JPH08119645A - Mold for glass formation and formation of glass product for cathode-ray tube - Google Patents

Abstract

PURPOSE: To produce a mold for glass formation excellent in releasing property and oxidation resistance and hardly causes scratch on a surface of glass. CONSTITUTION: A nickel layer having 4μm thickness is deposited on the surface of SUS420J2 base material by using a nickel chloride bath, then, an outermost surface coating having a composition of Ni-W-Mo-P (wt. ratio is 69:20:6:5) and 22μm thickness is formed by using a plating liq. consisting essentially of nickel sulfate, sodium tungstate, sodium molybdate, sodium citrate, sodium hypophosphite and phosphoric acid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass molding die, in particular, a glass molding die used for press molding glass products such as television cathode ray tube panels and funnels, and a method for forming glassware for cathode ray tubes. Regarding

[0002]

2. Description of the Related Art The cathode ray tube of a television is the front (image area)
The panel and the funnel-shaped funnel and the neck are separately prepared, the inner surface of the panel is coated with a fluorescent substance, the shadow mask and the electrodes are attached, and then these are combined to be manufactured. Therefore, extremely strict quality control is required for the surface accuracy of the inner surface of the panel and the properties such as surface irregularities.

The molding of the panel is performed by pressing molten glass at a high temperature of about 1000 ° C. with a mold, and has mechanical strength, heat resistance, and chemical stability against high temperature glass. Characteristics are required.

As a molding die suitable for such a purpose,
Conventionally, stainless steel alloys with chromium plating or nickel tungsten alloy plating have been used.
Since the plating film deteriorates with use, the mold substrate is recycled by peeling off the film and newly plating. A chrome plating suitable for molds uses a Sargent bath,
There are mixed catalyst baths, high-efficiency baths, etc., but all contain highly toxic hexavalent chromium. In addition, there are drawbacks such that the glass surface is likely to be scratched during molding, a release agent needs to be applied frequently, and it is extremely weak against halogen.

On the other hand, the nickel-based alloy plating film is excellent in releasability, and is hard when the hardness is ensured by containing tungsten such as nickel-tungsten, cobalt-tungsten, nickel-phosphorus-tungsten, and nickel-boron-tungsten. Gold plating is being developed.

[0006] For example, nickel-tungsten alloy plating has the advantages that a film can be formed under the condition that chemical toxicity and odor do not pose a problem, the frequency of use of the release agent can be reduced, and that the glass surface is not easily scratched. It is said that the usage rate is increasing in recent years.

[0007]

However, since the tungsten contained in the nickel alloy coating containing tungsten is easily oxidized and the coating is rapidly oxidized, when it is used as the surface coating of the panel molding die, the chromium plating coating is used. It had the shortcoming of having a very short life compared to.

[0008]

The present invention has been made to solve the above-mentioned problems, and is made of stainless steel as a base material, and the following (1), (2), (3), A mold for glass molding is formed by forming a coating film containing (4) and (4). (1) nickel, (2) tungsten, (3) molybdenum and / or cobalt, (4) phosphorus and / or boron.

In the present invention, the outermost surface coating is preferably produced by a plating method, a CVD method, a PVD method or a thermal spraying method. The thickness of the outermost coating is preferably 1 to 500 μm, and if it is less than 1 μm, it is disadvantageous in that it is susceptible to high temperature oxidation, mechanical deformation, etc.
If it is thicker than μm, it takes a long time to form a film, and it is not preferable because it exceeds the technically and cost effective range.

In order to secure the characteristics of the nickel alloy, the content of nickel in the coating is preferably 40 to 94% by weight. Further, the content of tungsten is 5 to 59.
It is preferable that the content is wt% in order to secure the strength of the coating. Molybdenum and / or cobalt have the effect of imparting oxidation resistance to the alloy coating and securing the strength of the coating. The total content of these is preferably 0.5 to 40% by weight. Phosphorus and / or boron have the function of imparting oxidation resistance to the alloy coating and securing the strength of the coating, and the total content of these is preferably 0.5 to 20% by weight.

A more preferable range of these contents is 50 to 85% by weight of nickel and 10 to 47 of tungsten.
Wt%, molybdenum and / or cobalt in a total amount of 2-3
0% by weight, the total amount of phosphorus and / or boron is 1 to 5% by weight.

Further, it is preferable that a thin film containing at least one element selected from Group 8, 9, 10 and 11 as a main component is provided between the stainless steel substrate and the outermost surface coating. 8 between the mold substrate and the outermost alloy coating
At least one selected from the group 9, 9 and 11
By forming a thin film containing at least one kind of metal, these bonds can be strengthened and the alloy film on the outermost surface can be easily produced.

The thin film between the stainless steel substrate and the outermost coating is, for example, nickel, cobalt, iron, palladium,
Copper or the like is produced by a plating method, a CVD method, a PVD method, or a thermal spraying method. Particularly, the plating method is preferable in terms of film forming speed, smoothness, cost and the like. The metal selected from the groups 8, 9, 10 and 11 is 40 to 10 as the main component.
The content of 0% by weight is preferable in order to make full use of the characteristics of these metals.

The thickness of the thin film between the stainless steel substrate and the outermost coating is preferably 0.1 to 50 μm. 0.
If it is thinner than 1 μm, it is difficult to effectively cover the entire surface, and if it is thicker than 50 μm, the residual strain increases and it becomes meaningless as an intermediate layer.

Further, the stainless steel substrate is preferably martensitic stainless steel from the viewpoint of mechanical strength, corrosion resistance, thermal conductivity, thermal expansion characteristics and the like.

The present invention also provides a method for forming a glass product for a cathode ray tube, which comprises forming a glass for a cathode ray tube containing silicon oxide, sodium oxide, potassium oxide, strontium oxide and barium oxide using the glass forming mold. When the glass for cathode ray tubes is molded using the glass molding die of the present invention, excellent mold releasability, surface accuracy,
A panel having good surface properties such as surface irregularities and a glass product for cathode ray tubes such as a funnel are preferable. Similarly, the case of glass for cathode ray tubes containing silicon oxide, sodium oxide, potassium oxide and lead oxide is also preferable.

The inventors of the present invention have conducted extensive studies on a mold for glass molding which uses a mold release agent less frequently and is less likely to cause scratches on the glass surface and has excellent oxidation resistance. , Nickel, tungsten, molybdenum and / or cobalt, phosphorus and / or boron,
A glass molding die formed by forming a coating containing Mn has much higher oxidation resistance than conventional ones, and therefore has an extremely long life and is excellent in releasability as a characteristic of a nickel alloy coating. We also found that it also has the property that scratches are unlikely to occur.

As the method for forming the alloy coating film on the outermost surface of the mold, a commonly used thin film forming method such as electroplating, chemical plating, thermal spraying, CVD, PVD method can be applied. In particular, the plating method is suitable because the thin film forming speed is fast and a smooth surface along the mold substrate can be easily obtained, and the cost is relatively low.

That is, it is composed of nickel-tungsten-molybdenum-phosphorus and / or boron, nickel-tungsten-cobalt-phosphorus and / or boron, nickel-tungsten-molybdenum-cobalt-phosphorus and / or boron metal. A coating whose content falls within the above range has a mold release characteristic of nickel, a low defective product rate, and oxidation resistance equivalent to or higher than that of chromium, and a mold with an extremely long life can be obtained. preferable.

[0020]

It is considered that the deterioration of the mold is due to the oxidation and mechanical deformation of the surface coating due to the molding of the glass at a high temperature of about 1000 ° C. That is, this oxidation process consists of corrosion by air before and after contact with the glass, so-called high temperature oxidation, and mechanochemical reaction with molten salt called molten glass in the panel forming process.

In order to suppress the deterioration, it is important to secure the chemical and mechanical stability of the outermost surface coating, and the conventional chromium plating is extremely chemically stable and mechanically dense. Heat resistance is obtained by the generation of chromium oxide. When the outermost surface oxide film has a weak protective property, oxygen in the atmosphere diffuses and permeates into the metal film through the oxide film layer, and the deterioration progresses. Also, at the glass melting temperature, it is in a temperature range where the movement of metal atoms in the metal lattice becomes active,
Iron contained in stainless steel, which is the metal substrate, diffuses toward the surface.

Although the mechanism for improving the oxidation resistance and the mechanical strength obtained by adding molybdenum and / or cobalt, phosphorus and / or boron to the nickel-tungsten system in the coating film according to the present invention is not necessarily clear,
The addition of these elements facilitates the formation of a dense oxide film, the movement of the elements in the film is suppressed, and the mechanical properties and heat transfer properties are suitable for glass molding dies. It is thought to be because.

[0023]

EXAMPLES Detailed examples of the present invention are shown below, but the present invention is not necessarily limited to these. In addition, Examples 1 to 7 are examples, and Examples 8 and 9 are comparative examples.

(Example 1) Martensite SUS420
A nickel layer having a thickness of 4 μm was deposited on the surface of a J2 (JIS G4303) substrate using a nickel chloride bath. Thereafter, a plating solution containing nickel sulfate, sodium tungstate, sodium molybdate, sodium citrate, sodium hypophosphite, and phosphoric acid as its main components was used to form nickel-tungsten-molybdenum-phosphorus (weight ratio 69:20: An outermost surface coating having a thickness of 22 μm composed of 6: 5) was formed.

Vickers hardness, Taber abrasion test and atmospheric oxidation increase measurement were performed on this coating, and a cathode ray tube panel was molded using a mold provided with this coating. The results are shown in Table 1.

Example 2 A nickel layer having a thickness of 4 μm was deposited on the surface of a SUS420J2 substrate using a nickel chloride bath. Then, a plating solution containing nickel sulfate, sodium tungstate, cobalt sulfate, potassium citrate, boric acid and dimethylamine borane as its main components was used to form nickel-tungsten-cobalt-boron (weight ratio 55: 34: 8: 3). 18 μm in thickness was formed on the outermost surface coating. Table 1 shows the results of the same evaluations as in Example 1 for this coating.

Example 3 A nickel layer having a thickness of 6 μm was deposited on the surface of a SUS420J2 substrate using a nickel chloride bath. Then, a plating solution containing nickel sulfate, sodium tungstate, cobalt sulfate, sodium molybdate, sodium citrate, phosphorous acid, phosphoric acid and boric acid as the main components is used to form nickel-tungsten-molybdenum-cobalt-phosphorus-boron. (54: 3 by weight)
An outermost surface coating having a thickness of 16 μm and formed of 3: 7: 4: 1: 1) was formed. Table 1 shows the results of the same evaluations as in Example 1 for this coating.

Example 4 A cobalt layer having a thickness of 5 μm was deposited on the surface of a SUS420J2 substrate using a cobalt chloride bath. After that, a plating solution containing nickel sulfate, sodium tungstate, sodium molybdate, sodium citrate, and boric acid as its main components was used to form nickel-tungsten-molybdenum-boron (weight ratio 68:
25: 5: 2) and a 17 μm thick outermost coating was formed. Table 1 shows the results of the same evaluations as in Example 1 for this coating.

Example 5 A 5 μm thick palladium layer was deposited on the surface of a SUS420J2 substrate using a tetraaminopalladium bromide bath. Then, using a plating solution containing nickel sulfate, sodium tungstate, cobalt sulfate, sodium citrate, and phosphoric acid as its main components,
Nickel-Tungsten-Cobalt-Phosphorus (6 in weight ratio
The outermost surface coating having a thickness of 18 μm and formed of 7: 24: 5: 4) was formed. Table 1 shows the results of the same evaluations as in Example 1 for this coating.

Example 6 A nickel layer having a thickness of 4 μm was deposited on the surface of a SUS420J2 substrate using a nickel chloride bath. Then, a nickel-palladium layer was deposited using an ammonia alkaline electroless plating bath containing palladium chloride as a reducing agent using hypophosphorous acid. Thereafter, a plating solution containing nickel sulfate, sodium tungstate, sodium molybdate, sodium citrate, and sodium hypophosphite as its main components was used to form nickel-tungsten-molybdenum-phosphorus (weight ratio 65: 24: 6:
The outermost surface coating of 5) having a thickness of 15 μm was formed.
Table 1 shows the results of the same evaluations as in Example 1 for this coating.

Example 7 A nickel layer having a thickness of 4 μm was deposited on the surface of a SUS420J2 substrate using a nickel chloride bath. Then, a nickel-palladium-phosphorus layer was deposited using an ammonia alkaline electroless plating bath containing palladium chloride to which nickel sulfate was added using hypophosphorous acid as a reducing agent. Then, a nickel-tungsten-molybdenum-phosphorus-boron (weight ratio 66: 23: 7 :) plating solution containing nickel sulfate, sodium tungstate, sodium molybdate, sodium citrate, phosphoric acid, and boric acid as its main components. 3: 1) consisting of 1
An outermost coating having a thickness of 8 μm was formed. Table 1 shows the results of the same evaluations as in Example 1 for this coating.

In Examples 1 to 4, 62.0% by weight of silicon oxide, 7.5% by weight of sodium oxide, 8.1% by weight of potassium oxide, 11.6% by weight of strontium oxide and barium oxide were used as glass for cathode ray tube panels. CRT glass containing 2.2% by weight and 8.6% by weight of zirconium oxide and the like was used. For Examples 5-7,
Silicon oxide 64.6% by weight, sodium oxide 6.0% by weight, potassium oxide 2.5% by weight, lead oxide 3.0% by weight,
In addition, glass for CRT containing 23.9% by weight of strontium oxide and the like was used.

Example 8 A 16 μm thick outermost coating was formed on the surface of a SUS420J2 substrate using a chromium sulfate bath. Table 1 shows the results of the same evaluations as in Example 1 for this coating.

Example 9 A nickel layer having a thickness of 6 μm was deposited on the surface of a SUS420J2 substrate using a nickel chloride bath. Then, a plating solution containing nickel sulfate, sodium tungstate, and potassium citrate as its main components was used to form nickel-tungsten (weight ratio 71: 2).
The outermost surface coating of 9) having a thickness of 20 μm was formed.
Table 1 shows the results of the same evaluations as in Example 1 for this coating.

In Examples 8 and 9 above, the same glass as in Examples 1 to 4 was used as the glass for the cathode ray tube panel so that the difference in the effect due to the molds would be clear.

In Table 1, the Taber index, oxidation weight gain,
The panel molding characteristics are shown by relative values when Example 8 was set to 10.

[0037]

[Table 1]

[0038]

As described in the examples, the present invention provides a conventional structure by forming a coating film containing nickel, tungsten, molybdenum and / or cobalt, phosphorus and / or boron on the outermost surface of stainless steel as a structural substrate. It has excellent releasability than a chromium coating, is less likely to cause scratches on the glass surface, and has much better oxidation resistance than a nickel-tungsten coating.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number in the agency FI Technical indication location C25D 3/56 Z H01J 9/24 A (72) Inventor Atsushi Takenaka Hazawa-machi, Kanagawa-ku, Yokohama-shi, Kanagawa 1150 Asahi Glass Co., Ltd. Central Research Laboratory

Claims (7)

[Claims] 1. A glass molding die characterized in that a stainless steel substrate is used, and a coating film containing the following (1), (2), (3), and (4) is formed on the outermost surface of the substrate. . (1) nickel, (2) tungsten, (3) molybdenum and / or cobalt, (4) phosphorus and / or boron. 2. The above-mentioned (1), (2), and
The glass molding die according to claim 1, wherein the contents of (3) and (4) are as follows. (1) 40 to 94% by weight of nickel, (2) 5 to 59% by weight of tungsten, (3) 0.5 to 40% by weight in total of molybdenum and / or cobalt, (4) phosphorus and / or boron Is 0.5 to 20% by weight in total. 3. Between the stainless steel substrate and the outermost coating, 8
At least one selected from the group 9, 9 and 11
3. A thin film containing a seed element as a main component.
Mold for glass molding. 4. The glass molding die according to claim 3, wherein the thickness of the thin film between the stainless steel substrate and the outermost surface coating is 0.1 to 50 μm. 5. The glass molding die according to claim 1, wherein the stainless steel substrate is a martensite type. 6. A glass product for a cathode ray tube, which comprises forming a glass for a cathode ray tube containing silicon oxide, sodium oxide, potassium oxide, strontium oxide and barium oxide by using the glass forming mold according to any one of claims 1 to 5. Molding method. 7. A glass for a cathode ray tube containing silicon oxide, sodium oxide, potassium oxide and lead oxide.
A method for forming a glass product for a cathode ray tube, which is formed by using the glass forming mold according to any one of 5 above.