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 do toughened ceramics lose some of their advantages at high temperatures?

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.

Toughened ceramics often lose their mechanical advantages at elevated temperatures due to the degradation of the specific mechanisms that provide their toughness. The reasons for this loss vary by the type of toughening method employed:1

  • Transformation-toughened ceramics: In materials like transformation-toughened zirconia, toughness relies on a stress-induced phase transformation. As the temperature rises, the driving force for this phase change decreases and eventually disappears, causing the material to lose its toughening effect.1
  • Reinforced composites: In ceramics reinforced with whiskers or fibres, these components are frequently susceptible to high-temperature oxidation. When oxidation occurs, these agents are effectively eliminated, causing the ceramic matrix to revert to its inherent, brittle behavior.1

Because these toughening mechanisms are not inherently stable at high heat, a primary challenge for engineers is developing microstructures that maintain their integrity and toughness in such demanding environments.1