Qualitative measurement of residual carbon in wet-chemically synthesized powders

Emerson R. Camargo, Elson Longo, Edson R. Leite, Masato Kakihana

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Sodium niobate powders were prepared by the polymerizable complex (PC) method using a water-soluble Nb-malic acid complex and sodium carbonate. Niobium oxide pentahydrated was dissolved in hot oxalic acid (OA) solution, followed by the addition of NH3 (30%) until pH 11, precipitating niobic-acid that was added into a solution of DL-malic acid (MA) at mole ratio of [MA]:[Nb]=2:1. Na2CO3 was added in the mole ratio [Na]:[Nb]=1:1, and the solvent was eliminated at 70°C, forming a yellow gel without any segregation. The gel was calcined at 300°C for 3h, and the (Na-Nb-MA) heated material was calcined in the range of temperatures from 400 to 900°C, from 5min to 8h. Pure NaNbO3 (NN), free from amorphous carbon, which crystallized at temperatures higher than 450°C, was confirmed by a combined analysis using X-ray diffraction and UV-Raman spectroscopy. A correlation between the presence of residual carbon and the crystallite size, which was calculated using the Scherrer formula, was observed and qualitatively used to infer about this presence of residual carbon.

Original languageEnglish
Pages (from-to)2235-2239
Number of pages5
JournalCeramics International
Volume30
Issue number8
DOIs
Publication statusPublished - 2004 Nov 15
Externally publishedYes

Keywords

  • A. Powders: chemical preparation
  • B. Grain size
  • B. X-ray methods
  • D. Niobates

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Materials Chemistry

Fingerprint Dive into the research topics of 'Qualitative measurement of residual carbon in wet-chemically synthesized powders'. Together they form a unique fingerprint.

Cite this