JPH0340935A - Fluoride glass composition - Google Patents

Abstract

PURPOSE:To obtain the fluoride glass composition having good transmitting characteristics to infrared rays and suitable to optical fiber and the material for optical parts by blending specified ratios of AlF3, PbF2, YF3 and MgF2+ CaF2+SrF2+BaF2. CONSTITUTION:The fluoride glass is constituted of, by mol, 25 to 60% AlF3, 1 to 19% PbF2, 5 to 30% YF3, 0 to 15% MgF2, 0 to 30% CaF2, 0 to 20% SrF2, 0 to 20% BaF2, 20 to 55% total content of MgF2+ CaF2+SrF2+BaF2. The fluoride glass can be manufactured by preparing the above fluoride and melting it. AlF3 is the main components constituting a glass network structure. YF3 works as the auxiliary components and PbF2 furthermore works so that the glass structure is supplemented to stabilize the glass structure and to facilitate the vitrification. MgF2, CaF2, SrF2 and BaF2 are the network modifying components to reduce the melting temp. and to facilitate the vitrification. Furthermore, since the glass is constructed from the fluoride having low meltability to water, high water resistance can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a fluoride glass that has good transmission characteristics for infrared rays and is suitable for optical fibers and optical component materials.

[Prior Art] Fluoride glass is a material that is transparent in a wide wavelength range from visible to infrared, and is expected to be used in infrared-transmitting optical fibers, lenses, and the like. As fluoride glass,
ZrF, -BaF2 glass (Special Publication No. 58-2173
Glass type (Special Publication No. 6) whose main components are ALF and ALF.
2-59066) is known.

[Problems to be Solved by the Invention] However, the above-mentioned glass system had the following problems. ZrF4-BaF2 glass has the disadvantage that it has poor weather resistance, and that moisture diffuses from the surface and forms OH bonds, resulting in devitrification of the glass. AIF,
Glass systems containing as a main component have the disadvantage that stability against glass crystallization is low and it is difficult to obtain large homogeneous glasses.

[Means for Solving the Problems] The present invention was made to solve the above-mentioned problems, and in terms of mol%, AlF3 25-60%PbFz 1
~19%, YF, 5~30%, MgF20~15%C
aFi 0-30%, 5rFa 0-20%, BaFz
o~2o%MgFz + CaFz + 5rFz
+ A fluoride glass characterized in that the total amount of BaFz is 20 to 55%.

In the present invention, AIFi is 25 to 60% in mol%
If it is less than 25% or more than 60%, it will crystallize and not vitrify, and it is particularly desirable to keep it at 30 to 50% in order to prevent crystallization. PbF.

is 1-19%, and if it is less than 1% and exceeds 19%, crystals will precipitate in the glass and a homogeneous glass will not be produced. Desirable for improving stability. MgF20~15
%, preferably 5-10%, CaFx 0-30%, preferably 5-25%, 5rFz 0-20%, preferably 5-15%, BaFa 0-20%, preferably 5-25%.
15%, MgFz + CaFz + SrF, +
BaF2 content of 20-55%, preferably 25-5
It is desirable to set it to 0% because it prevents crystallization.

The fluoride glass of the present invention can be manufactured by mixing and melting each fluoride in accordance with a conventional method.

[Function] In the present invention, AIF is the main component constituting the glass network structure, YF works as an auxiliary component, and PbFz works to complement the glass structure to stabilize the glass structure. to make it easier to vitrify.

MgFx, CaFa, 5rFi, and BaFa are glass network modifying components that lower the melting temperature and facilitate vitrification. Furthermore, since it is composed of fluoride that has low solubility in water, it has high water resistance.

[Example] (Example 1) AIFs, PbFa, YFs as starting materials
, MgFa.

CaFz, 5rFa, and BaFa were used. Table 1
As shown in AIF, 35.0 mol%, PbF2
15.0 mol%.

Yl's 13.0 mol%, MgF, 6.2 mol%
, CaFa IL6 mol%, 5rF26-2 mol%
, A total of 20 g was weighed and mixed so that the proportion of BaFa was 6.2 mol%.Next, this was placed in a glassy carbon crucible, placed in an electric furnace at 900 ° C., and heated with N.
After melting for 1 hour in an Fa + Ari combined gas atmosphere, the crucible was allowed to cool. Then, it was kept at 380°C for 1 hour and slowly cooled to obtain a disk-shaped glass with a diameter of 30 mm and a diameter of 4 mm. No crystals were observed in the glass, which was colorless, transparent, and homogeneous.

(Example 2) As starting materials, AIFs, PbFz, YFs,
MgFi.

CaFz, 5rFa, and BaFz were used. As shown in Table 1, AIF: 35.0 mol%, PbF: 5 mol%, YF: 13.0 mol%, MgF: 27.8 mol%, CaFa: 23.5 mol%.

A total of 20 g was weighed so that the ratio of 5rF was 27.8 mol % and BaF was 27.8 mol %, and a disk-shaped glass of 30 mmφ x 4 mmt was obtained in the same manner as in Example i. No crystals were observed in the glass, which was colorless, transparent, and homogeneous.

(Example 3) As starting materials, AIFa, PbF2. YF3. ,
MgFi.

CaFz, SrF2. BaFz was used. As shown in Table 1, AIF, 43.0 mol%, PbFi 15.
0 mol%, YF.

1'6.0 mol%, MgFz 4.2 mol%, Ca
Fa 12.5 mol%, 5rF 24.2 mol%, B
A total of 20 g was weighed so that the ratio of aF was 24.2 mol%, and 30 mo + φX4 m was prepared in the same manner as in Example 1.
A disc-shaped glass of mt was obtained. No crystals were observed in the glass, which was colorless, transparent, and homogeneous.

(Example 4) As starting materials, AlF3, PbFz, YF3,
MgFz.

CaFz, 5rFz, and BaFi were used. As shown in Table 1, AIFs 29.0 mol%, PbF, 15
．． 0 mol%, YF.

11.0 mol% 2MgFa 7.5 mol%, CaFz
22.5 mol%, 5rFa 7.5 mol%, Ba
F, total amount 20 g so that the ratio is 7.5 mol%
Weighed and made 30rrlIIlφ in the same manner as in Example 1.
A disk-shaped glass of X, 4+++mt was obtained. No crystals were observed in the glass.

It was colorless, transparent, and homogeneous.

Further, Table 1 shows various physical properties of the glasses of Examples 1 to 4.

In addition, the conventional technology ZrF4-BaFz glass, A
A comparison of IF and type glasses is also shown. When the AIFn type glass shown in Comparative Example 2 was melted in the same manner as in Example 1, many crystallized substances were observed in the produced glass, and a homogeneous glass could not be produced. There wasn't.

Table 1 As can be seen from Table 1, the glass of the present invention has high stability against crystallization and good water resistance and acid resistance.

In addition, water resistance and acid resistance are based on Japan Optical Glass Industry Association standards JOG.
Measured based on rS-1975.

Furthermore, as can be seen from the spectral transmittance curve shown in FIG. 1, it exhibits good transmittance in the visible to infrared region.

[Effects of the Invention] According to the present invention, a fluoride glass having high weather resistance and good stability against crystallization can be obtained, and optical fibers and optical component materials can be used.

[Brief explanation of drawings]

FIG. 1 shows the transmittance of the glass of Example 1 of the present invention in the visible to infrared range.

Claims (1)

[Claims] (1) AlF_3 25-60%, Pb in mol%
F_2 1-19%, YF_3 5-30%, MgF_
2 0-15%, CaF_20-30%, SrF_2
0-20%, BaF_2 0-20%, MgF_2+C
The total amount of aF_2 + SrF_2 + BaF_2 is 20 to 55
% fluoride glass.