Carburized La2O3 and Lu2O3 co-doped Mo filament cathode

Abstract

A carburized La.sub.2O.sub.3 and Lu.sub.2O.sub.3 co-doped Mo filament cathode is made from lanthanum oxide (La.sub.2O.sub.3) and lutetium oxide (Lu.sub.2O.sub.3) doped molybdenum (Mo) powders, the lanthanum oxide (La.sub.2O.sub.3) and lutetium oxide (Lu.sub.2O.sub.3) doped molybdenum (Mo) powders contain La.sub.2O.sub.3, Lu.sub.2O.sub.3 and Mo with the total concentration of La.sub.2O.sub.3 and Lu.sub.2O.sub.3 being 2.0-5.0 wt. % and the rest being Mo.

Claims

1. A rare earth oxide doped molybdenum filament cathode material, comprising lanthanum oxide (La.sub.2O.sub.3), lutetium oxide (Lu.sub.2O.sub.3) and molybdenum (Mo), wherein the total concentration of La.sub.2O.sub.3 and Lu.sub.2O.sub.3 is 2.0-5.0 wt. % and the rest is Mo.

2. The rare earth oxide doped molybdenum filament cathode material of claim 1, wherein the total concentration of La.sub.2O.sub.3 and Lu.sub.2O.sub.3 ranges from 3 to 4.5 wt. %.

3. The rare earth oxide doped molybdenum filament cathode material of claim 1, wherein La.sub.2O.sub.3 and Lu.sub.2O.sub.3 have a weight ratio of (2-5):1.

4. The rare earth oxide doped molybdenum filament cathode material of claim 1, wherein La.sub.2O.sub.3 and Lu.sub.2O.sub.3 have a weight ratio of 4:1.

5. The rare earth oxide doped molybdenum filament cathode material of claim 1, consisting of lanthanum oxide (La.sub.2O.sub.3), lutetium oxide (Lu.sub.2O.sub.3) and molybdenum (Mo).

6. The rare earth oxide doped molybdenum filament cathode material of claim 1, wherein the concentration of lanthanum oxide (La.sub.2O.sub.3) is higher than that of lutetium oxide (Lu.sub.2O.sub.3).

7. The rare earth oxide doped molybdenum filament cathode material of claim 1, wherein La.sub.2O.sub.3, Lu.sub.2O.sub.3 and Mo are evenly mixed.

8. A filament cathode made from lanthanum oxide (La.sub.2O.sub.3) and lutetium oxide (Lu.sub.2O.sub.3) doped molybdenum (Mo) powders, wherein the lanthanum oxide (La.sub.2O.sub.3) and lutetium oxide (Lu.sub.2O.sub.3) doped molybdenum (Mo) powders comprise La.sub.2O.sub.3, Lu.sub.2O.sub.3 and Mo with the total concentration of La.sub.2O.sub.3 and Lu.sub.2O.sub.3 being 2.0-5.0 wt. % and the rest being Mo.

9. The filament cathode of claim 8, wherein the total concentration of La.sub.2O.sub.3 and Lu.sub.2O.sub.3 ranges from 3 to 4.5 wt. %.

10. The filament cathode of claim 8, wherein the concentration of La.sub.2O.sub.3 is higher than that of Lu.sub.2O.sub.3.

11. The filament cathode of claim 10, wherein La.sub.2O.sub.3 and Lu.sub.2O.sub.3 have a weight ratio of (2-5):1.

12. The filament cathode of claim 11, wherein La.sub.2O.sub.3 and Lu.sub.2O.sub.3 have a weight ratio of 4:1.

13. The filament cathode of claim 8, wherein the lanthanum oxide (La.sub.2O.sub.3) and lutetium oxide (Lu.sub.2O.sub.3) doped molybdenum (Mo) powders consist of La.sub.2O.sub.3, Lu.sub.2O.sub.3 and Mo.

14. The filament cathode of claim 8, wherein the filament cathode is carburized and has a working temperature in a magnetron ranges from 1200 to 1400 C.

15. The filament cathode of claim 8, wherein La.sub.2O.sub.3, Lu.sub.2O.sub.3 and Mo are evenly mixed in the lanthanum oxide (La.sub.2O.sub.3) and lutetium oxide (Lu.sub.2O.sub.3) doped molybdenum (Mo) powders.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The techniques of the present disclosure will now be described in detail with reference to the accompanying drawings.

(2) FIG. 1 is a lifetime graph of output power of microwave oven versus time of a cathode as illustrated in example 5.

EXAMPLES

(3) From the foregoing it will be appreciated that, although specific embodiments of the present disclosure have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the present disclosure. Accordingly, the present disclosure is not limited except as by the appended claims.

Example 1

(4) Rare earth oxide was quantified in a weight fraction of 2 wt. % based on the rare earth oxide co-doped Mo powders, and the rest was Mo. Dissolving 42.53 g of La(NO.sub.3).sub.3.6H.sub.2O, 9.43 g of Lu(NO.sub.3).sub.3.6H.sub.2O, 1803.5 g of (NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O and 1855 g of C.sub.6H.sub.8O.sub.7.H.sub.2O in de-ionized water respectively and completely, adding the citric acid, La(NO.sub.3).sub.3 and Lu(NO.sub.3).sub.3 solution into the (NH.sub.4).sub.6Mo.sub.7O.sub.24 solution slowly with persistently agitation; setting the mixed solution in a water-bath heating environment to obtain a wet gel; drying the wet gel to obtain the xerogel; calcining the xerogel at 500 C. to obtain La.sub.2O.sub.3 and Lu.sub.2O.sub.3 co-doped MoO.sub.3 powers; and calcining the mixed trioxide powders in hydrogen atmosphere at 550 C. to obtain La.sub.2O.sub.3, Lu.sub.2O.sub.3 doped MoO.sub.2 powders thoroughly; calcining the mixed oxide powders further in hydrogen at 980 C. to obtain La.sub.2O.sub.3 and Lu.sub.2O.sub.3 doped Mo powders completely; pressing the mixed powers into REO co-doped Mo billet at 150 MPa and remained for 15 mins; and sintering the REO co-doped Mo billets to obtain REO co-doped Mo rods at 1800 C. Rotary swaging the Mo rods for a few times to become the Mo sticks. Drawing the Mo sticks to decrease the diameter of the sticks to obtain the Mo filaments by multi drawing process. Cleaning the colloidal graphite on the surface of the Mo filament by electrolytic cleaning processes, and straightens the cleaned Mo filament. Winding Mo filament to a coil spring filament and annealing and modeling the Mo coil spring filament; cutting the molybdenum coil spring filament to small segments and each segment as a Mo filament cathode. First assembly of the filament cathodes and doing the carburization treatment of the REO co-doped Mo filament cathode at 1800 C. for 70 s and the carburization degree was 32.3%. Second assembly of the vacuum tubes and doing the out-gassing treatment of the magnetrons equipped with the carburized REO co-doped Mo filament cathode at 1800 C. for 30 minutes; and then third assembly of magnetrons and doing the activation treatment of the REO co-doped Mo filament cathode at 1600 C. for 30 minutes. Testing the direct current emission property of the electronic tube and the result was shown in Table 1. Then we tested the output power of the magnetron tube when the working temperature was 1250 C.

Example 2

(5) Rare earth oxide was quantified in a weight fraction of 2.5 wt. % based on the rare earth oxide co-doped Mo powders, and the rest was Mo.

(6) Dissolving 53.16 g of La(NO.sub.3).sub.3.6H.sub.2O, 11.79 g of Lu(NO.sub.3).sub.3.6H.sub.2O, 1794.2 g of (NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O and 1859 g of C.sub.6H.sub.8O.sub.7.H.sub.2O in de-ionized water respectively and completely, adding the citric acid, La(NO.sub.3).sub.3 and Lu(NO.sub.3).sub.3 solution into the (NH.sub.4).sub.6Mo.sub.7O.sub.24 solution slowly with persistently agitation; setting the mixed solution in a water-bath heating environment to obtain a wet gel; drying the wet gel to obtain the xerogel; calcining the xerogel at 550 C. to obtain La.sub.2O.sub.3 and Lu.sub.2O.sub.3 co-doped MoO.sub.3 powers; and calcining the mixed trioxide powders in hydrogen atmosphere at 550 C. to obtain La.sub.2O.sub.3, Lu.sub.2O.sub.3 doped MoO.sub.2 powders thoroughly; calcining the mixed oxide powders further in hydrogen at 950 C. to obtain La.sub.2O.sub.3 and Lu.sub.2O.sub.3 doped Mo powders completely; pressing the mixed powers into REO co-doped Mo billet at 150 MPa and remained for 15 minutes; and sintering the REO co-doped Mo billets to obtain REO co-doped Mo rods at 1800 C. Rotary swaging the Mo rods for a few times to become the Mo sticks. Drawing the Mo sticks to decrease the diameter of the sticks to obtain the Mo filaments by multi drawing process. Cleaning the colloidal graphite on the surface of the Mo filament by electrolytic cleaning processes, and straightens the cleaned Mo filament. Winding Mo filament to a coil spring filament and annealing and modeling the Mo coil spring filament; cutting the molybdenum coil spring filament to small segments and each segment as a Mo filament cathode. First assembly of the filament cathodes and doing the carburization treatment of the REO co-doped Mo filament cathode at 1800 C. for 70 s and its carburization degree was 34.1%. Second assembly of the vacuum tubes and doing the out-gassing treatment of the magnetrons equipped with the carburized REO co-doped Mo filament cathode at 1800 C. for 30 mins; and then third assembly of magnetrons and doing the activation treatment of the REO co-doped Mo filament cathode at 1600 C. for 30 mins. Testing the direct current emission property of the electronic tube and the result was shown in Table 1. Then we tested the output power of the magnetron tube when the working temperature was 1250 C.

Example 3

(7) Rare earth oxide was quantified in a weight fraction of 3 wt. % based on the rare earth oxide co-doped Mo powders, and the rest was Mo.

(8) Dissolving 63.79 g of La(NO.sub.3).sub.3.6H.sub.2O, 14.15 g of Lu(NO.sub.3).sub.3.6H.sub.2O, 1785.0 g of (NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O and 1862.9 g of C.sub.6H.sub.8O.sub.7.H.sub.2O in de-ionized water respectively and completely, adding the citric acid, La(NO.sub.3).sub.3 and Lu(NO.sub.3).sub.3 solution into the (NH.sub.4).sub.6Mo.sub.7O.sub.24 solution slowly with persistently agitation; setting the mixed solution in a water-bath heating environment to obtain a wet gel; drying the wet gel to obtain the xerogel; calcining the xerogel at 550 C. to obtain La.sub.2O.sub.3 and Lu.sub.2O.sub.3 co-doped MoO.sub.3 powers; and calcining the mixed trioxide powders in hydrogen atmosphere at 550 C. to obtain La.sub.2O.sub.3, Lu.sub.2O.sub.3 doped MoO.sub.2 powders thoroughly; calcining the mixed oxide powders further in hydrogen at 950 C. to obtain La.sub.2O.sub.3 and Lu.sub.2O.sub.3 doped Mo powders completely; pressing the mixed powers into REO co-doped Mo billet at 150 MPa and remained for 15 mins; and sintering the REO co-doped Mo billets to obtain REO co-doped Mo rods at 1850 C. Rotary swaging the Mo rods for a few times to become the Mo sticks. Drawing the Mo sticks to decrease the diameter of the sticks to obtain the Mo filaments by multi drawing process. Cleaning the colloidal graphite on the surface of the Mo filament by electrolytic cleaning processes, and straightens the cleaned Mo filament. Winding Mo filament to a coil spring filament and annealing and modeling the Mo coil spring filament; cutting the molybdenum coil spring filament to small segments and each segment as a Mo filament cathode. First assembly of the filament cathodes and doing the carburization treatment of the REO co-doped Mo filament cathode at 1700 C. for 75 s and its carburization degree was 28.2%. Second assembly of the vacuum tubes and doing the out-gassing treatment of the magnetrons equipped with the carburized REO co-doped Mo filament cathode at 1800 C. for 30 mins; and then the third assembly of magnetrons and doing the activation treatment of the REO co-doped Mo filament cathode at 1600 C. for 30 mins. Testing the direct current emission property of the electronic tube and the result was shown in Table 1. Then we tested the output power of the magnetron tube when the working temperature was 1250 C.

Example 4

(9) Rare earth oxide was quantified in a weight fraction of 3.5 wt. % based on the rare earth oxide co-doped Mo powders, and the rest was Mo.

(10) Dissolving 74.43 g of La(NO.sub.3).sub.3.6H.sub.2O, 16.50 g of Lu(NO.sub.3).sub.3.6H.sub.2O, 1775.8 g of (NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O and 1866.7 g of C.sub.6H.sub.8O.sub.7.H.sub.2O in de-ionized water respectively and completely, adding the citric acid, La(NO.sub.3).sub.3 and Lu(NO.sub.3).sub.3 solution into the (NH.sub.4).sub.6Mo.sub.7O.sub.24 solution slowly with persistently agitation; setting the mixed solution in a water-bath heating environment to obtain a wet gel; drying the wet gel to obtain the xerogel; calcining the xerogel at 600 C. to obtain La.sub.2O.sub.3 and Lu.sub.2O.sub.3 co-doped MoO.sub.3 powers; and calcining the mixed trioxide powders in hydrogen atmosphere at 600 C. to obtain La.sub.2O.sub.3, Lu.sub.2O.sub.3 doped MoO.sub.2 powders thoroughly; calcining the mixed oxide powders further in hydrogen at 920 C. to obtain La.sub.2O.sub.3 and Lu.sub.2O.sub.3 doped Mo powders completely; pressing the mixed powers into REO co-doped Mo billet at 150 MPa and remained for 15 minutes; and sintering the REO co-doped Mo billets to obtain REO co-doped Mo rods at 1850 C. Rotary swaging the Mo rods for a few times to become the Mo sticks. Drawing the Mo sticks to decrease the diameter of the sticks to obtain the Mo filaments by multi drawing process. Cleaning the colloidal graphite on the surface of the Mo filament by electrolytic cleaning processes and straightens the cleaned Mo filament. Winding Mo filament to a coil spring filament and annealing and modeling the Mo coil spring filament; cutting the molybdenum coil spring filament to small segments and each segment as a Mo filament cathode. First assembly of the filament cathodes and doing the carburization treatment of the REO co-doped Mo filament cathode at 1700 C. for 75 s and its carburization degree was 29.3%. Second assembly of the vacuum tubes and doing the out-gassing treatment of the magnetrons equipped with the carburized REO co-doped Mo filament cathode at 1800 C. for 30 mins; and then the third assembly of magnetrons and doing the activation treatment of the REO co-doped Mo filament cathode at 1600 C. for 30 mins. Testing the direct current emission property of the electronic tube and the result was shown in Table 1. Then we tested the output power of the magnetron tube when the working temperature was 1250 C.

Example 5

(11) Rare earth oxide was quantified in a weight fraction of 4 wt. % based on the rare earth oxide co-doped Mo powders, and the rest was Mo.

(12) Dissolving 85.06 g of La(NO.sub.3).sub.3.6H.sub.2O, 18.86 g of Lu(NO.sub.3).sub.3.6H.sub.2O, 1766.6 g of (NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O and 1870.5 g of C.sub.6H.sub.8O.sub.7.H.sub.2O in de-ionized water respectively and completely, adding the citric acid, La(NO.sub.3).sub.3 and Lu(NO.sub.3).sub.3 solution into the (NH.sub.4).sub.6Mo.sub.7O.sub.24 solution slowly with persistently agitation; setting the mixed solution in a water-bath heating environment to obtain a wet gel; drying the wet gel to obtain the xerogel; calcining the xerogel at 600 C. to obtain La.sub.2O.sub.3 and Lu.sub.2O.sub.3 co-doped MoO.sub.3 powers; and calcining the mixed trioxide powders in hydrogen atmosphere at 600 C. to obtain La.sub.2O.sub.3, Lu.sub.2O.sub.3 doped MoO.sub.2 powders thoroughly; calcining the mixed oxide powders further in hydrogen at 900 C. to obtain La.sub.2O.sub.3 and Lu.sub.2O.sub.3 doped Mo powders completely; pressing the mixed powers into REO co-doped Mo billet at 150 MPa and remained for 15 minutes; and sintering the REO co-doped Mo billets to obtain REO co-doped Mo rods at 1900 C. And rotary swaging the Mo rods for a few times to become the Mo sticks. Drawing the Mo sticks to decrease the diameter of the sticks to obtain the Mo filaments by multi drawing process. Cleaning the colloidal graphite on the surface of the Mo filament by electrolytic cleaning processes, and straightens the cleaned Mo filament. Winding Mo filament to a coil spring filament and annealing and modeling the Mo coil spring filament; cutting the molybdenum coil spring filament to small segments and each segment as a Mo filament cathode. First assembly of the filament cathodes and doing the carburization treatment of the REO co-doped Mo filament cathode at 1600 C. for 80 s and its carburization degree was 28.2%. Second assembly of the vacuum tubes and doing the out-gassing treatment of the magnetrons equipped with the carburized REO co-doped Mo filament cathode at 1800 C. for 30 mins; and then the third assembly of magnetrons and doing the activation treatment of the REO co-doped Mo filament cathode at 1600 C. for 30 mins. Testing the direct current emission property of the electronic tube and the result was shown in Table 1. Then we tested the output power of the magnetron tube when the working temperature was 1250 C.

Example 6

(13) Rare earth oxide was quantified in a weight fraction of 4.5 wt. % based on the rare earth oxide co-doped Mo powders, and the rest was Mo.

(14) Dissolving 95.69 g of La(NO.sub.3).sub.3.6H.sub.2O, 21.21 g of Lu(NO.sub.3).sub.3.6H.sub.2O, 1757.4 g of (NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O and 1874.3 g of C.sub.6H.sub.8O.sub.7.H.sub.2O in de-ionized water respectively and completely, adding the citric acid, La(NO.sub.3).sub.3 and Lu(NO.sub.3).sub.3 solution into the (NH.sub.4).sub.6Mo.sub.7O.sub.24 solution slowly with persistently agitation; setting the mixed solution in a 80 C. environment to obtain a wet gel; drying the wet gel to obtain the xerogel; calcining the xerogel at 650 C. to obtain La.sub.2O.sub.3 and Lu.sub.2O.sub.3 co-doped MoO.sub.3 powers; and calcining the mixed trioxide powders in hydrogen atmosphere at 600 C. to obtain La.sub.2O.sub.3, Lu.sub.2O.sub.3 doped MoO.sub.2 powders thoroughly; calcining the mixed oxide powders further in hydrogen at 980 C. to obtain La.sub.2O.sub.3 and Lu.sub.2O.sub.3 doped Mo powders completely; pressing the mixed powers into REO co-doped Mo billet at 150 MPa and remained for 15 mins; and sintering the REO co-doped Mo billets to obtain REO co-doped Mo rods at 1950 C.; rotary swaging the Mo rods for a few times to become the Mo sticks. Drawing the Mo sticks to decrease the diameter of the sticks to obtain the Mo filaments by multi drawing process. Cleaning the colloidal graphite on the surface of the Mo filament by electrolytic cleaning processes, and straightens the cleaned Mo filament. Winding Mo filament to a coil spring filament and annealing and modeling the Mo coil spring filament; cutting the molybdenum coil spring filament to small segments and each segment as a Mo filament cathode. First assembly of the filament cathodes and doing the carburization treatment of the REO co-doped Mo filament cathode at 1600 C. for 80 s and its carburization degree was 27.3%. Second assembly of the vacuum tubes and doing the out-gassing treatment of the magnetrons equipped with the carburized REO co-doped Mo filament cathode at 1800 C. for 30 mins; and then the third assembly of magnetrons and doing the activation treatment of the REO co-doped Mo filament cathode at 1600 C. for 30 mins. Testing the direct current emission property of the electronic tube and the result was shown in Table 1. Then we tested the output power of the magnetron tube when the working temperature was 1250 C.

Example 7

(15) Rare earth oxide was quantified in a weight fraction of 5 wt. % based on the rare earth oxide co-doped Mo powders, and the rest was Mo.

(16) Dissolving 106.32 g of La(NO.sub.3).sub.3.6H.sub.2O, 23.58 g of Lu(NO.sub.3).sub.3.6H.sub.2O, 1748.2 g of (NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O and 1878.1 g of C.sub.6H.sub.8O.sub.7.H.sub.2O in de-ionized water respectively and completely, adding the citric acid, La(NO.sub.3).sub.3 and Lu(NO.sub.3).sub.3 solution into the (NH.sub.4).sub.6Mo.sub.7O.sub.24 solution slowly with persistently agitation; setting the mixed solution in a 80 C. environment to obtain a wet gel; drying the wet gel to obtain the xerogel; calcining the xerogel at 680 C. to obtain La.sub.2O.sub.3 and Lu.sub.2O.sub.3 co-doped MoO.sub.3 powers; and calcining the mixed trioxide powders in hydrogen atmosphere at 650 C. to obtain La.sub.2O.sub.3, Lu.sub.2O.sub.3 doped MoO.sub.2 powders thoroughly; calcining the mixed oxide powders further in hydrogen at 850 C. to obtain La.sub.2O.sub.3 and Lu.sub.2O.sub.3 doped Mo powders completely; pressing the mixed powers into REO co-doped Mo billet at 150 MPa and remained for 15 minutes; and sintering the REO co-doped Mo billets to obtain REO co-doped Mo rods at 2000 C.; rotary swaging the Mo rods for a few times to become the Mo sticks. Drawing the Mo sticks to decrease the diameter of the sticks to obtain the Mo filaments by multi drawing process. Cleaning the colloidal graphite on the surface of the Mo filament by electrolytic cleaning processes, and straightens the cleaned Mo filament. Winding Mo filament to a coil spring filament and annealing and modeling the Mo coil spring filament; cutting the molybdenum coil spring filament to small segments and each segment as a Mo filament cathode. First assembly of the filament cathodes and doing the carburization treatment of the REO co-doped Mo filament cathode at 1550 C. for 100 s and its carburization degree was 25.4%. Second assembly of the vacuum tubes and doing the out-gassing treatment of the magnetrons equipped with the carburized REO co-doped Mo filament cathode at 1800 C. for 30 mins; and then the third assembly of magnetrons and doing the activation treatment of the REO co-doped Mo filament cathode at 1600 C. for 30 mins. Test the direct current emission property of the electronic tube and the result was shown in Table 1. Then we tested the output power of the magnetron tube when the working temperature was 1250 C.

(17) TABLE-US-00001 TABLE 1 Table of the date of the carburizing degree and emission current tested without magnetic field Sample Emission Current (mA) 1 637 2 640 3 632 4 633 5 651 6 637 7 636