JPH05201734A - Production of oxynitride glass - Google Patents

Abstract

PURPOSE:To produce glass at a low temp. in short time in the production where raw material including oxide and nitrogen-contg. compounds is melted by using an oxygen compound as a nitrogen supply source. CONSTITUTION:When melting raw material including oxide and nitrogen-contg. compounds to produce oxynitride glass, oxides are used as glass raw material. As the oxide, Si2N2O is especially preferable. The oxides, such as Si2N2O, etc., have the structure similar to that where oxygen atoms of SiO2 as main raw material of silica glass, are substituted by nitrogen atoms and in which nitrogen atoms are dispersed in advance. For that, it is presumed that dispersion into glass structure is made easier compared with the case where Si3N4 or metal nitride is used.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing oxynitride glass having a high nitrogen content in a short time.

[0002]

2. Description of the Related Art Oxynitride glass has a structure in which a part of oxygen in the oxide glass is replaced by nitrogen having a bond valence and trivalence. Therefore, more chemical bonds are formed than the oxide glass to strengthen the glass network, and it has excellent physical properties such as high transparency and high elasticity and high strength.

Such an oxynitride glass is generally manufactured by a melting method, and a nitride raw material such as SiO _{2 and} Si ₃ N ₄ and AIN is mixed with another glass raw material such as a metal oxide to produce an inert gas. It melts for a long time inside. In such a melting method, first, it is necessary to break the interatomic bond of the metal nitride such as Si ₃ N ₄ which is a raw material and sufficiently diffuse nitrogen atoms into the glass structure to cause a vitrification reaction. The raw material must melt at high temperature for a long time.

An object of the present invention is to shorten the vitrification time in the production of oxynitride glass and to easily perform vitrification.

[0005]

[Means for Solving the Problems] The inventors of the present invention have made various studies on shortening the vitrification time. As a result, by using oxynitride as a nitrogen supply source, a good oxynitride glass can be obtained in a short time. The present invention has been completed based on the finding that it can be obtained.

That is, the present invention provides a method for producing an oxynitride glass using an oxynitride as a glass raw material in producing an oxynitride glass by melting a raw material containing an oxide and a nitrogen-containing compound. Is. Si ₂ N ₂ O is particularly preferable as such an oxynitride.

In the case of Si ₃ N ₄ or a metal nitride which has been conventionally used as a nitrogen source of oxynitride glass,
High energy is required to break the interatomic bonds and disperse the nitrogen atoms in the glass structure, and thus it is considered that vitrification requires high temperature and long time heating. On the other hand, the structure of oxynitride such as Si ₂ N ₂ O is similar to the structure in which oxygen atom of SiO ₂ which is the main raw material of silicate glass is replaced by nitrogen atom. Thus, it is presumed that the nitrogen atoms are dispersed in advance and are easily dispersed in the glass structure as compared with the case of using Si ₃ N ₄ or metal nitride.

In a typical method for producing an oxynitride glass by the above method, first, (i) SiO ₂ and (ii) Si
₂ N ₂ O or another metal oxynitride, (iii) at least one metal oxide, (iv) CaO or CaO + MgO are mixed.

Examples of silicon oxynitride other than ( ₂ ) Si ₂ N ₂ O include Si ₅ N ₆ O. Other oxynitrides include, for example, metal oxynitrides (Al _{2n + 1} O _3n N
Etc.), sialon (Si _6-x Al _x O _x N _8-x etc.), compounds of silicon oxynitride and metal (La ₄ Si ₂ O ₇ N ₂ etc.) and the like. All of these are S of oxynitride glass.
It has a bond between i, O, and N from the beginning, is convenient for vitrification, and can realize a high nitrogen content.

As the nitrogen source, Si ₃ N ₄ , AlN, BN or the like which has been conventionally used may be used in combination with the oxynitride.

As the metal oxide of (iii), Al ₂ O ₃ ,
BaO, Sb ₂ O ₃ , SrO, Na ₂ O, K ₂ O, La ₂ O ₃ , Ce
O ₂ , Y ₂ O ₃ , ZrO ₂ , TiO ₂ , B ₂ O ₃ , Cr ₂ O ₃ , Pb
_{O, V 2 O 5, SnO} 2 , etc., or carbonates comprising these metal oxides by thermal decomposition, hydroxides, may be blended oxalate. Further, instead of CaO and MgO, a compound which becomes CaO or MgO by thermal decomposition, such as carbonate, hydroxide or oxalate may be used.

These raw materials are thoroughly mixed and heated,
Melt to obtain oxynitride glass. The mixture is preferably melted at 1400 to 1900 ° C. for 3 to 100 hours at a heating rate of 10 to 800 ° C./min in an atmosphere of an inert gas such as nitrogen or argon to vitrify.

A preferred oxynitride glass obtained by the production method of the present invention is Si-Ca-M-O-N or S.
It has an i-Ca-Mg-M-O-N glass system. Metal M is Al, Sr, La, Ba, Y, Ti, Zr, Ce, N
It is at least one kind of a, K, Sb, B, Cr, Pb, V, Sn and the like. Further, this oxynitride glass contains SiO ₂ 0 to 40 mol%, CaO 26 to 70 mol%,
It is preferable to contain 0 to 20 mol% of MgO and 22 atom% or less of M ₂ and contain 5 atom% or more of nitrogen.
It is preferred to have a tightly crosslinked structure based on the bonds. The preferred glass obtained has a nitrogen content of 5 to 30 atom%, an elastic modulus of 100 to 220 GPa, and a tensile strength of 1.0 to 7 GPa.
Have. The nitrogen content can be adjusted by the amount of oxynitride or nitride in the raw material.

[0014]

EXAMPLES Next, the present invention will be described more specifically based on examples. In the examples,% means mol%.

[Example 1] SiO as a glass raw material
₂ (0.7%), Si ₂ N ₂ O (35.6%), CaO (55.
5%), MgO (6.3%), and Al ₂ O ₃ (1.9%) [nitrogen content 22.7 atomic%] were used. This glass raw material is mixed and the melting crucible in the heating device (inner diameter 50 m
m, height 200 mm). The mixture in the crucible was melted at 1770 ° C. under a nitrogen atmosphere. It was completely vitrified within 1 hour of melting.

[Example 2] An oxynitride glass was produced in the same manner as in Example 1 except that the melting temperature was 1720 ° C. The raw material was completely vitrified within 5 hours of melting.

Example 3 As a glass raw material, SiO ₂ (1
9.2%), Si ₂ Al ₄ O ₄ N ₄ (16.7%), CaO (4
1.2%), Al ₂ O ₃ (22.9%) [nitrogen content 13.7
Atom%] of each powder was used. The glass raw materials were mixed and supplied to the crucible in the same manner as in Example 1, and the nitrogen atmosphere was set to 1.
Melted at 740 ° C. It was completely vitrified within 3 hours of melting.

[Comparative Example 1] An oxynitride glass was produced in the same manner as in Example 1. Si as a glass raw material
O ₂ (18.5%), Si ₃ N ₄ (17.8%), CaO (5
5.5%), MgO (6.3%), Al ₂ O ₃ (1.9%)
Each powder having a [nitrogen content of 22.7 atomic%] was used. These glass raw materials are mixed and mixed in a melting crucible under a nitrogen atmosphere for 1
Melted at 770 ° C. Unmelted material was present in 1 hour of melting and uniform glass was not obtained, and uniform glass was obtained in 5 hours of melting.

[Comparative Example 2] As in Comparative Example 1, except that the melting temperature was 1720 ° C. and melting was carried out. Even after 5 hours, the unmelted material was too much to vitrify. ..

[Comparative Example 3] SiO as a glass raw material
₂ (2.2%), Si ₃ N ₄ (14.3%), CaO (35.5)
%) And Al ₂ O ₃ (48.2%) [nitrogen content 13.7 atom%]. This glass raw material was mixed and treated in the same manner as in Example 1 in a molten crucible under a nitrogen atmosphere, 176.
When melted at 0 ° C., it was vitrified in 5 hours of melting.

[0021]

According to the method of the present invention, oxynitride glass can be easily manufactured at low temperature and in a short time.

Claims (1)

[Claims] 1. A method for producing an oxynitride glass, wherein an oxynitride is used as a glass raw material in producing an oxynitride glass by melting a raw material containing an oxide and a nitrogen-containing compound.