LUDOX® HS-40 is an alkaline silica (SiO2) present as a dispersion with 40% solids containing an average particle size of 12 nanometers. The amorphous silica particles in this product are rich in silanol functional groups. These particles carry a negative charge that provides stability in the dispersion with sodium counterions present. LUDOX® HS-40 is an effective surface modifier and binder for metals, oxides, siliceous materials, and polymers with reactive functional groups.

LUDOX® HS-40 behaves as an inorganic glue in ceramic applications by binding with siliceous materials and metals. This behavior of LUDOX® HS-40 improves cohesive strength and thermal shock resistance within ceramic shapes and inorganic catalysts, like zeolites. Additionally, LUDOX® HS-40 can be utilized in water-based coating formulations, where silica particles are an integral part of improving the durability, antiblocking, and antisoiling of latex films. This grade is also useful in latex-based adhesives to increase shear strength while not compromising adhesive strength. LUDOX® HS-40 is also an extremely effective active ingredient in concrete densifier formulations, where the silica nanoparticles penetrate porous concrete more easily. This ability results in an increase in the depth, density, and hardness of the concrete.