Dunt (nomen Anglicum) est vitium quod fieri potest cum res ceramica in fornace accendatur, genus "fracturae quae in fictilibus accensis ut exitus tensionis a calore adductae fit,"[1][2] et ex nimis refrigerationis post accensum efficitur.[3][4][5] Quamquam haec vitia per refrigerationem plerumque fiunt, vitia etiam per rapidas calorifactionis proportiones fieri possunt. Quae vitia ex rotundis rimarum marginibus agnoscuntur, quia illitio? postea maturuit, quandoquidem vitiis ex refrigeratione factis sunt margines acutae.[6][7]

Investigationes monstrant corpora quarzo potius quam silice formulata fissioni obnoxia esse, praecipue cum iterum accendantur. Quod pertinere potesse dicitur ad inferiorem modulum Youngianum corporum in quarzo funditorum.[8]

Hoc fissionis genus etiam in fictilibus ex corporibus argillae montmorillinitis factis fit, propter prolationem voluminis cristobalitis per eius inversionem cum refrigeretur. "Liberatio silicae liberae in montmorillonite supra 950 C fit, sed paene bis summa silicae liberatur, contra kaolinitem. Ergo, corpora argillosa quibus magna proportio montmorillonitis est magnam silicae liberae proportionem post accensum continent, quod rem rimosam fieri per refrigerationem efficere potest."[9][10]

NotaeRecensere

  1. Anglice "Cracking that occurs in fired ceramic bodies as a result of a thermally induced stress."
  2. "Standard Terminology of Ceramic Whitewares and Related Products." ASTM C242-01. ASTM International.
  3. Anglice "ware cooled too quickly after it has been fired."
  4. Dodd et Murfin, 1994.
  5. "Dunting Temperature Measurement." K.Marshall, W.Roberts. British Ceramic Research Association. TN 143.1969.
  6. Dodd et Murfin 1994.
  7. Mukherji 1984.
  8. Marshall et Roberts 1969.
  9. Anglice "The release of free silica, takes place in montmorillonite above 950 C, but almost double the silica is released, compared to kaolin. Therefore, clay bodies with high amounts of montmorillonite contain a high percentage of free silica after firing, which may cause the ware to crack during cooling."
  10. Henrik Norske, Clay Materials: For the self reliant potter (Norske 1990).

BibliographiaRecensere

  • Dodd, A. et A. D. Murfin. 1994. Dictionary of Ceramics. Ed. 3a. Institute of Materials. ISBN 0-901716-56-1.
  • Marshall, K., et W. Roberts. 1969. "Quartz V Flint. Pt. 2. Aspects Related To Refire Dunting." British Ceramic Research Association 141, pars 2.
  • Mukherji, S. K. 1984. "Dunting: A Serious Problem of Ceramics Industry." Indian Ceramics 27 (2): 36.
  • Norske, Henrik. 1990. "Clay Materials: For the self reliant potter." GTZ.

Nexus interni