Fused Alumina

SEPASIL® is a synthetic fused alumina, also called corrundum. Typical properties imparted are high transparency and an extremely high level of hardness (only diamonds being harder on the Mohs scale). For this reason it is commonly used in abrasion resistant coatings and lacquers.

Various particle size grades are available, ready for use. This saves the customer needing to mill them which can be problematic due to the high level of hardness. Each grade is then available with an optional silane surface treatment to faciliate dispersion and cross-linking into the particular binder or polymer that the products is being used in.

Due to its high level of electrical insulation you will also commonly find it being used in cast resin insulators and high-voltage insulators.


    • High purity fused alumina (corundum).

    • Different particle sizes available. Narrow particle size distribution.

    • Optional surface treatments possible.

    • Extremely high hardness- 9-9.5 on Mohs scale.

    • Chemically inert.


    • Excellent scratch and abrasion resistance.

    • High level of chemical resistance.

    • Transparent appearance in many systems.

    • Highly electrically insulating.

Typical Applications

    • Cast resin insulators and high-voltage insulators.

    • High abrasion resistant wood and decorative coatings.

    • Laminates.

Featured grades with technical datasheets

A brief overview of the key grades is given below. You will find the Technical Datasheets (TDS) available for download. If you are looking for a Safety Datasheet (SDS) or Product Safety Information (PSI) then please get in touch by phone or via the contact buttons at the top of the page.

Should you not find what you are looking for here then please note that we have further grades available besides these. One of our Technical Sales team will be happy to help. All of the sales team are technically qualified and will be able to advise you on which product to choose. You can either call us, email us or fill in a quick form at the top of the page to get us to call you (Request a Callback). A sample can be requested via the button at the top of the page as well. Please note that by providing us with your contact details, you are agreeing for us to potentially contact you.

Related brochures & technical literature

You will find some of the key product brochures available for download below. There are more brochures available upon request. If you would like to discuss your enquiry further then please get in contact by phone or by filling in the "Request a Callback" form at the top of the page. Someone from the technical sales team will then call you within 24 hours, to discuss your project further.

SEPASIL® and TREMINEX® for Water Based 2k PU Resin Systems

SEPASIL® is an extremely hard filler used in abrasion resistant coatings and lacquers.

SEPASIL® and TREMINEX® for Water Based 2k PU Resin Systems Brochure /