What is SiO2?

SiO2 is silica dioxide, also known as silica or quartz, a compound made up of silicon and oxygen atoms. It is a common mineral found in the earth's crust and is a key component of many types of rock, including sand,  and granite. SiO2 is also known as silica or silicon dioxide. It is a hard, crystalline substance that is resistant to chemical attack and is an excellent insulator.

It is the core ingredient in the majority of ceramic coatings. It is a common element and the raw material isn't expensive by any means, but it takes a certain kind of magic to turn it into a ceramic coating.

While silica is essentially sand, in certain forms, silica dioxide can become highly hydrophobic, making it an idea ingredient for waterproof coatings.

You’ll often hear the words silicon, silica (SiO₂) and silicone used interchangeably, but they’re not the same thing. Our coatings are built on silica / SiO₂ chemistry that bonds to the clear coat and cures into a hard, glass-like network. Some formulas also include organosilicone resins (siloxanes) as modifiers. These don’t turn it into 'just silicone', they tweak the behaviour, extra slickness, stronger water beading, better spread and self-levelling during application, without replacing the underlying SiO₂ backbone that gives durability and chemical resistance.

It’s also why supermarket “ceramic” sprays feel super slippery: many rely heavily on silicone polymers for fast gloss and hydrophobics. Nothing wrong with that as a topper, but it isn’t the same as a true nano-ceramic that cross-links with the paint. One practical note: fresh, uncured silicones can cause fisheyes if you’re about to paint a panel, which is why bodyshops are wary of “silicone.” A fully cured ceramic coating is different, it’s inert and stable. If a panel ever needs repainting, we simply decontaminate and mechanically prepare it as usual. In short: SiO₂ gives the hard, long-term protection; silicone components, when present, are there to fine-tune application and slickness, not to replace the ceramic.

What SiO₂ means in ceramic coatings

On a ceramic coating data sheet, SiO₂ is shorthand for silicon dioxide – the hard, glass-like part of the formula that cures into a thin, transparent network on your clear coat. In a finished coating it is not loose sand or quartz dust, it is part of a cross-linked structure that gives the product its toughness, chemical resistance and hydrophobic behaviour.

How SiO₂ behaves inside the coating

• Forms the backbone: The SiO₂ content is what turns the liquid coating into a solid, glass-like film once it has cured.
• Bonds to the clear coat: Properly prepared paint allows the SiO₂ network to anchor to microscopic peaks and valleys in the clear coat.
• Creates a smooth surface: As it cures it levels out tiny irregularities, helping water bead and giving that slick, easy-to-wash feel.
• Resists chemicals and UV: The SiO₂ structure is more resistant to cleaners, traffic film and sunlight than bare clear coat or wax alone.

About SiO₂ percentages on the bottle

• Headline numbers like “70% SiO₂” are usually by weight in the concentrate, not the thickness of the layer on your car.
• A higher number does not automatically mean a better coating – the quality of the chemistry, solvents, resins and curing system all matter.
• Very high SiO₂ content can make a product harder to apply without streaks or high spots unless the installer is trained and conditions are controlled.
• Good manufacturers balance SiO₂ with other ingredients so the coating is durable, glossy and practical to install, not just impressive on paper.

SiO₂, silicon and silicone – clearing up the language

• Silicon: The element (Si) found in sand, chips and solar panels.
• Silica / SiO₂: Silicon dioxide – the hard, mineral material that forms the backbone of most true ceramic coatings.
• Silicones: Flexible silicone-based polymers (often called siloxanes) used to add slickness, gloss and water behaviour.
• Professional coatings may use both SiO₂ and silicone resins together – SiO₂ for structure and durability, silicone components to fine tune the way the coating spreads, self-levels and feels.

Where people get misled by SiO₂ marketing

• Short-term “ceramic” sprays often boast SiO₂ content but behave more like traditional sealants – they are fine as toppers, not substitutes for a full coating.
• Some products lean on SiO₂ percentages and “nano” buzzwords while saying very little about preparation, curing or aftercare.
• Rebadged or white-label products may quote impressive numbers without any test data or installer training behind them.
• If the seller cannot explain what the SiO₂ is doing in plain English, the percentage alone should not be your deciding factor.

What SiO₂ cannot do on its own

• Cannot hide poor paintwork: The SiO₂ layer is clear and microns thin, so it shows whatever swirls, sanding marks or dull patches are underneath.
• Cannot make paint bulletproof: Even with high SiO₂ content, coatings do not stop stone chips or deep scratches from physical impacts.
• Cannot replace preparation: Without proper decontamination and polishing, the SiO₂ network cannot bond properly and performance will suffer.
• Cannot remove the need for washing: SiO₂ makes cleaning easier and safer, but the car still picks up dirt and needs regular maintenance.

Best-practice checklist when you see SiO₂ on a label

• Ask whether the product is a true, professionally applied ceramic coating or a maintenance topper that contains some SiO₂.
• Look at the whole system – preparation, application, curing and aftercare – not just the quoted SiO₂ percentage.
• Favour coatings supplied through trained, accredited installers who can explain how the SiO₂ chemistry benefits your car in day-to-day use.
• Use compatible shampoos and toppers so the SiO₂-based layer can keep doing its job for as long as possible.

Written by Danny Argent. Last updated 24/11/2025 15:51