Evaluation of mechanical hardness and fracture toughness of Co and Al co-doped ZnO

R. Siddheswaran, R. V. Mangalaraja, Ricardo E. Avila, D. Manikandan, C. Esther Jeyanthi, S. Ananthakumar

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


Combustion synthesized nanocrystalline Co and Al co-doped ZnO powders [(Zn1-x-yCoxAlyO; x=0.04, 0.03, 0.02; y=0.01, 0.02, 0.03)] were fabricated into cylindrical discs by uni-axial pressing and sintered intentionally at 1000°C for 2h to assess the mechanical performance. The crystallinity of the pure and doped ZnO was confirmed by X-ray diffraction analysis. The microstructures of the sintered samples were investigated by scanning electron microscopy (SEM) to examine the density, porosity, grain size and its distribution. Grains of 0.5-3μm were observed for the samples sintered at 1000°C. The mechanical properties such as micro-hardness, fracture toughness and strain hardening co-efficient were investigated by the Vickers indentation method. It was found that the crack mode observed during the indentation on the samples belongs to median cracks under a load of 19.6N. Also, the hardness was enhanced with increasing mol% of Co, while the trend was reversed with the increase of Al content. In addition, the strain hardening coefficient and fracture toughness were calculated using the indentation data.

Original languageEnglish
Pages (from-to)456-461
Number of pages6
JournalMaterials Science and Engineering A
StatePublished - 15 Dec 2012
Externally publishedYes


  • Co, Al co-doped ZnO
  • Fracture toughness
  • Micro-hardness
  • Strain hardening coefficient
  • Surface morphology
  • Vickers indentation


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