| 摘要 |
PURPOSE: To obtain a visually readable recording card excellent in durability and deterioration resistance by employing a gold based low melting point alloy as the material for thermal indication layer. CONSTITUTION: A thermal indication layer 2 on the surface of a substrate 1 has a composition of Sn: 16-25 wt.%, the remainder: Au and inevitable impurities or Sn: 10-25 wt.% Si: 0.1-4 wt.% or Ge: 0.1-12.5 wt.% or Ga: 0.5-15 wt.%, and the remainder: Au and inevitable impurities. A low melting point Au alloy is harder than Sn and excellent in corrosion resistance and when the thermal indication layer composed of such an alloy is heated locally by means of a thermal printer head, or the like, the heated part is fused. Since the fused metal exhibits no wettability to the substrate or an underlying layer, the substrate or the underlying layer is exposed to display a character, or the like. |
