A novel powder aluminizing technology assisted by direct current field at low temperatures

A novel, low-temperature powder aluminizing technology was developed by applying direct current field (DCF) between the treated sample and the powder agents. The treating temperature was from 923 K–1023 K. The cross-sectional microstructures and the aluminizing coating thickness were studied; high temperature oxidation resistance was investigated as well. The results show that DCF can significantly reduce the treating temperature comparing with the conventional Al pack cementation processes, providing a novel and practical approach with great energy saving. When the treating temperature was 973 K and 1023 K with 4 h heating duration, there were almost no aluminizing coatings formed in conventional Al pack cementation; while by applying appropriate intensity of DCF, the aluminizing coatings with thickness around 180 μm were produced for both 45 steel and 20 steel. The aluminizing coating produced at lower temperature assisted by DCF had good oxidation resistance below 1123 K.