Open AccessNovel Nanocrystalline Intermetallic Coatings for Metal Alloys in Coal-fired Environments
Author(s) -
Zhang Fang,
Heung-Rak Sohn
Publication year - 2009
Language(s) - English
Resource type - Reports
DOI - 10.2172/978339
Subject(s) - materials science , aluminide , metallurgy , intermetallic , nickel aluminide , alloy , coating , nanocrystalline material , conversion coating , aluminium , porosity , thermal spraying , aluminium alloy , substrate (aquarium) , composite material , nial , nanotechnology , oceanography , geology
Intermetallic coatings (iron aluminide and nickel aluminide) were prepared by a novel reaction process. In the process, the aluminide coating is formed by an in-situ reaction between the aluminum powder fed through a plasma transferred arc (PTA) torch and the metal substrate (steel or Ni-base alloy). Subjected to the high temperature within an argon plasma zone, aluminum powder and the surface of the substrate melt and react to form the aluminide coatings. The prepared coatings were found to be aluminide phases that are porosity-free and metallurgically bonded to the substrate. The coatings also exhibit excellent high-temperature corrosion resistance under the conditions which simulate the steam-side and fire-side environments in coal-fired boilers. It is expected that the principle demonstrated in this process can be applied to the preparation of other intermetallic and alloy coatings