| 摘要 |
<p>An ultra-black film is disclosed, which essentially consists of a base (1), a Ni-P alloy layer (2) formed on said base and a phosphate (3) layer formed on said Ni-P layer, the spectral reflectance of said ultra-black film being 0.04 to 0.4 %. Ihe ultra-black film is obtainable by one of four methods, i.e., a first method, which comprises sequential steps of effecting primary etching of a Ni-P alloy film surface with an aqueous nitric acid solution and effecting secondary etching of the surface with an aqueous sulfuric-acid-containing nitrate solution, a second method, which comprises of effecting said secondary etching of a Ni-P alloy film surface a third method, which comprises sequential steps of forming a Ni-P alloy film on a base by using a plating solution basically composed of nickel salt, sodium phosphate, D, L-malic acid and malonic acid and effecting said secondary etching to the alloy film surface and a fourth method, which comprises sequential steps of forming a Ni-P alloy film on a base by using a plating solution basically composed of nickel salt, sodium phosphate, D, L-malic acid and succinic acid or basically composed of nickel salt, sodium phosphate, D, L-malic acid lactic acid and malonic acid and effecting said primary etching to the surface.</p> |
