Partner: E. Bełtowska-Lehman

Institute of Metallurgy and Materials Science, Polish Academy of Sciences (PL)

Recent publications
1.Mróz K.P., Kucharski S., Doliński K., Bigos A., Mikułowski G., Bełtowska-Lehman E., Nolbrzak P., Failure modes of coatings on steel substrate, BULLETIN OF THE POLISH ACADEMY OF SCIENCES: TECHNICAL SCIENCES, ISSN: 0239-7528, DOI: 10.1515/bpasts-2016-0027, Vol.64, No.1, pp.249-256, 2016
Abstract:

The critical monotonic strain of Ni-W and MoS2(Ti,W) coatings on steel substrates was studied. The idea of axisymmetric bending test (called here as coin bending test) limited to monitoring of the coating failure was used. Experiments revealed mechanism of the coating failure, as cracking initiated from coating surface defects and/or substrate was demonstrated using indentation technique. By pushing the center of the uncoated side of a circular plate, the axisymmetric stress state was generated in the coating. The stress components varied gradually from the greatest value in the center to the smallest value at the edge of the specimen. The changes of the sample surface as a result of loading were monitored step by step via optical microscopy.

Keywords:

Ni-W coating, MoS2(Ti.W) coating, steel substrate, fracture, coatings strength, axisymmetric bending test

Affiliations:
Mróz K.P.-IPPT PAN
Kucharski S.-IPPT PAN
Doliński K.-IPPT PAN
Bigos A.-Institute of Metallurgy and Materials Science, Polish Academy of Sciences (PL)
Mikułowski G.-IPPT PAN
Bełtowska-Lehman E.-Institute of Metallurgy and Materials Science, Polish Academy of Sciences (PL)
Nolbrzak P.-Łódź Technical University (PL)
2.Mróz K.P., Bigos A., Kucharski S., Doliński K., Bełtowska-Lehman E., Ni-W Electrodeposited Coatings on Low Carbon Steel Substrate: Fatigue Observations, Journal of Materials Engineering and Performance, ISSN: 1059-9495, DOI: 10.1007/s11665-014-1149-7, Vol.23, No.10, pp.3459-3466, 2014
Abstract:

The fatigue response of electrodeposited Ni-W on low carbon steel substrate was studied. The considered Ni-W coatings are a promising substitute for toxic hard chromium coatings which, according to EU directives (2000/53/WE, 2011/37/UE), must be eliminated. Specimens of pure substrate and those covered by coating were compared. Coated specimens exhibited lower fatigue resistance under higher stress amplitudes than their non-coated counterparts in stress-controlled fatigue experiments. However, at lower stress amplitudes, the fatigue strength of both specimen types was similar. The cyclic softening of the coatings was demonstrated using indentation techniques.

Keywords:

fatigue, hardness, indentation, low carbon steel substrate, Ni-W coatings, S-N curve

Affiliations:
Mróz K.P.-IPPT PAN
Bigos A.-Institute of Metallurgy and Materials Science, Polish Academy of Sciences (PL)
Kucharski S.-IPPT PAN
Doliński K.-IPPT PAN
Bełtowska-Lehman E.-Institute of Metallurgy and Materials Science, Polish Academy of Sciences (PL)