Structure and sliding wear behavior of 321 stainless steel/Al composite coating deposited by high velocity arc spraying technique

A new type of composite coating (321—Al coating) was prepared by using the 321 austenitic stainless steel wire feed stock as the anode and aluminum wire as the cathode in arc spraying process. In order to compare with the new composite coating, the traditional 321 coating with twin 321 stainless steel wires was fabricated. The microstructure and wear resistance of the coatings were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersion spectroscope (EDS) and MM-200 ring-block type sliding wear tester. Results showed that, except for the aluminum phase addition in the 321—Al coating, no other extra phases produce in comparing with the 321 coating. However, due to the additional aluminum, the 321—Al coating performs quite different microstructure characteristics and tribological behavior. The oxygen content and microhardness of the 321—Al coating are lower than that of the 321 coating, but wear losses are pretty much under the oil lubricated sliding condition. The effect of the microstructure on the wear behavior of the 321—Al coating was also discussed, which is mainly relevant to the characteristic of “ductile aluminum and hard stainless steel composite phases inter-depositing”.

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Microstructural and Corrosion Behavior of High Velocity Arc Sprayed FeCrAl/Al Composite Coating on Q235 Steel Substrate

Coatings ◽

10.3390/coatings9090542 ◽

2019 ◽

Vol 9 (9) ◽

pp. 542 ◽

Cited By ~ 2

Author(s):

Ndumia Joseph Ndiithi ◽

Min Kang ◽

Jiping Zhu ◽

Jinran Lin ◽

Samuel Mbugua Nyambura ◽

...

Keyword(s):

Corrosion Resistance ◽

Composite Coating ◽

High Velocity ◽

Steel Substrate ◽

Arc Spraying ◽

Spray Parameters ◽

Q235 Steel ◽

Electrochemical Tests ◽

Al Composite ◽

Al Coating

High velocity arc spraying was used to prepare FeCrAl/Al composite coating on Q235 steel substrate by simultaneously spraying FeCrAl wire as the anode and Al wire as the cathode. The composite coating was sprayed with varying voltage and current to obtain optimum coating characteristics. FeCrAl coating was also prepared for comparison purposes. The surface microstructure of the coatings was characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). The average microhardness of the coatings and the substrate was analyzed and compared. Corrosion resistance was investigated by means of electrochemical tests. The image results showed that a lamellar structure consisted of interwoven layers of FeCrAl and Al. Al and FeCr constituted the main phases with traces of oxides and AlFe intermetallic compounds. The average porosity was reduced and microhardness of the coatings was improved with increasing voltage and current. The FeCrAl/Al coating formed alternating layers of hard and ductile phases; the corrosion resistance of the coatings in the sodium chloride (NaCl) solution depended on the increase in Al content and spray parameters. The corrosion resistance tests indicated that FeCrAl/Al coating had a better corrosion resistance than the FeCrAl coating. FeCrAl/Al can be used to coat steel substrates and increase their corrosion resistance.

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