C

5

F

10

O gas has excellent insulation and environmental protection characteristics

and has good application prospects as an insulating dielectric in medium-and low-voltage grade electrical equipment. However

the compatibility of C

5

F

10

O/CO

2

gas mixture with ethylene-propylene-diene monomer（EPDM） sealing materials commonly used in gas insulation equipment needs to be studied before its engineering app

lication. In this paper

the compatibility of C

5

F

10

O gas and EPDM rubber was studied by building a rubber compatibility test platform and using the method of thermally accelerated aging. After the tests

the changes in the composition of gas mixture

the mechanical properties

surface morphology and element changes of the EPDM rubber were tested. Studies have shown that

under thermal aging conditions

chemical reactions between EPDM and C

5

F

10

O gas may occur

and EPDM will react with C

5

F

10

O and C

3

F

6

to reduce the C

3

F

6

produced by the decomposition of C

5

F

10

O gas; however

in the meantime

the decomposition of C

5

F

10

O gas will be promoted to produce C

3

F

6

O and C

3

HF

7

. After the end of the aging test

the surface of the EPDM rubber is covered with a layer of oily substances. EPDM rubber becomes brittle and reduces its mechanical properties

and a large number of crystal particles will appear on the surface. After C

5

F

10

O gas corrodes EPDM rubber

the aging of EPDM rubber will be accelerated and its service life will be shortened. Related test results will provide references for the design and manufacturing process of C

5

F

10

O gas insulation equipment.