溶融塩電析法による 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

Abstract

The formation of a Ni aluminide coating layer containing Zr on a Ni substrate was attempted by the electrodeposition of Zr and Al. The cyclic oxidation resistance of the Ni covered with the coating was then evaluated. Zr and Al were deposited by molten salt electrolysis. For the sample treated with the Al deposition, a layer consisting of Ni2Al3 was uniformly formed. On the other hand, for the sample treated with the Zr deposition, followed by the Al deposition, a layer consisting of Ni2Al3 and a Ni aluminide layer containing Zr on the Ni2Al3 layer were formed. Furthermore, when the Zr electrodeposition conditions were changed, the concentration of Zr in the Ni aluminide layer containing Zr, formed on the surface, changed. The cyclic oxidation test showed that for the sample with the Al deposition, the mass reduction due to scale exfoliation took place, whereas for the sample treated with a small deposit of Zr, followed by Al deposition, no mass reduction was observed. For this sample, after the cyclic oxidation test, a scale consisting of α-Al2O3 adhering to the substrate was formed. Consequently, it was found that the cyclic oxidation resistance of the Ni was improved by a small of Zr, followed by Al deposition.