effect on the composition of the non-metallic inclusions,
as a majority of the inclusions contained Ti.
The addition of zirconium had a great effect on the
size distribution and the number of non-metallic
inclusions. The inclusions were significantly smaller and
the number was much higher (300 % compared to
PK942), the result was a large reduction in the total
non-metallic inclusion surface area (37 % reduction).
Most of the inclusions contained Zr. This means that the
de-oxidation with zirconium is potentially beneficial for
the production of clean steel.
The addition of both titanium and zirconium also
resulted in smaller (over 60 % of non-metallic inclusions
are smaller than 1 μm) but more numerous non-metallic
inclusions that had a reduced total non-metallic inclusion
surface area (28.5 %) in comparison to the PK942
sample. The vast majority of inclusions contain both Ti
and Zr.
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Int. 41 (2001) 626–640
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lation of accelerated stationary creep rate activation energy for a steel
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Mater. Tehnol., 46 (2012) 661–664
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(2008), 43–52
9 Y. Li, X.L. Wan, W.Y. Lu, A.A. Shirzadi, O. Isayev, O. Hress, K.M.
Wu, Effect of Zr-Ti combined deoxidation on the microstructure and
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10 H. Suito, A.V. Karasev, M. Hamada, R. Inoue, K. Nakajima, Influ-
ence of Oxide Particles and Residual Elements on Microstructure
and Toughness in the Heat-Affected Zone of Low-Carbon Steel
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11 J. Janis, A. Karasev, K. Nakajima, P. Jönsson, Effect of Secondary
Nitride Particles on Grain Growth in a Fe-20 mass% Cr Alloy
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12 L. Zhang, T. Kannengiesser, Austenite grain growth and microstruc-
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trolled Cooling Process on Microstructures of Ti – Zr Deoxidized
Low Carbon Steel, ISIJ Int., 56 (2016), 1800–1807, doi:10.2355/isij-
international.ISIJINT-2016-106
15 P. V. Bizyukov, S.R. Giese, Effects of Zr, Ti and Al Additions on
Nonmetallic Inclusions and Impact Toughness of Cast Low-Alloy
Steel, J. Mater. Eng. Perform., 26 (2017), 1878–1889, doi:10.1007/
s11665-017-2583-0
16 Y. Du, K.M. Wu, L. Cheng, Y. Li, O. Isayev, O. Hress, Effect of
Zr–Ti deoxidisation on the hydrogen-induced cracking of X65
pipeline steels, Mater. Sci. Technol., 32 (2016), 728–735,
doi:10.1080/02670836.2016.1157971
17 ASTM International, ASTM E112-13 Standard Test Methods for
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Size, 2013, doi:10.1520/E0112
18 H. Suito, H. Ohta, S. Morioka, Refinement of solidification micro-
structure and austenite grain by fine inclusion particles, ISIJ Int., 46
(2006), 840–846. doi:10.2355/isijinternational.46.840
19 F. Tehovnik, F. Vodopivec, L. Kosec, M. Godec, Hot ductility of
austenite stainless steel with a solidification structure, Mater.
Tehnol., 40 (2006), 129–137
20 H. Ohta, H. Suito, Dispersion Behavior of MgO, ZrO2, Al2O3,
CaO-Al2O3 and MnO-SiO2 Deoxidation Particles during Solidi-
fication of Fe-10mass%Ni Alloy, ISIJ Int., 46 (2006), 22–28,
doi:10.2355/isijinternational.46.22
21 A. V Karasev, H. Suito, Quantitative evaluation of inclusion in deo-
xidation of Fe-10 mass% Ni alloy with Si, T, Al, Zr, and Ce, Metall.
Mater. Trans. B Vol.30B, 30B (1999), 249–257, doi:10.1007/
s11663-999-0054-1
22 A. V. Karasev, H. Suito, Nitride Precipitation on Particles in
Fe–10mass%Ni Alloy Deoxidized with Ti, M (M=Mg, Zr and Ce)
and Ti/M, ISIJ Int., 49 (2009), 229–238, doi:10.2355/isijinter-
national.49.229
23 H. Ohta, H. Suito, Precipitation and Dispersion Control of MnS by
Deoxidation Products of ZrO2, Al2O3, MgO and MnO – SiO2
Particles in Fe – 10mass % Ni Alloy, ISIJ Int., 46 (2006), 480–489
24 Y. Min, X. Li, Z. Yu, C. Liu, M. Jiang, Characterization of the
Acicular Ferrite in Al-Deoxidized Low-Carbon Steel Combined with
Zr and Mg Additions, Steel Res. Int., 87 (2016), 1503–1510,
doi:10.1002/srin.201500440
M. KOLE@NIK et al.: DE-OXIDATION OF PK942 STEEL WITH Ti AND Zr
1036 Materiali in tehnologije / Materials and technology 51 (2017) 6, 1031–1036
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
M. HO^EVAR et al.: CORROSION ON POLISHED AND LASER-TEXTURED SURFACES OF AN Fe–Mn ...
1037–1041
CORROSION ON POLISHED AND LASER-TEXTURED SURFACES
OF AN Fe–Mn BIODEGRADABLE ALLOY
PRIMERJAVA KOROZIJSKIH LASTNOSTI POLIRANE IN
LASERSKO TEKSTURIRANE POVR[INE BIORAZGRADLJIVE
ZLITINE Fe–Mn
Matej Ho~evar1, ^rtomir Donik1, Irena Paulin1, Aleksandra Kocijan1,
Franc Tehovnik1, Jaka Burja1, Peter Gregor~i~2, Matja` Godec1
1Institute of Metals and Technology, Lepi pot 11, 1000 Ljubljana, Slovenia
2Faculty of Mechanical Engineering, University of Ljubljana, A{ker~eva 6, 1000 Ljubljana, Slovenia
matej.hocevar@imt.si
Prejem rokopisa – received: 2017-08-21; sprejem za objavo – accepted for publication: 2017-09-12
doi:10.17222/mit.2017.140
Fe-based biodegradable alloys such as Fe–Mn are interesting for biodegradable implants; however, their corrosion rate for such
applications is too low. Here, nanosecond-laser surface texturing is applied as a successful surface treatment for increasing the
degradation rate of an Fe–Mn alloy. Laser texturing increases the surface area by increasing the surface porosity and generating
a super-hydrophilic surface. Electrochemistry tests revealed that the laser-textured samples have a higher corrosion rate than a
polished sample, thus enhancing the biodegradability of the Fe–Mn alloy. EDS analyses revealed a significantly higher content
of Mn on the surface in the oxidized layer compared to the bulk Fe–Mn composition, which is one of the reasons for the
increased corrosion rate. This work demonstrates the potential of laser-treated surfaces of biodegradable metals for biomedical
applications.
Keywords: Fe–Mn alloy, laser texturing, corrosion, biodegradable, EDS analyses
Biolo{ko razgradljive zlitine, kot so na primer Fe–Mn zlitine, so zanimive za uporabo v obliki biolo{ko razgradljivih implanta-
ntov, vendar je njihova hitrost korozije za ciljne aplikacije {e vedno prenizka. Lasersko teksturiranje povr{ine predstavlja
uspe{no povr{insko obdelavo za pove~anje hitrosti razgradnje Fe–Mn zlitine. Obdelava povr{ine z laserjem pove~a dele`
izpostavljene povr{ine na ra~un ve~je poroznosti, obenem pa je novonastala povr{ina superhidrofilna. Elektrokemijski testi so
pokazali, da imajo vzorci, obdelani z laserjem, ve~jo stopnjo korozije v primerjavi s poliranimi vzorci, s ~imer se pove~a
biorazgradljivost zlitine Fe–Mn. EDS analiza je pokazala pove~ano vsebnost Mn na povr{ini v oksidirani plasti v primerjavi s
kemijsko sestavo osnovnega materiala Fe–Mn, kar predstavlja eno od razlag za pove~anje hitrosti korozije. Raziskava dokazuje
potencial laserske obdelave povr{ine biolo{ko razgradljivih kovin za biomedicinske aplikacije.
Klju~ne besede: zlitina Fe–Mn, lasersko teksturiranje, korozija, biorazgradljivost, EDS analiza
1 INTRODUCTION
In recent years, biodegradable metals, such as Fe and
Mg alloys, have emerged as a promising alternative in
bone surgery, orthopaedic and cardiovascular applica-
tions.1–4 The advantages of biodegradable metals are
temporary support during tissue healing, progressive
degradation, as well as reducing the long-term risks and
side effects.1,2,5,6 Despite the high potential of these
Fe-based materials, which possess similar mechanical
properties to stainless steel, they exhibit one main
weakness – the corrosion rate is too slow.6–8 However,
with the addition of Mn as an alloying element, a trace
element necessary in many enzymatic reactions, the
corrosion rate is enhanced.2,9 Although the degradation is
faster it is still too low, which represents a major prob-
lem for these recently developed Fe–Mn alloys. Another
way to influence the corrosion rate of an Fe–Mn alloy
without changing its chemical composition is to modify
the surface morphology via mechanical treatments,
including machining, sand blasting and laser surface mo-
dification.10–15 Increased surface areas, porous surfaces
and surfaces with increased wettability (super-hydro-
philic surfaces) have higher corrosion rates.11,16,17 How-
ever, not so many studies has been made on biode-
gradable Fe metals, and many of the existing treatments
are usually applied to biocompatible materials with
passivating surfaces such as AISI 316L stainless steel,
titanium alloys, cobalt-chromium alloys and other simi-
lar alloys to improve the corrosion properties.11,18,19
The aim of the present study was to investigate the
influence of a laser surface treatment on the corrosion
behaviour of the Fe–Mn alloy due to changes in the
surface properties. In contrast to other authors the con-
tent of Mn in our study was below 20 % of mass
fractions, with no additional changes in the chemical
composition. Like the majority of the previous studies to
simulate in-vivo conditions, the corrosion properties
were investigated using Hank’s solution.
Materiali in tehnologije / Materials and technology 51 (2017) 6, 1037–1041 1037
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
UDK 620.193:62-4-023.731:669.017.1 ISSN 1580-2949
Original scientific article/Izvirni znanstveni ~lanek MTAEC9, 51(6)1037(2017)
2 EXPERIMENTAL PART
2.1 Material preparation
An Fe-Mn alloy with 17 % of mass fractions of Mn
was produced from pure Fe with the addition of Mn to
the alloy. The laboratory material was made in a 20 kg
Leybold Heraeus vacuum induction furnace. The two 60
mm × 60 mm × 500 mm ingots of Fe-Mn alloy were cast
and hot rolled to 60 mm × 20 mm × 150 mm. The
hot-rolled material was solution annealed at 1200 °C and
quenched in oil. The chemical composition of the
Fe–Mn alloy was determined with an X-ray fluorescence
spectrometer XRF (Thermo Scientific Niton XL3t
GOLDD+) and a carbon and sulphur analyser (ELTRA
CS-800). The chemical composition of produced Fe-Mn
alloy in % of mass fractions of: 0.58 % C, 0.067 % Si,
17.0 % Mn, 0.051 % Cu, 0.31 % Mo, 0.058 % Ti,
balance Fe.
2.2 Surface modification
The Fe–Mn samples were cut into 15 mm × 15 mm
size squares and prepared by wet grinding down to 1200
grit followed by polishing down to 1 μm with a diamond
suspension to produce a smooth mirror finish. Selected
samples were further textured by using a nanosecond
laser (Nd:YAG) with a wavelength of 1064 nm and pulse
duration of 95 ns. The beam spot size was 0.05 mm and
it was led in lines with a velocity of 1.6 mm/s using a
scanning head. The scan line separation equalled 50 μm.
The texturing was performed with a pulse energy of
0.6 mJ and frequency of 1kHz. Before laser texturing,
the samples were cleaned with detergent, rinsed tho-
roughly with water and immersed in an ultrasonic bath in
absolute ethanol for 12 min.
2.3 Electrochemical measurements
Electrochemical measurements were performed on
polished and laser-treated Fe–Mn samples at room
temperature in a simulated physiological Hank’s solu-
tion, containing 8 g/L NaCl, 0.40 g/L KCl, 0.35 g/L
NaHCO3, 0.25 g/L NaH2PO4, 0.06 g/L Na2HPO4,
0.19 g/L CaCl2, 0.41 g/L MgCl2, 0.06 g/L MgSO4 and
1 g/L glucose, stabilized at pH = 7.8. All the chemicals
were from Merck, Darmstadt, Germany. A three-elec-
trode, flat BioLogic® corrosion cell (volume 0.25 L) was
used for the corrosion measurements. The test specimen
was employed as the working electrode (WE). The
reference electrode (RE) was a saturated calomel elec-
trode (SCE, 0.242 V vs. SHE) and the counter electrode
(CE) was a platinum mesh. Electrochemical measure-
ments were recorded using a BioLogic® Modular
Research Grade Potentiostat/Galvanostat/FRA Model
SP-300 with an EC-Lab® software V11.10. The speci-
mens were immersed in the solution 1 h prior to the
measurement in order to stabilize the surface at the
open-circuit potential (OCP). The linear polarization
measurements were performed at ± 25 mV according to
the OCP, using a scan rate of 0.01 mV s–1.
2.4 Surface and metallographic investigation
The surface morphologies of the polished and laser-
textured samples were examined with a scanning elec-
tron microscope (SEM JEOL JSM-6500F) coupled with
an energy-dispersive spectrometer (EDS INCA ENER-
GY 400) and a non-contact Alicona G4 3D optical
Infinite-Focus Measuring (IFM) device. A cross-section
of the laser-textured samples was studied using EDS line
scan and EDS mapping analyses.
3 RESULTS AND DISCUSSION
3.1 Surface characterization
3D optical measurements (Figure 1) and SEM
images (Figure 2) of the laser-modified sample reveal
100-μm-deep visible micro-channels, separated by
50 μm. The bimodal structure with a typical dimension
of 10 μm is formed at the top of these micro-channels
due to laser ablation and melting. This nanostructured
surface is covered by a Fe–Mn oxide layer (Figure 2b).
A 3D profile of the polished surface is shown in Fig-
ure 1b, where an ultra-smooth surface is visible with a
surface roughness Sa < 0.04 μm compared to the laser-
textured ultra-rough sample with Sa > 25 μm. Addition-
ally, the laser-textured sample exhibited super-hydro-
philic behaviour after the treatment ( = 0°), whereas the
static contact angle on the polished surface is approach-
ing the hydrophobic area ( = 70°). As previously shown
by other authors11,16,17 the increased surface roughness,
M. HO^EVAR et al.: CORROSION ON POLISHED AND LASER-TEXTURED SURFACES OF AN Fe–Mn ...
1038 Materiali in tehnologije / Materials and technology 51 (2017) 6, 1037–1041
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
Figure 1: 3D height image representing the surface topography of a) laser-textured Fe–Mn sample and b) polished Fe–Mn sample
porosity and also the super-hydrophilic behaviour of
laser-treated Fe–Mn, significantly enhance the corrosion
rate compared to the polished sample.
EDS analyses revealed a noticeable surface oxide
layer. From the surface to the bulk the concentration of O
is decreasing with increased Mn concentration (Figures
3 and 4). This is a known mechanism for increasing the
corrosion rate.20 This increase of Mn causes depletion of
the Fe in the oxide layer and the ratio shifts to Mn > Fe
(Figures 3 and 4).
3.2 Electrochemical measurements
3.2.1 Linear polarization
Figure 5 shows the linear polarization curves for the
polished and laser-textured Fe–Mn samples in a
simulated physiological Hank’s solution at pH = 7.8. The
calculations from the linear polarization measurements
used the Equation (1):
Rp = 
a 
c/(2.3 Icorr (
a + 
c)) (1)
The polarization resistance, Rp, is evaluated from the
linear polarization curves by applying a linear least-
squares fit of the data around OCP, ± 10 mV. The corro-
sion current, Icorr, is calculated from Rp, the least-squares
slope, and the Tafel constants, 
a and 
c, of 120 mV
decade–1. The value of E(I=0) is calculated from the least-
squares intercept. The corrosion rates were calculated
using the following conversion in Equation (2):
M. HO^EVAR et al.: CORROSION ON POLISHED AND LASER-TEXTURED SURFACES OF AN Fe–Mn ...
Materiali in tehnologije / Materials and technology 51 (2017) 6, 1037–1041 1039
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
Figure 2: a) SEM image of surface topography of Fe–Mn laser-textured sample with micro-channels and b) highly magnified nanostructured
surface covered by Fe–Mn oxide layer
Figure 4: SEM cross-section image of laser-textured Fe–Mn sample
and corresponding EDS elemental maps showing composition (O, Fe,
Mn)
Figure 3: a) SEM cross-section image of laser-textured Fe–Mn
sample and b) the corresponding EDS line scan
2 EXPERIMENTAL PART
2.1 Material preparation
An Fe-Mn alloy with 17 % of mass fractions of Mn
was produced from pure Fe with the addition of Mn to
the alloy. The laboratory material was made in a 20 kg
Leybold Heraeus vacuum induction furnace. The two 60
mm × 60 mm × 500 mm ingots of Fe-Mn alloy were cast
and hot rolled to 60 mm × 20 mm × 150 mm. The
hot-rolled material was solution annealed at 1200 °C and
quenched in oil. The chemical composition of the
Fe–Mn alloy was determined with an X-ray fluorescence
spectrometer XRF (Thermo Scientific Niton XL3t
GOLDD+) and a carbon and sulphur analyser (ELTRA
CS-800). The chemical composition of produced Fe-Mn
alloy in % of mass fractions of: 0.58 % C, 0.067 % Si,
17.0 % Mn, 0.051 % Cu, 0.31 % Mo, 0.058 % Ti,
balance Fe.
2.2 Surface modification
The Fe–Mn samples were cut into 15 mm × 15 mm
size squares and prepared by wet grinding down to 1200
grit followed by polishing down to 1 μm with a diamond
suspension to produce a smooth mirror finish. Selected
samples were further textured by using a nanosecond
laser (Nd:YAG) with a wavelength of 1064 nm and pulse
duration of 95 ns. The beam spot size was 0.05 mm and
it was led in lines with a velocity of 1.6 mm/s using a
scanning head. The scan line separation equalled 50 μm.
The texturing was performed with a pulse energy of
0.6 mJ and frequency of 1kHz. Before laser texturing,
the samples were cleaned with detergent, rinsed tho-
roughly with water and immersed in an ultrasonic bath in
absolute ethanol for 12 min.
2.3 Electrochemical measurements
Electrochemical measurements were performed on
polished and laser-treated Fe–Mn samples at room
temperature in a simulated physiological Hank’s solu-
tion, containing 8 g/L NaCl, 0.40 g/L KCl, 0.35 g/L
NaHCO3, 0.25 g/L NaH2PO4, 0.06 g/L Na2HPO4,
0.19 g/L CaCl2, 0.41 g/L MgCl2, 0.06 g/L MgSO4 and
1 g/L glucose, stabilized at pH = 7.8. All the chemicals
were from Merck, Darmstadt, Germany. A three-elec-
trode, flat BioLogic® corrosion cell (volume 0.25 L) was
used for the corrosion measurements. The test specimen
was employed as the working electrode (WE). The
reference electrode (RE) was a saturated calomel elec-
trode (SCE, 0.242 V vs. SHE) and the counter electrode
(CE) was a platinum mesh. Electrochemical measure-
ments were recorded using a BioLogic® Modular
Research Grade Potentiostat/Galvanostat/FRA Model
SP-300 with an EC-Lab® software V11.10. The speci-
mens were immersed in the solution 1 h prior to the
measurement in order to stabilize the surface at the
open-circuit potential (OCP). The linear polarization
measurements were performed at ± 25 mV according to
the OCP, using a scan rate of 0.01 mV s–1.
2.4 Surface and metallographic investigation
The surface morphologies of the polished and laser-
textured samples were examined with a scanning elec-
tron microscope (SEM JEOL JSM-6500F) coupled with
an energy-dispersive spectrometer (EDS INCA ENER-
GY 400) and a non-contact Alicona G4 3D optical
Infinite-Focus Measuring (IFM) device. A cross-section
of the laser-textured samples was studied using EDS line
scan and EDS mapping analyses.
3 RESULTS AND DISCUSSION
3.1 Surface characterization
3D optical measurements (Figure 1) and SEM
images (Figure 2) of the laser-modified sample reveal
100-μm-deep visible micro-channels, separated by
50 μm. The bimodal structure with a typical dimension
of 10 μm is formed at the top of these micro-channels
due to laser ablation and melting. This nanostructured
surface is covered by a Fe–Mn oxide layer (Figure 2b).
A 3D profile of the polished surface is shown in Fig-
ure 1b, where an ultra-smooth surface is visible with a
surface roughness Sa < 0.04 μm compared to the laser-
textured ultra-rough sample with Sa > 25 μm. Addition-
ally, the laser-textured sample exhibited super-hydro-
philic behaviour after the treatment ( = 0°), whereas the
static contact angle on the polished surface is approach-
ing the hydrophobic area ( = 70°). As previously shown
by other authors11,16,17 the increased surface roughness,
M. HO^EVAR et al.: CORROSION ON POLISHED AND LASER-TEXTURED SURFACES OF AN Fe–Mn ...
1038 Materiali in tehnologije / Materials and technology 51 (2017) 6, 1037–1041
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
Figure 1: 3D height image representing the surface topography of a) laser-textured Fe–Mn sample and b) polished Fe–Mn sample
porosity and also the super-hydrophilic behaviour of
laser-treated Fe–Mn, significantly enhance the corrosion
rate compared to the polished sample.
EDS analyses revealed a noticeable surface oxide
layer. From the surface to the bulk the concentration of O
is decreasing with increased Mn concentration (Figures
3 and 4). This is a known mechanism for increasing the
corrosion rate.20 This increase of Mn causes depletion of
the Fe in the oxide layer and the ratio shifts to Mn > Fe
(Figures 3 and 4).
3.2 Electrochemical measurements
3.2.1 Linear polarization
Figure 5 shows the linear polarization curves for the
polished and laser-textured Fe–Mn samples in a
simulated physiological Hank’s solution at pH = 7.8. The
calculations from the linear polarization measurements
used the Equation (1):
Rp = 
a 
c/(2.3 Icorr (
a + 
c)) (1)
The polarization resistance, Rp, is evaluated from the
linear polarization curves by applying a linear least-
squares fit of the data around OCP, ± 10 mV. The corro-
sion current, Icorr, is calculated from Rp, the least-squares
slope, and the Tafel constants, 
a and 
c, of 120 mV
decade–1. The value of E(I=0) is calculated from the least-
squares intercept. The corrosion rates were calculated
using the following conversion in Equation (2):
M. HO^EVAR et al.: CORROSION ON POLISHED AND LASER-TEXTURED SURFACES OF AN Fe–Mn ...
Materiali in tehnologije / Materials and technology 51 (2017) 6, 1037–1041 1039
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
Figure 2: a) SEM image of surface topography of Fe–Mn laser-textured sample with micro-channels and b) highly magnified nanostructured
surface covered by Fe–Mn oxide layer
Figure 4: SEM cross-section image of laser-textured Fe–Mn sample
and corresponding EDS elemental maps showing composition (O, Fe,
Mn)
Figure 3: a) SEM cross-section image of laser-textured Fe–Mn
sample and b) the corresponding EDS line scan
vcorr = C(EW/d)(Icorr/A), (2)
where EW is the equivalent weight of the sample in g, A
is the sample area in cm2, d is its density in g/cm3, and
C is a conversion constant that is dependent upon the
required units. The results from the laser-treated Fe–Mn
demonstrate steeper linear polarization curves and there-
fore a lower corrosion resistance compared the other
two samples of polished Fe–Mn alloy, which have
curves with similar inclines. The corrosion parameters
calculated from the linear polarization with potentio-
dynamic measurement data in a simulated physiological
Hank’s solution indicated that the corrosion stability is
higher for the polished Fe–Mn than for the laser-
textured surface. A higher corrosion rate indicates better
biodegradability of laser-textured Fe–Mn sample. This
was proven with the higher corrosion currents (Icorr),
higher corrosion rates (vcorr) and lower polarization
resistances (Rp), compared to the polished sample
(Table 1). These results corroborate the results of earlier
studies,21,22 where the corrosion rate is directly linked to
the roughness and hydrophobicity.
Table 1: Corrosion characteristics of studied materials calculated from
linear polarisation measurements
Icorr /μA Ecorr /mV vcorr /nm year–1 Rp/W
Fe–Mn laser 70.6 –775 770 395
Fe–Mn polished 11.4 –705 123 850
4 CONCLUSIONS
Laser structuring using a nanosecond laser creates a
super-hydrophilic surface with an increased exposed
surface area containing nanostructured high-temperature
oxides. In the present study, an electrochemical investi-
gation confirmed that the laser treatment of the Fe–Mn
alloy increases the corrosion rate by more than six times
compared to the polished Fe–Mn alloy. The EDS line
scan and the mapping showed a corrosion-favourable
chemical composition changes, with Mn increasing and
Fe depleting in the exposed surface layer. The results in
our study revealed that an increased exposed porous
surface, super-hydrophobicity and Fe depletion in the
oxide layer are the three main reasons leading to an
increased biodegradability of the Fe–Mn alloy. We have
shown that laser-surface texturing has a high potential
for surface modification in biomedical applications,
since the proposed approach might also be applicable to
other biodegradable metals to increase the biodegrada-
tion.
Acknowledgement
The authors acknowledge the financial support from
the Slovenian Research Agency (research core funding
Nos. P2-0132 and P2-0392).
5 REFERENCES
1 A. Francis, Y. Yang, S. Virtanen, A.R. Boccaccini, Iron and iron-
based alloys for temporary cardiovascular applications, J. Mater. Sci.
Mater. Med., 26 (2015), 138, doi:10.1007/s10856-015-5473-8
2 H. Hermawan, Biodegradable Metals: From Concept to Applications,
Springer, Berlin Heidelberg, 2012, doi:10.1007/978-3-642-31170-3
3 J. Cheng, B. Liu, Y.H. Wu, Y.F. Zheng, Comparative in vitro Study
on Pure Metals (Fe, Mn, Mg, Zn and W) as Biodegradable Metals, J.
Mater. Sci. Technol., 29 (2013), 619–627, doi:10.1016/j.jmst.
2013.03.019
4 H. Hermawan, D. Mantovani, Degradable metallic biomaterials: the
concept, current developments and future directions, MINERVA
Biotecnol., 21 (2009), 207–216
1 L. Tan, X. Yu, P. Wan, K. Yang, Biodegradable Materials for Bone
Repairs: A Review, J. Mater. Sci. Technol., 29 (2013), 503–513,
doi:http://dx.doi.org/10.1016/j.jmst.2013.03.002
5 M. P. Staiger, A. M. Pietak, J. Huadmai, G. Dias, Magnesium and its
alloys as orthopedic biomaterials: A review, Biomaterials, 27 (2006),
1728–1734, doi:10.1016/j.biomaterials.2005.10.003
6 Z. Zhen, T. XI, Y. Zheng, A review on in vitro corrosion performance
test of biodegradable metallic materials, Trans. Nonferrous Met. Soc.
China, 23 (2013), 2283–2293, doi:10.1016/S1003-6326(13)62730-2
7 B. Liu, Y. F. Zheng, Effects of alloying elements (Mn, Co, Al, W, Sn,
B, C and S) on biodegradability and in vitro biocompatibility of pure
iron, Acta Biomater., 7 (2011), 1407–1420, doi:10.1016/j.actbio.
2010.11.001
8 H. Hermawan, D. Dubé, D. Mantovani, Developments in metallic
biodegradable stents, Acta Biomater., 6 (2010), 1693–1697,
doi:10.1016/j.actbio.2009.10.006
9 J. Zhou, Y. Yang, M. Alonso Frank, R. Detsch, A. R. Boccaccini, S.
Virtanen, Accelerated Degradation Behavior and Cytocompatibility
of Pure Iron Treated with Sandblasting, ACS Appl. Mater. {&}
Interfaces, 8 (2016), 26482–26492, doi:10.1021/acsami.6b07068
10 U. Trdan, M. Ho~evar, P. Gregor~i~, Transition from superhydro-
philic to superhydrophobic state of laser textured stainless steel
surface and its effect on corrosion resistance, Corros. Sci., (2017),
doi:10.1016/j.corsci.2017.04.005
11 L. De Lara, R. Jagdheesh, J. L. Ocana, Corrosion resistance of laser
patterned ultrahydrophobic aluminium surface, Mater. Lett., 184
(2016), 100–103, doi:10.1016/j.matlet.2016.08.022
12 M. S. Brown, C. B. Arnold, Fundamentals of Laser-Material Inte-
raction and Application to Multiscale Surface Modification, in: K.
Sugioka, M. Meunier, A. Piqué (Eds.), Laser Precis. Microfabr.,
Springer Berlin Heidelberg, Berlin, Heidelberg, 2010: 91–120,
doi:10.1007/978-3-642-10523-4_4
M. HO^EVAR et al.: CORROSION ON POLISHED AND LASER-TEXTURED SURFACES OF AN Fe–Mn ...
1040 Materiali in tehnologije / Materials and technology 51 (2017) 6, 1037–1041
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
Figure 5: Linear polarization curve for polished and Fe–Mn laser-
textured samples
13 M. Svantner, M. Kucera, S. Houdkova, J. Riha, Influence of laser
ablation on stainless steel corrosion behaviour, in: Met. 2011 20TH
Anniv. Int. Conf. Metall. Mater., Tanger LTD, Keltickova 62,
Slezska, Ostrava 710 00, Czech Republic, 2011: 752–757
14 A. Kocijan, I. Paulin, C. Donik, M. Hocevar, K. Zelic, M. Godec,
Influence of Different Production Processes on the Biodegradability
of an FeMn17 Alloy, Mater. Tehnol., 50 (2016), 805–811,
doi:10.17222/mit.2016.055
15 G. Ryan, A. Pandit, D. P. Apatsidis, Fabrication methods of porous
metals for use in orthopaedic applications, Biomaterials, 27 (2006),
2651–2670, doi:10.1016/j.biomaterials.2005.12.002
16 Z. Zhen, T. Xi, Y. Zheng, A review on in vitro corrosion performance
test of biodegradable metallic materials, Trans. Nonferrous Met. Soc.
China, 23 (2013), 2283–2293, doi:10.1016/S1003-6326(13)62730-2
17 Y. F. Zheng, X. N. Gu, F. Witte, Biodegradable metals, Mater. Sci.
Eng. R Reports, 77 (2014), 1–34, doi:10.1016/j.mser.2014.01.001
18 M. T. Mohammed, Z. A. Khan, A. N. Siddiquee, Surface
Modifications of Titanium Materials for developing Corrosion
Behavior in Human Body Environment: A Review, Procedia Mater.
Sci., 6 (2014), 1610–1618, doi:10.1016/j.mspro.2014.07.144
19 A. Kawashima, K. Asami, K. Hashimoto, Effect of Manganese on
The Corrosion Behavior of Chromium-Bearing Amorphous
Metal-Metalloid Alloys, Sci. Reports Res. Institutes Tohoku Univ.
Ser. A-PHYSICS Chem. Metall., 29 (1981), 276–283
20 J. E. Tang, M. Halvarsson, H. Asteman, J. E. Svensson,
Microstructure of oxidised 304L steel and the effects of surface
roughness on oxidation behaviour, in: R.W.I.G.K.R.C.C.M.G.A.
Streiff (Ed.), 2001: 205–214
21 A. Dunn, K. L. Wlodarczyk, J. V Carstensen, E. B. Hansen, J.
Gabzdyl, P. M. Harrison, J. D. Shephard, D. P. Hand, Laser surface
texturing for high friction contacts, Appl. Surf. Sci., 357 (2015),
2313–2319, doi:10.1016/j.apsusc.2015.09.233
M. HO^EVAR et al.: CORROSION ON POLISHED AND LASER-TEXTURED SURFACES OF AN Fe–Mn ...
Materiali in tehnologije / Materials and technology 51 (2017) 6, 1037–1041 1041
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
vcorr = C(EW/d)(Icorr/A), (2)
where EW is the equivalent weight of the sample in g, A
is the sample area in cm2, d is its density in g/cm3, and
C is a conversion constant that is dependent upon the
required units. The results from the laser-treated Fe–Mn
demonstrate steeper linear polarization curves and there-
fore a lower corrosion resistance compared the other
two samples of polished Fe–Mn alloy, which have
curves with similar inclines. The corrosion parameters
calculated from the linear polarization with potentio-
dynamic measurement data in a simulated physiological
Hank’s solution indicated that the corrosion stability is
higher for the polished Fe–Mn than for the laser-
textured surface. A higher corrosion rate indicates better
biodegradability of laser-textured Fe–Mn sample. This
was proven with the higher corrosion currents (Icorr),
higher corrosion rates (vcorr) and lower polarization
resistances (Rp), compared to the polished sample
(Table 1). These results corroborate the results of earlier
studies,21,22 where the corrosion rate is directly linked to
the roughness and hydrophobicity.
Table 1: Corrosion characteristics of studied materials calculated from
linear polarisation measurements
Icorr /μA Ecorr /mV vcorr /nm year–1 Rp/W
Fe–Mn laser 70.6 –775 770 395
Fe–Mn polished 11.4 –705 123 850
4 CONCLUSIONS
Laser structuring using a nanosecond laser creates a
super-hydrophilic surface with an increased exposed
surface area containing nanostructured high-temperature
oxides. In the present study, an electrochemical investi-
gation confirmed that the laser treatment of the Fe–Mn
alloy increases the corrosion rate by more than six times
compared to the polished Fe–Mn alloy. The EDS line
scan and the mapping showed a corrosion-favourable
chemical composition changes, with Mn increasing and
Fe depleting in the exposed surface layer. The results in
our study revealed that an increased exposed porous
surface, super-hydrophobicity and Fe depletion in the
oxide layer are the three main reasons leading to an
increased biodegradability of the Fe–Mn alloy. We have
shown that laser-surface texturing has a high potential
for surface modification in biomedical applications,
since the proposed approach might also be applicable to
other biodegradable metals to increase the biodegrada-
tion.
Acknowledgement
The authors acknowledge the financial support from
the Slovenian Research Agency (research core funding
Nos. P2-0132 and P2-0392).
5 REFERENCES
1 A. Francis, Y. Yang, S. Virtanen, A.R. Boccaccini, Iron and iron-
based alloys for temporary cardiovascular applications, J. Mater. Sci.
Mater. Med., 26 (2015), 138, doi:10.1007/s10856-015-5473-8
2 H. Hermawan, Biodegradable Metals: From Concept to Applications,
Springer, Berlin Heidelberg, 2012, doi:10.1007/978-3-642-31170-3
3 J. Cheng, B. Liu, Y.H. Wu, Y.F. Zheng, Comparative in vitro Study
on Pure Metals (Fe, Mn, Mg, Zn and W) as Biodegradable Metals, J.
Mater. Sci. Technol., 29 (2013), 619–627, doi:10.1016/j.jmst.
2013.03.019
4 H. Hermawan, D. Mantovani, Degradable metallic biomaterials: the
concept, current developments and future directions, MINERVA
Biotecnol., 21 (2009), 207–216
1 L. Tan, X. Yu, P. Wan, K. Yang, Biodegradable Materials for Bone
Repairs: A Review, J. Mater. Sci. Technol., 29 (2013), 503–513,
doi:http://dx.doi.org/10.1016/j.jmst.2013.03.002
5 M. P. Staiger, A. M. Pietak, J. Huadmai, G. Dias, Magnesium and its
alloys as orthopedic biomaterials: A review, Biomaterials, 27 (2006),
1728–1734, doi:10.1016/j.biomaterials.2005.10.003
6 Z. Zhen, T. XI, Y. Zheng, A review on in vitro corrosion performance
test of biodegradable metallic materials, Trans. Nonferrous Met. Soc.
China, 23 (2013), 2283–2293, doi:10.1016/S1003-6326(13)62730-2
7 B. Liu, Y. F. Zheng, Effects of alloying elements (Mn, Co, Al, W, Sn,
B, C and S) on biodegradability and in vitro biocompatibility of pure
iron, Acta Biomater., 7 (2011), 1407–1420, doi:10.1016/j.actbio.
2010.11.001
8 H. Hermawan, D. Dubé, D. Mantovani, Developments in metallic
biodegradable stents, Acta Biomater., 6 (2010), 1693–1697,
doi:10.1016/j.actbio.2009.10.006
9 J. Zhou, Y. Yang, M. Alonso Frank, R. Detsch, A. R. Boccaccini, S.
Virtanen, Accelerated Degradation Behavior and Cytocompatibility
of Pure Iron Treated with Sandblasting, ACS Appl. Mater. {&}
Interfaces, 8 (2016), 26482–26492, doi:10.1021/acsami.6b07068
10 U. Trdan, M. Ho~evar, P. Gregor~i~, Transition from superhydro-
philic to superhydrophobic state of laser textured stainless steel
surface and its effect on corrosion resistance, Corros. Sci., (2017),
doi:10.1016/j.corsci.2017.04.005
11 L. De Lara, R. Jagdheesh, J. L. Ocana, Corrosion resistance of laser
patterned ultrahydrophobic aluminium surface, Mater. Lett., 184
(2016), 100–103, doi:10.1016/j.matlet.2016.08.022
12 M. S. Brown, C. B. Arnold, Fundamentals of Laser-Material Inte-
raction and Application to Multiscale Surface Modification, in: K.
Sugioka, M. Meunier, A. Piqué (Eds.), Laser Precis. Microfabr.,
Springer Berlin Heidelberg, Berlin, Heidelberg, 2010: 91–120,
doi:10.1007/978-3-642-10523-4_4
M. HO^EVAR et al.: CORROSION ON POLISHED AND LASER-TEXTURED SURFACES OF AN Fe–Mn ...
1040 Materiali in tehnologije / Materials and technology 51 (2017) 6, 1037–1041
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
Figure 5: Linear polarization curve for polished and Fe–Mn laser-
textured samples
13 M. Svantner, M. Kucera, S. Houdkova, J. Riha, Influence of laser
ablation on stainless steel corrosion behaviour, in: Met. 2011 20TH
Anniv. Int. Conf. Metall. Mater., Tanger LTD, Keltickova 62,
Slezska, Ostrava 710 00, Czech Republic, 2011: 752–757
14 A. Kocijan, I. Paulin, C. Donik, M. Hocevar, K. Zelic, M. Godec,
Influence of Different Production Processes on the Biodegradability
of an FeMn17 Alloy, Mater. Tehnol., 50 (2016), 805–811,
doi:10.17222/mit.2016.055
15 G. Ryan, A. Pandit, D. P. Apatsidis, Fabrication methods of porous
metals for use in orthopaedic applications, Biomaterials, 27 (2006),
2651–2670, doi:10.1016/j.biomaterials.2005.12.002
16 Z. Zhen, T. Xi, Y. Zheng, A review on in vitro corrosion performance
test of biodegradable metallic materials, Trans. Nonferrous Met. Soc.
China, 23 (2013), 2283–2293, doi:10.1016/S1003-6326(13)62730-2
17 Y. F. Zheng, X. N. Gu, F. Witte, Biodegradable metals, Mater. Sci.
Eng. R Reports, 77 (2014), 1–34, doi:10.1016/j.mser.2014.01.001
18 M. T. Mohammed, Z. A. Khan, A. N. Siddiquee, Surface
Modifications of Titanium Materials for developing Corrosion
Behavior in Human Body Environment: A Review, Procedia Mater.
Sci., 6 (2014), 1610–1618, doi:10.1016/j.mspro.2014.07.144
19 A. Kawashima, K. Asami, K. Hashimoto, Effect of Manganese on
The Corrosion Behavior of Chromium-Bearing Amorphous
Metal-Metalloid Alloys, Sci. Reports Res. Institutes Tohoku Univ.
Ser. A-PHYSICS Chem. Metall., 29 (1981), 276–283
20 J. E. Tang, M. Halvarsson, H. Asteman, J. E. Svensson,
Microstructure of oxidised 304L steel and the effects of surface
roughness on oxidation behaviour, in: R.W.I.G.K.R.C.C.M.G.A.
Streiff (Ed.), 2001: 205–214
21 A. Dunn, K. L. Wlodarczyk, J. V Carstensen, E. B. Hansen, J.
Gabzdyl, P. M. Harrison, J. D. Shephard, D. P. Hand, Laser surface
texturing for high friction contacts, Appl. Surf. Sci., 357 (2015),
2313–2319, doi:10.1016/j.apsusc.2015.09.233
M. HO^EVAR et al.: CORROSION ON POLISHED AND LASER-TEXTURED SURFACES OF AN Fe–Mn ...
Materiali in tehnologije / Materials and technology 51 (2017) 6, 1037–1041 1041
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS