JPH01115837A - Forming mold for formed glass article - Google Patents

Abstract

PURPOSE:To provide a forming mold having a surface layer formed by dispersing a B compound in a substance composed of at least two components consisting of Pt and Cr, and giving a formed glass article having high precision without polishing after press-forming. CONSTITUTION:The surface layer is formed of a substance composed of at least two components consisting of Pt and Cr and containing 5-40wt.% of Cr. One or more B compounds selected from TiB2, ZrB2, VB2, etc., are dispersed in the substance in an amount of 0.02-30vol.%. An intermediate layer containing one or more components selected from Ni, Ti, Cr, Mo, etc., and their mixture is interposed between said surface layer and the substrate base. The surface layer of the forming mold has dense texture, high hardness and strength, excellent chemical reaction resistance and good releasability of the press-formed glass article.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a mold for press-molding glass, and particularly to a mold for molding into a high-precision glass molded body that does not require polishing after press-molding. 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 heating and softening it, and then 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 (SiC) and silicon nitride (Si3N-
) (Japanese Unexamined Patent Publication No. 52-45613), tungsten carbide (Japanese Unexamined Patent Application No. 56-59641), and zirconium oxide (ZrOz) as base materials, and on top of that, platinum-rhodium (pt-Rh) alloy or , a coating film formed of an iridium (Pt-1r) alloy 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, When heavy flint-based optical glass containing lead is used, it has high chemical reactivity with lead, making it difficult to form it 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 a boron compound is dispersed in a substance consisting of at least two components, platinum (Pt) and chromium (Cr). It is being formed.

Preferably, the substance consisting of at least two components, platinum (pt) and chromium (Cr), contains 5 to 5 chromium (Cr).
40-1%, and the boron compound is TiB2, ZrB
z, VB2, N b B z, TaB2, MnB, N
Consisting of at least one selected from iB, FeB, CrB2, and CoB, with a dispersion amount of 0.02 to 30νo1%
Further, between the surface layer and the underlying base, nickel (Ni), titanium (Ti), chromium (Cr), molybdenum (Mo), cobalt (Co), titanium nitride (TiN), titanium carbide (Tic), silicon carbide (SiC), and mixtures 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, it will be difficult to obtain a uniform film, and if it is too thick, not only will the film formation time become longer, but the surface condition of the film will become rough.

In addition to chromium, iridium (
If a boron compound is dispersed in a platinum alloy containing I r), rhodium (Rh), and gold (Au), -i
It 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), silicon nitride (Si,N, ), and the like can be used. Further, as long as the pressure during press forming does not cause a problem in deformation of the base plate, the same alloy as the above-mentioned surface layer and intermediate layer materials may be used as the board material.

(Function) The surface layer of the mold of the present invention not only has good airtightness, hardness, strength, workability, and chemical reaction resistance, but also has good moldability with respect to press-molded glass moldings. In addition, crystal growth is suppressed and film roughness is suppressed. That is, boron compounds, specifically TiB2, ZrB2, VB2, NbB2, Ta
Bz, MnB, NtB.

By dispersing FeB, CrBz, CoB, etc., the mold releasability from the glass molded body is particularly improved, and
It is possible to maintain the degree of area. Its variance is 0.02
The reason why the boron compound was set at ~30vol% was 0.02ν
If it is less than 1%, the hardness will be low and scratches will easily occur, and the effect of suppressing crystal growth and film roughness due to the dispersion effect will not be sufficiently obtained. This is because mold releasability deteriorates.

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 1
and the lower mold 2 are arranged inside the guide mold 3 so that their respective outer peripheral surfaces slide on the inner peripheral surface of the indoor mold 3. These upper mold l and lower mold 2 each have a base m1 a
and a surface layer 1b, a group 12a, and a surface layer 2b, and the surface layer 1b.

2b are arranged facing each other.

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

The concave spherical surfaces of the substrates 1a and 2a were coated with a sputtering device using targets having the material compositions of Examples 1 to 21 shown in the table, and a surface i of a predetermined thickness was formed under predetermined film forming conditions.
1b and 2b were formed. In addition, in this case, the group IMla, 2
In order to further strengthen the adhesion between the substrates 1b and 2b, it is effective to clean each surface of the substrates 1a and 2a by reverse sputtering prior to forming the surface layers 1b and 2b.

For example, in Example 1, the argon gas pressure lXl0-'To
rr, platinum-chromium 5wt%, DCIKW, 500 people/
m! n, titanium board, RF400W, 5 people/mi
n (dispersion 1 vol%), electrode path 111100 mm
, the rotation speed was 20 rpm+, and the film thickness was 0.5 μm.

In addition, in this example, binary sputtering was described in which separate targets for platinum-chromium and titanium boride are sputtered at the same time, 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 La 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.
It is different from the upper mold 2 and the lower mold 2 in FIG. 1 in that the first intermediate layer IC and the second intermediate layer 1d and the first intermediate layer 2C and the second width Jff12d are interposed between However, the structure is otherwise the same. The middle layer is 2N (not shown), but 1
It may have only one layer or three or more layers. 1 middle layer on the front
Examples 11 to 13, 16 to 19, and 21 are examples in which only the layer is used, and Example 14 is an example in which the intermediate layer is 2N.
15 and 20.

For example, in Example 11, these intermediate layers and surface layers are formed by ion etching Mlla, 2a and then by ion blating under predetermined film forming conditions (vacuum degree 5
l0-'T o r r, film formation rate 300 people/win,
The first intermediate layer 1c made of titanium at a substrate voltage of -300V)
, 2c (thickness: 0.05 μm), and then platinum (954%)-chromium 5 & 4 was deposited on it by sputtering.
Targeting t% and titanium boride, surfaces 11b and 2b (film thickness 3.OAIm) were formed under the predetermined film forming conditions (described above).
It was formed by forming a film.

In addition, in Example 20, the base! After ion etching a and 2a, the concave spherical surface was subjected to ion blating under predetermined film forming conditions (nitrogen gas pressure 5 Xl0
-'T o r r, film formation rate 300 people/1 Itn,
A second intermediate lid, 2d (film thickness 0.3 μm) made of titanium nitride was formed at a substrate voltage of −300 V).
Next, a sputtering method was used under predetermined film forming conditions (argon gas pressure I
00 people/mtn) and a first intermediate layer tc made of nickel;
2c (thickness: 0.05 μm), and then by the same method, platinum (80 wt%) - chromium (10 wt%) -
Targeting iridium (10 imt%) alloy and titanium boride, the surface Qlb was
, 2b (ff! thickness 1.0 am) was formed.

In other Examples, the intermediate layer and surface layer were formed by substantially the same method as these.

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 R5 made of stainless steel and having a 14-shaped cross section. Reference numeral 7 denotes a push rod made of stainless steel. These are housed inside a quartz tube 8, and the molds 1, 2.3 and the glass to be formed 4 are heated by an induction heating coil 9 placed on the outer periphery. It is lowered to the head of the mold 1, and the glass to be formed 4 is press-molded. Temperature control is performed by measuring the mold temperature with a thermocouple IO disposed inside the lower mold 2. Next, a specific example will be explained.

As the glass to be formed 4, the glass composition is -t% and S io
z:27.8. A2□03:2.0. NazO: 1.8
．． KzO: 1.2. P b O: 65.2. Ti
O□: 2.0 heavy flint optical glass (transition temperature 435°C) was processed into a spherical glass lump with a diameter of 10m+++, and the mold temperature was 50°C in an N2 gas atmosphere.
A pressure of 40 kg/c was applied for 30 seconds at 0°C. 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 and formed into a biconvex spherical lens. The glass molded body thus formed 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.

Note that the surface layer of the mold of the present invention may be oxidized during film formation and press molding, but even if it is oxidized, there is no problem in its use.

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 a boron compound in a substance consisting of at least two components, platinum and chromium, which improves density, hardness, strength, and resistance. Good results can be obtained in both chemical reactivity and retention of surface precision by suppressing crystal growth, and 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'-one type, la, 2a-base, 1b, 2b・-
Surface layer, lc, ld, 2c, 2d...intermediate layer, 2.2
'...lower mold. Applicant Tanaka Kikinzoku Kogyo Co., Ltd. Hoya Co., Ltd. Figure 1 Figure 2 Figure 3

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 formed by press molding to form a glass molded object, in which the surface layer is made of at least platinum (Pt) and chromium (Cr). A mold for a glass molded article, characterized in that it is formed by dispersing a boron compound in a substance consisting of two components. (2) The surface layer is mainly composed of platinum (Pt) and chromium (C
The mold according to claim 1, characterized in that the mold is formed by dispersing a boron compound in a substance consisting of at least two components containing 5 to 40 wt% of r). (3) Boron compounds are TiB_2, ZrB_2, VB_
2, NbB_2, TaB_2, MnB, NiB, FeB
, CrB_2, and CoB, and is formed by dispersing 0.02 to 30 vol% of the mold according to claim 1 or 2. . (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.