Effects of chlorides on the phase transformation of alumina. Issue 9 (15th June 2018)

• Record Type: Journal Article
• Authors: Zou, Xiuxiu; Wang, Peng; Wang, Zongde; Fan, Guorong; Chen, Shangxing; Liao, Shengliang; Si, Hongyan; Lu, Meijuan
• Is Part Of: Ceramics international. Volume 44:Issue 9(2018)
• Page Start: 10847
• Page End: 10851
• Publication Date: 2018-06-15
• Subjects: Phase transformation -- Alumina -- Chlorides; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2018.03.133
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: The discovery that γ -alumina can be prepared at lower calcination temperature from an ammonium aluminum carbonate hydroxide (AACH) precursor templated with rosinyl trimethyl ammonium chloride has led to the assumption that Cl - is capable of lowering the temperature of the phase transformation of AACH to γ -alumina. To verify this hypothesis, several chlorides were introduced into the calcination process of the AACH precursor. The samples were characterized using X-ray diffraction, thermogravimetry and differential scanning calorimetry as well as X-ray photoelectron spectroscopy. The results showed that Cl - has great effects on the crystallinity of γ -alumina obtained by the calcination of AACH. The effects varied with the type, dosage and introduction method of the particular chloride. It was also found that Cl - began to take effect only after the AACH had been decomposed to form amorphous alumina. Therefore, the true function of Cl - is to decrease the temperature of the phase transformation from the amorphous phase to γ -alumina: the phase transformation temperature decreases by as much as 115 K.