Development of Cr-Al Coating on Zircaloy-4 for Enhanced Accident Tolerant Fuel

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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Corrosion resistance of zinc-based systems in NaCl environment

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun201361051487 ◽

2013 ◽

Vol 61 (5) ◽

pp. 1487-1495 ◽

Cited By ~ 2

Author(s):

Jiří Votava

Keyword(s):

Corrosion Resistance ◽

Salt Spray ◽

Current Trend ◽

Zinc Coating ◽

Degradation Process ◽

Engineering Industry ◽

Anticorrosion Protection ◽

Al Coating ◽

Measurement Of Thickness

Metal components in engineering, industry and agriculture are subjects of degradation process influenced by corrosion which result in changes of mechanical characteristics. The current trend of anticorrosion protection is aimed at inorganic metal zinc-based coatings, such as zinc dipping which can be improved by duplex protection. This paper deals with two types of corrosion protection of steel components by zinc coating, first of which is produced by hot dip galvanizing, the other by Zn-Al spray. Hot dip galvanizing was processed in working conditions; the Zn-Al coating was sprayed following the instructions of producer. It is a special aerosol with particles of Zn and Al sized approximately 5 µm. There have been processed the following tests: analysis of element structure, test of corrosion resistance in aggressive environment of salt spray according to ČSN ISO 9227, further measurement weight of applied coatings according to ČSN EN ISO 3892 and measurement of thickness of passivating coating. There was also made an analysis of coating tenacity on bending pin according to ČSN EN ISO 8401. Quality of applied coatings was evaluated following the metallographic scratch pattern.

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