| The low cost intermetallic compound Fe-Al has a relatively high corrosion resistance as stainless steel and exhibits even higher resistance in H2S atmosphere. It is a potential constructional material, which can be used under high temperature. However, its low ductile and handling characteristic greatly limited the application of FeAl materials in some way. Lots of references and researches show that intermetallic compound FeAl coatings deposited by thermal spraying technology can solve the problem and also exhibited great corrosion and wear resistance.There are many types of thermal spraying, and they show different characteristic in depositing coatings. Generally, air plasma spraying (APS) were widely used in many industrials due to high temperature of plasma jet which can melt lots of high melting point materials; High velocity oxygen-fuel spraying(HVOF) has the characteristic of high velocity, low flame temperature and high cost benefit; Low pressure plasma spraying(LPPS) was developed based on APS technology, the LPPS technology operates under low chamber pressure, so LPPS coatings can deposited without being affected by air atmosphere, which can greatly reduce oxides of coatings. Until now, there are not many researches focused on coatings deposited by all these three spraying technologies above, which limit our choices when choosing proper processing technique.Three kinds of thermal spraying technology were used in this paper in order to investigate effects of different spraying process on micro structure and mechanical properties of FeAl coatings. The results indicated:the APS and HVOF coatings exhibited similar microhardness, about 540HV0.3, which is much lower than 860HV0.3 of LPPS coatings,. The elastic modulus measured for APS, HVOF and LPPS coatings using Knoop indentation were 96,84,176GPa, respectively. The APS coatings were also observed to have lower elastic moduli values in the in-planer direction than those in the perpendicular direction, as a result of microcracks scattered within the coatings. In fracture toughness tests, the LPPS coatings revealed the lowest fracture toughness, as compared with other two spraying processes, indicating low porosity and crack levels are related to low fracture toughness.
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