Pressureless sintered high-strength mullite from commercial powder

R. L. Lehman, Y. Umezu

Research output: Contribution to journalArticlepeer-review


High-strength monolithic mullite ceramics were prepared from commercial-grade power by carefully controlled processing of the powder followed by pressureless sintering at 1700 °C. Mullite powder was mechanically and chemically dispersed, ball milled, and screened prior to slip casting. Specimens were sintered to 97% of theoretical density under pressureless conditions. The furnace ramp and soak schedule was an important variable. Four-point flexural strengths of 250 MPa were achieved, exceeding literature values for pressureless sintering of Baikowski mullite powder.[a] Pore sizes were small and were not strength limiting. Griffith calculations suggest a critical flaw size of 20 μm, in good agreement with the maximum observed crystal size in the microstructure.

Original languageEnglish (US)
Pages (from-to)543-546
Number of pages4
JournalJournal of Materials Engineering and Performance
Issue number4
StatePublished - Aug 1992

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering


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