JPH04119941A - Production of crystallized glass - Google Patents

Abstract

PURPOSE:To obtain a crystallized glass having heat resistance and high hardness by subjecting a crystallized glass components composed essentially of SiO2, Al2O3, and Y2O3, and containing specific metal oxides as nucleating agents to melting and then to slow cooling. CONSTITUTION:Crystallized glass components which has a composition containing, by weight, 5-50% SiO2, 5-70% Al2O3, and 10-70% Y2O3 as essential components and also containing 0.1-30% of one or more additives among MgO, TiO2, ZrO2, La2O3, etc., as nucleating agents are melted and slowly cooled, or a melt prepared by melting is rapidly cooled, and the resulting glass is subjected to heat treatment at 900-1250 deg.C for <=100hr, by which microcrystals can be precipitated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing crystallized glass that has high hardness, excellent heat resistance, and corrosion resistance, and particularly relates to a method for producing crystallized glass that is highly hard, heat resistant, and corrosion resistant. The present invention relates to a method for producing the same glass, which can be advantageously applied to the production of the same glass.

[Conventional technology]

Although conventional glass is easy to manufacture, it has the disadvantage of softening at high temperatures of several hundred degrees Celsius or higher. Among them, SjO□,
Glasses whose main components are AlzOs and Y2O- have a melting point of about 1350°C or higher and can be used up to relatively high temperatures, but they still have the drawback of softening at temperatures above 900°C. On the other hand, sintered bodies such as alumina can be used up to even higher temperatures, but they must be sintered at a high temperature of about 1700° C., which has the disadvantage of being expensive.

[Problem that the invention seeks to solve]

In view of the above-mentioned technical level, the present invention improves heat resistance by several hundred degrees Celsius by precipitating a large amount of microcrystals of alumina, garnet, etc. in order to reduce the effect of softening of glass at high temperatures.
By making the raw material powder into fine powder and mixing it uniformly in advance, the time required for homogenization heat treatment with high-temperature melt can be shortened, making it possible to use it even at relatively high temperatures. The present invention aims to provide a method for obtaining crystallized ceramics in which homogeneous and fine crystals are dispersed while shortening the process at higher temperatures. In addition, in order to precipitate many fine crystals, it is generally necessary to generate many crystal nuclei, so by adding substances that tend to become crystal nuclei for crystal growth as additives, the crystallization of glass is promoted. This is intended to provide a possible method.

For this reason, the present invention involves producing ceramics with various compositions and first experimentally determining the compositional range of the coexistence region of the solid phase and liquid phase at high temperatures, which is necessary to produce crystallized glass. The team then clarified the conditions for crystallizing the glass phase.

[Means for solving problems]

The present invention has SiO2: 5 to 50% by weight, A120°:
5-70%, Y, 0. : A crystallized glass component containing 10 to 70% as a main component and 0.1 to 30% of one or more of additives such as MgO, TiO2, ZrO7 as a nucleating agent is melted and slowly cooled. Alternatively, the glass obtained by rapidly cooling a molten solution is heat-treated at a temperature of 900 to 1250° C. for up to 100 hours to precipitate microcrystals to produce crystallized glass. In addition, in the present invention, in order to uniformly mix the powder having the above composition in advance, 100 parts by weight of the raw material fine powder having an average particle size of 0.1 to 300 μm,
20 to 150 parts by weight of water or an organic solvent such as alcohol, benzene, or xylene as a solvent, and 0.1 part of an organic component such as water-soluble acrylic resin, polyethylene glycol, polyethylene amine, or anionic polymer to uniformly disperse the powder. After adding ~10 parts by weight and mixing to uniformly mix and disperse the ceramic powder, the solvent was evaporated to obtain a homogeneously mixed powder.
After degreasing by heating to a temperature of
This is a method for producing crystallized glass in which microcrystals are precipitated by heat treatment at a temperature of 00 to 1250°C for up to 100 hours.

[Effect]

Glasses whose main components are Al2O3, Y2L, Sl[+□ and which do not contain alkali metals such as Na, etc.
Compared to normal alkali glass, it has a higher softening temperature and melting point, but in order to improve properties such as heat resistance and hardness, it is necessary to produce crystals such as alumina Al2O3 and garnet Al5Y30.2, which have high hardness. It is necessary to precipitate it. Therefore, by optimizing the composition range of the main components, the amount of the nucleating agent added, and the method of mixing the raw material fine powder, the desired objective could be achieved. The effect will be explained below.

(1) 5ID2: 5-50% by weight as the main component, A
12 [+3: 5-70%, Y, 03: 10-7
Contains 0%. With compositions other than this, either no glass is produced, or the amount of liquid phase produced is very small in the high-temperature solid-liquid coexistence state, and only a sintered body is produced, so the sample cannot be obtained unless heated to a high temperature of around 1700°C. It has disadvantages that cannot be avoided. Note that within this composition range, in order to precipitate a large amount of crystals such as alumina and garnet, it is particularly necessary to select the S10□ concentration from 5 to 30%.

(2) MgD, TlO2, ZrDz as nucleating agents
, 0.1 to 30% of one or more oxides such as La2O5
Added.

If the amount added is less than 0.1%, the effect of promoting crystallization is not so great, and if it is added in an amount of 30% or more, the problem is that the melting point becomes lower than the effect of promoting crystallization, which is not preferable. Furthermore, since the melting point of the glass decreases as more types of additives are added, it is preferable to use only one type of nucleating agent if possible. The effect of the nucleating agent is that the additive dissolves in the glass to form a multi-component solid solution and strengthens the tendency of the glass to undergo microscopic phase separation through crystallization heat treatment. It was confirmed in the Examples described later that it works to promote the precipitation of crystals.

(3) Crystallization heat treatment is performed by heating to 900-1250℃,
Hold within 00 hours. If no nucleating agent is added, crystallization occurs at a temperature of about 1000-1270°C, but
If a nucleating agent is added, crystallization can be performed at even lower temperatures.

Further, the heat treatment time may be within 100 hours. This means that even by heating to that temperature, crystallization partially progresses, and 10
Since crystallization is completed within a heat treatment time of 0 hours, the degree of crystallinity does not increase even if heat treatment is performed any further. In addition, in order to promote crystallization, in addition to heating the glass to a high temperature again, it is possible to cool the melt heated to a high temperature in an electric furnace at a cooling rate of 20°C.
A similar effect can be obtained even if the cooling is performed at a slow rate of less than /min.

(4) The process for uniformly mixing raw material fine powder has the following effects. The particle size of the raw material powder is 0.1-3
00 μm. Ultrafine particles finer than this are expensive, and coarse particles larger than this require a long melting time to make the glass homogeneous during melting, and are therefore unsuitable.

Preferably, by using a powder with a particle size of about submicron, the melting time during production can be shortened. 100 parts by weight of raw material powder, 20 to 150 parts by weight of solvent, 0 parts by weight of organic matter
．． Add 1 to 10 parts by weight. If the amount of solvent is less than 20, the fluidity of the mixture is poor, and even if more than 150 is added, the mixture remains a suspension, and there is no need to add any more solvent. The organic substance only needs to have the effect of mainly dispersing the powder, so if the amount added is less than 0.1, the effect will be small, and if it is more than 10, the degreasing time will become longer, leading to the problem that more than the necessary amount is added. be.

It is preferable that the raw material powder mixing step be performed as described above.

(5) If the resulting powder mixture containing organic components is heated to 300 to 700°C in the air or under reduced pressure, the organic components will decompose and vaporize, resulting in degreasing, but this step involves heating the powder in an electric furnace. However, it may be a part of the melting process, and there is no need to specifically set a degreasing process. Also, heat the powder,
The melting conditions are, for example, a temperature of 1300 to 1500°C.
．． It can be heated in an aluminum crucible for 1 to 5 hours. In order to produce glass, it is necessary for a liquid phase to appear at a high temperature, and therefore the heating temperature does not need to be particularly limited as it is the temperature at which a melt appears. When the solvent used is water, the organic component is preferably a water-soluble acrylic resin, an anionic polymer, etc., and if the solvent is an organic solvent, a polymer such as polyethyleneimine or a surfactant that is soluble in the solvent can be used. Note that dispersing in water is cheaper in terms of cost.

〔Example〕

An example of crystallized glass produced as an example of the present invention will be described below.

As shown in Table 1, 50 parts by weight of water and 2 parts by weight of anionic polymer were added to 100 parts by weight of raw powder with a predetermined composition of submicron particle size, and the powder was mixed in a container for 20 hours.
100 parts by weight of ethanol and 2 parts by weight of polyethyleneamine were added as a solvent and mixed for 20 hours to prepare a powder.

These powders are 0. After heating and holding at 500° C. for 1 hour in a vacuum of I Torr, variations in the diffraction intensity of the powder were examined by X-ray diffraction, and it was confirmed that the powders were all mixed uniformly.

This mixed powder was placed in an aluminum crucible, heated and held at 1500 t' for 1 hour, and then rapidly cooled.
After heat treatment at 00° C. for 2 hours, crystallized glass as shown in Table 2 was obtained.

In addition, as another example, white crystallized glass could be similarly obtained by heating and melting sample 4 at 1500° C. for 1 hour and then slowly cooling it at a rate of 10° C./min.

As shown in Table 2, when a nucleating agent is added, the crystallization initiation temperature (
Sample 4.5.6) was seen to be lower than additive-free sample (8), so MgO, TlO2, Z
It has been found that oxides such as rL are effective in promoting crystallization. When synthesizing glass from powder with a particle size of about 100 μm using the conventional method, it was necessary to hold it in a molten state for a long time in order to create a uniform glass. If you let me, 1
It was found that a sufficiently homogeneous glass could be obtained by heating at 500° C. for about 0.1 hour, indicating that the present invention using fine raw material powder is highly effective. The glass transition temperature of the obtained glass is about 900°C, but by precipitating a large amount of crystals, the crystallization temperature can be raised to about 1000°C. It turns out that it can be obtained by a simple method of simply heating. Note that the amount of S10° is 3 in 2 in the glass.
It was found that at 0 to 50%, crystalline Sin precipitates in the glass, and at more than that, it shifts from the vitrified region. Furthermore, when glasses of various compositions are crystallized, the hardness of Al2O2, A15Y30. It has been found that in order to precipitate microcrystals of , the 5in2 concentration needs to be 30% or less.

[Effects of the invention] By using fine powder as a raw material and adding a nucleating agent, it is possible to produce heat-resistant and highly hard crystallized glass, which has industrial utility value such as wear-resistant parts that can be used at high temperatures. is high. In particular, by uniformly dispersing fine powder in advance, the present invention has the effect of reducing manufacturing costs by simplifying the glass melting process, and furthermore, the present crystallized glass is alkali-free, chemically stable compared to normal alkali glass, and has improved durability even in corrosive atmospheres, making it useful.

Claims (2)

[Claims] (1) In weight%, SiO_2: 5-5%, Al_2O_
3:5 to 70%, Y_2O_3: 10 to 70% as main components, MgO, TiO_2, ZrO_2, La
0.1-30% of one or more additives such as _2O_3
By melting the crystallized glass component contained as a nucleating agent,
1. A method for producing crystallized glass, characterized in that glass obtained by slow cooling or rapid cooling of a molten solution is heat-treated at a temperature of 900 to 1250° C. for up to 100 hours to precipitate microcrystals. (2) In order to uniformly mix the powder having the composition of claim (1) in advance, add 20 parts by weight of water or an organic solvent as a solvent to 100 parts by weight of the raw material fine powder with an average particle size of 0.1 to 300 μm.
~150 parts by weight, and 0.1 to 10 parts by weight of organic components such as water-soluble acrylic resin, polyethylene glycol, polyethylene amine, anionic polymer, etc. to uniformly disperse the powder.
After adding parts by weight and mixing to uniformly mix and disperse the ceramic powder, the solvent was evaporated to obtain a homogeneously mixed powder, which was heated to a temperature of 300 to 700 ° C. to degrease it, and then A crystallized glass characterized by precipitating microcrystals by melting at a high temperature and slowly cooling, or by heat-treating the glass obtained by rapidly cooling a molten solution at a temperature of 900 to 1250°C for within 100 hours. Production method.