EVONIK CORPORATION › AEROSIL® R 974 AEROSIL® R 974 $0.00 AEROSIL® R 974 is a hydrophobic-fumed silica after treated with DDS (dimethyldichloro/silane). Quantity: Add To Cart Added! AEROSIL® R 974 is a hydrophobic-fumed silica after treated with DDS (dimethyldichloro/silane). You Might Also Like AEROSIL® OX 50 AEROSIL® TT 600 AEROSIL® R 8200 AEROSIL® R 816 AEROSIL® R 711