, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polycrystalline M suitable for forming an MgO film of an AC type plasma display panel.
The present invention relates to a gO vapor deposition material and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, liquid crystal (Liquid Crystal Display):
Research and development and commercialization of various flat displays, including LCDs, are remarkable, and their production is increasing rapidly. Recently, color plasma display panels (PDPs) have been actively developed and put into practical use. PDPs are easy to increase in size, are at the shortest distance from large screen wall-mounted televisions for high-definition televisions, and prototypes of 40-inch diagonal PDPs have already been developed. PDPs are classified into an AC type in which a metal electrode is covered with a glass dielectric material in terms of an electrode structure, and a DC type in which a metal electrode is exposed in a discharge space.

At the beginning of the development of the AC type PDP, since the glass dielectric layer was exposed to the discharge space, the glass dielectric layer was directly exposed to the discharge, and the surface of the dielectric layer was changed by ion bombardment, and the discharge starting voltage was lowered. Was rising. For this reason, attempts have been made to use various oxides having high sublimation heat as protective films for the dielectric layer. This protective film plays an important role because it is in direct contact with the discharge gas. That is, the characteristics required for the protective film are a low discharge voltage, resistance to sputtering during discharge, fast discharge responsiveness, and insulation. Materials satisfying these conditions include M
gO is used for the protective film. This protective film made of MgO protects the surface of the dielectric layer from sputtering at the time of discharge, and plays an important role in extending the life of the PDP.

At present, as the above protective film of AC type PDP,
An MgO film formed by an electron beam evaporation method using a crushed single crystal MgO as an evaporation material is known. The MgO film formed by the electron beam evaporation method can be formed at a high speed of 1000 Å / min or more. The crystal orientation of the formed MgO film is such that a film oriented in the (111) plane can be driven at the lowest sustaining voltage, and furthermore, exists in the film (11
1) As the amount of surface increases, the emission ratio of secondary electrons increases,
It is said that the driving voltage also decreases. The single crystal M
The crushed product of gO is obtained by melting MgO clinker having a purity of 98% or more or lightly burned MgO (MgO sintered at 1000 ° C. or less) in an electric arc furnace (arc furnace), that is, into an ingot by electromelting. It is manufactured by taking out a single crystal part from this ingot and crushing it.

[0005]

However, since the above-mentioned conventional crushed single crystal MgO is a rectangular parallelepiped, high energy is locally applied to the edge of the deposition material during electron beam evaporation using the crushed product as a deposition material. When given, the vapor deposition material is scattered (splash), and the vapor deposition efficiency is reduced. In order to prevent the generation of the splash, it is considered effective to increase the size of the vapor deposition material.
Since the crushed product is fragile, it is easy to be pulverized, and it has been difficult to uniformly prepare the crushed product into a certain size larger than the current particle size of 1 to 5 mm. In addition, the conventional single crystal Mg
It has been difficult to uniformly form an MgO film on a large-area glass dielectric layer during electron beam evaporation using a crushed O product as a deposition material, and there has been a problem that the film thickness is not uniform.
As a result, the glass dielectric layer on which the MgO film was formed
In this case, there is a problem that electric characteristics, for example, a discharge starting voltage and a driving voltage are increased or changed.

On the other hand, MgO clinker and lightly burned MgO often use MgCl ₂ obtained from seawater as a raw material, and this MgCl ₂ contains a relatively large amount of Ca, Si, Fe.
And the like, these impurities are contained in the single crystal M
Remains in gO. Further, in the ingot in the production process of the single crystal MgO, the amount of impurities continuously increases from the center of the ingot toward the surface portion. Therefore, the purity of the product varies very easily depending on how the single crystal portion is taken out. As a result, there is a problem that the stability and reliability of the purity of the single crystal MgO are lacking.

In order to solve these problems, a single crystal MgO
Alternatively, a method using polycrystalline MgO may be considered. However, high-density polycrystalline MgO densified by the addition of various sintering aids has a problem that defects are systematically present at crystal grain boundaries, and a problem that the density is lowered when the purity is increased. was there. As a result, MgO was added to the glass dielectric layer by electron beam evaporation using these polycrystalline MgO evaporation materials.
When a film is formed, the amount of orientation of the crystal orientation to the (111) plane is reduced, and the electrical characteristics when this glass dielectric layer is incorporated into a PDP are reduced. Therefore, polycrystalline MgO is used as a vapor deposition material. could not.

An object of the present invention is to provide a polycrystalline MgO vapor deposition material capable of forming a film at high speed and uniformly without generating a splash even when vapor deposition is performed by an electron beam vapor deposition method, and a method for producing the same. Another object of the present invention is to form a deposited Mg
An object of the present invention is to provide a polycrystalline MgO vapor deposition material capable of improving the film characteristics of an O film and a method for producing the same. Still another object of the present invention is to provide a polycrystalline MgO vapor-deposited material that does not powder sintered compacts, has low equipment costs, and is suitable for mass production, and a method for producing the same.

[0009]

The invention according to claim 1 is
As shown in FIG. 1, a sintered compact pellet 1 of polycrystalline MgO having an MgO purity of 99.5% or more and a relative density of 96% or more.
1 and a polycrystalline M in which the pellet 11 is formed in a spherical shape.
gO vapor deposition material. The polycrystalline M according to claim 1
In the case of a gO vapor deposition material, when a MgO film such as an AC-type PDP is formed using a high-purity and high-density polycrystalline MgO sintered pellet 11, a stable film can be formed at a high speed with little splash. Further, since the sintered pellet 11 is formed in a spherical shape, chipping or cracking of the pellet 11 does not occur. As a result, since the pellets 11 are not powdered, the occurrence of splash is further reduced. Therefore, the film thickness distribution can be improved, and an MgO film having substantially uniform film quality can be obtained.

A second aspect of the present invention is the invention according to the first aspect, further characterized in that the crystal grain size of the sintered compact pellet of polycrystalline MgO is 1 to 500 μm. In the polycrystalline MgO vapor-deposited material according to the second aspect, since crystals having various particle sizes within the above range are sintered in a mosaic shape to form a sintered body pellet, the strength and density of the pellet are reduced. As a result, the grain boundaries of adjacent crystal grains are brought into close contact with each other, so that generation of pores at the grain boundaries can be reduced. As a result, the formed MgO film has excellent film properties.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein the impurities of Si and Al contained in the sintered compact of polycrystalline MgO each have an element concentration of 200 ppm or less. , Ca impurities have an element concentration of 250 ppm or less, and Zr impurities have an element concentration of 1 ppm or less.
50 ppm or less, and the impurities of Fe
ppm or less, the impurities of Cr, V and Ni are respectively 10 ppm or less in element concentration, the impurities of Na and K are each 20 ppm or less in element concentration, and the impurity of C is 70 ppm or less in element concentration. Features. In the polycrystalline MgO vapor deposition material according to the third aspect, the impurities contained in the formed MgO film are extremely small, so that the film characteristics of the MgO film are improved.

According to the present invention, as shown in FIGS. 1 and 2, the purity is 99.5% or more and the average particle size is 0.1 to 0.1%.
A step of putting the 3 μm MgO powder into the rotating plate 13b of the tumbling granulator 13 and then granulating the MgO powder by spraying an organic solvent containing a binder to form a spherical compact 14; A step of repeatedly adding MgO powder and spraying an organic solvent containing a binder to grow a spherical molded body 14 to a predetermined size; and a step of sintering the grown molded body 14 at a predetermined temperature. Polycrystalline M containing
This is a method for producing a gO vapor deposition material. In the method for producing a polycrystalline MgO vapor deposition material according to claim 4, the MgO purity described in claim 1 is 99.5% or more and the relative density is 96.
% Or more of the polycrystalline MgO sintered body pellets 11 can be obtained.

The invention according to claim 5 has a purity of 99.5%.
A step of kneading and crushing the MgO powder having an average particle diameter of 0.1 to 3 μm and a binder, and putting the MgO powder containing the crushed binder into a rotary dish of a tumbling granulator, followed by an organic solvent. To form a spherical molded body by granulating MgO powder by spraying
Polycrystalline MgO deposition including a step of growing a spherical molded body to a predetermined size by repeating an operation of adding gO powder and spraying an organic solvent, and a step of sintering the grown molded body at a predetermined temperature. It is a method of manufacturing a material. Claim 5
In the method for producing a polycrystalline MgO vapor-deposited material according to the present invention, the MgO purity is 9
9.5% or more and polycrystalline MgO having a relative density of 96% or more
Of polycrystalline MgO can be obtained. In addition, the spherical molded body is 1250-1350 ° C.
After primary sintering at a temperature of 1500 to 1650
It is preferable to perform secondary sintering at a temperature of ° C.

[0014]

Embodiments of the present invention will now be described with reference to the drawings. As shown in FIG. 1, the polycrystalline MgO vapor deposition material of the present invention has a MgO purity of 99.5% or more, more preferably 99.9% or more, and a relative density of 96% or more, more preferably 97.5% or more. Of sintered compact pellets 11 of polycrystalline MgO. The sintered body pellet 11 is formed in a spherical shape. The diameter of the pellet 11 is 1 to 10 m
m, preferably in the range of 3 to 6 mm. The reason why the diameter of the pellet 11 is limited to the above range is that the moldability is good and the handling is convenient. Further, the crystal grain size of the sintered pellet 11 is preferably in the range of 1 to 500 μm. The crystal grain size of the pellets 11 is limited to 1 to 500 μm because crystals of various sizes within this range are sintered in a mosaic shape, so that the strength is increased and the grain boundaries of adjacent crystal grains are closely adhered. This is because the generation of pores at the grain boundaries can be reduced.

The impurities (Si, Al, Ca, Zr, Fe, Cr,
V, Ni, Na, K and C) content is 850p in total
pm or less. The individual contents of the impurities are as follows: the impurities of Si and Al are each 200 ppm or less in elemental concentration, the impurities of Ca are 250 ppm or less in elemental concentration, and the impurities of Zr are 150 ppm or less in elemental concentration. Fe impurity is 5 in elemental concentration
0 ppm or less, impurities of Cr, V and Ni are each 10 ppm or less in element concentration, impurities of Na and K are each 20 ppm or less in element concentration, and impurities of C are 70 ppm or less in element concentration. preferable. If each of the above impurities exceeds the above value in the element concentration, Mg
When a glass substrate on which an O vapor deposition material is formed by an electron beam vapor deposition method is incorporated into a panel, the film quality varies, so that electrical characteristics, for example, a driving voltage becomes high or becomes unstable. There is.

A method of manufacturing the polycrystalline MgO vapor deposition material having the above-described structure will be described with reference to FIGS. First, MgO having a purity of 99.5% or more and an average particle size of 0.1 to 3 μm is obtained in a state where the rotating plate 13b of the rotating plate-type tumbling granulator 13 is rotated in the direction shown by the solid arrow in FIG. Powder on rotating dish 1
After being put in 3b, the organic solvent including the binder is sprayed with the sprayer 13f while watching that the MgO powder flows uniformly on the inclined bottom of the rotating plate 13b, that is, moves up and down if the MgO powder rolls. As a result, while the MgO powder becomes core particles and moves up and down in the rotating plate 13b, the core particles are combined with each other and tightened to form a spherical molded body 14 having a high raw density.

Here, the average particle size of the MgO powder is 0.1 to
The reason why the diameter is limited to 3 μm is that if the diameter is less than 0.1 μm, the powder is too fine and agglomerates, so that the handling of the powder is deteriorated. It is not possible. Also M
When the average particle size of the gO powder is limited to the above range, there is an advantage that a desired sintered body pellet 11 can be obtained without using a sintering aid. It is preferable to use polyethylene glycol or polyvinyl butyral as a binder and to use ethanol or propanol as an organic solvent. It is sufficient to add 0.2 to 2% by weight of the binder.

The rotary dish-type rolling granulator 13 of this embodiment
As shown in detail in FIG. 2, a rotating shaft (not shown) is attached to the support base 13a so as to be capable of changing the inclination angle and rotatable, and a rotating plate having an inclined flat bottom fixed to the tip of the rotating shaft. 13b and a molded-body shooter 13 connected to a molded-body outlet 13c formed on the periphery of the rotating plate 13b.
d. The MgO powder is used as a raw material shooter 13e.
Is supplied to the rotating plate 13b, and the organic solvent containing the binder is configured to be sprayed from the plurality of nozzles 13g of the sprayer 13f. The plurality of nozzles 13g are connected to a pipe (not shown). Reference numeral 13h in FIG.
b is a side scraper for scraping off the granulated powder adhered to the inner peripheral surface of b.

Next, MgO powder is further charged from the raw material shooter 13e into the rotating plate 13b and a plurality of nozzles 13g are provided.
Is sprayed with an organic solvent containing a binder. As a result, the spherical compact 14 grows. By repeating this operation, a compact 14 having a sufficiently high density and a predetermined particle size (predetermined diameter) close to a true sphere can be obtained. The molded body 14 having a predetermined size is used as the molded body shooter 13.
Rolled and discharged from d. Since the molded body 14 is not molded by pressure as in a mechanical press (die pressing method), the molded body 14 is not strongly rubbed or compressed with a mold, and the molded body 14 does not contain impurities. In the die pressing method, a spray dryer is required as a pretreatment for press molding.
The use of No. 3 eliminates the need for a spray dryer, so the equipment cost is low and suitable for mass production.

Further, the spherical molded body 13 is sintered at a predetermined temperature. Before sintering, the compact 13 is heated to 350 to 620 ° C.
It is preferable to perform a degreasing treatment at a temperature of This degreasing treatment is performed to prevent color unevenness after sintering of the molded body 13,
It is preferable to perform the treatment sufficiently over time. Sintering 125
Primary sintering performed at a temperature of 0 to 1350 ° C. for 1 to 5 hours, followed by further heating to a temperature of 1500 to 1650 ° C.
This is performed by two-stage sintering including secondary sintering performed for 10 hours.

When the temperature of the molded body 13 is first raised for primary sintering, sintering starts at 1200 ° C., and proceeds considerably at 1350 ° C. By primary sintering at this temperature,
Even if the grain size is large, there is no sintering unevenness (difference in microstructure) between the surface and the inside, and the sintered body is subjected to secondary sintering at a temperature of 1500 to 1650 ° C., whereby the relative density is close to 100%. 11 is obtained. As a result, when the high-purity and high-density sintered MgO pellets 11 of the present invention are formed on a plasma display panel, the pellets 11 are spherical. A membrane is obtained.

In this embodiment, a rotary dish type rolling granulator having a flat bottom rotating dish has been described, but a rotary dish type rolling granulator having a multi-stage, deformed or spherical bottom rotating dish. Machine. Further, the heating rate during the two-stage sintering is set to 20 to 30 ° C.
If the time is slowed down, the density can be further increased. Further, in this embodiment, the molded body is sintered by two-stage sintering, but the molded body may be sintered by single-stage sintering at a sintering temperature of 1500 to 1650 ° C.

Next, another method for producing the polycrystalline MgO vapor deposition material of the present invention will be described. First, MgO powder having a purity of 99.5% or more and an average particle size of 0.1 to 3 μm and a binder are kneaded and crushed to a predetermined particle size. As the binder, it is preferable to use polyethylene glycol or polyvinyl butyral, and the amount of the binder is 0.2 to 2% by weight.
It is preferred that The average particle size after crushing is 10
It is preferable that it is within the range of 100 μm. Next, after putting the crushed MgO powder containing the binder into the rotating plate of the tumbling granulator, the organic solvent is sprayed with a sprayer while watching that the MgO powder containing the binder moves up and down if it rolls. It is preferable to use ethanol, propanol, or the like as the organic solvent. As a result, similarly to the first embodiment, while the MgO powder becomes core particles and moves up and down in the rotating dish, the core particles are connected to each other and tightened to form a spherical particle having a high raw (green) density. A compact is formed.

In this embodiment, the rotating dish-type rolling granulator having the inclined rotating dish of the first embodiment or the rotating dish-type rolling granulator having the horizontal rotating dish is used. Next, MgO powder containing a binder is further put into the above rotating dish, and an organic solvent is sprayed. As a result, the spherical shaped body grows, and by repeating this operation, a shaped body having a predetermined size, that is, a predetermined diameter can be obtained. The following sintering steps are the same as those in the first embodiment, and a repeated description will be omitted.

[0025]

As described above, according to the present invention, the polycrystalline MgO vapor deposition material is formed of sintered polycrystalline MgO pellets having an MgO purity of 99.5% or more and a relative density of 96% or more. Since this pellet was formed into a spherical shape,
When an MgO film such as an AC-type PDP is formed by using the high-purity and high-density sintered polycrystalline MgO pellet, an MgO film having a substantially uniform film thickness can be formed efficiently with little splash. Obtainable. Further, by forming the sintered body pellets into a spherical shape, chipping or cracking of the pellets does not occur, so that the pellets are not powdered and the occurrence of splash is further reduced. As a result, even if the film area of the MgO film is large, the film can be formed substantially uniformly. For example, when the glass dielectric layer on which the MgO film is formed is incorporated in the PDP, the discharge starting voltage and the driving voltage are reduced. The voltage can be kept low and constant, and the electrical characteristics of the PDP can be improved.

Further, when the crystal grain size of the sintered polycrystalline MgO pellet is formed in the range of 1 to 500 μm, crystals having various grain sizes within this range are sintered in a mosaic shape to form a sintered pellet. Therefore, the strength and density of the pellets are increased, and the grain boundaries of adjacent crystal grains are brought into close contact with each other, so that generation of pores at the grain boundaries can be reduced. As a result, the deposited MgO
The film has excellent film properties. Further, the impurities of Si and Al contained in the sintered body pellets of polycrystalline MgO are respectively 200 ppm or less in element concentration, the impurities of Ca are 250 ppm or less in element concentration, and the impurities of Zr are 1 element in concentration.
To 50 ppm or less, the impurity of Fe should be
m, the impurities of Cr, V and Ni are each reduced to an element concentration of 10 ppm or less, the impurities of Na and K are each reduced to an element concentration of 20 ppm or less, and the impurity of C is reduced to an element concentration of 70 ppm or less. Since the impurities contained in the MgO film become extremely small, the film characteristics of the MgO film are improved.

Further, MgO powder having a purity of 99.5% or more and an average particle diameter of 0.1 to 3 μm is put in a rotating dish of a tumbling granulator, and then an organic solvent containing a binder is sprayed thereon to make the MgO powder. The operation of granulating to form a spherical molded body, further adding MgO powder to a rotating dish and spraying an organic solvent containing a binder is repeated to grow the spherical molded body to a predetermined size, and the grown molding is formed. If the body is sintered at a certain temperature,
MgO purity of 99.5% or more and relative density of 96%
Polycrystalline M made of sintered pellets of the above polycrystalline MgO
A gO vapor deposition material can be obtained. Further 99.5% purity
As described above, MgO powder having an average particle size of 0.1 to 3 μm and a binder are kneaded and crushed, and M containing the crushed binder is mixed.
The gO powder is put into a rotating dish of a tumbling granulator, and then the organic solvent is sprayed to granulate the MgO powder to form a spherical molded body. Even when the operation of spraying the solvent is repeated, the spherical molded body is grown to a predetermined size, and the grown molded body is sintered at a predetermined temperature.

[Brief description of the drawings]

FIG. 1 is a front view of a sintered pellet of polycrystalline MgO according to an embodiment of the present invention.

FIG. 2 is a front view of a rotary dish type rolling granulator for forming a slurry.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Sintered body pellet 13 Rotary dish-type rolling granulator 13b Rotating dish 14 Molded

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[Procedure amendment]

[Submission date] October 27, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0027

[Correction method] Change

[Correction contents]

Further, MgO powder having a purity of 99.5% or more and an average particle diameter of 0.1 to 3 μm is put in a rotating dish of a tumbling granulator, and then an organic solvent containing a binder is sprayed thereon to make the MgO powder. granulated molding a molded article of spherical, further put MgO powder in time Utatesara and repeated the work of spraying an organic solvent containing a binder to grow compact of spherical predetermined size, grown molding If the body is sintered at a predetermined temperature, the polycrystalline Mg composed of a sintered body pellet of polycrystalline MgO having a purity of 99.5% or more and a relative density of 96% or more is obtained.
An O vapor deposition material can be obtained. Further, the binder is kneaded with MgO powder having a purity of 99.5% or more and having an average particle diameter of 0.1 to 3 μm and crushed, and Mg containing the crushed binder is mixed.
The O powder is put into a rotating plate of a tumbling granulator, and then an organic solvent is sprayed to granulate the MgO powder to form a spherical molded body. Even when the operation of spraying the solvent is repeated, the spherical molded body is grown to a predetermined size, and the grown molded body is sintered at a predetermined temperature. ────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] December 18, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 4

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

According to the present invention, as shown in FIGS. 1 and 2, the purity is 99.5% or more and the average particle size is 0.1 to 0.1%.
A step of forming a spherical compact by granulating the MgO powder by spraying an organic solvent containing a binder after putting the 3 μm MgO powder into the rotating plate 13b of the tumbling granulator 13 ; Further, a step of repeating the operation of adding the MgO powder and spraying the organic solvent containing the binder to grow the spherical compact 14 to a predetermined size, and a step of sintering the grown compact 14 at a predetermined temperature. Containing polycrystalline Mg
This is a method for producing an O vapor deposition material. In the method for producing a polycrystalline MgO vapor deposition material according to claim 4, the MgO purity according to claim 1 is 99.5% or more and the relative density is 96%.
A polycrystalline MgO vapor deposition material composed of the above-described sintered pellet 11 of polycrystalline MgO can be obtained.

Claims (6)

[Claims] 1. A polycrystalline MgO sintered body pellet (11) having a MgO purity of 99.5% or more and a relative density of 96% or more, wherein said pellet (11) is formed into a spherical shape.
gO vapor deposition material. 2. The polycrystalline MgO according to claim 1, wherein the crystal grain size of the sintered polycrystalline MgO pellet is 1 to 500 μm.
Evaporation material. 3. The method according to claim 1, wherein each of Si and Al impurities contained in the polycrystalline MgO sintered pellet has an element concentration of 200%.
ppm or less, and the impurity of Ca is 250
pm or less, and the Zr impurity is 150 pp in elemental concentration.
m or less, the impurities of Fe are 50 ppm or less in elemental concentration, the impurities of Cr, V, and Ni are 10 ppm or less in elemental concentration, and the impurities of Na and K are 20 ppm or less in elemental concentration, respectively. 3. The polycrystalline MgO vapor deposition material according to claim 1, wherein an impurity of the element has an element concentration of 70 ppm or less. 4. 4. A composition having a purity of 99.5% or more and an average particle size of 0.5%.
A rotating dish (13) of a rolling granulator (13)
b) granulating the MgO powder by spraying an organic solvent containing a binder after the step (b) to form a spherical molded body (14), further adding MgO powder to the rotating dish (13b), and Repeating the operation of spraying an organic solvent containing a binder to grow the spherical molded body (14) to a predetermined size; andsintering the grown molded body (14) at a predetermined temperature. A method for producing a polycrystalline MgO vapor-deposited material. 5. The method according to claim 5, wherein the purity is 99.5% or more and the average particle size is 0.5%.
A step of kneading and pulverizing a 1 to 3 μm MgO powder and a binder, and placing the MgO powder containing the pulverized binder in a rotating dish of a tumbling granulator, and then spraying the organic solvent with the MgO powder. The step of granulating the powder to form a spherical molded body, and further adding the MgO powder containing a binder to the rotary dish and spraying an organic solvent to repeat the operation of forming the spherical molded body into a predetermined size. A method for producing a polycrystalline MgO vapor deposition material, comprising: a step of growing; and a step of sintering the grown compact at a predetermined temperature. 6. After a spherical molded body is primarily sintered at a temperature of 1250-1350 ° C., the temperature is raised to 1500-1650 ° C.
The polycrystalline Mg according to claim 4 or 5, wherein secondary sintering is performed at a temperature of
Manufacturing method of O vapor deposition material.