Al と Zr の同時電析法による Zr を含む Ni アルミナイド表面層の形成とその耐サイクル酸化性

抄録

  A Ni aluminide layer containing Zr was formed on a Ni specimen by a synchronous electrodeposition of Al and Zr using molten-salt bath. Al and Zr were hardly electrodeposited and an electrodeposited layer was not formed when the simultaneous electrodeposition of Al and Zr was tried using molten NaCl-KCl containing 3.5 mol%AlF₃ and 3.5 mol%ZrF₄. On the other hand, the electrodeposited layer consisting of Ni₂Al₃ layer as an inner layer and NiAl₃ layer as an outer layer, in which ZrAl₃ particles were formed at the surface region, was formed when the simultaneous electrodeposition of Al and Zr was carried out using the molten NaCl-KCl containing 3.5 mol%AlF₃ and 0.05 mol%ZrF₄. The cyclic oxidation resistance of the Ni covered by the Ni aluminide containing Zr was evaluated in air at 1423 K. The specimen covered with the Ni aluminide containing the ZrAl₃ particles, which was formed using the melt containing 3.5 mol%AlF₃ and 0.05 mol%ZrF₄, showed a high cyclic-oxidation resistance. On this specimen after the oxidation test, an adhesive scale having a spiked shape, which consisted of Al₂O₃, was formed.