Cr/Fe ratio by XPS spectra of magnetoelectropolished AISI 316L SS fitted by Gaussian-Lorentzian shape lines

U radu su predstavljene analize XPS spektara željeza Fe2p3/2 i kroma Cr2p3/2 podešavanjem pomoću simetričnih i asimetričnih oblika linija. Izračuni su provedeni na AISI 316L SS biomaterijalu nakon postupka magnetoelektropoliranja MEP. Najbolji rezultati su postignuti za podešavanje pomoću oblika linija GL(30) i LA(1,3; 4; 5) plus GL(40). Ustanovljeno je da se nakon postupka magnetoelektropoliranja MEP omjer kroma i željeza povećao od 16,4 do 22,4 puta u odnosu na onaj u rasutom materijalu.In the paper, the analyses of Fe2p3/2 and chromium Cr2p3/2 XPS spectra with fitting by symmetrical and asymmetrical line shapes, are presented. The calculations are performed on AISI 316L SS biomaterial after magnetoelectropolishing MEP operation. The best results were obtained for fitting by GL(30) and by LA(1,3; 4; 5) plus GL(40) line shapes. It was found, the chromium-to-iron ratio after magnetoelectropolishing MEP was increasing in the range from 16,4 to 22,4 times versus that one of bulk material

Comparative SEM and EDX analysis of surface coatings created on niobium and titanium alloys after plasma electrolytic oxidation (PEO)

U radu su opisani rezultati SEM i EDS analize površinskih slojeva nastalih na legurama niobija i titanija (TNZ, NiTi, Ti6Al4V) nakon plazma elektrolitičke oksidacije (PEO), poznate i kao mikro lučna oksidacija (Micro Arc Oxidation - MAO). Za eksperiment PEO postupka upotrebljen je nekonvencionalni elektrolit, temeljen na koncentriranoj ortofosfornoj kiselini. Nakon PEO dobiveni su i proučavani bakrom obogaćeni površinski slojevi na biomaterijalu. Prikazane su i statistički obrađene opće značajke površine u odnosu na kovinske biomaterijale nakon PEO postupka, uz značajne razlike u rezultatima.In the paper, the SEM and EDS study results of the surface coatings formed on the niobium and titanium alloys (TNZ, NiTi, Ti6Al4V) after the Plasma Electrolytic Oxidation (PEO), also known as Micro Arc Oxidation (MAO), are described. For the experiment of the PEO treatment, a non-conventional electrolyte, based on the concentrated orthophosphoric acid, was used. Copper-enriched surface coatings on the biomaterials after the PEO were obtained and studied. General surface characteristics, regarding the metallic biomaterials after the PEO treatment, with the significant differences of the results, have been displayed and statistically developed

Experimental studies using minimum quantity cooling (MQC) with molybdenum disulfide and graphite-based microfluids in grinding of Inconel® alloy 718

In the paper, the results of experimental studies related with determination of the influence of the supply of a grinding fluid (GF) doped with powdered graphite and MoS2 into the machining zone with the minimum quantity cooling (MQC) method on the course and results of the reciprocating internal cylindrical grinding of rings made from Inconel® alloy 718 have been presented. As a grinding fluid, water aerosols were used. The aerosols delivered the following into the grinding zone: water slurry MoS2 with a concentration of 30 g/dm3, water slurry of graphite with a concentration of 30 g/dm3, 5% water solution of Syntilo RHS oil and pure demineralized water. The obtained results of carried out experiments showed that the most favorable conditions of grinding wheel operation were obtained when MQC-based delivering an aerosol of water slurry made from demineralized water doped with MoS2 and graphite with a minimum flow rate and when delivering an aerosol of 5% water slurry of Syntilo RHS oil. It was proved that doping GF with powdered MoS2 and graphite, with delivery in the form of an aerosol with a minimum flow rate, has a substantial influence on the intensity of clogging grinding wheel active surface (GWAS). Additionally, it has been demonstrated that the solid grease MoS2 and graphite particles reached the area of contact of the GWAS and the machined surface effectively, actively influencing its tribological conditions of the grinding process.Web of Science1011-466163

Development of porous coatings enriched with magnesium and zinc obtained by DC plasma electrolytic oxidation

Coatings with developed surface stereometry, being based on a porous system, may be obtained by plasma electrolytic oxidation, PEO (micro arc oxidation, MAO). In this paper, we present novel porous coatings, which may be used, e.g., in micromachine's biocompatible sensors' housing, obtained in electrolytes containing magnesium nitrate hexahydrate Mg(NO3)(2)center dot 6H(2)O and/or zinc nitrate hexahydrate Zn(NO3)(2)center dot 6H(2)O in concentrated phosphoric acid H3PO4 (85% w/w). Complementary techniques are used for coatings' surface characterization, such as scanning electron microscopy (SEM), for surface imaging as well as for chemical semi-quantitative analysis via energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), glow discharge optical emission spectroscopy (GDOES), and X-ray powder diffraction (XRD). The results have shown that increasing contents of salts (here, 250 g/L Mg(NO3)(2)center dot 6H(2)O and 250 g/L Zn(NO3)(2)center dot 6H(2)O) in electrolyte result in increasing of Mg/P and Zn/P ratios, as well as coating thickness. It was also found that by increasing the PEO voltage, the Zn/P and Mg/P ratios increase as well. In addition, the analysis of XPS spectra revealed the existence in 10 nm top of coating magnesium (Mg2+), zinc (Zn2+), titanium (Ti4+), and phosphorus compounds (PO43-, or HPO42-, or H2PO4-, or P2O74-).Web of Science97art. no. 33

ANSYS analysis of stress and strain after cones plastic deformation

The paper deals with study of stress and strain after cones plastic deformation by ANSYS software. There are shown the new results of FEM analysis, what is the base for the further experimental studies.Web of Science22250850

SEM, EDS and XPS analysis of nanostructured coating formed on NiTi biomaterial alloy by Plasma Electrolytic Oxidation (PEO)

Plasma elektrolitička oksidacija (PEO) NiTi legure proučavana je u elektrolitu koji se uobičajeno sastojao od koncentrirane ortofosforične kiseline s dodatkom nitrata bakra II. Taj se PEO postupak primijenio za dobivanje nanostrukturirane prevlake na Nitinol površini. Metode analize površinskog sloja kao što su skeniranje elektronskim mikroskopom (SEM) s energetski disperzivnom rendgenskom spektroskopijom (EDS) i rendgenskom fotoelektronskom spektroskopijom (XPS), omogućile su određivanje strukture i sastava najočekivanijih prevlaka i otkrivanje uvjeta za njihovo dobivanje. Ustanovilo se da se porozna PEO prevlaka dobivena u elektrolitu koji je sadržavao bakreni nitrat u količini većoj od 1,6 mol/L sastoji uglavnom od fosfata bakra-titanija-nikla. Uz to, u usporedbi s matricom, karcinogeni nikal u prevlaci srećom se javlja u vrlo malim količinama, tj. ispod 1 at%.Plasma Electrolytic Oxidation (PEO) of NiTi alloy was studied in the electrolyte consisting generally of concentrated orthophosphoric acid with an addition of copper II nitrate. The PEO process was used to obtain a nanostructured coating on the Nitinol surface. The surface layer analyses methods, such as scanning electron microscopy (SEM) with the energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS), allowed determining the structure and composition of the most expected coatings and revealing the conditions for obtaining them. It was found that the porous PEO coating obtained in the electrolyte containing copper nitrate in an amount higher than 1,6 mol/L consists mainly of copper-titanium-nickel phosphates. Moreover, in comparison with matrix, the emergence of carcinogenic nickel appearing in the coating fortunately appears in very small quantities, i.e. below 1 at%

XPS measurements of AISI 316LVM SS biomaterial tubes after magnetoelectropolishing

XPS (X-ray Photoelectron Spectroscopy) mjerenja obavljena su na uzorcima cijevi od biomaterijala AISI 316LVM nehrđajućeg čelika koji služi za stentove, nakon uobičajenog elektropoliranja (EP) i magnetoelektropoliranja (MEP). Nakon izvršenih operacija elektropoliranja, uzorci su se, zapakirani u foliji, držali otprilike četiri godine. Rezultati XPS analize pokazuju značajnu razliku u vrijednostima mjerenja i računanja, ovisno o metodi površinske obrade: EP i/ili MEP. Izračunat je sastav površinskog sloja čelika i PREN (ekvivalentni broj otpornosti na točkastu eroziju). Najveći su iznosi tih vrijednosti dobiveni na uzorcima poslije MEP-a kada su i vrijednosti spojeva kroma (Cr 2p) i molibdena (Mo 3d) porasle više od tri puta u odnosu na te vrijednosti nakon postupka EP. Izračunati PRENMEP (Fe, Cr, Mo, Mn, Ni, P, S, O) = 16,37, s PRENMEP (Fe, Cr, Mo, Mn, Ni, P, S) = 36,89, u odnosu na PRENEP (Fe, Cr, Mo, Mn, Ni, P, S, O) = 3,12, s PRENEP (Fe, Cr, Mo, Mn, Ni, P, S) = 8,53. Postignuti rezultati ukazuju na korisno i neobično djelovanje magnetskog polja tijekom MEP-a.XPS (X-ray Photoelectron Spectroscopy) measurements were performed on AISI 316LVM stainless steel tubes of biomaterial samples, serving for stents, after a standard electropolishing (EP), and magnetoelectropolishing (MEP). After electropolishing operations, the samples were kept in a closed foil pack for about four years. The results of XPS analysis indicate a significant difference in the measurement and calculation values, dependent on surface treatment method: EP and/or MEP. The steel surface film composition and PREN (pitting resistance equivalent number) were calculated. The highest numbers of these values were obtained on samples after MEP where both chromium compounds (Cr 2p) and molybdenum (Mo 3d) increased over three times against these values after EP treatment. The calculated PRENMEP (Fe, Cr, Mo, Mn, Ni, P, S, O) = 16,37, with PRENMEP (Fe, Cr, Mo, Mn, Ni, P, S) = 36,89, versus PRENEP (Fe, Cr, Mo, Mn, Ni, P, S, O) = 3,12, with PRENEP (Fe, Cr, Mo, Mn, Ni, P, S) = 8,53. The results obtained point to an advantageous and unusual effect of the magnetic field action during MEP

XPS analysis of nanolayer formed on AISI 304L SS after High-Voltage Electropolishing (HVEP)

U radu se predlaže novi postupak nazvan elektropoliranje pod visokim naponom - High-Voltage Electropolishing (HVEP) kako bi se dobila specifična svojstva površine obrađivanog metalnog materijala. Za HVEP obradu kao biomaterijal korišten je AISI 304L nehrđajući čelik. Druga karakteristika ovoga rada je primjena koncentrirane otopine fosforne kiseline kao elektrolita u bakrovom nitratu. Osnovna svrha HVEP-a u toj vrsti elektrolita bila je uključivanje bakarnih iona u pasivni površinski sloj. Takav se modificirani nanosloj analizirao primjenom X-ray Photoelectron Spectroscopy (XPS) kako bi se otkrio sastav dobivenog sloja. Učinjena je usporedba numeričkih rezultata, ovisno o primijenjenom naponu. Uz to, određeni su omjeri Cr/Fe i Cu/P kako bi se pokazale prednosti tog elektrokemijskog HVEP postupka.In the paper, a novel process named the High-Voltage Electropolishing (HVEP) is proposed to gain the specific surface properties on the treated metallic material. The AISI 304L stainless steel as the biomaterial was used for the HVEP treatment. Another feature of this work is using a concentrated phosphoric acid solution within the copper nitrate as electrolyte. The main purpose of the HVEP processing in that kind of electrolyte was to incorporate the copper ions into the passive surface film. Such a modified surface nanolayer was studied by means of the X-ray Photoelectron Spectroscopy (XPS) to reveal the composition of the obtained film. The comparison of the numerical results, dependent on the voltage applied, was performed. Moreover, the Cr/Fe and Cu/P ratios were determined to show the advantages of this electrochemical HVEP treatment

SEM, EDS and XPS analysis of the coatings obtained on titanium after plasma electrolytic oxidation in electrolytes containing copper nitrate

In the paper, the Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Photoelectron Spectroscopy (XPS) results of the surface layer formed on pure titanium after plasma electrolytic oxidation (micro arc oxidation) at the voltage of 450 V are shown. As an electrolyte, the mixture of copper nitrate Cu(NO3)2 (10–600 g/L) in concentrated phosphoric acid H3PO4 (98 g/mol) was used. The thickness of the obtained porous surface layer equals about 10 m, and it consists mainly of titanium phosphates and oxygen with embedded copper ions as a bactericidal agent. The maximum percent of copper in the PEO surface layer was equal to 12.2 0.7 wt % (7.6 0.5 at %), which is the best result that the authors obtained. The top surface layer of all obtained plasma electrolytic oxidation (PEO) coatings consisted most likely mainly of Ti3(PO4)4 nH3PO4 and Cu3(PO4)2 nH3PO4 with a small addition of CuP2, CuO and Cu2O.Web of Science95art. no. 31