Zirconium silicate - Calcium carbonate - Titanium dioxide

15/05/2024

Zirconium silicate

Zirconium silicate (ZrSiO₄) is a white, odorless powder, insoluble in water.

Thanks to its high hardness (6.5-7.5 Mohs), it is used in coatings to exponentially increase resistance to abrasion and wear.

Chemical stability: Zirconium silicate has high chemical stability and is resistant to acids, alkalis and most organic solvents. This inertia allows it to maintain its properties even in difficult environments.

Low thermal expansion: with a low coefficient of thermal expansion and a high melting point, it is valuable in refractory or fireproof coatings, ceramic glazes, opacifiers, pigments and as a binder in investment casting molds, where it helps to improve the resistance of the mold, reduce cracking and improve the surface finish of castings.

Finishing additive: added to formulations helps improve opacity, color and shine, resulting in better aesthetics.

Zirconium silicate is a more expensive mineral than traditional fillers used in coatings, it is therefore not used as a filler or support, but rather represents an active raw material in the functionality of special coatings.

Calcium carbonate

Calcium carbonate (CaCO3) is a carbonate mineral widely used in the coating sector, thanks to its low cost, good hardness (3 Mohs) and properties that make paint and plaster formulations versatile and flexible. Like all carbonates, it is susceptible to acids.

Interior wall paints undoubtedly represent the most important application in this context. Calcium carbonate can significantly improve some paint characteristics such as gloss, opacity (hiding power) and wear resistance.

In industrial coatings, it is mainly used for protection from adverse environmental conditions, with particular attention to durability. Suitable both in primers and in upper finishing layers, where high gloss and maintenance of the same are required.

Also present in mortars and plasters, as a filler and protector from water, environmental damage and wear, as well as to give brightness and improve their appearance.

Partially soluble in water and dispersible in silicates, it is a good rheology and viscosity regulator, usable in formulation even at high percentages.

Titanium oxide

Titanium dioxide (TiO₂) is the most important white pigment used in the coating industry. It is widely used because it efficiently disperses visible light, thus imparting whiteness, brightness and covering power (much greater than calcium carbonate or zinc oxide).

The particles are spherical in shape and the hardness varies from 5.5 to 6.5 Mohs, depending on the crystalline structure (Anatase or Rutilium). The hardness, chemical inertness and resistance to atmospheric agents make it suitable for wall and external coverings, whether water, oil or solvent based. The Rutilium structure is preferable in coatings as it interacts with light more efficiently and is more stable and durable than Anatase. The latter is mostly used where the "chalking" effect is required, for example in wall paintings.

Thanks to its great characteristics, including excellent anti-corrosive capacity, TiO2 is widely used in paints, enamels and coatings for walls, furniture and metal surfaces, making it a key component in the construction and automotive sectors.

The cost of titanium dioxide is significantly higher than traditional fillers, which is why it could be partially replaced or combined with other mineral fillers in the formula, however, in the most high-performance coatings and professional paints, the total percentage of titanium dioxide can exceed 30%.