HIGH-TEMPERATURE RESISTANT DEVICE AND METHOD FOR FABRICATING THE SAME

Abstract

A method for fabricating a high-temperature resistant device includes providing a tantalum substrate as a device body, performing an oxidation treatment on the tantalum substrate in an oxygen-containing environment to form a tantalum oxide layer on a surface of the tantalum substrate, and then embedding the tantalum substrate after the oxidation treatment in a carbonaceous matter for performing a carbonization reaction in an inert gas, so that the tantalum oxide layer is transformed into a tantalum carbide layer. A temperature of the oxidation treatment is between 100 C. and 1100 C.

Claims

1. A method for fabricating a high-temperature resistant device, comprising: providing a tantalum substrate as a device body; performing an oxidation treatment on the tantalum substrate in an oxygen-containing environment to form a tantalum oxide layer on a surface of the tantalum substrate, wherein a temperature of the oxidation treatment is between 100 C. and 1100 C.; and embedding the tantalum substrate after the oxidation treatment in a carbonaceous matter for performing a carbonization reaction in an inert gas, so that the tantalum oxide layer is transformed into a tantalum carbide layer.

2. The method for fabricating the high-temperature resistant device according to claim 1, wherein the oxygen-containing environment comprises oxygen, water vapor, an inert gas, or a combination of the above.

3. The method for fabricating the high-temperature resistant device according to claim 1, wherein a pressure of the oxidation treatment is a normal pressure.

4. The method for fabricating the high-temperature resistant device according to claim 1, wherein a time of the oxidation treatment is between 15 minutes and 120 minutes.

5. The method for fabricating the high-temperature resistant device according to claim 1, wherein the tantalum carbide layer is represented by a chemical formula Ta.sub.xO.sub.y, where y/x is between 0.5 and 2.5.

6. The method for fabricating the high-temperature resistant device according to claim 1, wherein the inert gas comprises argon, helium, or a combination of the above.

7. The method for fabricating the high-temperature resistant device according to claim 1, wherein a pressure of the carbonization reaction is a normal pressure, a reaction temperature is between 1500 C. and 2100 C., and a reaction time is between 15 minutes and 2 hours.

8. The method for fabricating the high-temperature resistant device according to claim 1, wherein the carbonaceous matter comprises carbon powder, graphite powder, activated carbon, polyvinyl alcohol (PVA), polyvinyl butyral (PVB), sucrose, glucose, or a combination of the above.

9. The method for fabricating the high-temperature resistant device according to claim 1, further comprising carbon removal after the carbonization reaction.

10. A high-temperature resistant device, comprising: a tantalum substrate; and a tantalum carbide layer, being a layer formed on a surface of the tantalum substrate, wherein a thickness of the tantalum carbide layer is between 2 m and 100 m.

11. The high-temperature resistant device according to claim 10, wherein the tantalum carbide layer has a specific surface area between 0.1 cm.sup.2/g and 2 cm.sup.2/g.

12. The high-temperature resistant device according to claim 10, wherein the high-temperature resistant device comprises a crucible, an aerospace mechanism accessory, a high-temperature reaction vessel accessory, or a crystal growth accessory.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a step diagram of a fabricating process of a high-temperature resistant device according to an embodiment of the disclosure.

[0009] FIG. 2A is a schematic diagram of the oxidation treatment of step 110 depicted in FIG. 1.

[0010] FIG. 2B is a schematic diagram of the carbonization reaction of step 120 depicted in FIG. 1.

[0011] FIG. 3 is a scanning electron microscope (SEM) image of the sample of Experimental Example 3 of the disclosure.

[0012] FIG. 4 is an SEM image of the sample of Experimental Example 27 of the disclosure.

[0013] FIG. 5 is an SEM image of the sample of Experimental Example 4 of the disclosure.

[0014] FIG. 6 is an SEM image of the sample of Experimental Example 14 of the disclosure.

[0015] FIG. 7 is an SEM image of the sample of Comparative Example 1.

[0016] FIG. 8 is an SEM image of the sample of Comparative Example 2.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

[0017] FIG. 1 is a step diagram of a fabricating process of a high-temperature resistant device according to an embodiment of the disclosure.

[0018] Referring to FIG. 1, first, in step 100, a tantalum substrate is provided as a device body, where the tantalum substrate refers to a substrate whose entire material is tantalum. The tantalum substrate may be a sheet-shaped substrate, a strip-shaped substrate, a ball-shaped substrate, or a substrate made into a specific structure.

[0019] Then, in step 110, an oxidation treatment is performed on the tantalum substrate in an oxygen-containing environment to form a tantalum oxide layer on a surface of the tantalum substrate. The oxide of tantalum is represented by a chemical formula Ta.sub.xO.sub.y, where y/x is between 0.5 and 2.5, y/x=0.5 in the tantalum oxide layer generated in a low-oxygen environment, and y/x=2.5 in the tantalum oxide layer generated in an oxygen-rich environment. The oxygen-containing environment includes oxygen, water vapor, an inert gas, or a combination of the above. For example, the oxygen-containing environment is a combination of oxygen and an inert gas or a combination of water vapor and an inert gas. In an embodiment, the oxygen-containing environment refers to an environment with an oxygen content of 1 vol % to 100 vol %. In an embodiment, a temperature of the oxidation treatment is between 100 C. and 1100 C., such as between 120 C. and 1100 C., between 500 C. and 1100 C., or between 120 C. and 500 C. In an embodiment, a pressure of the oxidation treatment is a normal pressure, such as 1 atm. In an embodiment, a time of the oxidation treatment is between 15 minutes and 120 minutes, such as between 30 minutes and 120 minutes. FIG. 2A is a schematic diagram of the oxidation treatment of step 110, in which a tantalum substrate 200 may be placed in an alumina crucible 210 and the above oxidation treatment is performed.

[0020] Then, in step 120, the tantalum substrate after the oxidation treatment is buried in a carbonaceous matter, and a carbonization reaction is performed in an inert gas, so that the tantalum oxide layer is transformed into a tantalum carbide layer. The carbonaceous matter includes, but is not limited to, carbon powder, graphite powder, activated carbon, polyvinyl alcohol (PVA), polyvinyl butyral (PVB), sucrose, glucose, or a combination of the above. In an embodiment, the inert gas includes argon, helium or a combination of the above. In an embodiment, a pressure of the carbonization reaction is a normal pressure, such as 1 atm. In an embodiment, a reaction temperature is between 1500 C. and 2100 C. In an embodiment, a reaction time is between 15 minutes and 2 hours. FIG. 2B is a schematic diagram of the carbonization reaction of step 120, in which the tantalum substrate 200a after oxidation treatment may be placed in a graphite crucible 220 containing a carbonaceous matter 230, and the carbonization reaction is performed.

[0021] After step 120, step 130 may also be performed. Step 130 is carbon removal. For example, high-temperature treatment may be used to remove remaining carbonaceous matter, where the temperature of the high-temperature treatment is about 800 C. to 900 C., and the temperature holding time is about 1 h to 2 h in the atmospheric environment, but the disclosure is not limited thereto.

[0022] Another embodiment of the disclosure is a high-temperature resistant device formed using the above process. Therefore, the high-temperature resistant device includes a tantalum substrate and a tantalum carbide layer, and the tantalum carbide layer is a layer formed on the surface of the tantalum substrate. Such a high-temperature-resistant device may be used at temperatures exceeding 1000 C., for example as a crucible, an aerospace mechanical accessory, a high-temperature reaction vessel accessory, or a crystal growth accessory. In the embodiment, a thickness of the tantalum carbide layer is, for example, between 2 m to 100 m. If the thickness of the tantalum carbide layer is 2 m or more, it may meet the uniformity requirements of the tantalum carbide layer; if the thickness of the tantalum carbide layer is 100 m or less, it may reduce the probability of film separation. In the embodiment, a specific surface area of the tantalum carbide layer is between 0.1 cm.sup.2/g to 2 cm.sup.2/g. If the specific surface area of the tantalum carbide layer is 0.1 cm.sup.2/g or less, the effect of adsorbing carrier gas may be poor; if the specific surface area of the tantalum carbide layer is 2 cm.sup.2/g or more, the film structure may be unstable, thereby reducing the mechanical strength.

[0023] The following experiments are listed to verify the implementation effect of the disclosure, but the disclosure is not limited to the following content.

<Raw Material>

Experimental Examples 1 to 29

[0024] First a sheet-shaped tantalum substrate was prepared, and then the tantalum substrate was placed in an alumina crucible and an oxidation treatment listed in Table 1 was performed under a normal pressure. The oxidation treatment was performed in an atmospheric furnace. Then, the tantalum substrate after oxidation treatment (with a tantalum oxide layer formed on the surface) was embedded in a graphite crucible filled with carbon powder (purchased from SEC-Carbon, with an average particle size of 20 m), and the carbon powder was used as a carbonaceous matter for performing the carbonization reaction listed in Table 1 under a normal pressure. The inert gas for the carbonization reaction was argon or helium. Finally, carbon removal was performed under conditions of 800 C., and finally the samples of Experimental Examples 1 to 29 may be obtained.

Comparative Examples 1 to 2

[0025] Except for the oxidation treatment, the same process as the above Experimental Example was used for carbonization. The carbonization conditions are shown in Table 1.

Scanning Electron Microscope (SEM) Analysis:

[0026] An SEM scale bar was used to observe the thickness of the tantalum oxide layer formed after the oxidation treatment in Experimental Examples 1 to 29. The measurement results are recorded in Table 1 below.

[0027] An SEM was used to observe the sample cross sections of Experimental Examples 1 to 29 and Comparative Examples 1 to 2, and the thickness of the tantalum carbide layer was obtained according to the SEM scale bar. The measurement results are recorded in Table 1 below.

TABLE-US-00001 TABLE 1 Thickness Thickness of of Oxidation heat Whether tantalum Carbonization tantalum Specific treatment water oxide reaction carbide surface Peeling Temperature Time vapor is layer Temperature Time layer area resistance Sample ( C.) (minute) introduced (m) ( C.) (minute) (m) (m.sup.2/g) (/X) Experimental 120 30 X 0.5 1500 15 ~3 6.94 Example 1 Experimental 120 120 X 1 2100 15 ~5 5.87 Example 2 Experimental 120 120 4 2100 60 ~8 4.80 Example 3 Experimental 500 30 X 8 1500 15 ~10 3.74 Example 4 Experimental 500 30 X 11 1900 60 18 3.74 Example 5 Experimental 500 30 19 1900 60 12 0.13 Example 6 Experimental 500 30 X 11 2000 60 21 0.25 Example 7 Experimental 500 30 19 2000 60 21 0.14 Example 8 Experimental 500 30 68 2100 60 ~80 1.60 Example 9 Experimental 500 60 X 14 1900 60 18 1.27 Example 10 Experimental 500 60 21 1900 60 14 0.18 Example 11 Experimental 500 60 X 14 2000 60 23 0.30 Example 12 Experimental 500 60 21 2000 60 22 0.26 Example 13 Experimental 500 120 X 38 1500 15 ~45 0.22 Example 14 Experimental 500 120 75 1500 15 ~75 0.51 Example 15 Experimental 500 120 75 2100 15 ~80 0.80 Example 16 Experimental 500 120 75 2100 60 ~88 1.09 Example 17 Experimental 600 30 X 20 1900 60 20 0.31 X Example 18 Experimental 600 30 31 1900 60 16 0.17 Example 19 Experimental 600 30 X 20 2000 60 11 0.19 Example 20 Experimental 600 30 31 2000 60 46 0.18 X Example 21 Experimental 600 60 X 90 1900 60 43 0.22 X Example 22 Experimental 600 60 103 1900 60 20 0.15 Example 23 Experimental 600 60 X 90 2000 60 26 0.29 X Example 24 Experimental 600 60 103 2000 60 25 0.27 X Example 25 Experimental 1100 30 X 51 1500 15 ~20 0.24 X Example 26 Experimental 1100 120 50 1500 60 ~50 0.24 X Example 27 Experimental 1100 120 87 2100 60 ~94 0.24 X Example 28 Experimental 1100 120 87 2100 120 ~100 0.25 X Example 29 Comparative X ~0 2100 15 ~0 X X Example 1 Comparative X ~0 2100 480 ~50 X X Example 2

[0028] The O under Whether water vapor is introduced in Table 1 means that water vapor is introduced; X means that water vapor is not introduced.

[0029] The O under Peeling resistance in Table 1 represents excellent peeling resistance; the X represents poor peeling resistance.

Uniformity Analysis:

[0030] According to the SEM image, the difference between the thickest and thinnest microstructure thickness of the same film layer is taken as the evaluation data of uniformity. After measurement, Experimental Examples 1 to 4 and Experimental Examples 26 to 27 have the best uniformity (with thickness difference within 3 m); Experimental Examples 9 and 14 to 17 and Experimental Examples 28 to 29 also have satisfactory uniformity (with thickness difference ranging from 5 m to 10 m). As for Comparative Example 1, basically no tantalum carbide layer was formed, while the thickness difference of Comparative Example 2 was 10 m.

[0031] Density: The density of the tantalum carbide layer is obtained by measuring the specific surface area, and the results are expressed as relative values. The lower the specific surface area value, the better the density.

[0032] From the measured data, it can be seen that the specific surface area of the tantalum carbide layer in Experimental Examples 6 to 17 is roughly 0.13 cm.sup.2/g to 1.60 cm.sup.2/g. The tantalum carbide layer has excellent density and excellent peeling resistance, making it the preferred choice for its thermal conductivity benefits in back-end high-temperature processes and its practical application; the specific surface area of the tantalum carbide layer in Experimental Examples 1 to 5 is roughly 3.74 cm.sup.2/g to 6.94 cm.sup.2/g, and the specific surface area of the tantalum carbide layer in Comparative Example 2 is about 3.45 cm.sup.2/g, so the density is insufficient and is not conducive to back-end applications. In particular, Comparative Example 2 has insufficient density and takes too long to generate, so the thermal conductivity is poor.

[0033] Analysis of high-temperature resistance characteristics: The melting point of tantalum carbide is 3880 C. The general crystal growth process temperature is between 2000 C. and 2300 C. The material inherently possesses a temperature exceeding the temperature of the process temperature. Therefore, regardless of the thickness, uniformity, or density, the material may withstand high temperature processes without causing peeling, cracks, damage, or other adverse effects.

[0034] Peeling resistance analysis: A test piece was fixed, and a high-viscosity polymer film with a strong peeling force was used to peel off the surface of tantalum carbide, so that it may be observed whether the surface of tantalum carbide will peel off due to instantaneous force application. The detailed results are as follows: Experimental Examples 1 to 17, 19 to 20, and 23 have excellent peeling resistance, while the other Experimental Examples have poor peeling resistance. The tantalum carbide layer subjected to oxidation treatment at a temperature of 600 C. is quite unstable and fragile, and will completely peel off at 1100 C. As for Comparative Examples 1 to 2, since they have not undergone oxidation treatment, their peeling resistance is poor.

[0035] FIG. 3 and FIG. 4 are SEM images of the samples of Experimental Example 3 and Experimental Example 27 respectively. It can be seen from Table 1, FIG. 3, and FIG. 4 above that increasing the oxidation temperature from 120 C. to 1100 C. results in the increase in the thickness of the tantalum oxide layer from 8 m to 50 m. FIG. 5 and FIG. 6 are SEM images of the samples of Experimental Example 4 and Experimental Example 14. It can be seen from the above Table 1, FIG. 5, and FIG. 6 that the difference between Example 4 and Example 14 lies only in the time of the oxidation treatment. Consequently, the length of the oxidation treatment also affects the thickness of the tantalum carbide layer.

[0036] In addition, by comparing Experimental Example 4 with Experimental Example 9, it is observed that the introduction of water vapor results in the increase in the thickness of the tantalum oxide layer from 8 m to 68 m. Therefore, it can be verified that the thickness of the tantalum oxide layer is affected by the oxidation temperature, oxidation time, and water vapor. The thickness of the tantalum oxide layer increases with an increase in the oxidation temperature, an increase in the oxidation time, or an introduction of the water vapor.

[0037] For example, by comparing Experimental Example 15 with Experimental Example 16, it is observed that the increase in the carbonization temperature from 1500 C. to 2100 C. results in the increase in the thickness of the tantalum carbide layer from 75 m to 80 m. For example, by comparing Experimental Example 28 with Experimental Example 29, it is observed that the increase in the carbonization time from 60 minutes to 120 minutes may result in the increase in the thickness of the tantalum carbide layer from 94 m to 100 m. Therefore, when the tantalum oxide layer has the same thickness, the thickness of the tantalum carbide layer is mainly affected by the carbonization temperature, but the degree of change is not significant. On the other hand, by comparing Experimental Example 3 with Experimental Example 17, it is observed that, at the same carbonization temperature of 2100 C. and carbonization time of 60 minutes, the thickness of the tantalum carbide layer increased from 8 m to 88 m, and the original thickness of the tantalum oxide was respectively 4 m and 75 m. Therefore, it can be verified that the thickness of tantalum carbide formation is more easily affected by the thickness of the tantalum oxide layer.

[0038] FIG. 7 and FIG. 8 are SEM images of the samples of Comparative Example 1 and Comparative Example 2 respectively. It can be seen from the above Table 1, FIG. 7, and FIG. 8 that almost no tantalum carbide is formed in Comparative Example 1, and the tantalum carbide layer in Comparative Example 2 has insufficient density.

[0039] In summary, in the disclosure, the tantalum oxide is first generated on the surface of the tantalum substrate through oxidation treatment, and then a carbonization reaction is performed to transform the tantalum oxide into tantalum carbide, such that compared with the direct carbonization of tantalum at a higher temperature and in a longer time, TaC may be generated from carbon in situ reaction at a lower temperature and in a shorter time. Therefore, the disclosure not only has the following advantages, including but not limited to, a simplified fabrication process, an environmentally friendly and non-toxic nature, an adjustable and highly uniform film thickness, a highly densified film layer, and a high reusability rate, but it may also solve the problem of coating peeling caused by the existing way of forming TaC coating on the surface of the graphite crucible.

[0040] Although the disclosure has been described with reference to the embodiments above, the embodiments are not intended to limit the disclosure. Any person skilled in the art can make some changes and modifications without departing from the spirit and scope of the disclosure. Therefore, the scope of the disclosure will be defined in the appended claims.