JPH04323339A - Iridium wire and sheet - Google Patents

Abstract

PURPOSE:To obtain an iridium wire and sheet used in an atmosphere in which chemical, thermal oxidative or electric corrosion occurs and capable of being worked at high density without cracking the surface. CONSTITUTION:This iridium wire and sheet contain 20-5,000ppm of at least one member selected from among zirconium, hafnium and yttrium in iridium.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to iridium wire and sheet materials used in chemical, thermal oxidative or electrically aggressive atmospheres.

0002

[Prior art and its problems] Iridium material takes advantage of the characteristics of iridium metal itself, which has a high melting point and corrosion resistance.
It has been used in areas that require corrosion resistance, such as the pin tips of dot printers and electrode materials that involve electrical discharge. These materials are used in the form of cut wires with a diameter of 1 mm or less or thin plates with a thickness of 1 mm or less, but the conventional method of hot drawing pure iridium produces many small cracks in the direction perpendicular to the longitudinal direction of the wire. was generated on the surface, causing the wire to break and corrosion to occur during use. A similar problem also occurred with thin plate materials, with cracks occurring on the surface of the plate materials during hot rolling. These cracks can be ignored in rod-shaped materials with large diameters and thick plate materials, but they have become an important problem especially when hot working thin wire rods and thin plate materials while applying tensile force. The reason for this is thought to be that iridium oxidizes and volatilizes during hot working, causing the material surface to become rough. Methods to avoid such problems include powder metallurgy and cutting rolled material into thin pieces, but powder metallurgy makes it difficult to increase the density to over 98%, resulting in significant wear and tear during use. . In addition, the method of cutting a rolled material into thin pieces takes time and effort to cut, and there is a lot of metal loss during cutting, making it uneconomical and not a practical method.

0003

[Object of the Invention] The present invention has been made in view of the above circumstances, and is used to prevent material breakage during processing and to prevent material breakage during processing in the wire drawing method and roll-based thin plate processing that can provide high-density and inexpensive materials. The purpose is to provide a material without cracks on the material surface to prevent erosion.

0004

[Means for Solving the Problems] The present invention is an iridium wire and thin plate material characterized by containing 20 to 5000 ppm of at least one metal selected from zirconium, hafnium, and yttrium in iridium.

Zirconium, hafnium, and yttrium are more easily oxidized than iridium, and are used to prevent iridium itself from being oxidized, thereby preventing surface roughness that could lead to breakage during processing even when exposed to high temperatures in an oxidizing atmosphere. Furthermore, when used in an corrosive atmosphere, for example, when exposed to high temperatures of 1000°C or higher in an oxidizing atmosphere, the oxidation and volatilization of iridium increases; however, the zirconium, hafnium,
By adding at least one type of yttrium, the amount of consumption during use can be reduced.

On the other hand, even if at least one of the above-mentioned zirconium, hafnium, and yttrium is added, recrystallization occurs when exposed to high temperatures of 1400° C. or higher or when the processing rate is small, and sufficient properties cannot be obtained. Therefore, a total of 50% of
The above processing is required. Furthermore, if the amount of at least one of zirconium, hafnium, and yttrium added exceeds 5000 ppm, the pulling force becomes particularly large, causing breakage of the opening portion and making processing difficult.

[0007] Examples of the present invention will be described below, but these examples are not intended to limit the present invention.

[0008]

[Example] 99.96% purity (Other contained elements include several hundred ppm of platinum and rhodium, and several tens of ppm of manganese and iron.
0 to 8,000 ppm of zirconium, hafnium, and yttrium were added stepwise as shown in Table 1 to iridium powder containing 1,000 to 1,000 ppm of zirconium, and several ppm of others) and dissolved therein, followed by hammering at 1,500° C. to obtain an 8 mm square ingot. After recrystallizing this at 1500℃,
One reduction is 10-25% in the temperature range of
After hot working with a cross-section reduction rate of 95%, the cross-sectional structure of the material was observed at 200x magnification, and the ABC ranking was performed in descending order of grain size, as well as the number of fractures during processing and the 10 cm
The number of visually visible cracks present along the length was counted. In addition, each 5 cm length was exposed to the atmosphere at 1200° C. for 8 hours to observe the surface roughness, and the surface roughness was ranked ABC in descending order of roughness, which was used as a measure of corrosion during use. For comparison, the results also include those dissolved with only iridium powder and treated in the same manner. The results are shown in Table 1.

[0009]

[Table 1]

0010

Effects of the Invention As is clear from the above explanation, by using a material containing 20 to 5000 ppm of at least one of zirconium, hafnium, and yttrium in iridium, the occurrence of cracks can be prevented and the number of breaks during processing can be reduced. It can be said to be an epoch-making product that has made it possible to solve the conventional problems by preventing surface roughness and eliminating surface roughness.

Claims (1)

[Claims] 1. An iridium wire and thin plate material containing 20 to 5000 ppm of at least one metal selected from zirconium, hafnium, and yttrium in iridium.