Study On Al-Base Cored Wire And High Tempreture Protection Performance Of Its Coating By Arc Spraying

Fe-Al intermetallics not only have remarkable high-temperature strength, but also possess excellent high-temperature corrosion resistance at high-temperature and multi-corrosion circumstance. Fe-Al coatings were deposited on structural materials by arc spraying process. Not only the challenge to machining Fe-Al alloys can be resolved, but also excellent high-temperature corrosion resistance of Fe-Al coatings can be utilized. In other words, Fe-Al coatings have a great value for industries. Al-base cored wires were prepared by using Al-strip to wrap Fe, Ni powder and other elements such as B and RE. Al-base coatings were produced by arc spraying process. Not only conventional performance (bonding strength, microhardness and porosity) and corrosion resistance (high-temperature oxidation corrosion, salt coated corrosion and sulfidation corrosion) of Al-base coatings were investigated, but also microstructures of original coatings and corroded coatings were characterized by SEM, XRD and EDS. Mechanisms of high-temperature oxidation corrosion, salt coated corrosion and sulfidation corrosion were discussed. Results are as follows. 1. Al-base cored wires were prepared by using Al-strip to wrap metal powder, and their parameters for arc spraying process have been optimized. Typical layered Al-base coatings were fabricated. Al-base coatings contained the intermetallics of Al-Fe-Ni system as the major constituent, which were no lack of high-Al intermetallics. 2. Temperature and flight velocity of sprayed particles were measured by SprayWatch online thermal spraying monitor system. Result showed that temperature and flight velocity of sprayed particles fluctuated smaller, sprayed particles molted more completely, and spraying process was more stable. 3. Corrosion resistance of Al-base coatings was investigated. â‘´When Al-base coatings oxidized at high temperature, the surface formed Al2O3 barrier which could protect coatings from oxidation further. Therefore, high-temperature oxidation corrosion of Al-base coatings is excellent.