Surface Sealants

These sealants are used to seal in dust/fibers/contamination on ceramics.

Rigidizer that Seals in Surface Dust on Refractories While Providing a Refractory Surface
Toughseal is a water-alcohol-based liquid which can be applied by bristle-brush, foam-rubber-brush, pump-sprayers and the like to most refractory materials … brick, blankets, foams, pulp-molded surfaces, etc. The Toughseal has a pH of 2-3 … which should be considered for some possible interactions [i.e., the surface being treated should be stable with an acidic material]. Toughselcan sometimes provide a good “base” for applying refractory topcoatings[i.e., when used on fibrous surfaces etc.]working well with acidic pH coatings. Other properties – relativelyshort shelf life of 3-6 months; used in all atmospheres to 1600 C (2912 F). The Toughseal can also be used as a binder/suspender for making a paintable ceramic coating – with materials that are OK with its acidic system.

Link to more information on Toughseal

Water-Based, Light Syrup-Appearing Liquid for Sealing Ceramic Surfaces

  • Usable to 1650 F (900 C) – Ideal for “used” hot-top billet casting tables
  • Ready-to-apply, like ordinary paint primers by brush or air-spray
  • Clean, safe-to-use

This water-based, clear light-syrup-appearing liquid is designed for sealing the surfaces of porous ceramics and boards. It is desirable to clean off as much residual dust and contamination as possible. By merely painting or swabbing this material onto the ceramic, the surfaces become much more amenable to topcoating with boron nitride coatings such as Boron Nitride Lubricoat Blue which would otherwise react with residual Bone Ash and red mud. By using the Z-PRIMERCOAT, spalling and mud-cracking can be prevented. Other properties — long shelf life of over 12 months;used in all atmospheres to 900 C. The Z-Primercoat can also be used as a binder/suspender for making apaintable ceramic coating – with materials that are OK with its pH-Alkaline/Basic system.

For new billet casting tables, Z-Primercoat is normally not necessary

  • Allows old [“used”] casting tables to be boron nitride coated
  • Seals the surface porosity of the ceramic
  • Seals in the dust and contaminants
  • Allows ready topcoating with acidic bn paints
  • Can also be used as a ph-alkaline/basic binder that gives tough coatings

Link to more information on Z-Primercoat


A Protective, Silica-Free Zirconia (ZrO2 ) Coating
Stable with molten metals, glasses, fluxes, slags, and gases

Z-Guard is a relatively low-viscosity coating that produces a hard, abrasion and chemical resistant zirconia (ZrO2) layer that is protective to all ceramic bodies against most molten metals and corrosive environments to above 3272 F(1800 C). Z-Guard can be used as a sealant, since its binder will penetrate porous surfaces – acting as a surfacerigidizer while producing a more wear-resistant surface layer of Zirconium Oxide which is also resistant to most high- temperature reactions that could degrade the ceramic.

The “shelf life” of Z-Guard is a relatively-short 3-6 months.

Link to more information on Z-Guard

These sealants are used to seal the surface of fused silica with a vitreous impervious layer.

Vitragard FS

Surface Sealing Coating Composition for Fused Silica
Vitragard FS is a ready-to-use, water-based brushable paste that seals the surface of fused silica with a vitreous impervious layer. After applying, drying, and one-time firing to 900-950 C, the Vitragard FS is permanently bonded to the fused silica substrate. For fused silica containing up to 85% porosity, the erosion-resistant layer will enhance the substrate toughness without degrading the thermal properties of the fused silica. The sealed surface is also protected from gases permeating the body to attack the underlying substrate. Vitragard-coated porous fused silica parts are still highly thermally insulating and can now be top-coated with any of our Boron Nitride coatings to enhance resistance to molten aluminum and its alloys.
Link to more information on Vitragard FS