In order to enhance the output power

prolong the lifetime of the high power magnetron

a method of refractory rare-earth oxide Gd

2

O

3

doped transition metal oxide HfO

2

was used to prepare direct-heated rare-earth Gd

2

Hf

2

O

7

ceramic cathode. The thermionic emission and life characteristics of the Gd

2

Hf

2

O

7

cathode had been measured. The results show that the cathode can provide

0.1A/cm

2

current density for the space charge limitation at 1300℃br

more than 1.93A/cm

2

at 1600℃br under 300V anode voltage. The lifetime for the cathode is more than 4000 h with an initial load of 0.5A/cm

2

at 1500℃br. Finally

the molecular structure

surface microstructure

element composition and content of the Gd

2

Hf

2

O

7

ceramic cathode had been analyzed by the XRD

SEM

EDS

AES (equipped with argon ion etching in-depth analysis) respectively. The analysis results show that the single Gd

2

Hf

2

O

7

phase has formed in the high sintering temperature. When the Gd

3+

valences Gd

2

O

3

doped the Hf

4+

valences HfO

2

the substitutional solid solution will be formed. In order to maintain the electrical neutrality of the Gd

2

Hf

2

O

7

lattice

an oxygen vacancy will be generated in the lattice. During the cathode activating

aging

and thermally testing

the oxygen vacancy will be generated fast. The more oxygen vacancies are obtained

the better the conductivity of the cathode surface has. Besides

the work function of the cathode can also be reduced due to the improvement of the electro-conductivity that enhances the thermionic emission capability of the cathode.