What Are Ceramic Knives?

Ceramic knives offer some advantages, like hardness, over steel.

Ceramic knives are typically made of zirconium oxide (ZrO2, also called zirconia). They are exceptionally hard and do not rust, hence their use by professional chefs and in high-end kitchens.

Manufacturing

Ceramic knife manufacturer Kyocera uses super-high pressure (300 tons per square inch) to mold zirconia powder into blanks, then fires the blanks for days at around 1,000 degrees Celsius. Finally, they sharpen the blanks on a diamond wheel.

Hardness

Ceramic knives are harder than steel. On the Mohs scale of mineral hardness, hardened steel rates 6.5 Mohs; ceramic blades, 8.2 to 8.5 Mohs; and diamond, 10 Mohs.

Use

Chefs use ceramic blades as they do steel blades. Unlike steel blades, which can cut wood and plastic surfaces, ceramic knives can only cut wood and plastic surfaces.

Diving

Because they do not rust at all, dive knife manufacturers increasingly use ceramics in their manufacturing. Stainless steel corrodes in the harsh salt water environment.

Disadvantages

Sharpening ceramic knives calls for expensive equipment. They must be hand washed to avoid chipping in a dishwasher. And again, they are useful only on wood and plastic surfaces.

References

• Kyocera Ceramic Knife FAQs
• Scuba Diving Magazine: Diving Knives
• Specialty Blades: Zirconia Ceramic