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Effect of Applied Stress on IR transmission of Spark Plasma‐Sintered Alumina
Author(s) -
Chakravarty Dibyendu,
Sundararajan G.
Publication year - 2010
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2009.03509.x
Subject(s) - materials science , transmittance , spark plasma sintering , nanocrystalline material , porosity , composite material , sintering , grain size , stress (linguistics) , optoelectronics , nanotechnology , philosophy , linguistics
The effect of applied stress on IR transmittance of nanocrystalline alumina prepared by spark plasma sintering was evaluated. Transparent alumina with maximum transmittance >80% was obtained over the entire mid‐IR wavelength range of 3–5 μm by applying a high stress of 275 MPa at 1150°C using specially designed high‐strength compound dies. The transmittance observed was similar to previous reports at identical wavelengths, but at a lower sintering temperature. The transparent samples have an average grain size of 0.3 μm and a hardness of 23 GPa. At lower stresses and sintering temperatures, transmittance reduced drastically due to remnant pores in the matrix as observed from the microstructural analysis. The effect of porosity was found to be critical in developing transparency as even a marginal decrease in porosity led to substantial increase in transmittance.