VAMAS TWA #3
Project #9: Conventional Hardness of Whisker Reinforced Ceramics Round Robin
Hardness II
Organized by the National Industrial Research Institute of Nagoya (Dr. Sakaguchi) and the Japan
Fine Ceramics Center (Dr. Mizuno)
Objectives
- Evaluate whether conventional Vickers and Knoop hardness test methods are suitable for
Whisker-Reinforced Ceramic Composites
- Determine whether Knoop indentation can detect hardness anisotropy in the hot-pressed
ceramic composite plates.
- Obtain data in support of hardness standardization in ISO TC 206.
Approach
- Three hot-pressed silicon nitride specimens with various SiC whisker contents (0, 10,
20%) were distributed to each laboratory.
- Test matrix included two loads for two indenter types:
Vickers 1 kg and 10 kg and Knoop 1 kg and 2 kg
- Test matrix included two or more indentations (different surfaces or different indenter
orientations)
Outcome
All testing completed. Final report completed and printed (February 1998).
Results from 21 participating labs.
Principal Findings
- Both Knoop and Vickers hardness methods were suitable for the composite.
- Best within-lab repeatability and between-lab reproducibility were for the higher
indentation loads: Vickers 10 kg and Knoop 2 kg.
- Hardness followed the expected load dependence: the higher the load, the lower the
hardness.
- Any orientation dependence of hardness usually was hidden within the scatter.
- Hardness increased with whisker content.
- Results were statistically analyzed with ISO standard 5725.
Standards Impact
The Scope of International Standard Organization draft standard 14705 may be expanded to include whisker reinforced ceramics.
Publications
- S. Sakaguchi and M. Mizuno, "Hardness Round Robin Test on Whisker Reinforced Ceramic
Composites," pp 505 - 510 in Ceramic Materials and Components for Engines, Proceedings of
the 6th International Symposium, Japan, October 1997.
- S. Sakaguchi and M. Mizuno, "VAMAS Round Robin on Conventional Hardness Test on
Whisker Reinforced Ceramics," VAMAS Report #34, NIRIN, Nagoya, February, 1998.
For more information or copies of the reports, contact:
Dr. Shuji Sakaguchi, NIRIN, Materials Characterization Lab1-1, Hirate-cho, Kita-ku, Nagoya, 462, JAPAN, Tel: +81 (52) 911 2111,
email: ssakagu@nirin.go.jp
or
Dr. Mineo Mizuno, Japan Fine Ceramics Center, 2-4-1 Mutsuno Atsuka-ku, Nagoya, Aichi-ken 456, JAPAN, Tel: +81 (52) 871 3500
email: mizuno@jfcc.or.jp
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