Quantitative Analysis of Zinc Vaporization from Manganese Zinc Ferrites

• Published in: Journal of the American Ceramic Society Vol. 86; no. 5; pp. 765 - 768
• Main Authors: Suh, Jung Ju, Han, Young Ho
• Format: Journal Article
• Language: English
• Published: Westerville, Ohio American Ceramics Society 01.05.2003; Blackwell; Wiley Subscription Services, Inc
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; Condensed matter: structure, mechanical and thermal properties; Electrotechnical and electronic ceramics; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; ferrites; Physics; sinter/sintering; Solid-vapor transitions; Specific phase transitions; Technical ceramics; vaporization; zinc oxide; Iron oxide; Weight loss; Temperature effect; Experimental study; Oxide ceramics; Vaporization; Ferrite materials; Phase transformation; Manganese oxides; Pressure effect; Ferrites spinels; Partial pressure; Transition metal compounds; Sintering; Zinc oxide; Manufacturing; Oxygen pressure; Quantitative analysis; Electroceramics
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1151-2916.2003.tb03372.x

Zinc vaporization of Mn‐Zn ferrites was quantitatively characterized in terms of oxygen partial pressure PO2, temperature, grain size and sample geometry. The amount of zinc loss was measured as a function of time at various temperatures by a thermogravimetric method. The weight loss due to irreversible zinc vaporization showed a linear behavior with time and increased exponentially with temperature. The observed weight loss due to zinc evaporation at 1100°C was small, whereas a significant weight change was detected at 1200°C. The weight loss was even greater in a reducing atmosphere (PO2= 5 × 10−5). Below 1300°C, the diffusion of elemental zinc was sufficiently fast to compensate the zinc loss at the interface region, resulting in a linear dependence on time. At temperatures ≥1400°C, the weight change no longer followed the linear dependence and showed a rather parabolic behavior with a concave upward slope. The core shape and the gas flow around ferrite cores were important factors that affected the rate of zinc vaporization, but not the grain size.