JPH0317070B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a clad container.

Conventionally, containers made of Ta or Ta alloys have been widely used in crucibles for melting ores containing high-temperature glass and metal oxides, trays for vacuum deposition, boats, etc. This is because Ta has a very high melting point of approximately 3000°C and is highly ductile and malleable, making it easy to process. However, when the temperature exceeds 400 degrees Celsius, Ta tends to react with oxygen in the air and form oxides, making it difficult to use it in an inert atmosphere. Furthermore, even when used in such an inert atmosphere, when melting glass or ore containing metal oxides, oxygen and Ta contained in the melt may be used.
The drawback was that the Ta in the container was eluted, shortening the life of the container. For this reason, attempts have been made to improve wear resistance by adding other metals to the alloy, but the reality is that no alloy has been discovered that is sufficient to prevent Ta from oxidizing.

The present invention has been made in view of the above drawbacks,
The purpose is to provide a long-life container with excellent wear resistance.

The present invention is a clad container characterized in that the surface of Ta or Ta alloy is coated with Ir or Ir alloy.

In the present invention, Ir or Ir alloy is used because
This is because the melting point of Ir is 2454°C, which is as high as Ta, and it also has excellent oxidation resistance at high temperatures, especially against metal oxides. However, innocent
Since Ir and Ir alloy containers are expensive and difficult to process, we decided to coat them. For coating, physical vapor deposition such as ion plating, sputtering or vapor deposition is better than wet vapor deposition. According to physical vapor deposition, this is Ta
This is because Ir atoms are buried in the surface layer of the container, increasing the adhesion hardness of the Ir and Ta joint surface, resulting in a clad container with high mechanical strength. In this way, Ir
Or a crucible coated with Ir alloy has excellent oxidation resistance,
The mechanical strength of the joint surface is also excellent, resulting in a long life. The Ir alloys include Pt-Ir,
There is Rh-Ir.

Examples and conventional examples will be described below.

Example 1 Pt was applied to a thickness of 10 μm on the inner wall of a U-shaped Ta crucible with a wall thickness of 5 mm, a height of 100 mm, and an inner diameter of 80 mm under the following conditions.
Ion plating was performed up to.

Atmospheric gas: 2.0×10 ^-4 mmHg Ionization voltage, current: 40 V, 5 A Electron beam melting: 9 kV, 300 mA Thermal electron: 10 V, 100 A This is referred to as Example 1.

Example 2 Pt--Ir alloy was magnetron sputtered to a thickness of 0.1 mm on the inner and outer walls of a Ta crucible having the same shape as in Example 1 under the following conditions.

Pressure: Ar gas 3 x 10 ^-3 mmHg Applied voltage: 400V High frequency power source: 13.56MHz This will be implemented product 2.

Conventional example The Ta crucible used in Example 1 was used as a conventional product.

Next, we added SiO ₂ − to the above-mentioned products 1 and 2 and the conventional product.
Put 500g of Al ₂ O ₃ glass in Ar atmosphere, temperature about 2200.
It was used at ℃×60 minutes. When this process was repeated 10 times, 50μ of the conventional product was removed from the surface of the Ta container, whereas only 5μ was removed from the product 1 and 3μ was removed from the product 2.

Next, when the bottoms of the containers of Implementation Product 2 and the conventional product were directly heated in the atmosphere with a heater and held at a temperature of approximately 1000°C for 10 hours, it was found that in the conventional product, most of the Ta was oxidized;
On the other hand, Example 2 was hardly oxidized.

The hardness of the surface layer of the conventional product and the hardness of the boundary layer of the implemented products 1 and 2 are 100Hv, 220Hv, and 160Hv, respectively.
It was hot.

From these facts, the clad crucible of the present invention has significantly superior oxidation resistance as a crucible for dissolving metal oxides compared to conventional products, and in addition, Example 2, which is coated with Ir alloy up to the outer wall, has oxidation resistance even when heated in the atmosphere. It turns out that it is excellent. Furthermore, the hardness of the boundary layer of the implemented product is much higher than the hardness of the surface layer of the conventional product, which indicates that the implemented product has excellent mechanical strength.

As described in detail above, according to the present invention, it is possible to provide a clad container with excellent wear resistance and long life. Moreover, if the Ta container is completely coated, it can have a long life even in the atmosphere, does not require expensive equipment, and requires only a small amount of expensive Ir, making it inexpensive.

Claims (1)

[Claims] 1. A clad container characterized in that the surface of Ta or Ta alloy is coated with Ir or Ir alloy.