Cerium-based oxide fiber and its fabricating method

Abstract

This invention discloses a kind of cerium-based oxide fiber and its fabricating method. The cerium-based hydrate fiber can be synthesized by aging under the boiling point of water for 10 hours to 50 hours by the addition of a chemical modifier. The fibers show a diameter of submicron to micron size, and the aspect ratio is greater than 100. The hydrate fibers can transform to oxide fiber after calcination at high temperature.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of the method of fabricating a cerium-based fiber according to a preferred embodiment of the present invention;

FIG. 2 is a schematic view of the effect of an aging time of samples as described in Attachments 1c and 1d on the aspect ratio of cerium hydrate;

FIGS. 3 a to 3e are schematic views of the XRD diffraction spectra of made fibers (sample no. 1-4) under the treatment of different aging periods or calcination at 600° C. for 2 hours.

Claims

1. A cerium-based fiber, comprises a composition of (Ce1−x−y, M1w, M2x)O2−y−z(OH)2y(CO3), having a first trivalent cation (M1) with w mole (mol) %, a second trivalent cation (M2) with x mole (mol) %, a hydroxyl ion matter with y mole (mol) %, and a carbonate compound with z mole (mol) %, and said fiber is converted into an oxide and maintaining its fibrous form after going through a calcination.

2. The cerium-based fiber of claim 1, wherein said M1 and said M2 are gadolinium or samarium, and the molar concentration of ions falls into a range of 0<x<0.20.

3. The cerium-based fiber of claim 1, wherein said M1 is gadolinium, and 0.0<w<0.165.

4. The cerium-based fiber of claim 1, wherein said M2 is samarium, and 0.0<x<0.147.

5. The cerium-based fiber of claim 1, wherein said hydroxyl ionic substance contains 0.0<y<0.30.

6. The cerium-based fiber of claim 1, wherein said carbonate compound contains 0.0<z<0.90.

7. The cerium-based fiber of claim 1, said long fiber has an aspect ratio from 40 to 200.

8. The cerium-based fiber of claim 1, said long fiber has a diameter from a submicron to a micron.

9. The cerium-based fiber of claim 1, further comprising a hydrate and a carbonate, and said hydrate and said carbonate substance are changed to an oxide after going through a calcination process.

10. The cerium-based fiber of claim 9, wherein said calcination is performed at a temperature from 400° C. to 1300° C. for 0.1 hour to 50 hours.

11. The cerium-based fiber of claim 10, wherein said hydrate and said carbonate have a remained quantity of less than 1 mole % after going through said calcination process.

12. A cerium-based fiber fabrication method, comprising the steps of: adding a modifier, cerium nitrate, sodium hydroxide, and metal (M1, M2) nitrate into an a solution according to a predetermined ratio (h) of sodium hydroxide to cerium nitrate and a predetermined ratio of M1, M2 to cerium nitrate;waiting till solutes of said solution are dissolved completely;placing said solution into a constant temperature machine for holding the temperature; andremoving said solution and a produced precipitate in several hours after the reaction, and rinsing said precipitate several times by deionized water.

13. The fabrication method of claim 12, wherein said modifier is a citric acid or a citric acid derivative compound.

14. The fabrication method of claim 13, wherein said sodium hydroxide and said citric acid have a ratio (h), and 0.25<h<0.7.

15. The fabrication method of claim 12, wherein said fiber has an aspect ratio from 40 to 200.

16. The fabrication method of claim 12, wherein said fiber has a diameter from a submicron to a micron.

17. The fabrication method of claim 12, wherein said holding temperature ranges from 60° C. to 99° C. and said holding time ranges from 2 hours to 30 hours.

18. The fabrication method of claim 12, wherein said cerium-based fiber contains (Ce1−x−y, M1w, M2x))O2−y−z(OH)2y(CO3)z.

19. The fabrication method of claim 18, wherein said M1 and said M2 are gadolinium or samarium.

20. The fabrication method of claim 18, wherein said M1 is gadolinium, and 0.0<w<0.165.

21. The fabrication method of claim 18, wherein said M2 is samarium, and 0.0<x<0.147.

22. The fabrication method of claim 18, wherein said cerium-based fiber contains 0.0<y<0.30.

23. The fabrication method of claim 12, wherein said cerium-based fiber contains 0.0<z<0.90.

24. The fabrication method of claim 12, further comprises a calcination step of changing said fiber into oxide after said hydrated fiber goes through said calcination step.

25. The fabrication method of claim 24, wherein said calcination step is conducted at a temperature from 400° C. to 1300° C. for 0.1 hour to 50 hours.