JPH01115829A - Forming mold for glass molded article - Google Patents

Abstract

PURPOSE:To obtain a forming mold consisting of upper and lower bases providing surface layer formed by dispersing a nitride into a substance consisting of at least Pt and Au and especially capable of affording a glass molded article having high precision and requiring no polishing after press molding. CONSTITUTION:The surface layer of the above-mentioned forming mold is formed from a substance obtained by dispersing one or more nitrides selected from TiN, BN, Si3N4, HfN, NbN and ZrN into a substance consisting of preferably at least 2 components of Pt and Au. The substance contains 5-45wt.% Au and the dispersing amount of the above-mentioned nitride is 0.02-30vol.%. An intermediate containing Ni, Ti, Cr, Mo, etc., and one or more of mixture thereof is preferably provided between the above-mentioned surface layer and the ground base. The glass forming mold formed thus has excellent denseness, hardness, strength and chemical resistance as well as good releasability.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a mold for press-molding glass, and in particular to a mold for forming a high-precision glass molded body that does not require polishing after press-forming. Regarding molds.

(Prior art) In general, when forming glass by press molding, pre-softened glass to be formed is placed (or The surface layer of the mold is transferred to the glass to be molded by placing the molded glass in a mold and then heating and softening it, and applying a predetermined pressure to the mold. Therefore, since the shape of the surface layer of the mold is directly transferred as the surface shape of the glass molded object, the surface layer of the mold has no defects such as pores, and can be precisely processed into a dense and mirror-like surface. It is required to meet requirements such as maintaining sufficient hardness and strength at high temperatures.

Conventionally, materials for such molds include silicon carbide (S i C) and silicon nitride (St3).
NJ) (Japanese Unexamined Patent Publication No. 52-45613), tungsten carbide (Japanese Unexamined Patent Application No. 56-59641), zirconium oxide (ZrOz) as a base material, and platinum-rhodium (Pt-Rh) alloy or platinum - A method in which a coating film of an iridium (Pt-Ir) alloy is formed has been proposed (Japanese Patent Application Laid-open No. 176930/1983).

(Problem to be solved by the invention) However, although molds with a surface layer of silicon carbide or silicon nitride are dense and have excellent hardness and strength, they contain a large amount of lead in the glass to be molded. When a heavy flint-based optical glass containing lead is used, it has high chemical reactivity with lead, making it difficult to mold into a high-precision glass molded body.

Next, although tungsten carbide molds have excellent workability, they are susceptible to oxidation at high temperatures, causing roughness on the mold surface and making it impossible to maintain an optical surface. There was also the problem that it easily reacted with the glass to be formed.

In addition, it is said that the advantage of coatings formed with platinum-rhodium or platinum-iridium alloys is that they do not cause chemical reactions with the glass to be formed, but according to experiments conducted by the present inventors, There has been a problem in that mold releasability from the glass molded product has been poor since the beginning of press molding.

(Means for Solving the Problems) A mold for a glass molded article according to the present invention has a surface layer of the mold in which nitride is dispersed in a substance consisting of at least two components, platinum (Pt) and gold (Au). It is being formed.

Preferably, the substance consisting of at least two components of platinum (Pt) and gold (Au) contains 5 to 45 wt of gold (Au).
%, and the nitride is T i N, T a N.

AI! N, BN, Si, N4, HfN, NbN.

It is made of at least one selected from ZrN, and has a dispersion amount of 0.02 to 30vo 1%, and further contains nickel (Ni), titanium (
Ti), chromium (Cr), molybdenum (Mo), cobalt (Co), titanium nitride (TiN), titanium carbide (TiC), silicon carbide (SiC)
and an intermediate layer containing at least one selected from a mixture thereof.

These surface layers and intermediate layers are formed on a substrate processed into a predetermined shape by a sputtering method, an ion blasting method, or the like. The film thickness is preferably about 0.05 to 10 μm. If it is too thin, a uniform film will not be obtained; if it is too thick, not only will it take longer to form the film, but the surface of the film will become rough.

In addition to gold, iridium (I) is used as the surface layer material.
r), rhodium (Rh), and osmium (O3)
If nitride is dispersed in a platinum alloy containing ruthenium (Ru), palladium (Pd), etc., the layer can withstand use in high-temperature presses.

The base material of the mold is not particularly limited as long as it satisfies the hardness, strength, heat resistance, etc. generally required for a base, and examples include stainless steel, tungsten carbide (WC), zirconium oxide (ZrOz), cermet, Silicon carbide (S i C) and silicon nitride (SisN4) can be used. Further, as long as the pressure during press molding does not cause a problem in deformation of the base, the base material may be the same alloy as the materials of the above-mentioned surface layer and intermediate layer.

(Function) The surface layer of the mold of the present invention not only has good density, hardness, strength, workability, and chemical reaction resistance, but also has good releasability from a press-molded glass molded body. In addition, crystal growth is suppressed and film roughness is suppressed. That is, platinum-gold alloy (platinum 50 wt% or more, gold 5
~45wt%), specifically TiN5Ta
N, AlNx BN.

By dispersing Si, N, HfN, NbN, ZrN, etc., it is possible to particularly improve mold releasability from the glass molded body and maintain surface accuracy. The reason why the dispersion was set to 0.02 to 30vo 1% is that the nitride is 0.0
If it is less than 2 vol%, the hardness will be low and scratches will easily occur.
In addition, if the dispersion effect suppresses crystal growth and prevents film roughness, if the amount exceeds 30 vol%, the releasability from the glass molded body will deteriorate.

Further, the intermediate layer has the effect of increasing the affinity between the base and the surface layer and extending the life of the mold.

(Example) FIG. 1 is a sectional view of a mold showing an example of the present invention. The mold is composed of an upper mold 1 and a lower mold 2. Upper mold l
and the lower mold 2 are arranged inside the guide mold 3 so that their outer peripheral surfaces slide on the inner peripheral surface of the guide mold 3. These upper mold 1 and lower mold 2 each consist of a base 1a and a surface layer 1b, and a base 2a and a surface layer 2b.

2b are arranged facing each other.

The bases 1a and 2a are made of tungsten carbide that has been made dense by HIP treatment during sintering, and is made into a cylindrical shape (
18 m in diameter and 28 mm in height), one end surface of which was ground into a concave spherical shape, and as a final finish, polished to a high-precision optical mirror surface using a diamond grindstone, each having a predetermined radius of curvature (32 mm). processed. The surface roughness of this concave spherical surface was 100 Å or less.

This base! Form surface layers 1b and 2b of a predetermined thickness on the concave spherical surfaces 1a and 2a under predetermined film forming conditions using a sputtering device and using targets having the material compositions of Examples 1 to 21 shown in the table. did. In addition, in that case, the bases 1a, 2a
In order to further strengthen the adhesion between the substrates 1a and 2b, it is effective to clean each surface of the substrates 1a and 2a by reverse sputtering prior to forming the surfaces 11b and 2b.

For example, in Example 1, the argon gas pressure is 1 x 107'o
r rs white alloy 5wt%, DCIKW, 500 people/m
1ns titanium nitride, RF 400W, 5 people/
m1n (dispersion 1 vol%), distance between electrodes 100 mm,
The rotation speed was 2° rpm, and the film thickness was 0.5 μm.

In addition, in this example, binary sputtering was described in which separate targets for platinum, gold, and titanium nitride are sputtered simultaneously, but a composite target in which two types of targets are arranged in a mosaic pattern and the dispersion is adjusted by the area ratio is also available. It is good to use. Furthermore, the target itself may be decentralized. In any case, the sputtering rates of each are considered and combined.

In addition, in this embodiment, the guide mold 3 is the base plate 1a of the upper mold and the lower mold,
It is made of tungsten carbide similar to 2a.

FIG. 2 is a sectional view of a mold showing another embodiment of the present invention. The upper mold 1' and the lower mold 2' of this embodiment are arranged between the base 1a and the surface layer 1b and between the base 2a and the surface layer 2, respectively.
This is different from the upper mold 1 and the lower mold 2 in FIG. 1 in that the first intermediate layer IC and the second intermediate FiIid and the first intermediate layer 2C and the second intermediate Jlff 12d are interposed between the upper mold 1 and the lower mold 2 shown in FIG. , otherwise the structure is the same. Although two intermediate layers are illustrated, the intermediate layer may include only one layer or three or more layers. Examples 11 to 13 and 16 to 19 with only one intermediate layer are shown in the table.
and 21, and Examples 14, 15 and 20 are examples in which the intermediate layer is two layers.

For example, in Example 11, these intermediate layers and surface layers are formed by ion etching the substrates 1a and 2a, and then using the ion blating method under predetermined film forming conditions (degree of vacuum 5 x
to-”r o r r, film-forming rate 300 people/win
After forming the first intermediate layers 1c and 2c (thickness: 0.05 μm) made of titanium at a voltage of −300 V and a substrate voltage of −300 V, platinum (95 ht%)-gold 5
wt% and titanium nitride (T i N) as targets, surface layers lb, 2b (
It was formed by forming a film with a film thickness of 3.0 μm).

In Example 20, after the substrates 1a and 2a were ion-etched, a film was formed on the concave spherical surface by the ion-blating method under predetermined film-forming conditions (nitrogen gas pressure of 5 x lO
-'T o r r, film formation rate 300 people/lll1n
A second intermediate layer [1d, 2d (film thickness: 0.3 crm) made of titanium nitride was formed at a substrate voltage of −300 V). Next, a sputtering method was applied under predetermined film-forming conditions (argon gas pressure 1 x to "r o r r,
First intermediate layers lc and 2c (thickness: 0.05 μm) made of nickel were formed at a deposition rate of 400 people/m1n), and then platinum (80 wt%)-gold (10 wt%) was formed using the same method.
%)-iridium (10 wt%) alloy and titanium nitride (T i N) as targets, surface layers 1b and 2b (film thickness 1.0 μm) were formed under the predetermined film forming conditions (described above).

In other Examples, the intermediate layer and surface layer were formed by substantially the same method as these. - (The following is a blank space) Next, how to use such a mold will be explained using the mold shown in FIG. 1 as an example.

FIG. 3 is a sectional view showing the main parts of the press molding machine.

This press molding machine uses the above-mentioned upper mold 1. A lower mold 2 and a guide mold 3 are provided, and a glass to be formed 4 is placed on the lower mold 2.

These molds 1, 2.3 are supported by a support base 6 also made of stainless steel via a holder 5 made of stainless steel and having an H-shaped cross section. Reference numeral 7 denotes a push rod made of stainless steel, which is housed inside a quartz tube 8. The mold 1.2.3 and the glass to be formed 4 are heated by an induction heating coil 9 placed on the outer periphery, and the push rod 7 is pushed upward. It is lowered to the head of the mold 1, and the glass to be formed 4 is press-molded. Temperature suppression is
The mold temperature is measured by a thermocouple 10 disposed inside the lower mold 2. Next, a specific example will be explained.

As the glass to be formed 4, Si with glass composition strength <wt%
Oz: 27.8. A 1 zoz:2. O+N
azo:1.8. KtO:1.2. PbO:
65.2. Heavy flint optical glass (transition temperature 435°C) with T i O□: 2.0 was processed into a spherical glass lump with a diameter Ion-, and the mold temperature was 500°C and the pressure was 40°C in an N2 gas atmosphere. kg/cJ was added for 30 seconds. After that, the pressure is released, and the press-molded glass molded body is slowly cooled to the above transition temperature while in contact with the upper mold 1 and the lower mold 2, and then rapidly cooled to room temperature.
The glass molded body formed into a biconvex spherical lens is taken out from the mold.

The above press molding method is similarly performed using the mold shown in FIG. Then, in the press molding machine shown in FIG. 3, the heavy flint glass was molded 1000 times each under the same conditions as described above using the upper and lower molds having the surface layer or intermediate layer of Examples 1 to 21. I did it repeatedly. As a result, for all molds of Examples, the glass molded product had good releasability from the mold, and no chemical reaction was observed on the contact surface with the mold.
The surface area and mirror surface of the lower mold surface layer were maintained in their original state, and the surface precision of the glass molded product was 100 Å or less, and the transparency was also good.

For comparison, platinum-rhodium and platinum-
When press forming was performed in the same manner as in the above-mentioned example using forming molds each coated with a coating film of each iridium alloy, the releasability between the glass molded body and the forming mold was poor from the first press forming. A chemical reaction was observed at the mutual contact surfaces.

Although the shape of the surface layer of the mold has been described above as a concave spherical surface, the present invention is not limited to such a shape, and any shape such as a convex spherical surface, an aspherical surface, a flat surface, etc. may be used.

In addition, the intermediate layer has the same effect as long as it contains the substance used in each of the above-mentioned examples as a main component. It may be something.

Furthermore, since good results were obtained using heavy flint optical glass, which is relatively easy to cause chemical reactions, other optical glasses can also be molded using the mold of the present invention. It goes without saying that it can be done.

Moreover, some kind of coating layer may be further formed on the surface layer, and the coating layer may be interposed between the surface layer and the glass to be formed.

(Effects of the Invention) According to the present invention, the surface layer of the mold is formed by dispersing nitride in a substance consisting of at least two components, platinum and gold, which improves density, hardness, strength, and resistance. In addition to achieving good results in terms of chemical reactivity and retention of surface precision by suppressing crystal growth,
The releasability from the glass molded body is also improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a mold showing one embodiment of the present invention;
The figure is a sectional view showing another embodiment of the present invention, and FIG. 3 is a sectional view showing an example of the configuration of a press molding machine. 1.1'-upper mold, 1a, 2a-base, 1b, 2b...
・Surface layer, lc, ld, 2c, 2d-intermediate layer, 2.2'
−・−Lower mold. Applicant Tanaka Kikinzoku Kogyo Co., Ltd.

Claims (4)

[Claims] (1) A mold comprising a base and a surface layer, in which the shape of the surface layer is transferred to the glass to be molded by press molding to form a glass molded object, in which the surface layer is composed of platinum (Pt) and gold (
A mold for a glass molded article, characterized in that it is formed by dispersing nitride in a substance consisting of at least two components of Au). (2) The surface layer is mainly composed of platinum (Pt) and gold (Au).
The mold according to claim 1, wherein the mold is formed by dispersing nitride in a substance consisting of at least two components containing 5 to 45 wt% of nitride. (3) Nitride is TiN, TaN, AlN, BN, Si_
3N_4, HfN, NbN, and ZrN, and is formed by dispersing 0.02 to 30 vol%, according to claim 1 or 2. mold. (4) An intermediate layer is provided between the base and the surface layer, and the intermediate layer is composed of nickel (Ni), titanium (Ti), and chromium (Cr).
), molybdenum (Mo), cobalt (Co), titanium nitride (TiN), titanium carbide (TiC),
4. The mold according to claim 1, wherein the mold is made of a material containing at least one selected from silicon carbide (SiC) and a mixture thereof.