JP6406939B2 - Amorphous alloy, mold for molding, and method of manufacturing optical element - Google Patents

Description

  The present invention relates to a molding die used in a method for producing a molded body such as an amorphous alloy and a camera lens using the amorphous alloy, and a method for producing an optical element using the molding die.

  A glass material press molding technique that does not require a grinding process or a polishing process has a simple manufacturing process and can manufacture an optical element. For this reason, in recent years, not only lenses but also prisms and other optical elements are generally used as optical elements.

  Properties required for a mold material used for press molding of a glass optical element include excellent heat resistance, chemical stability, hardness, releasability, and workability.

  Regarding the mold for molding, Patent Document 1 discloses that a cemented carbide excellent in heat resistance, oxidation resistance, and hardness is processed into a desired shape, and its surface is chemically stable and has releasability from a glass material. There has been proposed a mold in which a noble metal is coated as a release film.

  However, in recent years, various glass materials have been used for optical elements in order to realize various optical designs. Some of these glass materials contain highly reactive components such as phosphorus and fluorine. For molding such glasses, there is no reaction due to corrosive components emitted from the glass materials. A mold release film is required. As such a mold, Patent Document 2 proposes a glass molding mold using an amorphous alloy having high corrosion resistance.

JP 60-246230 A WO2007 / 046437

  However, although the amorphous alloy with high corrosion resistance described in Patent Document 2 is chemically stable, it is used for a cutting layer and does not have high hardness. Among the amorphous alloys described in Patent Document 2, some of the alloys with high hardness were selected and measured. Among them, the composition of the amorphous alloy with the highest hardness was Pt of 58 at%, Hf of 21 at%, Zr of 12 at%, Ni of 10 at%, and the hardness was measured to be 9 GPa.

  At the time of glass molding, cemented carbides are rubbed against each other at the molding die and the sliding portion of the apparatus, and cemented carbide powder is generated. The hardness of the carbide used as the mold material is about 13 to 18 GPa. When glass molding is performed in a state where the cemented carbide powder generated in the sliding portion is placed on the mold, the cemented carbide powder is strongly pressed against the mold by the glass. At this time, if the coating used for the mold is about 9 GPa as in the release film described in Patent Document 2, the mold may bite the carbide scrap when molding, and the coating may be damaged. is there. When a glass optical element is molded with a molding die having such scratches, the scratches on the molding die are also transferred to the glass optical element, resulting in poor appearance of the glass optical element.

  The present invention has been made in view of such background art, and is formed using an amorphous alloy that is chemically stable, has high corrosion resistance, and has high hardness, and that uses the amorphous alloy that is difficult to be damaged during molding. A mold is provided. Moreover, this invention provides the manufacturing method of the optical element using the said shaping | molding die.

The present invention is an amorphous alloy containing Nb, W and Ni, and the amorphous alloy has a Nb content of 7.5 at% or more and 52.9 at% or less, and a W content of 16.4 at% or more. 47.0At% Ri der less, the content of Ni is less 22.0At% or more 29.0 at%, the amorphous alloy, Nb, the total content of W and Ni at least 97.0At% The present invention relates to an amorphous alloy characterized by being.

Furthermore, the present invention may have a release layer formed by A Amorphous alloy on the mold bases, the amorphous alloy, the content of Nb is less 35.0At% or more 41.7at%, W The content of Ni is 35.4 at% or more and 40.4 at% or less, the Ni content is 22.0 at% or more and 25.0 at% or less, and the amorphous alloy has a total content of Nb, W and Ni. The present invention relates to a mold for molding characterized in that is 97.0 at% or more .

  Furthermore, this invention relates to the manufacturing method of the optical element characterized by having the process of pressing and shape | molding a glass preform using this shaping | molding die.

  According to the present invention, it is possible to provide an amorphous alloy that is chemically stable and has high hardness, and it is possible to provide a molding die that is difficult to be damaged during molding. In addition, according to the present invention, it is possible to provide a method for manufacturing an optical element using the molding die that is difficult to be damaged during molding.

It is the schematic which shows one embodiment of the shaping | molding die of this invention. It is explanatory drawing which shows an example of the sputtering device which performs film-forming, such as a coating of the amorphous alloy of this invention. It is the schematic explaining the inside of the chamber of the sputtering device which performs film-forming, such as a coating of the amorphous alloy of this invention. It is explanatory drawing which shows the sputtering device which performs the coating etc. of the amorphous alloy of this invention. It is the schematic of the molding machine used for the manufacturing method of the optical element of this invention.

  The present invention relates to a molding die used for manufacturing an optical element such as an amorphous alloy, a lens, and a prism by press molding a glass material, and a method for manufacturing the optical element.

  Hereinafter, embodiments of the present invention will be described in detail.

(Amorphous alloy)
The Nb—W—Ni amorphous alloy of the present invention is chemically stable and has a high hardness.

  The amorphous alloy of the present invention is an amorphous alloy containing Nb, W and Ni. The amorphous alloy of the present invention has an Nb content of 35.0 at% or more and 41.7 at% or less, a W content of 35.4 at% or more and 40.4 at% or less, and a Ni content of 22. It is 0 at% or more and 25.0 at% or less. The amorphous alloy of the present invention has a Nb content of 7.5 at% or more and 52.9 at% or less, a W content of 16.4 at% or more and 47.0 at% or less, and a Ni content of 22. It is preferably 0 at% or more and 29.0 at% or less.

  Further, the amorphous alloy of the present invention has an Nb content of 35.0 at% to 41.7 at% and a W content of 35.4 at% to 40.4 at%. The amount is preferably 22.0 at% or more and 25.0 at% or less. An amorphous alloy satisfying this composition has not only high hardness and high corrosion resistance, but also excellent heat resistance. In the present specification, “at%” indicates the atomic composition percentage.

  Since the amorphous alloy of the present invention is an Nb—Ni alloy and contains W, it has high hardness, is chemically stable, and has high heat resistance.

  In the amorphous alloy of the present invention, the total content of Nb, W and Ni is 97.0 at% or more and 100 at% or less, more preferably 99.0 at% or more and 100 at% or less, further preferably 99.8 at% or more and 100 at% or less. It is preferable that Inevitable impurities contained in the amorphous alloy of the present invention include Fe. The content of unavoidable components other than oxygen contained in the amorphous alloy of the present invention is preferably 0.2 at% or less, more preferably 0.03 at% or less with respect to the entire amorphous alloy.

(Molding mold)
The molding die of the present invention is characterized in that it has one or more release films formed of the Nb—W—Ni amorphous alloy on the surface.

  Further, since the release film used in the molding die of the present invention is made of an amorphous alloy having the above composition, it has excellent corrosion resistance and heat resistance and has a hardness equal to or higher than that of cemented carbide.

  The molding die of the present invention is chemically stable and has a high mold releasability because it is a chemically stable amorphous alloy, and has a high hardness so that it is difficult to be damaged during molding.

  Further, in the release film used in the molding die of the present invention, since W is contained in the Nb—Ni alloy, the desired film can be obtained at a relatively low cost compared to the case of using other highly hard and chemically stable noble metals. It is possible to obtain an alloy film having characteristics.

  In the release film used in the molding die of the present invention, elements other than Nb, W, and Ni are elements of unavoidable components due to trace impurities contained in the target material, particles in the film forming vacuum chamber, and residual gas. is there. Further, when the amorphous alloy is formed by vacuum film formation, oxygen may be taken into the film by a residual gas such as moisture in the film formation vacuum chamber during film formation. Ideally, there should be no oxygen in the film, but even if the adsorbed gas on the inner wall of the chamber is reduced by long-term evacuation or baking of the chamber, 0.1 to several at% of the entire amorphous alloy is taken in. May end up. The release film of the amorphous alloy of the present invention has a desired amorphous property (non-crystalline property), that is, an amorphous structure (amorphous structure) even if the film contains such inevitable oxygen during film formation. And has hardness.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic view showing an embodiment of the molding die of the present invention. In FIG. 1, a molding die 10 according to the present invention includes a mold base 11, an adhesion layer 12 laminated on the mold base 11, a protective layer 13 laminated thereon, and a release layer laminated thereon. And a mold layer 14. As the mold base 11, a cemented carbide which is a sintered body of tungsten carbide can be used, and ceramics such as SiC can be used. As the adhesion layer 12, a metal layer such as Ti or Cr can be used. The protective layer 13 can be made of a metal nitride such as TiN, CrN, or TiAlN. The release layer 14 is made of an amorphous alloy having the Nb—W—Ni composition of the present invention.

  The Ti layer 12, TiN layer 13, and release layer 14 are sequentially laminated on the cemented carbide substrate 11 by physical vapor deposition such as sputtering. Further, the release layer 14 having a desired alloy composition ratio is formed by a sputtering method using a target having a desired composition ratio, or multi-source sputtering using a sputtering apparatus 20 having a plurality of targets 25 and 26 as shown in FIG. Can be formed. As the physical vapor deposition method, ion plating, arc plasma vapor deposition method, ion beam sputtering method or the like may be used in addition to the sputtering method.

  In addition to film formation, it is possible to obtain an alloy having similar characteristics as a bulk by melting and mixing metal materials and then rapidly cooling them.

  2, 3, and 4 are explanatory diagrams illustrating an example of a sputtering apparatus that forms the release layer 14, the adhesion layer 12, and the protective layer 13 of an amorphous alloy. A film forming process for forming a Ti layer as the adhesion layer 12, a TiN layer as the protective layer 13, and an amorphous alloy as the release layer 14 will be described below with reference to FIGS.

  As shown in FIG. 2, the sputtering apparatus 20 includes a vacuum chamber 21, a substrate holder 22 in the vacuum chamber 21, a halogen lamp heater 23, and a thermocouple thermometer 24. The sputtering apparatus 20 includes an Nb sputtering target 25 and a W sputtering target 26. When three or more sputtering targets are used, as shown in FIG. 3, a target in which a Nb sputtering target 25, a W sputtering target 26, and a Ni sputtering target 30 are provided in a circular shape is used. The sputtering apparatus 20 includes an Nb sputtering target RF power source 27, a W sputtering target RF power source 28, and a Ni sputtering target RF power source (not shown). Further, a magnet 29 for Nb sputtering target, a magnet 210 for W sputtering target, and a magnet for Ni sputtering target (not shown) are provided. The sputtering apparatus 20 includes an Ar gas supply line 211 for an Nb sputtering target, an Ar gas supply line 212 for a W sputtering target, and an Ar gas supply line (not shown) for an Ni sputtering target. Furthermore, a mass flow controller 213 for Nb sputtering target, a mass flow controller 214 for W sputtering target, and a Ni sputtering target mass flow controller (not shown) are provided. A DC bias power source 215 for the substrate holder 22 is provided.

  As shown in FIG. 4, the vacuum chamber 21 includes a two-stage exhaust system for evacuation. The vacuum chamber 21 is connected to a dry pump 219 via a valve 217. A vacuum gauge 221 is provided between the system connecting the valve 217 and the dry pump 219. The vacuum chamber 21 is connected to a turbo molecular pump 220 via a valve 216, and this turbo molecular pump 220 is further connected to a dry pump 219 via a valve 218.

  In the production of the molding die of the present invention, the mold base 11 processed into a desired shape is placed on the substrate holder 22. At this time, first, a Ti sputtering target (not shown) is set as the sputtering target, the dry pump 219 is activated, the valve 217 is opened, and the vacuum chamber 21 is evacuated. After confirming with the TC vacuum gauge 221 that the vacuum was evacuated to a predetermined vacuum level of several Pa by the dry pump 219, the valve 217 was closed, the valves 218 and 216 were opened, and the turbo molecular pump 220 was started to perform vacuum. The chamber 21 is evacuated. The vacuum chamber 21 may be provided with a load lock chamber (not shown) so that the vacuum chamber 21 is not opened to the atmosphere when the mold is installed in the vacuum chamber 21.

  Next, the halogen lamp heater 23 is turned on to generate infrared rays, and the mold base 11 and the substrate holder 22 are warmed by the infrared rays. The temperatures of the mold base 11 and the substrate holder 22 are controlled by a thermocouple 24 installed in the vicinity of the halogen lamp heater 23. The temperature fluctuation read by the thermocouple 24 is reflected on the input power to the halogen lamp heater 23 as needed so as to stabilize the temperature.

Next, Ar gas is introduced into the vacuum chamber 21 from the mass flow controller 213 after reaching a high degree of vacuum of the order of 10 ⁻⁵ Pa in order to minimize the intake of residual gas in the vacuum chamber into the film. The inside of the vacuum chamber 21 is maintained at a pressure of about 0.2 to 1 Pa. Then, power is applied from the RF power source 27 to the target 25. In order to generate plasma discharge, a gas trigger is applied for several hundreds of milliseconds using the mass flow controller 213 such that the inside of the vacuum chamber 21 becomes several Pa. Then, the film material is released from the Ti target (not shown) by the plasma discharge and laminated on the surface of the mold base 11. At this time, pre-sputtering for removing the Ti oxide layer on the surface of the Ti target is preferably performed in advance. In this pre-sputtering, for example, a shutter (not shown) is placed on the target, and the Ti oxide layer on the surface of the target is formed by closing the shutter and preventing plasma from being deposited on the mold base 11. Is to be removed. In addition, by applying a bias potential to the substrate holder 22 and the mold base 11 using the power source 215 during film formation, Ar ions generated by plasma discharge collide with the film with the energy of the applied potential, Improves denseness and adhesion to the film mold. The film thickness of the Ti film 12 can be controlled by the film formation time.

Further, after the Ti film is formed, a mixed gas of Ar and N ₂ is introduced from the mass flow controller 213, and the inside of the vacuum chamber 21 is maintained at a pressure of about 0.2 to 1 Pa. Then, power is applied from the RF power source 27 to the Ti target 25. In order to generate plasma discharge, a gas trigger is applied for several hundred milliseconds using the mass flow controller 213 so that the inside of the vacuum chamber 21 becomes several Pa. Then, the film material is released from the Ti target 25 by the plasma discharge and laminated on the surface of the mold base 11. The Ti film is nitrided by N ₂ gas introduced into the vacuum chamber 21 to form a TiN layer 13. At this time, it is better to perform pre-sputtering for removing the Ti oxide layer on the surface of the Ti target in advance. For example, the Ti oxide layer on the target surface is removed by setting a shutter (not shown) on the target and setting the plasma discharge in a state where the shutter is closed so that no film is deposited on the mold base 11. Is. Further, by applying a bias potential to the substrate holder 22 and the mold base 11 using the power source 215 during film formation, Ar and N ₂ ions generated by plasma discharge collide with the film with the energy of the applied potential. Thus, the denseness of the film and the adhesion to the film mold can be improved. The film thickness of the TiN layer 13 can be controlled by the film formation time.

  And Ti sputtering target (not shown) is changed into the Nb sputtering target 25, and the same apparatus is used. A plasma is formed on the target by an RF power source and a magnet on the back of the target, and a ternary sputtering film of Nb, W, and Ni is formed on the mold base 11 on which the TiN layer 13 is applied, thereby forming a release layer 14. To do. It is possible to adjust the composition of the alloy film which is the release layer 14 by adjusting the power ratio of each RF power source.

(Optical element manufacturing method)
The method for producing an optical element of the present invention is characterized by including a step of pressing and molding a glass preform using the above-described molding die.

  FIG. 5 is a schematic view of a molding machine used in the method for producing an optical element of the present invention. An optical element manufacturing method will be described with reference to FIG. The molding machine 50 includes a molding die 10 having a chamber 51 and a release film formed of the amorphous alloy of the present invention. Further, the glass preform 52 to be molded is put into the molding die 10. The molding machine 50 includes a heater 53, a shaft 54 for pressing the upper die, a body die 55 for determining the shaft position when pressing the upper die, and a support base 56 for supporting the lower die and applying pressure.

  The inside of the chamber 51 is purged with nitrogen, and then the glass preform 52, the molding die 10, and the barrel die 55 are heated to a desired temperature by the heater 53. Thereafter, the glass preform 52 is press-molded by the upper and lower molding dies 10 using the shaft 54 and the support base 56.

  When molding is repeated, the upper mold slides with respect to the body mold, so that dust of super hard powder is generated from the sliding portion. The glass may be pressed while the super hard powder is involved, but the mold release film of the molding die 10 is harder than the super hard powder, so that the release film is hardly damaged. For this reason, it is possible to prevent the appearance defect of the glass molded product caused by the scratch on the molding die.

  In addition, since the molding die of the present invention is a release film of an amorphous alloy that is chemically stable by forming a stable passive film on the surface with no crystal grain boundary at the contact surface with the glass, Fusing to the mold is difficult to occur. The thickness of the release film is preferably 20 nm or more and 1000 nm or less. This is because if the film thickness is excessively thin, the film material does not have a sufficient layer shape at the time of film formation and becomes an island shape, and microscopically, there may be a portion where the amorphous alloy of the present invention is not laminated. If the film thickness is 20 nm or more, the film is formed into a layer by sputtering.

  Further, when the film thickness of the release film is on the order of μm exceeding 1000 nm, the film stress increases and the possibility of film peeling occurs. Although it is possible to form a film having a thickness of more than 1000 nm by controlling stress by adjusting the film forming conditions and taking a countermeasure against peeling by inserting an adhesion layer, such a film does not need to be formed. For this reason, when the film thickness is 1000 nm or less, it is possible to save the labor of stress control by adjusting the film forming conditions and peeling countermeasures by inserting the adhesion layer.

  Furthermore, it is possible to improve the releasability by coating the glass preform with DLC (diamond-like carbon). In this case, since the mold can be released at a high temperature after molding, the tact time can be shortened and the productivity can be improved. In such a case, since the hardness of the DLC film coated on the glass preform is 13 GPa or less, even if the amorphous alloy according to the present invention is used as a release film on the mold surface, the DLC film on the glass preform is molded. It is possible to suppress the occurrence of scratches due to contact with time.

  Examples of the optical element obtained by the production method of the present invention include a lens, a prism, and a diffraction grating.

  An alloy prepared by a film forming process using the sputtering apparatus described in the embodiment is shown as an example. The present invention is not limited to this film forming process. In the examples, evaluation was performed by the following method.

(composition)
The composition was measured with an XPS apparatus manufactured by ULVAC-PHI: PHI Quantera SXM. A survey scan was performed in advance, and a narrow scan was performed on the recognized elements. Further, for each measurement, 4 kV sputtering was performed three times for 1 minute to obtain a depth profile. Finally, the value at which the composition did not fluctuate was determined as the composition of the alloy.

(hardness)
Hardness was measured with a nanoindenter of Agilent Technologies, Inc. The sample was measured 10 points while shifting the sample side by side by 50 μm, and after removing data showing an abnormal value due to the influence of dust or the like, each measurement value was averaged to determine the value.

(crystalline)
The crystallinity was determined by measuring using the Philips X'pert θ-2θ method and confirming the presence or absence of a crystalline peak.

The crystallinity after heating was measured after heating at a temperature of 500 ° C. for 100 hours in a chamber evacuated to 1.5 × 10 ⁻⁵ Pa.

(Glass composition)
Elements other than F were analyzed by plasma emission analysis. F was measured with an ion meter after steam distillation.

Example 1
Examples of the Nb—W—Ni amorphous alloy film according to the present invention and a mold using the same will be described below.

In Example 1, a sintered Nb target material having a diameter of 76.2 mm (3 inches) and a purity of 99.9% was used as a raw material for the amorphous alloy. For W, a molten W target material having a diameter of 76.2 mm (3 inches) and a purity of 99.9% was used. As the Ni, a sintered Ni target material having a diameter of 76.2 mm (3 inches) and a purity of 99.9% was used. An alloy film was formed using these target materials, the sputtering apparatus shown in the embodiment, and the film formation process described above. The ultimate pressure before film formation is 5 × 10 ⁻⁵ Pa, the pressure in the chamber during film formation is 0.5 Pa, the DC bias to the substrate holder is −100 V, and the film formation rate is 0.2 nm / S.

  As for the molding die in Example 1, the upper die is ground and polished, the outer shape is 18 mm, and the surface of a carbide J05 die (manufactured by Fuji Dice) processed into a convex shape with a curvature radius of 22 mm is formed with a Ti layer and TiN. The layers were combined and laminated to a thickness of 1.2 μm. Further, as a release film, an amorphous alloy having a Nb content of 39.3 at%, a W content of 37.9 at%, and a Ni content of 22.9 at% is formed to a thickness of 170 nm. Laminated.

  The lower die was laminated with a thickness of 1.2 μm on the surface of a cemented carbide J05 die that had been machined into a concave shape with an outer diameter of 18 mm and a radius of curvature of 22 mm by grinding and polishing. Further, as a release film, an amorphous alloy having a Nb content of 39.3 at%, a W content of 37.9 at%, and a Ni content of 22.9 at% is formed to a thickness of 170 nm. Laminated.

The amorphous alloy had a hardness of 14.9 GPa. Moreover, it was amorphous as a result of X-ray diffraction. Further, after heating the alloy film at a temperature of 500 ° C. for 110 hours in a chamber evacuated to 1.5 × 10 ⁻⁵ Pa, the amorphous structure was maintained as a result of measurement by the measurement method. It was.

  Using this molding die, a glass preform of optical glass L-BAL42 manufactured by OHARA Inc. was molded. The glass preform was pressed at a temperature of 620 ° C. for 1 minute. When the mold was observed after the completion of molding, no problematic scratches or glass fusion were observed on the surface. Also, the molded glass had no appearance defects such as scratches.

  As described above, when the molding die according to the present invention is used, even in an environment in which dust is generated from the sliding portion, the mold or the molded product is not damaged, and molding with no appearance defect becomes possible.

(Example 2)
In Example 2, the same target material as in Example 1 was used. An alloy film was formed using these target materials and the film formation process described in the embodiment. An alloy film was formed on these target materials in the same manner as in Example 1. The ultimate pressure before film formation is 5 × 10 ⁻⁵ Pa, the pressure in the chamber during film formation is 0.5 Pa, the DC bias to the substrate holder is −100 V, and the film formation rate is 0.2 nm / S.

  In the molding die of Example 2, the upper die is ground and polished, the outer shape is 18 mm, and the surface of a carbide J05 die (manufactured by Fuji Dice) processed into a convex shape with a curvature radius of 22 mm is formed with a Ti layer and TiN. The layers were combined and laminated to a thickness of 1 μm. Further, as a release film, an amorphous alloy having a Nb content of 37.9 at%, a W content of 37.0 at%, and a Ni content of 25.0 at% has a thickness of 150 nm. Laminated.

  The lower die has a thickness of 1 μm with a Ti layer and a TiN layer on the surface of a cemented carbide J05 type (manufactured by Fuji Dice) that is ground and polished and has an outer shape of 18 mm and a radius of curvature of 22 mm. Laminated. Further, as a release film, an amorphous alloy having a Nb content of 37.9 at%, a W content of 37.0 at%, and a Ni content of 25.0 at% has a thickness of 150 nm. Laminated.

The amorphous alloy was amorphous as a result of X-ray diffraction. The hardness of this amorphous alloy was 14.7 GPa. This alloy film was heated in a chamber evacuated to 1.5 × 10 ⁻⁵ Pa using a SiC heater at a temperature of 500 ° C. for 110 hours, but the amorphous structure was maintained by the measurement method.

_SiO 2 _-57.0mol% using this _{type, B 2 O 3 -16.2mol%,} Al2O3-0.2mol%, K 2 O-12.3mol%, glass-flop is F 2 -14.3mol% A reform was formed. Before forming the glass preform, a diamond-like carbon film having a thickness of 20 nm was coated on the surface, and the glass preform was pressed at a temperature of 600 ° C. for 1 minute.

  No flaws or glass fusion that would cause problems on the mold surface after molding. The molded glass was not scratched to cause an appearance defect. In Example 2, since a glass preform containing a large amount of fluorine ions could be formed, the release film having the composition of Example 2 was excellent in corrosion resistance.

(Example 3)
In Example 3, the target material was used as in Example 1. An alloy film was formed using these target materials and the film formation process described in the embodiment. An alloy film was formed on these target materials in the same manner as in Example 1. The ultimate pressure before film formation is 5 × 10 ⁻⁵ Pa, the pressure in the chamber during film formation is 0.5 Pa, the DC bias to the substrate holder is −100 V, and the film formation rate is 0.2 nm / S.

  In the molding die in Example 3, the upper die is ground and polished, the outer shape is 18 mm, and the surface of a cemented carbide J05 type (manufactured by Fuji Dice) processed into a convex shape with a curvature radius of 22 mm is formed with a Ti layer and TiN. The layers were combined and laminated to a thickness of 1.2 μm. On top of that, an amorphous alloy having a Nb content of 35.0 at%, a W content of 40.4 at%, and a Ni content of 24.6 at% is formed to a thickness of 200 nm as a release film. Laminated.

  The lower die has a thickness of 1.2 μm with a Ti layer and a TiN layer on the surface of a cemented carbide J05 type (made by Fuji Dice) that has been ground and polished and has an outer shape of 18 mm and a radius of curvature of 22 mm. Laminated. On top of that, an amorphous alloy having a Nb content of 35.0 at%, a W content of 40.4 at%, and a Ni content of 24.6 at% is formed to a thickness of 200 nm as a release film. Laminated.

The hardness of the amorphous alloy was 15.9 GPa. As a result of X-ray diffraction, it was amorphous. Further, the amorphous structure was maintained after heating the alloy film at a temperature of 500 ° C. for 100 hours in a chamber evacuated to 1.5 × 10 ⁻⁵ Pa using a SiC heater.

CaO-9.7 _mol% with this _{type, SrO-9.4mol%, P 2} O 5 -6.3mol%, Al 2 O 3 -5.5mol%, BaO-4.2mol%, MgO-3. A glass preform of 9 mol% and F-61.0 mol% was molded. Molding was performed by pressing a glass preform at 510 ° C. for 1 minute.

  No flaws or glass fusion that would cause problems on the mold surface after molding. The molded glass was not scratched to cause an appearance defect. In Example 3, since a glass preform containing a large amount of fluorine could be formed, the release film having the composition of Example 3 was excellent in corrosion resistance.

(Examples 4 to 8, Reference Examples 1 to 15 )
In Examples 4 to 8 and Reference Examples 1 to 15 , amorphous alloy films and molds were produced in the same manner as in Example 1 except that the composition of the amorphous alloy was changed to the composition shown in Table 1. The evaluation results are shown in Table 1.

(Comparative Examples 1 to 6)
In Comparative Examples 1 to 6, an amorphous alloy film and a molding die were produced in the same manner as in Example 1 except that the composition of Nb—W—Ni was shown in Table 3. The evaluation results are shown in Table 1.

(Evaluation)
In Examples 1-8 and Reference Examples 1-15 , as shown in Table 1, the Nb content is 7.5 at% or more and 52.9 at% or less, and the W content is 16.4 at% or more and 47. An amorphous alloy having a Ni content of 22.0 at% or more and 53.3 at% or less was produced. In Examples 1 to 23, an amorphous alloy having an amorphous state and high hardness after film formation was obtained. In addition, a molding die using this amorphous alloy as a release layer can mold glass containing a large amount of fluorine ions, and has excellent corrosion resistance.

  In Examples 1 to 5, as shown in Table 1, the Nb content is 35.0 at% or more and 41.7 at% or less, and the W content is 35.4 at% or more and 40.4 at% or less. An amorphous alloy having a Ni content of 22.0 at% or more and 25.0 at% or less was produced. In Examples 1 to 5, amorphous alloys having high heat resistance, high hardness and high corrosion resistance even after heating to 550 ° C. were obtained.

  In Comparative Examples 1 to 6, as shown in Table 1, only amorphous alloys that became crystals and did not become amorphous or had low hardness were obtained.

It was found that when the amorphous alloys of Examples 1 to 8 and Reference Examples 1 to 15 were used, a mold having a release layer strength of 13.3 GPa or more and 19.8 GPa or less was obtained.

  Molds using the Nb-W-Ni amorphous alloy of the present invention and the amorphous alloy of the present invention are chemically stable, have good releasability, have high hardness, and are not easily damaged during molding. It can be used for molding optical elements such as lenses and prisms.

DESCRIPTION OF SYMBOLS 10 Mold for molding 11 Type | mold base material 12 Adhesion layer 13 Protective layer 14 Release layer

Claims (7)

An amorphous alloy containing Nb, W and Ni;
The amorphous alloy is the content of Nb is less 7.5 at% or more 52.9At%, Ri 47.0At% der less content than 16.4At% of W, the content of Ni 22.0At % To 29.0 at% ,
The amorphous alloy is characterized in that the total content of Nb, W and Ni is 97.0 at% or more .   The Nb content is 35.0 at% or more and 41.7 at% or less, the W content is 35.4 at% or more and 40.4 at% or less, and the Ni content is 22.0 at% or more and 25 The amorphous alloy according to claim 1, wherein the amorphous alloy is 0.0 at% or less. A release layer formed of A Amorphous alloys possess on the mold bases,
The amorphous alloy has a Nb content of 35.0 at% to 41.7 at%, a W content of 35.4 at% to 40.4 at%, and a Ni content of 22.0 at%. And not more than 25.0 at%,
The molding die , wherein the amorphous alloy has a total content of Nb, W and Ni of 97.0 at% or more . The strength of the release layer is 13.3 GPa or more and 19.8 GPa or less,
The mold according to claim 3 , wherein the strength of the release layer is greater than the hardness of the mold base. The mold according to claim 3 or 4 , wherein the mold has one or more metal layers between the mold release film and the mold base. A method for producing an optical element, comprising a step of pressing and molding a glass preform using the molding die according to any one of claims 3 to 5 . The method of manufacturing an optical element according to claim 6 , wherein the glass preform has a surface coated with diamond-like carbon.

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