Reactions of Metal Salts and Alkali Metal Nitrates. Role of the Metal Precursors and Alkali Metal Ions in the Resulting Phase of Zirconia

✍ Scribed by Pedro Marote; Bernard Durand; Jean-Pierre Deloume

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 525 KB
• Volume: 163
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2001.9393

✦ Synopsis

Zirconia powders are prepared by reaction of a zirconium precursor with an alkali metal nitrate. The major part of the reactions takes place before the melting points and then the reactions go slowly to completion at 4503C in the molten salts. The roles of the precursor and the alkali metal ion are discussed considering the reaction between two precursors, octahydrated zirconium oxychloride and zirconium tetrachloride, and two nitrates, LiNO 3 and NaNO 3 , and some resulting physico-chemical di4erences. The obtained zirconia powders contain very small amounts of alkali metal ions which act as stabilizing agent. Their e4ect on the balance tetragonal+monoclinic ZrO depends upon the homogeneity of their distribution which is related to their ability to di4use inside the bulk of particles and their polarizing power when located mainly on the surface.