Articles
  • Deterioration of mechanical properties by the curing of phenolic resin during fabrication of porous PSZ ceramics under high temperatures and high humidities
  • Sanghyeon Yoona, Janghoon Kimb, Hyun Parkc, Juntae Leed and Heesoo Leea,*
  • aSchool of Materials Science & Engineering, Pusan National University, Busan 609-735, Korea bNational Core Research Center for hybrid materials solution, Pusan National University, Busan 609-735, Korea cGlobal Core Research Center for Ships and Offshore Plants (GCRC-SOP), Pusan National University, Busan 609-735, Korea dMaterial Testing Center, Korea Testing Laboratory, Seoul, 152-718, Korea
Abstract
Mechanical and microstructural analyses of partially stabilized zirconia (PSZ) ceramics maintained under high temperature and a high relative humidity were investigated to elucidate the relation between the curing of the phenolic resin as a binder and the deterioration of the ceramics. The PSZ powders containing the binder were exposed to the high humidity (85%, 50 οC) and the high temperature (25%, 100 οC) atmospheres for 1 h before compaction. The green densities of the specimens decreased from 3.54 g/cm3 to 3.45 g/cm3 and to 3.35 g/cm3, respectively. The flexural strengths decreased about 3% and 8% compared to the specimen exposed to a lower humidity and temperature condition (25%, 50 οC). Rough surfaces and some agglomerated particles with a large volume of voids and internal spaces were observed in the fracture surfaces of the green bodies. These agglomerates were generated by the curing of the phenolic resin with the formation of methylene bridges. The reaction occurred by the decomposition of hexamine as a curing agent in the high temperature and the high humidity atmospheres.

Keywords: Porous PSZ ceramics, Deterioration, High temperature/humidity, Phenolic resin, Methylene bridges.

This Article

  • 2012; 13(5): 662-665

    Published on Oct 31, 2012