JPH0466823B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for forming an organic-inorganic composite vitreous coating on the surface of a phosphate-based laser glass, which increases the breaking strength of the laser glass against thermal stress. The present invention relates to a method for increasing chemical durability and chemical durability.

[Conventional technology]

Phosphate-based laser glass is currently the laser glass with the best laser oscillation characteristics. For this phosphate-based laser glass, high repetition rate,
Although there is an increasing demand for use in high average power oscillation, the breaking strength of phosphate-based laser glass is relatively weak, and currently, the heat of the excitation flash lamp causes damage inside the glass. It is said that the limit of oscillation output is that the glass is destroyed by thermal stress due to the temperature distribution. Glass itself is cooled by a liquid or gas coolant, but the thermal conductivity of glass is low and thermal stress cannot be resolved, so it is necessary to increase the strength against this thermal stress, that is, the thermal shock resistance. be done. In order to increase this thermal shock resistance, it is necessary to increase the breaking strength expressed, for example, in bending strength. In addition, phosphate-based laser glass is sensitive to water and moisture, and tends to cause blue or white discoloration on the surface of the laser glass when exposed to coolants or in normal environments, which can reduce its breaking strength. ,
Oscillation performance may deteriorate. Therefore, it is also necessary to improve the chemical durability of the glass surface.

[Problem that the invention seeks to solve]

Traditionally, the most common method for increasing the breaking strength of glass has been to create a compressive stress layer on the surface using ion exchange using molten salt, but this method cannot be applied to phosphate glasses. I understand. As a surface treatment method to solve this problem, the present applicant has already proposed an invention in Japanese Patent Application No. 58-237760 (Japanese Unexamined Patent Publication No. 60-131851) by coating a sol solution consisting of a metal alcoholate, water, and an organic solvent. We have found a method to increase the fracture strength of phosphate-based laser glass. However, there is a large difference in thermal expansion between the laser glass and the coating film, and firing at high temperatures will cause cracks in the coating film. Therefore, heat treatment is performed at a low temperature of around 350°C, and when water is used as a cooling medium, the coating film The drawback was that it peeled off easily.

In order to solve the above-mentioned problems, the present invention aims to prevent the occurrence of cracking of the coating and to increase the breaking strength and chemical durability of the glass.

[Means for solving problems]

The present invention relates to an organometallic compound represented by the general formula RMe(OR') _o-1 , and an organometallic compound represented by the general formula RMe(OR') _o and
At least one metal alcoholate represented by Me′(OR″) _o is mixed with an organic solvent [wherein R is CH ₃ , C ₂ H ₅ , C ₃ H ₇ and C ₆ An organic group selected from H ₅ , Me and Me′ are Si,
A metal selected from Al, Ti and Zr, and
Me and Me′ may be the same, R′ and
R″ is a lower alkyl group selected from CH ₃ , C ₂ H ₅ , C ₃ H ₇ and C ₄ H ₉ , and R′ and R″ may be the same, and n is Me and Me′ is the coordination number of ], further add water and acid to prepare a mixed solution, and coat the surface of the phosphate-based laser glass with the sol solution created by hydrolyzing and partially condensing the mixed solution, followed by firing in an oxygen gas atmosphere. It is characterized by the fact that it is then fired in an inert gas atmosphere, thereby forming an organic-inorganic composite vitreous film that does not crack and has good adhesion. be.

In the present invention, examples of organometallic compounds include CH ₃ Si(OC ₂ H ₅ ) ₃ , C ₂ H ₅ Si(OC ₂ H ₅ ) ₃ , C ₆ H ₅ Si(OC ₂ H ₅ ) ₃ , C ₂ H ₅ Al(OC ₂ H ₅ ) ₂ , etc., and metal alcoholates include Si(OCH ₃ ) ₄ , Si(OC ₂ H ₅ ) ₄ , Al(iOC ₃ H ₇ ) ₃ , Ti(OC _{2H5 ) 4} , Ti( _iOC3H7 ) ₄ , _Zr ( _{OC2H5 ) 4 ,} Zr( _OC4H9 ) ₄ , etc.

On the other hand, organic solvents include alcohols such as methanol, ethanol, propanol, isopropyl alcohol, and butanol, and solvents such as acetylacetone, ether, and benzene.

An organometallic compound represented by RMe (OR′) _o-1 ,
Mix with at least one metal alcoholate represented by Me(OR′) _o and Me′(OR″) _o and dissolve in an organic solvent.Add an appropriate amount of acidic water for hydrolysis to this, i.e. Add appropriate amounts of water and acid, mix thoroughly and stir to perform hydrolysis and partial condensation polymerization.At this time, the acid is, for example, HCl or HNO ₃ , and the mixing molar ratio of each component is Me (OR' ) _o and
At least one of Me′(OR″) _o /RMe(OR′) _o-1 /
Organic solvent/H ₂ O/acid = 1/0.01~1/1~10/
It is preferable to adjust it within the range of 2-20/0.01-1.0. The sol solution prepared in this manner is coated on phosphate-based laser glass by a dipping and pulling method, and is dried and heat-treated to form a glassy coating containing organic matter. The inclusion of organic matter reduces the shrinkage of the film, making it similar to the elongation of the laser glass substrate, resulting in cracking of the film even at much higher temperatures and thicker films compared to the firing temperature of inorganic-only films. It is now possible to bake without having to do anything. As a result of the increased firing temperature, adhesion between the glass and the film also improves. However, as for the heat treatment conditions, it is important not to burn the organic matter in the film, and the temperature range is 300℃~
At 350℃, the process is carried out for more than 5 hours in an oxygen gas atmosphere to completely burn out -OR' and increase the degree of polymerization of the film.Then, at a high temperature range of 400℃ to 500℃, the organic matter in the film burns, causing pinholes etc. prevent the occurrence of
In addition, in order to improve the adhesion between the film and the glass, the treatment is carried out in an inert gas atmosphere for 5 hours or more. Note that the inert gas is a rare gas, nitrogen, or the like. Phosphate-based laser glass with a glassy coating containing organic groups produced in this way has excellent chemical durability and increased breaking strength, resulting in high repetition rate and high output power of phosphate laser glass. Oscillation became possible.

〔Example〕

Next, examples will be described in order to explain the present invention more clearly. However, the present invention is not limited to the scope of the following examples.

Example 1 After mixing and stirring 0.2 mol of methyltriethoxysilane, 1.0 mol of tetraethoxysilane and 4 mol of ethanol, water for hydrolysis was acidified with hydrochloric acid for 5 mols.
mol (HCl0.03) was added, thoroughly mixed and stirred, and subjected to hydrolysis and partial condensation polymerization to obtain a coating liquid.
A phosphate laser glass polished to a diameter of 5 mm to 40 mm was immersed in this coating solution and pulled up at a constant speed of 6 cm/min to coat it. After drying at room temperature, the temperature was gradually raised to 330°C, held in an oxygen gas atmosphere for 12 hours, and then gradually heated to 440°C in a nitrogen gas atmosphere, held for 15 hours, and then CH ₃
It was made into a glassy coating containing groups. In this way, the bending strength of phosphate laser glass with a glass coating containing CH ₃ groups is 2700Kg/ ^cm2 , and the bending strength of laser glass without coating is 900Kg/ ^cm2.
It has been strengthened 3.0 times compared to . In addition, we conducted a water resistance test to measure chemical durability, and in an accelerated water resistance test in which the film was immersed in H ₂ O at 50°C, no peeling or deterioration of the film was observed even after immersion for 10 days. .

Example 2 After mixing and stirring 0.25 mol of phenyltriethoxysilane, 1 mol of tetraethoxysilane, and 6 mol of ethanol, 4 mol of water for hydrolysis was added with nitric acid, and the mixture was sufficiently mixed and stirred to cause hydrolysis and partial Condensation polymerization was performed to obtain a coating liquid. Apply this coating liquid to a 3 x 10 x 40 mm slab mold with 4 sides.
A surface-polished phosphate laser glass was coated by dipping and pulling at a constant speed of 4 cm/min. After drying at 120℃,
The temperature was gradually raised to 350℃ and the temperature was increased to 8℃ in an oxygen gas atmosphere.
The temperature was maintained for an hour, and then the temperature was gradually raised to 450° C. in a nitrogen gas atmosphere, and the temperature was maintained for 10 hours to form a glassy coating containing ₅ C ₆ H groups. In this way, the bending strength of phosphate laser glass with a glassy coating containing C ₆ H ₅ groups is 3100 Kg/ ^cm2 , compared to the bending strength of laser glass without coating, which is 1000 Kg/ ^cm2.
Enhanced by 2.5 times. In addition, as in Example 1, the coated laser glass was heated with H ₂ O at 50°C.
Although the film was immersed in water for 20 days, there was no peeling or deterioration of the film.

Example 3 0.3 mol of methyltrimethoxysilane, 1.2 mol of tetraethoxysilane and isopropyl alcohol
10 moles were mixed and stirred, 8 moles of water was added under hydrochloric acid acidity, and hydrolysis was carried out at 50°C. Add 0.5 mol of tetraisopropoxy zirconium diluted with isopropyl alcohol to this, stir at 50°C for 1 hour, and leave at room temperature for about 1 day to carry out a hydrolytic partial condensation reaction, and the coating liquid and did. A 5φ-40 mm sanded silicophosphate laser glass was immersed in this solution and coated by pulling it up at a constant speed of 6 cm/min. After drying at room temperature, the temperature is gradually raised to 350℃,
It was held in an oxygen gas atmosphere for 10 hours, and then heated to 470°C in a nitrogen gas atmosphere and held for 10 hours to form a glassy film containing CH ₃ groups. The bending strength of the silicophosphate laser glass on which a glassy coating containing CH ₃ groups was formed was 2500 Kg/cm ² , four times stronger than the 600 Kg/cm ² of glass without coating.

〔Effect of the invention〕

As described above, according to the method of forming a glassy coating on phosphate-based laser glass of the present invention, the breaking strength and chemical durability of the glass could be increased without causing cracking of the coating.

Claims (1)

[Claims] 1. An organometallic compound represented by the general formula RMe(OR′) _o-1 and at least one metal represented by the general formulas Me(OR′) _o and Me′(OR″) _o The alcoholate and the organic solvent are mixed [However, in the general formula, R is
is an organic group selected from CH ₃ , C ₂ H ₅ , C ₃ H ₇ and C ₆ H ₅ , and Me and Me′ are Si, Al, Ti and Zr
and Me and Me′ may be the same, and R′ and R″ are CH ₃ , C ₂ H ₅ ,
is a lower alkyl group selected from C ₃ H ₇ and C ₄ H ₉ , and R′ and R″ may be the same,
n is the coordination number of Me and Me'. ], further add water and acid to prepare a mixed solution, and coat the surface of the phosphate-based laser glass with the sol solution created by hydrolyzing and partially condensing the mixed solution, followed by firing in an oxygen gas atmosphere. and then firing in an inert gas atmosphere,
A method for forming a glassy film on phosphate-based laser glass. 2 The mixing molar ratio of the liquid mixture is expressed by the general formula
RMe(OR′) _o-1 : General formula Me(OR′) _o and general formula
At least one of Me′(OR″) _o : Organic solvent: Water:
Claim 1, characterized in that the acid ranges from 0.01 to 1:1:1 to 10:2 to 20:0.01 to 1.0.
A method for forming a glassy film on the phosphate-based laser glass described in 1. 3. Calcinate at 300°C to 350°C in an oxygen gas atmosphere for 5 hours or more, then in an inert gas atmosphere.
A method for forming a glassy coating on phosphate laser glass according to claim 1 or 2, characterized in that firing is performed at 400°C to 500°C for 5 hours or more.