The amounts of impurity metal ions incorporated into electrolytic manganese dioxide (EMD) during its preparation were measured as a function of metal ion concentrations and current densities. The amount of incorporated ions increased in proportion to the concentration in solution and at a fixed concentration it was different from ion to ion: Ni 2. < Zn 2. < Co 2. < Cu z* < Fe 3. < Pb 2+. The specific surface area of the formed EMD was larger for impurity ions with higher incorporation affinity. Further, the adsorption of ions on the surface of a ready-made manganese dioxide sample (IC12) was examined, and modeling of the adsorption behavior was attempted. The amounts of adsorbed ions at a fixed concentration in solution and pH 0.7 (where EMD is produced) were obtained by the ion-adsorption model. There was a strong correlation between the amount incorporated and the amount of adsorption, suggesting a mechanism in which EMD is eontaminated through adsorption on its new growing surface. The increase in specific surface area of EMD with contaminants was interpreted to be due to a suppression of the growth of EMD at the adsorbed foreign ion sites, resulting in EMD with many defects or smaller particle sizes. The opposite effect of current density on incorporation for the two groups of metal ions was discussed.

A hermetic‐sealing material for FED composed of thermosetting polyimide and inorganic filler has been developed. This material enables us to seal at a temperature around 350 °C in nitrogen atmosphere and shows superior performance suitable for glass‐to‐glass and glass‐to‐metal sealing.

Abstract— An hermetic‐sealing material for FEDs composed of thermosetting polyimide and glass fiber, has been developed. The main backbone and end‐capping material of polyimide were investigated to satisfy both high Tg and high flowability. A thermosetting function, 4‐phenylethynylphthalic anhydride (PEPA), was used as the end‐capping material. The fracture of a rigid and softening structure was optimized in the main polymer structure. The obtained polyimide demonstrated both a high Tg (265°C) and low viscosity (98 Pa‐sec at a sealing temperature of 350°C). In order to improve the gas permeability and the mechanical and thermal characteristics of the sealing material, a mixture of various types of ceramic fillers and polyimide has been investigated, and glass fiber was adopted. When 30 wt.% of glass fiber was combined when the developed polyimide, the Ar permeability and coefficient of thermal expansion of the sealing material decreased to below one‐half of the base polyimide. This material enables us to seal at a temperature of about 350°C in nitrogen atmosphere and shows superior performance suitable for glass‐to‐glass sealing.