Powder processing effects on the rapid low-temperature densification of ZrB 2-SiC ultra-high temperature ceramic composites using spark plasma sintering

Luke S. Walker, William R. Pinc, Erica L. Corral

Research output: Contribution to journalArticle

36 Scopus citations

Abstract

Investigating the powder processing effects on a ZrB 2-25 vol% SiC ceramic composite densified using spark plasma sintering (SPS) allows for identification of densification mechanisms and enables a reduction in sintering temperature to a minimum of 1650°C. Attrition milling (AM) and ball milling (BM) were investigated as processing methods to produce a fine and coarse powder densified using SPS with or without a tube furnace preheat treatment. Ceramics formed from AM and BM powders contain 1.66 wt% oxygen contamination, primarily ZrO 2 and SiO 2, and 0.35 wt% oxygen contamination as SiO 2, respectively. Heat treatment slightly reduces oxygen contamination but has significant impacts on the densification mechanisms. Without heat treatment, powder coarsening dominates the initial sintering process in the SPS inhibiting densification until ∼1350°C. After heat treatment, sintering and densification is enabled at low temperature, 1000°C-1100°C. The densification of ZrB 2-SiC composites can be broken into a two-step process with phase 1 as the sintering step based on powder surface area reduction and phase 2 as a forging step where high-temperature creep and pressure eliminate porosity after the primary grains have formed. A time-temperature-density plot illustrates the change in densification mechanism used to fully densify ZrB 2-SiC composites in SPS.

Original languageEnglish (US)
Pages (from-to)194-203
Number of pages10
JournalJournal of the American Ceramic Society
Volume95
Issue number1
DOIs
StatePublished - Jan 1 2012

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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