Patent Application
20080075648
Next, Examples and Comparative Examples of the present invention are explained. These Examples are merely illustrative, and the present invention shall in no way be limited thereby. In other words, the present invention shall only be limited by the scope of the present invention, and shall include the various modes and modifications other than the Examples of this invention.
A Zr sponge raw material with a purity level of 3 N was subject to electron beam melting and casting to prepare an ingot having a purity of 99.99 wt % or higher.
Next, the ingot was cut into a cut powder, the cut powder was hydrogenated into ZrH2, and this was pulverized into a ZrH2 fine powder having an average grain size of several mm. The pulverized ZrH2 was heated to a temperature of 800° C. and dehydrogenated into a Zr powder. A Zr powder having a purity of 99.99 wt % was obtained thereby.
The Zr powder was further heated to 800° C. and oxidized in an oxygen atmosphere into ZrO2 fine powder. Next, the ZrO2 fine powder was mixed with B (boron) having a purity of 99 wt %, and the ZrO2 was directly synthesized (reduced) with B to obtain a ZrB2 powder having a purity of 99.95 wt % or higher excluding C and gas components. Content of the respective impurities manufactured in Example 1 is shown in Table 1.
The ZrB2 powder was subject to the high frequency induction heating FZ method (Floating Zone Method) in order to prepare an ingot. As a result, it was possible to obtain a large single crystal ingot with few impurities.
The obtained single crystals were subject to mirror polishing and etching processing, the size of the single crystals were measured, and the number of defects such as pits and gas pockets of 1 μm or larger in the crystals were measured. The results are shown in Table 1.
A Zr sponge raw material with a purity level of 2 N and high Ti content was subject to electron beam melting and casting to prepare an ingot having a purity of 99.9 wt % or higher.
Next, the ingot was cut into a cut powder, the cut powder was hydrogenated into ZrH2, and this was pulverized into a ZrH2 fine powder having an average grain size of several mm. The pulverized ZrH2 was heated to a temperature of 600° C. and dehydrogenated into a Zr powder. A Zr powder having a purity of 99.9 wt % was obtained thereby.
The Zr powder was further heated to 800° C. and oxidized in an oxygen atmosphere into ZrO2 fine powder.
Next, the ZrO2 fine powder was mixed with B (boron) having a purity of 99 wt % and a low C content, and the ZrO2 was directly synthesized (reduced) with B to obtain a ZrB2 powder having a purity of 99.9 wt % or higher excluding C and gas components. Content of the respective impurities manufactured in Example 2 is shown in Table 1.
The ZrB2 powder was subject to the high frequency induction heating FZ method (Floating Zone Method) in order to prepare an ingot. As a result, it was possible to obtain a large single crystal ingot with few impurities.
The obtained single crystals were subject to mirror polishing and etching processing, the size of the single crystals were measured, and the number of defects such as pits and gas pockets of 1 μm or larger in the crystals were measured. The results are shown in Table 1.
A Zr sponge raw material with a purity level of 2 N and a high Hf content was subject to electron beam melting and casting to prepare an ingot having a purity of 99.9 wt % or higher.
Next, the ingot was cut into a cut powder, the cut powder was hydrogenated into ZrH2, and this was pulverized into a ZrH2 fine powder having an average grain size of several mm. The pulverized ZrH2 was heated to a temperature of 600° C. and dehydrogenated into a Zr powder. A Zr powder having a purity of 99.9 wt % was obtained thereby.
The Zr powder was further heated to 800° C. and oxidized in an oxygen atmosphere into ZrO2 fine powder. Next, the ZrO2 fine powder was mixed with B (boron) having a purity of 99 wt %, and the ZrO2 was directly synthesized (reduced) with B to obtain a ZrB2 powder having a purity of 99.9 wt % or higher excluding C and gas components. Content of the respective impurities manufactured in Example 3 is shown in Table 1.
The ZrB2 powder was subject to the high frequency induction heating FZ method (Floating Zone Method) in order to prepare an ingot. As a result, it was possible to obtain a large single crystal ingot with few impurities.
The obtained single crystals were subject to mirror polishing and etching processing, the size of the single crystals were measured, and the number of defects such as pits and gas pockets of 1 μm or larger in the crystals were measured. The results are shown in Table 1.
A Zr sponge with a purity level of 3 N was highly purified with solvent extraction, and electron beam melting was performed thereto several times in order to prepare an ingot having a purity of 99.999 wt %. A ZrO2 fine powder was prepared as with Example 1 and directly synthesized with B of 99.999 wt % to obtain ZrB2 of 99.99 wt % excluding C and gas components. Content of the respective impurities manufactured in Example 4 is shown in Table 1. The obtained single crystals were subject to mirror polishing and etching processing, the size of the single crystals were measured, and the number of defects such as pits and gas pockets of 1 μm or larger in the crystals were measured. The results are shown in Table 1.
Zr scrap with a purity level of 95 wt % and particularly high Hf content was hydrogenated into ZrH2, and this was pulverized into a ZrH2 fine powder having an average grain size of several mm. The pulverized ZrH2 was heated to a temperature of 600° C. and dehydrogenated into a Zr powder. A Zr powder having a purity of 95 wt % was obtained thereby.
The Zr powder was further heated to 800° C. and oxidized in an oxygen atmosphere into ZrO2 fine powder. Next, the ZrO2 fine powder was mixed with B (boron) having a purity of 95 wt %, and the ZrO2 was directly synthesized (reduced) with B to obtain a ZrB2 powder having a purity of 95 wt % or higher. Content of the respective impurities in the manufacture of Comparative Example 1 is shown in Table 2.
The ZrB2 powder was subject to the high frequency induction heating FZ method (Floating Zone Method) in order to prepare an ingot, but the crystals were minute, and it was not possible to obtain a single crystal ingot. Further, the numerous defects and gas pockets were at an unmeasurable level.
A Zr sponge with a purity level of 99 wt % and high content of Hf, Zr and C was hydrogenated and dehydrogenated into a Zr powder having a purity of 99 wt %. The Zr powder was mixed with a B powder with a purity level of 95% and directly synthesized into a ZrB2 powder. Content of the respective impurities in the manufacture of Comparative Example 2 is shown in Table 2. Further, the numerous defects and gas pockets were at an unmeasurable level.
The ZrB2 powder was subject to the high frequency induction heating FZ method (Floating Zone Method) in order to prepare an ingot, but the crystals were minute, and it was not possible to obtain a large single crystal ingot.
A Zr sponge with a purity level of 99.9 wt % and slightly high content of C and Hf was hydrogenated and dehydrogenated into a Zr powder having a purity of 99.9 wt %. The Zr powder was mixed with a B powder with a purity level of 95% and directly synthesized into a ZrB2 powder. Content of the respective impurities in the manufacture of Comparative Example 3 is shown in Table 2.
The ZrB2 powder was subject to the high frequency induction heating FZ method (Floating Zone Method) in order to prepare an ingot, but the crystals were minute, and it was not possible to obtain a large single crystal ingot. Although the defect density and stomatal density could finally be measured here, the result showed numerous defects at 4×107 defects/cm2, 53 gas pockets, respectively.
A Zr sponge with a purity level of 99.9 wt % and low content of Hf was hydrogenated, dehydrogenated and oxidized into a ZrO2 powder having a purity of 99.9 wt %. The ZrO2 powder was mixed with a B powder with a purity level of 99% and directly synthesized into a ZrB2 powder. Content of the respective impurities manufactured in Comparative Example 4 is shown in Table 2.
The ZrB2 powder was subject to the high frequency induction heating FZ method (Floating Zone Method) in order to prepare an ingot, but the crystals were minute, and it was not possible to obtain a large single crystal ingot. As with Comparative Example 3, although it was possible to measure the defect density and stomatal density, the result showed numerous defects at 6×105 defects/cm2, 15 gas pockets, respectively.
The present invention is capable of making the purity of a ZrB2 powder for use in sintering to be 99.9 wt % or higher, and it is thereby possible to significantly improve the purity of the sintered body required in the manufacturing of a ZrB2 single crystal substrate with the high frequency induction heating FZ method (Floating Zone Method). Thus, the present invention is extremely useful in the manufacture of a ZrB2 single crystal substrate since it is possible to enlarge a single crystal and reduce the manufacturing costs associated therewith.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-294873 | Oct 2004 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP05/16214 | 9/5/2005 | WO | 00 | 4/3/2007 |
