Influence of compaction manufacturing process on the physical and electrical characteristics of high-voltage varistor

• Published in: Journal of materials science. Materials in electronics Vol. 18; no. 9; pp. 957 - 962
• Main Authors: CAVENAGHI, José M, MOLISANI, André L, YOSHIMURA, Humberto N, DE SOUSA, Vania Caldas
• Format: Journal Article
• Language: English
• Published: Norwell, MA Springer 01-09-2007; Springer Nature B.V
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Density; Electric fields; Electronic devices; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Exact sciences and technology; Manufacturing; Materials handling; Materials science; Physics; Porous materials; granular materials; Pressing; Specific materials; Studies; Varistors; Performance evaluation; Surge protection; Electronic circuit; Compaction; Porous material; Non linear phenomenon; Optimization; Varistance; Electric field; High voltage; Manufacturing process; Sintering; Electrical transients; Zinc oxide; Microstructure; Electrical characteristic; Damaging
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-007-9313-6

Issue Title: Special Section: Organic Electronics; Guest Editor: Amlan J. Pal The zinc oxide varistor was originally used as surge protection in electronic circuits. Its energy handling capability was extensively developed by many companies for use in high-voltage surge arresters. Although varistor technology is well known, there is a need for continuous improvement in the varistor manufacturing process in order to achieve a reliable product that meets the requirements of the various international standards. This project focuses directly on the optimization of dry pressing techniques in the manufacturing process of high-voltage varistors in order to attain uniform density, low porosity and uniform distribution of secondary intergranular phase within the grains. The microstructural characteristics of varistor discs pressed in a double-action press machine (70 MPa) before (green) and after sintering are similar to those pressed under isostatic pressure, indicating the efficiency of double-action pressing. The breakdown electric field at 10 mA and nonlinearity coefficient (α) remain practically constant with increasing compaction pressure, increasing only in samples pressed above 70 MPa.[PUBLICATION ABSTRACT]