HDK® pyrogenic silica is a loose, bulky white powder. Due to our integrated production system with its statistical process control and highly efficient reactor dynamics, the pyrogenic silica we produce is exceptionally pure. Pyrogenic silica from WACKER is of a low order of toxicity, chemically inert and does not conduct either electricity or heat. All pyrogenic silicas feature a large specific surface area: 18 grams of a typical pyrogenic silica has a surface area that would cover the size of a football field.
Hydrophilic HDK® Grades
Hydrophilic HDK® is manufactured by the hydrolysis of volatile chlorosilanes in an oxyhydrogen flame. In chemical terms, the loose white powder consists of highly pure amorphous silicon dioxide. Hydrophilic silica is wetted by, and can be dispersed in, water.
HDK® Hydrophobic Grades
Hydrophobic HDK® is produced by the chemical reaction of hydrophilic HDK® with reactive silanes, e.g. chlorosilanes or hexamethyldisilazane. Hydrophobic silica has water-repellent properties and is not dispersible in water.