Japan As Represented by Director General of Agency of Industrial Science

Masanori Kuroda

Michio Araki

An inorganic thermochromic substance is proposed which is a composite oxide of strontium and manganese in a specified molar ratio as prepared by the calcination of a powder blend of strontium carbonate and manganese dioxide, instead of conventional manganese carbonate, at a specified temperature for a specified length of time. The temperature of the thermochromic color change is about -130.degree. C., much lower than the color-change point of most of conventional thermochromic substances. The color of the composite oxide is grey or pale green at room temperature but reversibly changes to pale red when it is chilled to -130.degree. C. or lower.

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Kure, Japan

Masanori Kuroda