Inexpensive Method for Bulk Manufacture of Crack- Free Ceramics at Reduced Temperatures

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Perspective drawing of three distinct precursor/ product phases in the synthesis of dense silicon based ceramicsSchematic representation of the method of the present invention for synthesizing bulk ceramics in a technique using sacrificial moldsDrawing of a top view of a dense silicon-based ceramic stmcture oftl1e present inventionDrawing of a side viewofadeusesiJicou-based ceramic stmcl1lre of the present invention
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Researchers
Linan An, Ph.D.
Weifeng Fei, Ph.D.
Arnold Hill
Managed By
Andrea Adkins
Assistant Director 407.823.0138
Patent Protection

Method for synthesizing bulk ceramics and structures from polymeric ceramic precursors

US Patent 8,119,057 B2
Publications
Polymer Derived Engineering Ceramics
Advanced Engineering Materials, 2000, 6, 339.
Amorphous Si(Al)OC Ceramic from Polysiloxanes: Bulk Ceramic Processing, Crystallization Behavior and Applications
Journal of the European Ceramic Society, 2004, 24, 3471

Ceramics are seeing increased use in industrial, aerospace and military applications. They are lightweight, strong and can be machined for a wide variety of applications. Ceramics have become highly desirable for use in jet engine turbine blades, for ballistic protection, and many other applications. A new generation of such materials called polymer derived ceramics (PDCs) is made from an initial liquid polymer solution. Deriving ceramics from polymers prevents the need for metal powders (which can result in non-homogenous ceramics), sintering aids (additives that require more additional processing time and money) and high curing temperatures. Several research groups have investigated alternate means of constructing these PDCs, but so far none of them have developed a simple, inexpensive process for forming dense, crack-free bulk ceramic structures.

Technical Details

UCF scientists have developed such a method by utilizing lightweight molds, such as polymeric foam or glass fiber mesh, and introducing a polymer solution into the mold. The polymer is then converted into a ceramic green body (or an unfired/uncured ceramic), during which the mold allows for the release of gases which are generated during the process. These gases would normally build in the mold, introducing cracks and pores into the ceramic, severally limiting its durability and strength. This inexpensive, lightweight mold is sacrificial and will burn away during the low temperature processing of the ceramics, also allowing for release of gases. The ceramic green body is easily shaped and machined before firing or curing. Ceramic structures created using this process are of high purity with increased structural integrity and are easily shaped into complex structures.

Benefits

  • Easy synthesis with low temperature/pressure processing (as little as 1000°C)
  • Prepare ceramics without any additives, fillers and/or powders
  • Creates crack-free ceramics for greater strength and durability
  • The ceramics can easily be machined into various shapes

Applications

  • Manufacture of crack-free, strong ceramic parts, crucibles, etc.
  • Industry currently creating/machining parts from ceramics
  • Automotive
  • Aerospace
  • Tool manufacturers