JPH01115832A - Forming mold for formed glass article - Google Patents

Abstract

PURPOSE:To provide a forming mold having a surface layer formed by dispersing an oxide in a substance composed at least of Pt and Au, and giving a formed glass article having high precision without polishing after press-forming. CONSTITUTION:The surface layer of the above forming mold is formed of a substance composed of at least two components consisting of Pt and Au and containing preferably 5-45wt.% of Au. One or more oxides selected from Al2O3, ZrO2 and Y2O3 are dispersed in said substance in an amount of 0.02-30vol.%. An intermediate layer containing at least one component 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 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 t C) and silicon nitride (S i
3N4) (Japanese Unexamined Patent Publication No. 52-45613), tungsten carbide (Japanese Unexamined Patent Application No. 56-59641),
Using zirconium oxide (ZrOz) as the base material,
It has been proposed to form a coating film of platinum-rhodium (Pt-Rh) alloy or platinum-iridium (Pt-rr) alloy thereon (Japanese Patent 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 heavy flint-based optical glass containing lead is used, it has high chemical reactivity with lead (and it becomes difficult to mold 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 an oxide is dispersed in a substance consisting of at least two components, platinum (PL) 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 w of gold (Au).
L%, and the oxide is AlzO3, Zr0z, Yz
The dispersion amount is 0.02 to 30vo 1%, and further, between the surface layer and the underlying base, nickel (Ni), titanium (Ti), an intermediate layer containing at least one selected from chromium (Cr), molybdenum (MO), cobalt (Co), titanium nitride (TiN), titanium carbide (TiC), silicon carbide (SiC), and mixtures thereof; It is something that has been mediated.

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, uniform nl will not be obtained; 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 gold, iridium ([r
), rhodium (Rh), and platinum alloys containing osmium (Os), ruthenium (Ru), palladium (Pd), etc., 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 (ZrO□), and cermet. , silicon carbide (S i C), silicon nitride (SitNn), and the like can be used. Also, the pressure during press molding is 7! As long as the deformation of the disc is not a problem, the base material may be made of the same alloy as the materials of the surface layer and the intermediate layer described above.

(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
~45-L%), specifically A 1 t O
By dispersing Z. The dispersion was set to 0.02 to 30 vol% because the oxide was 0.02 to 30 vol%.
If it is less than 30 vol%, 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 the releasability of the mold becomes worse.

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 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 F31b, a base 2a 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 treatment during sintering, and is made into a cylindrical shape (
One end surface is ground into a concave spherical shape, and as a final finish, it is polished to a high-precision optical mirror surface using a diamond grindstone, resulting in a concave spherical surface with a predetermined radius of curvature (32 ml). Processed into. 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 and the targets having the material compositions of Examples 1 to 21 shown in the table were used to form a surface 1 of a predetermined thickness under predetermined film forming conditions.
1b and 2b were formed. In addition, in that case, the bases 1a, 2a
In order to further strengthen the adhesion between the surface layers 1b and 2b, prior to the film formation of the surfaces 1b and 2b, reverse sputtering is performed to form a base layer. It is effective to clean each surface of la and 2a.

For example, in Example 1, the argon gas pressure lXl0-"'l
'orr, white alloy 5wt%, DCI KW, 50
0 people/m1ns zirconium oxide, RF 40
0W, 5 people/win (minute tlk 1 vol%)
, the distance between the electrodes was 100, the rotation speed was 2 Orpm, and the film thickness was 0.5 μm.

In addition, in this example, we have described binary sputtering in which separate targets of platinum-gold and zirconium oxide 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 their 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 1b, respectively.
The mold is different from the upper mold 1 and the lower mold 2 in FIG. , otherwise the structure is the same. The middle layer is shown as two layers, but one
It may have only one layer or three or more layers. 1 middle layer on the front
Examples with only one layer are shown as Examples 11 to 13, 16 to 19 and 21, and examples with two intermediate layers are shown as Example 14.
15 and 20.

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 formation rate 300 people/lll
After forming the first intermediate layers 1c and 2c (film rg, Q, 05 μm) made of titanium at a voltage of -300 V), platinum (95 w t
%) - 5i1t% of gold and yttrium oxide as targets, and under the predetermined film forming conditions (described above) on the surface 11b.

2b (11 film thickness, 0 μm).

In Example 20, after the bases ula 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 xio
-4 Torr, film-forming rate of 300 persons/min, substrate voltage of -300 V).
An intermediate lid, 2d (film thickness: 0.3 μm) was formed. Next, a sputtering method was used to form a film under predetermined film forming conditions (argon gas pressure of 1 x lo-" r o r r, film forming rate of 40
0 people/win) and the first intermediate layer 1c, 2 made of nickel
c (film [0.05 μm)] was formed using the same method, using platinum (80 wt%)-gold (1 hL%)-iridium (10 wt%) alloy and zirconium oxide as targets, and under predetermined film-forming conditions ( above), the surface layers 1b, 2
b (film thickness: 1.0 μm) was formed.

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 types! , 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 control 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, the glass composition is Si
Oz: 27.8+ A l 20: I: 2.0. N
a zo: 1-8+ KzO: 1.2. PbO:
65.2. T i O2:2. A heavy flint-based optical glass (transition temperature 435°C), which is O, was processed into a spherical glass lump with a diameter of 10 kg, and the pressure was 40 kg/cnl at a mold temperature of 500°C in an N2 gas atmosphere at a pressure of 30 kg/cnl.
Added 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 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 precision and mirror surface of the lower mold surface layer were maintained in their original state, and the surface precision of the glass molded body 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, and contains other substances such as platinum, iridium, rhodium, gold, molybdenum, or cobalt. It may be something that has been done.

Furthermore, since good results were obtained using heavy flint type optical glass, which is relatively easy to cause chemical reactions, other optical glasses can also be molded using the mold of the present invention. Needless to say, 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 an oxide 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'-m-upper mold, Ia, 2a-base, lb, 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 an oxide 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 an oxide in a substance consisting of at least two components containing 5 to 45 wt% of . (3) Oxides are Al_2O_3, ZrO_2, Y_2O
It consists of at least one selected from __3, and 0.
The mold according to claim 1 or 2, wherein the mold is formed by dispersing 02 to 30 vol%. (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.