JP3156733B2 - Black quartz glass, method for producing the same, and jig using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a black quartz glass used for a spectrophotometer cell and the like, and more particularly, to a black quartz glass obtained by uniformly dispersing a transition metal oxide in silica glass, and a black quartz glass obtained therefrom. The present invention relates to a manufacturing method and a jig using the black quartz glass.

[0002]

2. Description of the Related Art Conventionally, black quartz glass or white opaque quartz glass has been used as a material for a cell for a spectrophotometer or a high-temperature material such as a furnace core tube for a semiconductor.

Among them, a black quartz glass containing vanadium pentoxide has been disclosed (Japanese Patent Application Laid-Open No. Sho.
4-157121).

[0004]

However, when black quartz glass containing vanadium pentoxide is subjected to a heat treatment at 1000 ° C. or more, a crystallized portion is formed in the glass. There are drawbacks such as low yield and high cost.

[0005] Further, for a product requiring a heat treatment step at a higher temperature for glass processing, this crystallization has been a fatal defect.

Although opaque quartz glass used as a high-temperature material for a furnace core tube has an excellent heat-shielding effect as compared with transparent quartz glass, the light-transmitting light per 1 mm in thickness is a light source. Cannot be cut 100%.

[0007] Further, since the structure is made of opaque quartz glass containing bubbles, it is possible to improve the burning property by controlling the bubbles as compared with the case of transparent quartz glass, but the variation in heat diffusion due to the bubbles is avoided. However, the heat generation unevenness of the heating element becomes the heating unevenness as it is, so that a high-performance furnace cannot be expected in a furnace in which the uniformity of the furnace core tube depends on the capability of the furnace.

According to the present invention, heat conduction by light is almost 100%.
It is an object of the present invention to provide a black quartz glass which is cut, has a soaking effect, and does not crystallize even during heat treatment.

[0009]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of intensive studies to solve the above-mentioned object, black quartz glass prepared by performing a gas phase reduction treatment with 500 to 40000 ppm of niobium dioxide as a main coloring source is also available in the wavelengths in the ultraviolet visible region and the infrared region. The inventors have found that they have good light-shielding properties, cut heat conduction by heat rays almost 100%, have a soaking effect, and have found that they do not crystallize even during heat treatment.

In order to obtain the black quartz glass of the present invention, niobium chloride is first dissolved in an alcohol solution, and this solution is added to silica powder for producing quartz glass, which is wetted and dried.

As the silica powder, any one produced by any method such as quartz powder, amorphous silica, one kind of high-purity silicon oxide source such as cristobalite or a mixture thereof can be used.

Then, at 1100 ° C. in an electric furnace in a reducing atmosphere.
The high-temperature heat treatment described above is performed, and the obtained dry powder is melted in a vacuum furnace to obtain quartz glass.

In general, when an oxide is placed under a high temperature even in an inert gas atmosphere, reduction occurs without a reducing atmosphere, but in the case of niobium, this thermal reduction occurs at a normal high temperature. It is unlikely to occur, and heat treatment in a reducing atmosphere is most effective, and the reducing atmosphere is preferably a hydrogen atmosphere in view of the effect and ease of handling.

The obtained quartz glass has a black color and 185
The light transmittance is 1% or less even at a thickness of 1 mm in a wavelength range of ２５25000 nm.

In the production, niobium pentachloride is selected as a starting material because niobium pentoxide is insoluble in water and alcohols and is soluble only in HF in an acid. This is because it is difficult to handle, and even if it is dissolved in HF and put into silica powder, the silica powder is also dissolved.

[0016] Ammonium niobate can be used once it is synthesized, but it is not preferable because the cost is high in view of the labor and purification at the time of synthesis.

On the other hand, niobium pentachloride easily dissolves in an alcohol solution such as ethanol and methanol, and when dried, becomes niobium pentoxide, which can be uniformly dispersed in silica powder.

The silica powder, which is a raw material powder, can be melted even if a powder of about 60 mesh (250 μm) is used, but a fine powder of 150 mesh or more is preferable.
More preferably 200 mesh or more, 200 to 25
It is desirable that 50% to 60% of 0 mesh is included. When this is dissolved with normal powder including 60 mesh powder,
This is because, when the molten glass base material is made into a thin plate, unevenness in particle size appears, which is not preferable in appearance.

Niobium pentachloride (solid) is dissolved in an alcohol solution such as methanol, wetted and mixed with silica powder, and then dried, whereby it is oxidized in air to precipitate niobium pentoxide.

The addition amount of niobium pentachloride is preferably 3.0 to 3.5 times the value in terms of the weight of niobium dioxide contained in the quartz glass. For example, 1.5 kg of quartz powder (silica powder)
, 25 to 50 g of niobium pentachloride are added.
When this is converted to niobium dioxide, 0.77% by weight or more
It is about 1.5 wt%. However, in the oxidation step to niobium pentoxide, NbOC which is an intermediate is obtained by dry heat treatment.
It will vaporize a portion in the form of l ₃ etc. At the time of vitrification, with niobium dioxide terms, a glass containing about 0.5~1wt%.

The amount of niobium dioxide contained in the quartz glass is preferably from 500 to 40,000 ppm. 500pp
If it is less than m, blackening will be incomplete and 40,000p
If it exceeds pm, unreacted substances are generated, and the possibility of color unevenness or the surface crystallization or foaming during heat treatment increases, which is not preferable. It can be said that the amount of niobium dioxide is preferably from 0.25 to 1.5 wt% in terms of the amount of niobium dioxide from practical use.

The obtained quartz glass has a black color and 185
Even in the wavelength range of ２５25000 nm, even at a thickness of 1 mm, the light transmittance is 1% or less, and when this is used for a spectrophotometer cell, stray light in the cell can be suppressed to almost zero.

Further, it does not crystallize even at a high temperature, has heat resistance,
Because of its excellent thermal insulation properties, for example, if it is used between the pipe ends of a semiconductor core tube of a high-temperature furnace, even if the central part is heated, the furnace core tube end is not heated and has excellent heat insulation and heat uniformity. A jig made of quartz glass for high-temperature materials can be obtained.

[0024]

【Example】

Example 1 [Production of black quartz glass] 50 g of niobium pentachloride was dissolved in 300 ml of a methanol solution, and the resulting solution was mixed with 1.5 kg of quartz powder (200 to 200 kg).
(250 mesh 60%) and wet the entire powder. Next, the wet powder is dried in a drafter for about one week. At this time, niobium is oxidized in the drafter and chlorine is released. 4NbCl ₅ + 5O ₂ → 2Nb ₂ O ₅ + 10Cl ₂

Further, in a nitrogen atmosphere (500 ° C., 1 hour keep, nitrogen 600 ml / min), residual chlorine gas and the like are degassed and completely dried.

Then, in a hydrogen atmosphere (1150 ° C., 30
The reduction treatment is performed with a minute keep, hydrogen of 500 ml / min). Nb ₂ O ₅ + H ₂ → 2NbO ₂ + H ₂ O

After passing through a # 150 sieve, the secondary particle size is adjusted to a melting powder (niobium oxide concentration: 1.5 wt%, packing density: 0.85), placed in a molding container, and then vacuum melted (1850). ° C, degree of vacuum 0.4 Torr At 1850
C) to obtain a sample.

The obtained sample was subjected to X-ray diffraction.
At this time, for comparison, black quartz glass using vanadium as a coloring agent was also observed. Cristobalite was observed in the case of using vanadium as a coloring agent (FIG. 2), but cristobalite was observed in the black quartz glass of the present invention. Not performed (FIG. 1).

The measuring conditions of X-ray diffraction are as follows. Target: Cu, Voltage: 40KV, Current: 30mA, Full
Scale Range: 5kcps, Time Constant: 1sec, Scann
ing Speed: 2 ° / min, Chart Speed: 20cm / min, Race
iving Slit: 0.3mm

Further, the obtained samples were tested for crystallization prevention, light shielding properties, heat resistance and workability.

[Prevention of Crystallization] The black quartz glass of the present invention and black quartz glass containing vanadium as a coloring agent
When reheated to 200 ° C. and 1250 ° C. and compared for crystallization, products using vanadium as a coloring agent showed
Although it crystallized at 00 ° C. and was unfavorable in appearance and had a problem in commercial value, the product of the present invention did not crystallize even at 1250 ° C.

[Light-shielding property] The black quartz glass of the present invention
When the light transmittance was measured in the wavelength range of 5 to 25000 nm, it was almost zero when the thickness was about 1 mm.

[Heat resistance] When the viscosity value at 1200 ° C. was measured, the log poise value of the niobium additive of the present invention was almost the same as that of the transparent quartz glass as shown in Table 1 below. .

[Table 1]

[Workability] Since crystallization due to high-temperature heating does not occur, high-temperature processing such as bonding can be easily performed as compared with the vanadium additive, and processing such as cutting is equivalent to that of quartz glass.

Example 2 [Quartz Furnace Core Tube] As shown in FIG. 3, when the black quartz glass obtained in Example 1 was used between the details of the quartz furnace core tube, the furnace core tube left end even when the center was heated. Was not heated. When the central portion was made of black quartz glass as shown in FIG. 4, a furnace core tube having a high soaking effect with a temperature distribution difference of ± 1 ° C. in a soaking region was obtained.

The furnace core tube may have a multilayer structure in which the surface layer is made of another type of quartz glass having any desired characteristics and the intermediate layer is made of black quartz glass.

Example 3 Cell for Optical Analysis A cell for optical analysis shown in FIG. 5 was prepared using the black quartz glass obtained in Example 1 except for the light transmitting surface. Because of its excellent light-shielding properties in a wide wavelength range, stray light in cells outside the measurement wavelength range was suppressed to almost zero.

Also, when the cell is made, it has good adhesion at high temperature to the transparent quartz glass plate which is a light transmitting surface, and no crystallized portion is generated even at high temperature, so that the production efficiency is improved and the optical characteristics are improved. A stable cell for optical analysis is obtained.

[0039]

The black quartz glass of the present invention including the one obtained by thermally reducing niobium pentoxide in a stream of hydrogen hardly undergoes crystallization during production, and is resistant to heat treatment by reheating at 1000 ° C. or higher. It does not crystallize and has good workability such as welding.

Further, black quartz glass has a transparent thermal conductivity.
Since it is very good as compared with opaque quartz glass, when it is used for a high-temperature furnace core tube for semiconductors or the like, the effect of soaking the furnace core tube increases.

On the other hand, since the light transmittance is 1% or less at 1 mm and the light shielding property is excellent, there is an effect of suppressing heat conduction due to infrared light from the outside such as heat radiation from the outside. Unlike opaque quartz glass, which reflects light to prevent the temperature of the heated end from rising, if black quartz glass is used for the heated end of the quartz glass part, heat conduction by light is almost 100%.
%, And the blackening of the furnace core tube can also improve the soaking effect inside the furnace core tube.

As described above, the black quartz glass is useful as a high-temperature material for semiconductor soaking tubes, jigs, and the like, utilizing various characteristics of the quartz glass.

Furthermore, the cell for optical analysis using the black quartz glass of the present invention can suppress stray light to almost zero, and can obtain a product excellent in light-shielding properties in a wide wavelength range from ultraviolet to infrared. .

[Brief description of the drawings]

FIG. 1 is a diagram showing X-ray diffraction of the present invention.

FIG. 2 is a diagram showing an X-ray diffraction of a product using vanadium as a coloring agent.

FIG. 3 is a diagram showing a state in which black quartz glass is used for details of a furnace core tube.

FIG. 4 is a view showing a state in which black quartz glass is used in a central portion of a furnace core tube.

FIG. 5 is a cross-sectional view of an optical analysis cell using black quartz glass.

FIG. 6 is a side view of an optical analysis cell using black quartz glass.

FIG. 7 is a plan view of an optical analysis cell using black quartz glass.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Black quartz glass 2 Translucent plate 3 Furnace tube 4 Cell for optical analysis

Claims (8)

(57) [Claims] 1. Niobium dioxide of 500 to 40000 pp
Black quartz glass containing m. 2. Niobium dioxide of 500 to 40000 pp
m and a thickness of 1 m in a wavelength range of 185 to 25000 nm.
Black quartz glass having a light transmittance of 1% or less per m. 3. A method for producing black quartz glass, comprising subjecting a silica powder containing a niobium compound to a heat treatment in a reducing atmosphere. 4. A fine powder obtained by mixing a niobium compound and silica powder at a ratio of 500 to 40000 ppm in terms of niobium dioxide, performing a gas phase reduction treatment, and then forming a molten glass. A method for producing black quartz glass. 5. The method for producing black quartz glass according to claim 3, wherein the reducing treatment atmosphere is a hydrogen stream. 6. A solution in which niobium chloride is dissolved in an alcohol solution, the solution is wetted with silica powder, mixed, dried to obtain a fine powder, and further subjected to a high-temperature heat treatment in a hydrogen atmosphere.
A method for producing black quartz glass, comprising melting the dried powder in a vacuum. 7. Niobium dioxide of 500 to 40000 pp
A cell for optical analysis comprising a black quartz glass containing m. 8. Niobium dioxide of 500 to 40000 pp
A quartz glass jig for a high-temperature material having black quartz glass containing m.