Carbon foams always show the poor mechanical properties. For application demand-oriented in the field of aerospace

carbon microspheres/Mg

2

B

2

O

5

w hybrid reinforced carbon foam composites

were

prepared by the process of compression molding and carbonization

using modified phenolic resin as carbon source

hollow microspheres as dispersed phase

and magnesium borate whisker (Mg

2

B

2

O

5

w) as reinforcement

respectively

to improve their comprehensive performance. The mechanical properties

electromagnetic shielding effectiveness and oxidation resistance properties of carbon foam composites reinforced by carbon microspheres and different mass fractions of Mg

2

B

2

O

5

w

were investigated by SEM

and universal testing machine

respectively. The results showed that Mg

2

B

2

O

5

w played the role of crack deflection and bending bow

and increased the crack propagation path during compression

leading to Mg

2

B

2

O

5

w and hollow carbon microspheres improving the compressive properties of carbon foam composites synergistically. When the mass fraction of Mg

2

B

2

O

5

w is 2%

the compressive strength of the composites reached 11.8 MPa

157% higher than that of pure carbon foam. The electromagnetic shielding effectiveness of carbon foam composites in the X-band increased significantly

with the increase of Mg

2

B

2

O

5

w content. Mg

2

B

2

O

5

w dispersed on the surface of the matrix and microsphere phases

that increased the pore structure inside the composite material

prolonged the propagation path of electromagnetic waves

and increased the absorption of electromagnetic waves. When the mass fraction of Mg

2

B

2

O

5

w is 8%

the electromagnetic shielding performance reached 53.8 dB

68% higher than that of pure carbon foam. Mg

2

B

2

O

5

wpresented excellent antioxidant performance. They dispersed on the surface of the matrix and microsphere phase

preventing the contact of hot oxygen with the matrix and microsphere phase

and thus improving the oxidation resistance.

When the mass fraction of Mg

2

B

2

O

5

w is 5%

the mass loss rate of carbon foam composites is 24%

and the high-temperature oxidation resistance is the best

which is 12.1% higher than that of pure carbon foam.