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Ceramic Blades: Everything you Need to Know

The Properties of Ceramic Blades

First, let’s talk about what we mean by ceramics, because Slice ceramics are not the fragile ceramics of popular imagination. They’re actually part of a more recent category of material known variously as advanced ceramics, fine ceramics, or engineered ceramics. The material is composed of 100 percent zirconium oxide. This material, developed through the advances in ceramic research of the 1950s, has many useful properties.

A Versatile Material

Zirconium oxide has many advantages over steel, especially for industrial applications. Unlike metal, a zirconium oxide utility blade is chemically inert. This means no chance of chemical reactions while you cut, as well as a strong defense against harmful bacteria. Ceramic never rusts, which means it doesn’t require the same oils and lubricants used on metal blades to prevent premature rusting.

Industries as varied as pulp and paper and aerospace benefit from the use of engineered ceramic utility blades because of these inherent properties:

  • Non-magnetic
  • Anti-static
  • Non-conductive
  • Non-sparking
  • Safe up to 1600 degrees Celsius
  • Chemically inert and non-contaminating
  • Non-reactive: impervious to acids and salt
  • Non-porous and chemically resistant
  • Oil and lubricant free
  • Never rusts

Hard as Nails (Harder, Actually)

When customers used to metal blades try Slice tools for the first time, they’re comparing two very different cutting materials. There are important manufacturing differences between a Slice ceramic blade vs steel, due to the different properties of these materials. The primary difference is hardness.

Chart compares various materials on the Mohs relative hardness scale. Slice ceramics rate 8.2; much harder than steel, at 4.5.
Image 1. The Mohs hardness scale measures the relative hardness of various materials. As you can see, the zirconium oxide used in Slice ceramics is harder than steel by several factors.

As you can see in the chart above, zirconium oxide is harder than even the hardest steel, by several degrees. Why is hardness important? Because steel’s relative softness is the reason it’s sharpened to unsafe levels; it dulls too quickly. Zirconium oxide’s hardness allowed Slice to develop a proprietary manufacturing process that creates a finger-friendly edge. Learn more below.

Slice’s Finger-Friendly Ceramic Blade Edge

While other companies create extremely sharp ceramic blade knives, Slice was primarily interested in safety. We asked: What does it actually take to cut most materials? How much sharpness is necessary? It turns out that the only reason steel blades are dangerously sharp is because steel dulls so quickly. Manufacturers need to produce overly sharp blades just to give them a reasonable working lifespan. This workaround sacrifices safety for productivity. Because ceramics dull so slowly, they don’t need that workaround.

Chart compares Slice ceramic blades with metal blades in terms of initial sharpness and wear resistance.
Image 2. This test compared six Slice blades with six metal blades. Testers ran each blade through a series of 60 cuts, while measuring the depth of each cut (an indication of blade sharpness). After each cut, the depth from all the previous cuts was added to the total ("cumulative cut depth" on the x axis). This process measured the wear resistance of each blade over its lifetime. Slice blades lasted, on average, 11.2 times longer than metal blades.

The above chart demonstrates that, even though Slice blades don’t start out as sharp as steel (because they don’t have to), they outlast steel by an average factor of 11.2. This is a product of zirconium oxide’s extreme hardness.

While the inherent properties of advanced ceramics were attractive to kitchen knife manufacturers, Slice was the first to take advantage of zirconia’s hardness to develop a grind that is actually safer to touch. That’s what makes a Slice ceramic blade different from any other.

What Do We Mean by Finger Friendly?

Finger friendly simply means that Slice blades are safer to touch and handle than typical steel blades. You can pick up Slice replacement blades without fear of accidental injury. Compared with typical blades, for example, our utility blades are unlikely to cut you because they require much more force to do so. As shown below, you can run a Slice blade over a balloon’s surface and the balloon will remain intact. That’s simply not the case for steel blades.


If Slice Blades Cut Other Materials Effectively, How Do They Resist Skin?

Slice engineers first looked at why metal blades pierce the skin so easily. Not only are their edges overly sharp, but the blade itself is quite narrow. This means it requires little force to pierce the skin. 

Cross-sections of Slice ceramic blades and typical metal blades illustrate that the wider Slice blade requires more force to penetrate skin.
Image 3. The difference that blade thickness makes is clear: metal cuts skin easily while Slice ceramic blades require much more force before they’ll pierce skin.

The part of a blade that is intended to cut is known as the initial cutting zone. By grinding our blades with two different angles and using a wider blade overall, Slice made the initial cutting zone (the potentially dangerous portion of the blade) much smaller.

Cross sections of the blade compare cutting zones. Slice’s double-angle grind creates a much shallower cutting zone that significantly lowers your chances of sustaining an injury.
Image 4. The initial cutting zone is defined as the part of a blade’s edge that does the actual cutting. This zone is a result of the angle used to grind the blade. In a metal blade, the smaller angle creates a longer and sharper cutting zone, making users much more vulnerable to lacerations. Slice uses a patented double grind that shortens the cutting zone significantly. This creates an effective cutting edge that doesn’t endanger the user.

Finally, we took into account the properties of skin, which is harder on the surface, but pliable as a whole. Our grind dissipates the pressure on skin, making it harder to penetrate.

Illustration demonstrates how downward force is dispersed with a wider Slice blade, while narrow metal blades go straight into the skin.
Image 5. Skin is hard on outside and soft on the inside. Slice engineers took this into account when designing our blades. Our wider angle displaces the force of the blade against skin’s tougher, fleshy outer layer. In contrast, with nowhere for the exterior force to go but in, narrow metal blades easily pierce skin.

Can Slice Ceramic Blades Cut Your Skin?

Although they are much safer than steel knives, Slice blades are capable of cutting skin; they’re knives after all! We find that if you try to cut your skin with our blades, you will likely succeed. Our patented grind vastly cuts down on accidental lacerations, but the blades are still effective and therefore no match for the human determination to cut something.

Because our blades are so different from any you’ve seen before, we recommend that you touch the edge to understand just how much safer they are compared with steel blades. You’ll instantly feel the difference and understand why Slice ceramic safety blades are a wise choice to reduce injuries. Many industrial safety officers no longer require the use of safety gloves when workers use Slice blades.

Slice Ceramic Tool Categories

At Slice, our research and development is a continuous cycle. We’re in touch with safety experts across many industries to develop safer tools and reduce costs. Below are some of our tool categories.

Box Cutters

The Slice 10400 Manual Box Cutter is more ergonomic and safer than traditional knives
Slice Box Cutter handles are a safer and more ergonomic alternative to traditional handles.

This category includes our award-winning box cutters with ergonomic J-hook handles, our pen cutters and the Mini Cutter. Each of these products slices through typical corrugated packaging and can handle the majority of day-to-day cuts at home, in the office, or in a shipping and receiving facility.

Utility Knives

The Slice 10558 Smart-Retracting Utility Knife, with ceramic safety blade extended
The Slice 10558 features Smart Retract technology for added safety.

Slice has designed a number of different tools that fit into the utility knife category, including box cutters, pen cutters, utility knives, and mini tools. Our innovative and award-winning designs are represented in a wide variety of home and industrial settings.

Precision Knives

Slice precision knives allow more control and maneuverability. From fixed micro-ceramic-blade tools to replaceable ceramic blades, artists, lab technicians, and manufacturers alike use Slice tools to work well and stay safe.


Slice ceramic scissors take safety scissors to the next level. Not only do they feature rounded tips, these compact and lightweight scissors offer our proprietary finger-friendly edge.

Ceramic Replacement Blades

Slice Ceramic Safety Blade

Slice manufactures a variety of replacement blades, including ceramic utility blades, utility knife blades, and box cutter blades. Choose from rounded or pointed tips, with the assurance that our blades last an average of 11.2 times longer than steel blades. This means you won’t need to replace your blade any time soon.


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