Properties of Bi ₂ O ₃ /epoxy resin–coated composites for protection against gamma rays

In this paper, bismuth oxide (Bi ₂ O ₃ ) as the main functional powder, lead (Pb) and tantalum (Ta) as the metal additives, epoxy resin as the matrix and polyester–cotton blended woven fabric as the substrate, Bi ₂ O ₃ coating nuclear radiation protection composite, Bi ₂ O ₃ /Pb coating nuclear radiation protection composite, and Bi ₂ O ₃ /Ta coating nuclear radiation protection composite with different process parameters were prepared. The cross-section scanning analysis and the influence factor analysis of γ-ray protection performance were carried out, and the mechanical properties of the composites were discussed. The results show that an increase in Bi ₂ O ₃ content (mass fraction) and an increase in coating thickness can improve the shielding rate of the composite materials to γ-rays. When the thickness of the coating is 1.6 mm and the content of Bi ₂ O ₃ is 50%, the shielding rate of the composite to γ-rays (at 59.5 keV) reaches 46.1%. The shielding rate of the composite can be increased by adding appropriate metal additives, and the effect of adding Ta is better than that of Pb. The shielding rate of the composite to γ-rays (59.5 keV) can be increased from 28.4% to 31.5% by adding 5% Ta. An increase in Bi ₂ O ₃ content (mass fraction) and an increase in the coating thickness can aggravate the agglomeration of functional particles in the material. The addition of metal additives can reduce agglomeration to a certain extent. Bi ₂ O ₃ content, coating thickness, and metal additives all have an effect on the mechanical properties of the composite. If the coating is too thick or the functional particle content is too high, the tensile strength and elongation at break of the composite will be reduced.