Evaluation of corrosion resistance of Ni3Al produced by spark plasma sintering of mechanically activated powder mixtures

The corrosion resistance in alkaline solutions of Ni3Al intermetallic produced by the method of spark plasma sintering of powder mixtures with or without preliminary mechanical activation was investigated. It was found that nickel aluminide has high corrosion resistance in boiling solutions of strong alkalies, such as sodium and potassium hydroxide. The rate of corrosion in these media did not exceed 0.05 mm/year, even when corrosion activators were introduced into the solution. Solutions of weak alkalies have a more aggressive effect on the sintered material. It was shown that the corrosion rate of the intermetallic in an aqueous solution of ammonia was 0.22- 0.24 mm/year, which is still 1.4 times lower than that of nickel and an order of magnitude lower than that of aluminum. In all cases, mechanical activation did not affect the corrosion rate of the material; however, it did affect the nature of the surface corrosion damage. (C) 2019 Elsevier Ltd. All rights reserved.