CORRELATION BETWEEN MICROSTRUCTURAL AND CORRO-SION RESISTANCE OF BORON-MODIFIED DUPLEX STAINLESSSTEEL PROCESSED BY SPRAY-FORMING

In this work was investigated the duplex stainless steel modiβied by boronprocessed processed by spray-forming, in order to characterize the workpieceusing different techniques, optical microscopy, SEM-FEG, X-ray diffraction,Rama spectroscopy and Vickers hardness (VH) and Thermo-Calc software, withgoal of determining the corrosion resistance. The corrosion resistance test wasperformed in aerated solution of 0.1 M, immersed in different aggressive mediaelectrolytes, alkaline and acidic mediums. As result through the EDS techniquewas veriβied that in the ferrite phase the Cr element predominates, but in theaustenite phase the Fe and Ni elements prevail. Meanwhile XRD spectra showndifferent meta-stable phases and mainly the (FeCr)2B phase, the percentage ofthe austinite and ferrite phases are similar. Besides, the Vickers microhardnessmeasurement was around 460 HV. Furthermore, Nyquist impedance plots atdifferent electrolytes had linear behavior, which their polarization resistancesare extremely high in all solutions. However, the potential of corrosion whosemagnitude is small, also the corrosions rates were close to zero. Consequently,the corrosion resistance in all studied solutions were extremely high and it canbe attributed due to presence of the (FeCr)2B phase, meta-stables phases andsimilar proportion of the three phases present. This alloy can be successfullyused in the chemical, oil and gas industries and petrochemical process plants.