JPH0435431B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for bonding quartz glass materials together, and more particularly to a method for bonding quartz glass plates that can be advantageously used in manufacturing a dye solution cell for a high-power dye laser. (Prior Art) Conventional methods for joining quartz glass materials include (1) epoxy resin adhesive method, (2) electrodeposition method, and (3) fusion bonding method. Method (1) above is relatively easy to work with, but when the product comes into contact with organic solvents, such as alcohol and dioxane,
Problems arise with chemical durability. The method (2) above is
In polishing and finishing the bonding surface, precision of within five Newton rings is required, which not only requires equipment with high precision, but also leaves problems with the mechanical strength of the bonded portion. Furthermore, in the case of the above-mentioned melt bonding method (3), distortion basically occurs in the vicinity of the bonding surface, which poses a problem for products that require optical precision. For example, in the dye solution cell for a dye laser shown in Fig. 1, the thickness of the quartz glass side plates 1 and 2 used is thick, usually about 3 mm, and the concentration of the dye solution P is quite high, so the dye solution is exposed to the excitation light. In other words, most of the basic laser light (excimer laser light here) is absorbed by the inner wall of the cell, and the mirror
Dye laser oscillation occurs in the direction of the arrow at M ₁ and M ₂ .
By melting the vicinity of the adhesive surface 3, the side plate 1
Since distortion occurs in a considerable surface area including the dye laser oscillation optical path 4, it is difficult to carry out a melt bonding method that satisfies optical conditions due to light scattering, even with fairly sophisticated technology. By the way, in a dye solution quartz cell used for a dye laser pumped by a high-power laser, a part of the photoexcited dye undergoes a photochemical reaction, and the dye solution causes a local thermal reaction on the inner wall surface of the quartz cell. As a result, quartz cells frequently suffer peeling damage as shown in FIG. 2, and once damaged, quartz cells cannot be reprocessed. Since this quartz cell is extremely expensive, its replenishment and renewal account for a large portion of the cost burden in photophysical chemistry research that uses it.
Therefore, there has been a strong desire to replace damaged quartz glass plates in quartz cells and repair and regenerate them by bonding them with high optical precision, or to be able to easily manufacture quartz glass products with arbitrary specifications. I've been (Problems to be Solved by the Invention) The present inventors have succeeded in easily and highly accurately adhering quartz glass materials using a specific inorganic material, which had been considered extremely difficult in the past. Therefore, the objects of the present invention are: (a) resistant to chemicals, especially organic solvents; (b) resistant to temperature changes from high to low temperatures (1000°C to -200°C); and (c) bonding strength. (d) The quartz glass materials to be bonded are not subjected to distortion during bonding, and excellent adhesion between quartz glass materials can be achieved. A final object of the present invention is to repair expensive quartz glass optical instruments and to manufacture them according to arbitrary specifications with high precision and at low cost. (Means for Solving the Problems) The method of the present invention for achieving the above objects has a linear expansion coefficient of about 19×10 ^-7 to 21.5×10 ^-7 cm/cm°C and a softening temperature of about A slip-like mixture of a glass frit and an organic binder having a uniform composition at a temperature of 1050°C or higher and lower than the annealing temperature of silica glass is applied to the mating surfaces of a plurality of quartz glass materials, and the quartz glass is annealed at a temperature higher than the softening temperature and lower than the annealing temperature of the silica glass. The method is characterized in that the organic binder is heat-cleaned by heating to a temperature lower than that temperature, and the quartz glass materials are bonded to each other by fusing the glass frit. The configuration of the present invention will be explained in detail below along with its operation. The quartz glass material to which the method of the present invention is applied is transparent quartz glass made from quartz, and has a SiO ₂ content of 99.5.
% or more, preferably 99.98% or more, and contains extremely small amounts (PPM order) of impurities, such as Fe ₂ O ₃ ,
Contains TiO ₂ , Al ₂ O ₃ , CaO, K ₂ O, Na ₂ O, etc., linear expansion coefficient is 5.5×10 ^-7 cm/cm°C, softening temperature is 1580-1665°C, annealing temperature is approximately 1140°C shows. Normally, when bonding glass with inorganic materials, the conditions for the inorganic adhesive are: (1) the melting temperature of the adhesive is lower than the heat resistance limit (deformation temperature) of the material to be bonded; and (2) the bonding material. The linear expansion coefficients of the material and adhesive are close to each other, preferably the difference in expansion coefficient is 8×10 ^-7
It is required that the temperature be within cm/cm℃. Therefore, in order to bond two types of glasses with extremely different coefficients of expansion, a common method is to sequentially bond several types of intermediate glasses whose coefficients of expansion vary in stages. For example, in order to connect a hard borosilicate glass tube to the quartz glass tube listed in Table 1, the intermediate glasses listed in the table are sequentially heated in the order of (1), (2), and (3) from the quartz glass side. They are connected by bonding to avoid a sudden step in the coefficient of linear expansion and to prevent a decrease in bonding strength.

[Table] By the way, when bonding quartz glass materials to each other, especially when manufacturing high-precision optical equipment,
Heating the vicinity of the joint of quartz glass above its annealing temperature, which is approximately 1140°C, must be avoided from the perspective of preventing distortion. It is necessary to apply an inorganic material similar to that of the solder glass as a kind of solder glass. As such materials, intermediate glass (1) and (2) in Table 1 have a softening point of 1140°C or higher, and intermediate glass (3) has a low softening point but has an expansion coefficient that is too large to be used. Neither of these methods is suitable for the purpose of the present invention. However, the present inventors have discovered that if an inorganic material having a chemical composition between intermediate glasses (2) and (3) in Table 1 and exhibiting a moderately high softening and melting temperature is applied under specific conditions, Surprisingly, it was confirmed that although the coefficient of expansion was considerably larger than that of quartz glass, it was suppressed to an appropriate range and provided extremely strong adhesion with excellent temperature characteristics. The inorganic material applied to the method of the present invention has a linear expansion coefficient of about 19×10 ^-7 to 21.5×10 ^-7 cm/cm°C, preferably 20.5×10 ^-7 to 21×10 ^-7 cm/cm°C. The softening temperature is about 1050°C or higher and lower than the annealing temperature of quartz glass, preferably 1095 to 1120°C. Such an inorganic material is typically a glass having the following composition: SiO ₂ 83-85 mol% Na ₂ O 2.2-2.7 mol% B ₂ O ₃ 7.2-10 mol% Al ₂ O ₃ 1.5-1.7 mol% Also contains trace amounts of K ₂ O and CaO. Such inorganic materials can be produced from glass raw materials according to conventional methods, but they can also be easily obtained by crushing commercially available intermediate glasses, such as those listed in Table 1, and mixing and melting them in appropriate proportions. can. When pulverizing, mixing, and melting multiple types of intermediate glass, if the composition of the glass phase produced lacks uniformity, phase separation will occur upon remelting, and in severe cases, cracks may occur, making it impossible to achieve the desired result. unable to achieve the goal. Therefore, the inorganic material is required to have a sufficiently uniform composition. Inorganic materials are preferably crushed, crushed, etc.
A powdered glass frit of about 200 mesh or finer is prepared, and an organic binder is added to form a slurry-like or slip-like mixture. Examples of organic binders include polyvinyl alcohol, aqueous solutions such as CMC, polyvinyl butyral,
Organic solvent solutions such as polyvinyl acetate, polyvinyl acetal, nitrocellulose, etc. can be used, but an aqueous polyvinyl alcohol solution is particularly suitable. The above-mentioned slip-like mixture is applied by coating or spraying onto the surfaces of the joint parts of the quartz glass materials to be joined, and the quartz glass materials are placed in contact with each other in a heating device such as an electric furnace. and gradually heat it. The heating is preferably carried out for about 30 minutes or more at a temperature range that is higher than the softening temperature of the glass frit and lower than the annealing temperature of quartz glass (about 1140° C.). During the temperature rise process, the organic binder first thermally decomposes and flies off, undergoes heat cleaning, and then the glass frit softens and melts.
Forms an adhesive layer between quartz glass materials. The bond thus formed is extremely strong;
Not only does it exhibit excellent temperature characteristics, but the adhesive surface does not change even when heated to approximately 1000℃, and no change ^occurs even when quenched in liquid nitrogen.
It was confirmed that there was no change even when the pressure was reduced to a vacuum level of Torr., and that the bond was strong enough to tear apart the other surface if forcedly peeled off. Next, examples of the present invention will be shown. (Example) The method of the present invention was applied to manufacturing a quartz cell. FIG. 3 shows a procedure for manufacturing a dye solution quartz cell used in a dye laser in Examples and Comparative Examples described later. Process (1) Place the two quartz glass side plates 1 and 1' facing each other,
They are fixed in parallel to each other using a temporary fixing jig 5. First, an organic binder (organic binder not containing glass frit) is applied to the upper end surfaces A, A of the side plates 1, 1', and another quartz glass side plate 2 is placed and temporarily bonded. Step (2) The side plates temporarily bonded in step (1) above are turned upside down with the end surfaces A and A side facing down, and the slip-like mixture containing powdered glass frit is applied to the upper end surfaces B and B. Place another side plate 2' on top,
This frame-like assembly is placed into an electric furnace and heated to a predetermined temperature. Due to heating, the organic binder decomposes and flies away, and the two corners B and B are fused together by the glass frit.
are adhered, but the two lower corners A and A are temporarily unbonded due to thermal decomposition and volatilization of the organic binder. Step (3) Turn it upside down with the adhesively fixed corners B and B facing down.
The slip-like mixture is again applied to the end faces A and A, and the side plate 2 is placed on it and fired in an electric furnace to fuse the corners A and A. Step (4) A slip-like mixture is applied to one edge C of the frame consisting of the four side plates assembled and fixed in the above step, placed on the quartz glass bottom plate 6, and heated to a predetermined temperature in an electric furnace as described above. Heat and fuse to complete the cell. Throughout each of the above steps, the heating step was performed by using a quartz plate as an underlay and placing the cell thereon. Also, at the mutual joint surfaces of the four corners of the cell, the first
As shown in the figure, by chamfering the inner edge of the side plate, consideration was given to forming an adhesive surface that avoids the optical path so that the molten adhesive layer does not protrude and affect the dye laser oscillation optical path. Comparative Example 1 A glass rod (manufactured by Corning, product number 7729, RSC-1) having substantially the same composition as the intermediate glass (1) shown in Table 1 above was ground into a fine powder of 200 mesh or more, A quartz cell was manufactured using the powder material mixed with an aqueous polyvinyl alcohol solution to form a slip according to the manufacturing procedure described above.
In this case, since the softening point of the glass frit is as high as 1185°C, it is necessary to maintain the temperature inside the electric furnace around 1200°C, and since the annealing temperature of quartz glass is approximately 1140°C, the quartz glass plate used for the cell and underlay must be kept at around 1200°C. adhered and caused partial peeling, making it impossible to obtain satisfactory cells. Comparative Example 2 A glass rod (manufactured by Corning, product number 7729, RSC-3) having substantially the same composition as the intermediate glass (2) shown in Table 1 was powdered as in Comparative Example 1, and polyvinyl A quartz cell was manufactured using a slip-like mixture with an alcohol aqueous solution according to the manufacturing procedure described above. Since the softening point of the frit was similar to the annealing temperature of quartz glass, the results were unsatisfactory, similar to Comparative Example 1. Comparative Example 3 A quartz cell was prepared according to Comparative Example 1 using a glass rod (manufactured by Corning, product number 7729, RSC-4) having substantially the same composition as the intermediate glass (3) shown in Table 1 above. was produced. In this case, since the softening point of the glass frit is as low as 935°C, the electric furnace temperature could be set to approximately 950°C, and there were no problems as far as the temperature was concerned. Ta. This is considered to be because the expansion coefficient is relatively large. Comparative Example 4 A polyvinyl alcohol aqueous solution was added to a mixture of powders of intermediate glasses (2) and (3) used in Comparative Examples 2 and 3 above at a weight ratio of 2:3, kneaded to form a slip, and the above procedure was followed. Therefore, a quartz cell was fabricated. Figure 4 is a cross-sectional view reproduced from a microscopic photograph (x75) of this adhesive layer cross section (width approximately 3 mm), showing that the adhesive layer formed from uneven frits has phase separated and cracks have occurred. shows. In other words, the intermediate glass (3) rich phase is located on both sides with the intermediate glass (2) phase in the middle, and the intermediate glass has a large expansion coefficient.
(3) Cracks running through the phase are observed. Example 1 The powder mixture of intermediate glasses (2) and (3) used in Comparative Example 4 above was heated and melted to about 2800°C, mixed to form a homogeneous phase, solidified into a rod shape, and further crushed. 200
It was made into mesh or finer powdered glass frit. This frit has intermediate glass (2) and (3)
It has a composition intermediate ^between
cm/cm°C, and the softening point was 1100°C. This material was mixed with an aqueous polyvinyl alcohol solution, formed into a slip, applied to the mating surfaces of quartz glass plates, and heated in an electric furnace to 1100°C for 30 minutes to bond them. A cross-sectional view reproduced from a microscopic photograph (×75) of the cross-section of the adhesive layer is shown in FIG. As is clear from the figure, the adhesive surface was extremely uniform and good. Tests on this adhesive layer showed no change even when exposed to rapid temperature changes from high temperatures of about 1000°C to low temperatures of liquid nitrogen, and no change was observed even under vacuum levels of about 10 ^-5 Torr. I couldn't help it.
In addition, the bond was so strong that part of the surface of the quartz glass plate to which it was bonded was cracked due to tensile failure. Example 2 A powder mixture obtained by mixing the intermediate glasses (2) and (3) powders used in Comparative Examples 2 and 3 at a weight ratio of 3:7 was used as a starting material, and a homogeneous product was prepared in the same manner as in Example 1. We made a powdered glass frit. The average particle size is about 250 mesh, its linear expansion coefficient is 21.5×10 ^-7 cm/cm℃, and its softening point is
It showed 1050℃. Using this glass frit, a quartz glass plate was adhered in the same manner as in Example 1 to produce a dye solution quartz cell. The obtained cell was tested for temperature characteristics, mechanical strength, adhesive strength, etc., and as in Example 1, satisfactory results were obtained. Furthermore, the cell wall exhibited no distortion or deformation that would affect the dye laser oscillation optical path, and maintained a smooth surface with optical precision. (Effects of the Invention) According to the method of the present invention, a specific inorganic material prepared using materials that are easily available in the market is used as an adhesive medium to achieve high precision between quartz glass materials, which was previously considered almost impossible. Bonding is easy, there is no residual organic compound on the bonding surface, there is no distortion or deformation of the quartz glass material, the temperature characteristics are very good, and the bonding has extremely high mechanical and chemical bonding strength. Because it is possible to achieve this, we can manufacture quartz glass products that maintain the expected optical precision, which has been considered difficult until now, such as the optical path part of cryogenic dewars.
It is expected to have a wide range of applications, such as connecting thick quartz tubes and making shutoffs inside cells. It is particularly effective for manufacturing and repairing dye solution quartz cells used in dye lasers pumped by high-power lasers.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a dye solution cell for a dye laser to which the method of the present invention is applied, and FIG. 2 is a state diagram showing a state of exfoliation damage on the inner wall surface of the dye solution quartz cell.
FIG. 3 is a schematic explanatory diagram of the quartz cell manufacturing procedure, and FIG. 4 is an enlarged microscopic view (magnification: 75 times) of a cross section of the adhesive layer obtained by a method that does not satisfy the conditions of the method of the present invention.
Furthermore, FIG. 5 is an enlarged microscopic view (magnification: 75 times) of the adhesive layer obtained by the method of the present invention. 1, 1', 2, 2'... quartz glass side plate, 3...
Adhesive surface, 4... Dye laser oscillation optical path, 5... Temporary fixing jig, 6... Quartz glass bottom plate, A, B... Corner (end surface), C... Edge, M ₁ , M ₂ ... Mirror , P...
...Dye solution.

Claims (1)

[Claims] 1. Linear expansion coefficient of approximately 19×10 ^-7 to 21.5×10 ^-7 cm/cm
℃, and the softening temperature is about 1050℃ or higher and lower than the annealing temperature of silica glass.A slip-like mixture consisting of a glass frit of a uniform composition and an organic binder is applied to the mating surfaces of a plurality of quartz glass materials, and the softening temperature is Inorganic material adhesion between quartz glasses, characterized in that the organic binder is heat-cleaned by heating to a temperature above the temperature and below the annealing temperature of the quartz glass, and the quartz glass materials are bonded to each other by fusing the glass frits. Law. 2. The method for bonding inorganic materials between quartz glasses according to claim 1, wherein the heating is performed for at least about 30 minutes. 3 The linear expansion coefficient of glass frit is 20.5×10 ^-7 ~
21×10 ^-7 cm/cm℃, and the softening temperature is 1095 to 1120
The method for adhering inorganic materials between quartz glasses according to claim 1, wherein the temperature is .degree. 4. The glass frit contains the following components: SiO ₂ 83-85 mol% Na ₂ O 2.2-2.7 mol% B ₂ O ₃ 7.2-10 mol% Al ₂ O ₃ 1.5-1.7 mol% K ₂ O trace amount CaO trace amount A method for adhering inorganic materials between quartz glasses according to claim 1, having a composition as follows. 5. The method for adhering inorganic materials between quartz glasses according to claim 1, wherein the organic binder is an aqueous polyvinyl alcohol solution. 6. The quartz according to any one of claims 1, 2, 3, 4, and 5, wherein the quartz glass material is a quartz glass plate constituting a dye solution cell for a dye laser. Inorganic material adhesion method between glasses. 7. The inorganic material adhesion method between quartz glasses according to claim 6, wherein the mutual bonding surfaces are formed avoiding the dye laser oscillation optical path.