JPH0558672A - New AlF3 based Fluoride glass - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention transmits visible light to infrared light, has significantly better mechanical strength and chemical durability than ZBLAN, and is capable of introducing a large amount of rare earth ions and is crystallized. The object is to provide a stable and stable fluoride glass. [Structure] The above-mentioned object is PbF _{2 3 to} 45% in mol%, A
1-F _{3 5 to} 37%, YbF ₃ 14 to 37%, ZnF ₂ 3
_{~22%, BaF 2 3~22%,} ZrF 4 0~32%,
_{CaF 2 0~16%, MgF 2 0~5} %, MnF 2 0~
10%, LaF ₃ 0 to 7%, LiF or NaF 0 to 6%
It can be effectively achieved by an infrared transmitting fluoride glass characterized by containing

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is a novel infrared transparent fluorinated material.
Concerning object glass. In particular, the present invention transmits visible light to infrared light.
Pass (0.3-6 μm), mechanical strength, chemical durability
Conventional ZrF _Four-BaF₂Based fluoride glass
Much better than conventional AlF ₃Is the main component
Concerning stable fluoride glass that is harder to crystallize than glass
It The infrared transmitting fluoride glass of the present invention is in the near infrared or infrared region.
Used for various optical devices used in (~ 6 μm)
Lens, prism, filter, etc. or for optical communication, light
Glass fiber for measurement or laser light transfer
Used for. Furthermore, a large amount of various rare earth ions are introduced.
Therefore, it is very promising as a new laser material.
Is.

[0002]

2. Description of the Related Art ZrF_FourFluoride glass containing as a main component
Is French M. Discovered by Poulain by chance
Since then, research and development on various fluoride glasses
It has been actively promoted in the country. The main reason is
Fluoride glass covers a wide wavelength range of 0.3-6 μm
Therefore, since it has a high transmittance, the intrinsic loss is low and theoretically
Can be an extremely low loss fiber for communication
is there. In addition, various lenses and lenses used in the infrared region
Rhythm, filter, etc., or for optical measurement, laser
It can also be used for power transfer fibers,
Attracted attention because it is a promising host material
I am However, compared to ordinary oxide glass,
Fluoride glass has a high tendency to crystallize and is extremely devitrified.
It has a big drawback that it is easy to do. Past
Many fluoride glasses have been discovered in 10 years.
However, it is currently attracting attention as a practical fluoride glass.
Very few are wearing ZrF_Four-BaF₂The main
Minute glass and AlF ₃About glass
Is. Among them, the most widely used worldwide
Is ZrF_Four-BaF₂-LaF₃-AlF₃-NaF
(ZBLAN) type glass, which has a
The most thermally stable and hard to crystallize as a fluoride glass
This is because. However, the mechanical strength of ZBLAN is comparable.
Normally low in the atmosphere due to low chemical durability
When used in, it absorbs moisture and is easily deteriorated and damaged.
It has major drawbacks. Also a new laser
Amid growing interest in fluoride glass as a material
Therefore, a large amount of rare earth ions are added to ZBLAN glass.
What cannot be added is one of the ways to improve the laser oscillation efficiency.
It is a big obstacle.

On the other hand, AlF ₃ --BaF as a highly practical AlF ₃ fluoride glass containing AlF ₃ as a main component.
_{A 2-} CaF ₂ -YF ₃ system glass (ABCY) is known [T. Kanamori et al. , Jp
n. J. Appl. Phys. 20 (1981) L3
26]. Compared to ZBLAN glass, this type of glass is
Since it has relatively high mechanical strength and good chemical durability, it may be used for various optical devices, but it is thermally unstable and is more likely to crystallize and devitrify than ZBLAN. It has major drawbacks and it is difficult to make a uniform glass sample under normal conditions and very difficult to fiberize or industrially produce. Further, as a mixed glass of ZrF ₄ and AlF ₃ , AlF ₃ —BaF ₂ —
_{CaF 2 -YF 3 -SrF 2 -NaF-} ZrF 4 (AB
CYNZ) glass has been developed (Japanese Patent Laid-Open No. 62-2).
No. 75039). Although this glass has slightly improved thermal stability and good chemical durability and mechanical strength as compared to the above ABCY glass, it is still much more unstable than ZBLAN and has a uniform and large sample preparation or fiber. It is still difficult to convert.

[0004]

The problem to be solved here is that it transmits visible light to infrared light, has much better mechanical strength and chemical durability than ZBLAN, and can introduce a large amount of rare earth ions. Moreover, it is to provide the industry with stable fluoride glass that is difficult to crystallize.

[0005]

The inventors of the present invention have conducted extensive studies to solve the above-mentioned drawbacks and problems of the prior art, and as a result,
_{lF 3 -YbF 3 -PbF 2 -ZnF 2} -BaF 2 (A
It has been found that there is a fairly wide vitrification range in the YbPZB) system. Based on this discovery,
F ₂ , CaF ₂ , MnF ₂ , LaF ₃ , ZrF ₄ and L
When iF or NaF was added to the AYbPZB type glass, a fluoride glass was obtained which was very stable, was less likely to devitrify to the same extent as the ZBLAN type glass, and was considerably superior in chemical durability to the ZBLAN type glass. The present invention has been reached.

That is, according to the present invention, PbF ₂ 3
45%, AlF ₃ 5-37%, YbF ₃ 14-37%,
ZnF ₂ 3-22%, BaF ₂ 3-22%, ZrF ₄₀
~ 32%, CaF ₂ 0-16%, MgF ₂ 0-5%, M
nF ₂ 0-10%, LaF ₃ 0-7%, LiF or Na
It is an infrared transmitting fluoride glass characterized by containing F0 to 6%. This is, AlF ₃ -YbF ₃ -Pb
It is based on the discovery that F ₂ -ZnF ₂ -BaF ₂ 5 wide vitrification range-component is present. FIGS. 2 to 5 show the vitrification range in which a colorless and transparent sample having a thickness of about 5 mm was obtained with this five-component system. For reference in FIG. 1, AlF ₃ −
The vitrification range in which a sample having a thickness of about 5 mm was obtained in the YbF ₃ -PbF ₂ three-component system is shown. AlF ₃ -YbF ₃ -Pb
It is already known that the F ₂ ternary system vitrifies in a narrow range, but the glass is unstable (Japanese Patent Publication No. 63-50296), but ZnF ₂ and BaF ₂ are added to this ternary system. Not only did more stable glasses be obtained, but also the vitrification range was considerably widened. As is clear from FIG. 2-5, 15% Zn
The vitrification range is widest around F ₂ and 15% BaF ₂ . Overall, AlF ₃ = 18-37% in mol%, Y
bF ₃ = 18 to 37%, (PbF ₂ + ZnF ₂ + BaF
₂ ) Stable and uniform glass having a sample thickness of 5 mm or more was obtained within a considerably large range of 38 to 60%. Outside the range, uniform and large glass cannot be obtained by the usual method.

Further, various fluorides were introduced into the AYbPZB glass to stabilize the glass.
% CaF ₂ , 0-5% MgF ₂ , 0-10% Mn
F ₂ , 0 to 7% LaF ₃ , 0 to 32% ZrF ₄ , 0
It was found that the addition of ˜6% LiF or NaF was effective, and the addition of ZrF ₄ was the most effective.

In the present invention, glass stability was evaluated using differential scanning calorimetry (DSC). Usually, Tx (crystallization start temperature of glass) obtained from DSC during heating process
And Tg (glass transition temperature) are large, and the difference between Tm (melting start temperature after crystallization of glass) or Tl (melting end temperature after crystallization of glass) and Tx is small,
The glass becomes more stable and optically uniform. 6,
Composition 7 is 30AlF ₃ -25YbF ₃ - (45-2
x) PbF ₂ -xZnF ₂ -xBaF ₂ or (30,
_{-X) AlF 3 -xZrF 4 -25YbF 3} -25Pb
F ₂ -10ZnF ₂ -10BaF _2: shows (x mol%) Series respectively a DSC curve of the glass. 6 and 7
Therefore, in the glass of the present invention, by adjusting the composition, in particular, AlF ₃ —ZrF ₄ —YbF ₃ —PbF
_{In the 2-} ZnF ₂ -BaF ₂ (AZYbPZnB) system,
It can be seen that a glass having a very large (Tx-Tg) and a very small (Tm-Tx) or (Tl-Tx) can be obtained. (Tx-Tg) value of ABCY glass is 105 ^o
At C, the glass of the present invention proves to be very stable when compared to the (Tm-Tx) value of around 175 ^° C. In addition, according to the values of Tg, Tx, Tm and Tl and the measurement of isothermal thermal analysis (TTT curve), A of the present invention was measured.
It was revealed that the ZYbPZnB type glass is considerably more stable than ABCYSNZ and has the same thermal stability as ZBLAN.

The poor water resistance of ZBLAN is due to the large amount of ZrF ₄
It is generally well known to be attributed to the inclusion of NaF and NaF. The characteristics of the glass of the present invention, the alkali is little, or not included at all, ZrF ₄
Since it does not contain as a main component, it can be predicted that the chemical durability is much superior to that of ZBLAN as in the conventional AlF ₃ system glass.

Actually, the AZYbPZnB glass and the ZBLAN glass of the present invention were immersed in distilled water under exactly the same conditions for 2 hours, and the infrared transmission spectrum was measured.
In AN, a large absorption by water appeared near 3 μm, whereas in AZYbPZnB glass, there was almost no absorption by water. Since the glass of the present invention contains Yb ions, the absorption due to the Yb ions exists in the vicinity of 1 μm, so that near infrared rays in the vicinity cannot be used. However, Y
bF ₃ can be easily replaced by non-absorbing YF ₃ and LuF ₃ .

The fluoride glass of the present invention can be easily manufactured by a conventional method. That is, after crushing and mixing the raw materials,
It is melted with platinum, glassy carbon, a metal crucible or the like at around 1000 ° C., and glass is obtained by a casting method, a roll-out method or the like. At the time of melting, various active or inert gas (N ₂ A
r, NF ₃ , CCl _4, etc.) is preferably used.

[0012]

The present invention will be described below with reference to examples.
The invention is not limited to these examples.

Example 1 30AlF ₃ -30YbF ₃ -30PbF ₂ -5ZnF
_The batch was weighed from the powder raw material so that 20 g of glass having a composition of 2-5BaF ₂ (mol%) was finally obtained (2.77 g of AlF _{3 having a} purity of 99.9% or more, YbF ₃
7.60 g, PbF ₂ 8.10 g, ZnF ₂ 0.57
g, BaF ₂ 0.97 g), and mixed in an agate mortar. However, the fluoride raw material contains a small amount of oxide (MO _{n / 2} , where n is the valence of the metal M), which is considered to deteriorate the optical properties of the produced fluoride glass. Therefore, NH ₄ HF ₂ + MO _{n / 2} → MF _n + H ₂ O (g) +
By a high temperature reaction of NH ₃ (g), 10 wt% of NH ₄ HF ₂ was added to remove the oxide, and fluorination was performed during melting of the glass. Put the mixed batch powders in a platinum crucible with a lid, and at 2 1050 ° C in a nitrogen atmosphere.
After melting for 5 minutes, it was poured into a brass mold to obtain a colorless transparent glass having a thickness of about 5 mm. In this way, a glass satisfying the intended composition was obtained. About this glass
DSC measurement was performed at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere. The results are shown in Table 1 (No. 1).

Example 2 30AlF ₃ -25YbF ₃ -25PbF ₂ -10Zn
2.93 g of AlF ₃ having a purity of 99.9% or more, 6.69 g of YbF _{3 and} PbF so that 20 g of glass having a composition of F ₂ -10BaF ₂ (mol%) is finally obtained.
₂ 7.13 g, ZnF ₂ 1.20 g, BaF ₂ 2.04
A batch was weighed from g of the powdered raw material and mixed in an agate mortar. 2 g (corresponding to 10% by weight) of NH ₄ HF ₂ was added to the batch powder in a platinum crucible with a lid, which was melted in a nitrogen atmosphere at 1050 ° C. for 20 minutes, and then poured into a brass mold to a thickness of about 5 mm. A colorless transparent and uniform glass was obtained. The DSC curve measured in the same manner as in Example 1 is shown in FIG. 7 (x = 10% in the figure).

Example 3 15AlF ₃ -20ZrF ₄ -20YbF ₃ -15Pb
F ₂ -12ZnF ₂ -12BaF ₂ -6CaF ₂ so that the glass having a composition of (mole%) is finally obtained 100 g, AlF ₃ 99.9% or more purity 7.55 g, Z
rF ₄ 20.03 g, YbF ₃ 27.56 g, PbF ₂
22.03 g, ZnF ₂ 7.43 g, BaF ₂ 12.6
0g, CaF ₂ 2.81g was weighed and NH ₄ HF ₂ 10
mixed with g. Put the batch in a platinum crucible with a lid for 10
After melting at 50 ° C. for 50 minutes, it was poured into a warm brass mold and put together with the mold in an electric furnace at 330 ° C. for annealing. The glass thus obtained was a disk having a uniform transparency and a thickness of about 1 cm and a diameter of 5 cm. The obtained glass was measured by DSC, and the results are shown in Table 2 (No. 17).

Example 4 20AlF ₃ -15ZrF ₄ -20YbF ₃ -15Pb
F ₂ -12ZnF ₂ -13BaF ₂ -5CaF ₂ so that the glass having a composition of (mole%) is obtained finally 100 g, purity of 99.9% or more AlF ₃ 10.26 g,
YbF ₃ 28.09g, PbF ₂ 22.46g, ZnF
₂ 7.58 g, BaF ₂ 13.92 g, ZrF ₄ 15.
32 g and CaF ₂ 2.38 g were weighed and NH ₄ HF ₂ 1
Mixed with 0 g. Glass was melted, cast and annealed under the same conditions as in Example 3. When the obtained glass was polished and the infrared transmittance was measured, it was 4.7 mm.
With the sample thickness, the transmittance of 50% reached 6.9 μm (FIG. 8). In addition, when the infrared spectrum was measured before and after the glass was immersed in water for 2 hours, there was no change in the vicinity of 3 μm (No. 16).

[0017]

[Table 1]

[Table 2]

Tables 1 and 2 show the glass compositions of Examples 1, 3, and 4, as well as the glass compositions of other typical examples and the glass transition temperatures (Tg) and crystallization temperatures (Tx) of these glasses by DSC. , And melting onset temperature (Tm) or melting point (Tl). The glass was prepared in the same manner as in Example 1 above.

[0019]

The new AlF developed according to the present invention
Does the ₃ type fluoride glass contain a small amount of alkali ions,
Alternatively, it was confirmed that the chemical durability was considerably superior to that of the ZBLAN glass because it contained no Al and contained AlF ₃ as a main component. Further, it is much more stable than the conventional glass containing AlF ₃ as a main component, and the infrared transmission range reaches the long wavelength side (up to 6 μm), so it is very promising as a new infrared transmission material. .. The glass of the present invention is expected to be applied to various infrared optical devices, optical communication, measurement fibers and the like. Further, Yb in the glass of the present invention
Since F ₃ does not impair the stability of the glass and can be easily replaced with other rare earth fluorides (TmF ₃ , HoF ₃ , ErF ₃ ), it is very promising as a new laser material.

[Brief description of drawings]

FIG. 1 shows the vitrification range of an AlF ₃ —YbF ₃ —PbF ₂ three-component system.

FIG. 2 shows AlF ₃ —YbF ₃ —PbF ₂ —ZnF.
₂ shows the vitrification range of the _2- BaF ₂ system (white circles are glass, black circles are crystallized, white half circles are intermediates between glass and crystals, the same applies hereinafter), ZnF ₂
5% and BaF ₂ 5% are added respectively.

FIG. 3 shows AlF ₃ —YbF ₃ —PbF ₂ —ZnF.
₂ shows the vitrification range of _2- BaF ₂ system, Z
The case where 10% of nF _{2 and} 10% of BaF ₂ are added is shown.

FIG. 4 shows AlF ₃ —YbF ₃ —PbF ₂ —ZnF.
₂ shows the vitrification range of _2- BaF ₂ system, Z
The case where 15% of nF _{2 and} 15% of BaF ₂ are added is shown.

FIG. 5 shows AlF ₃ —YbF ₃ —PbF ₂ —ZnF.
₂ shows the vitrification range of _2- BaF ₂ system, Z
The case where 20% of nF _{2 and} 20% of BaF ₂ are added is shown.

FIG. 6 is a mole percentage of 30AlF ₃ -25YbF ₃ −.
Is a DSC curve of _{(45-2x) PbF 2 -xZnF 2 -xBaF} 2 series glass (x = 0~20 mol%). From low temperature to high temperature Tg, Tx, TM, T of each glass
1 is shown.

FIG. 7 shows (30-x) AlF ₃ -xZr in mol%.
_{F 4 -25YbF 3 -25PbF 2 -10ZnF 2} -1
It is a DSC curve of a glass 0BaF ₂ (x = 5~20 mol%).

FIG. 8 shows 20AlF ₃ -15ZrF ₄ -20Yb.
_{F 3 -15PbF 2 -12ZnF 2 -13BaF 2} -C
It is an infrared transmission spectrum with respect to a sample of aF ₂ (mol%) glass having a thickness of 4.7 mm (range 2.5 to 25 μm).
m).

Claims (1)

[Claims] 1. PbF in mol%₂3-45%, AlF₃
5 to 37%, YbF ₃14-37%, ZnF₂3-22
%, BaF₂3-22%, ZrF_Four0-32%, CaF
₂0-16%, MgF₂0-5%, MnF₂0-10
%, LaF₃0 to 7%, LiF or NaF 0 to 6%
An infrared-transmitting fluoride glass characterized by having.