THE INFLUENCE OF ALLOYING ELEMENTS ON THE HOT-DIP ALUMINIZING PROCESS AND ON THE SUBSEQUENT HIGH-TEMPERATURE OXIDATION

摘要

For hot dip aluminizing (HDA) an Al melt was doped with one of the elements Mo, W or Nb with a nominal composition of about 1 wt%. In case of W, the nominal composition was achieved, not so for Mo and Nb. The influence of these elements on the coating formed and on the following oxidation process was investigated. Hot dip aluminizing was carried out at 800 degrees C for 5 min under dry Ar atmosphere. The oxidation experiments were performed at 950 degrees C for 24 h in air. Compared to the HDA processes with pure Al, the addition of the alloying elements lead to thinner intermetallic layers. A change in the oxidation behavior was observed as well concerning the suppression of internal oxidation and the formation of dense and close oxide scales. (C) 1997 Elsevier Science B.V. [References: 18]