Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
Britannica Sources used in this answer

Why can transformation-toughened zirconia surfaces become polished during wear?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Steps in doctor blading, a tape-casting process employed in the production of ceramic films. Ceramic powder and solvent are mixed to form a slurry, which is treated with various additives and binders, homogenized, and then pumped directly to a tape-casting machine. There the slurry is continuously cast onto the surface of a moving carrier film. The edge of a smooth knife, generally called a doctor blade, spreads the slurry onto the carrier film at a specified thickness, thereby generating a flexible tape. Heat lamps gently evaporate the solvent, and the dry tape is peeled away from the carrier film and rolled onto a take-up reel for additional processing.
advanced ceramics Steps in doctor blading, a tape-casting process employed in the production of ceramic films. Ceramic powder and solvent are mixed to form a slurry, which is treated with various additives and binders, homogenized, and then pumped directly to a tape-casting machine. There the slurry is continuously cast onto the surface of a moving carrier film. The edge of a smooth knife, generally called a doctor blade, spreads the slurry onto the carrier film at a specified thickness, thereby generating a flexible tape. Heat lamps gently evaporate the solvent, and the dry tape is peeled away from the carrier film and rolled onto a take-up reel for additional processing.

In transformation-toughened zirconia (TTZ), the surface becomes polished during wear due to the nature of its phase transformation and particle size. When the material is subjected to surface stresses during wear, the embedded tetragonal particles are induced to transform into a monoclinic form, which places the surface into compression and strengthens it.1

If particles do pull out of the material during this process, they are typically in the submicrometre range. Because these particles are extremely small, they act to polish the surface rather than abrade it, which contrasts with materials like alumina that tend to develop a roughened, matte appearance due to larger grain pullout.1