Materials Sciences and Applicatio ns, 2011, 2, 1465-1470
doi:10.4236/msa.2011.210197 Published Online October 2011 (http://www.SciRP.org/journal/msa)
Copyright © 2011 SciRes. MSA
1465
Improvement Properties of the Cutting Tools
Using Technical Plasma Treatment
Ferkous Embarek1, Amara Idriss1, Djeribaa Abdeldjalil1, Boughouas Hamlaoui1, Achour Slimane2
1Engineering Mechanical Department, Engineering Sciences Faculty, University of Constantine, Algeria; 2Research Unit in Materials
Physics and Applications, University of Constantine, Algeria.
Email: ferkousembarek@yahoo.fr
Received May 31st, 2011; revised June 27th, 2011; accepted July 10th, 2011.
ABSTRACT
In spite of the considerable progress made in the domain of the sciences of materials, cutting tools subjected to an in-
tense abrasive wear and a very high temperature o f edge. They record during th eir use a reduced working life. The op-
erations of machining on lathe are regularly stopped for replacing these tools, which influences enormously the pro-
duction process. Indeed, the search the new materials of substitution, remain a domain very coveted, owing to the fact,
it belongs to one stake very significant industrial, in particular, in the mechanical domain and its varied sectors. The
recourse to the thermal treatmen ts traditional, limiting in an interval, reduces the wear and the excessive consumption
of these cutting tools, but the principal concern of the experts and researchers, in the domain of the mechanical engi-
neering, remain posed. The goal of this study is the introduction of the technique of plasmas, as physical phen omenon,
for making material of coating at base of titanium nitrides doped at iron, at the different concentrations. To this objec-
tive, one magnetron sputtering with plasma was used for the realization of the coatings deposed on the active parts of
the cutting tools. During the experimenta tion, it was noted that the cutting tools wh ich are treated by plasma, subjected
to the machining operations on lathe and the hardness tests, presents one improvement of their hardness and a re-
markable increase in their lifespan .
Keywords: Cutting Tools, Plasma, Nitride, Titanium, Doping, Target, Hardness
1. Introduction
The application of techniques of plasma like physical
phenomena in the development of new materials of sub-
stitution, allowing the improvement arouses as well a keen
interest with the meadows of the scientific community as
to the meadows of industrial circle [1-6]. Indeed, the
mechanisms intervening in the formation of a new mate-
rial from a target by ejection of the particles are very
complex [1,2,7-11]. The growth of the deposit, the quan-
tity of the species entering concerned, the reactions con-
trolling remain still known badly [7]. In order to improve
the mechanical properties of the cutting tools, namely the
hardness, the wear resistance and in particular their life-
span, we called upon the technique of plasmas, physical
phenomenon in the domain of mechanics, for the devel-
opment of the layers of titanium nitride doped out of iron,
like new material of coating of the active part of the cut-
ting tools. Cutting tools have attracted a lot of interest over
past decade, and a recent review [8] discusses a number of
experimental, analytical and numerical studies.
F. Kieckow [9], has studied the adhesion improvement
produced by bright plasma nitriding hardening of tool
steel prior to TiN deposition was investigated by angle-
resolved X-ray photoelectron spectroscopy and atomic
profiling with sub-nanometric depth resolution. Besides
hardening, analysis of the O1s, N1s, Ti2p, Fe2p, and Cr2p
photoelectron groups showed that the finely dispersed
chromium and iron nitrides produced by plasma nitriding
also replace in part the oxides and hydroxides in the
near-surface regions. Thus, the enhanced adhesion and
improved performance observed in duplex treated tool
steel are discussed in light of the present findings: 1)
stronger chemical bonding at the coating/substrate inter-
face promoted by bright plasma nitriding of the steel
substrate prior to TiN deposition; and 2) enhanced in-
ter-diffusion around the coating/substrate interface owing
to the removal of the oxides which constitute diffusion
barriers, producing an enlarged contact area and more
gradual coating/substrate interfaces.
Improvement Properties of the Cutting Tools Using Technical Plasma Treatment
1466
More recently S. Cardinal et al. [10] developed mate-
rials with both a good hardness and a good toughness. He
investigates the effect of TiN addition and binder content
on the microstructure and the properties of the TiC based
cermets elaborated by pressure less sintering. Results have
showed that dense cermets with specific core/rim struc-
ture have been obtained. The rupture strength and the
toughness increase with the addition of Ni. The optimum
values of mechanical properties were found for the cer-
mets with 15 wt% Ni and 10 wt% TiN additions, respec-
tively, which exhibit a vickers hardness over 1400 Hv and
a fracture toughness around 13.6 MP. B. Subramanian et
al. [11], investigated thin films of titanium nitride (TiN),
he was prepared on mild steel (MS) by a physical vapor
deposition (PVD) method namely direct current reactive
magnetron sputtering. With the aim of improving the
adhesion of TiN layer an additional Nickel interlayer was
brush plated on the steel substrates prior to TiN film
formation.
The phase has been identified with X-ray diffraction
(XRD) analysis, and the results show that the prominent
peaks observed in the diffraction patterns correspond to
the (1 1 1), (2 0 0) and (2 2 2) planes of TiN.
Cross-sectional SEM indicated the presence of dense
columnar structure. The mechanical properties (modulus
and hardness) of these films were characterized by
nano-indentation. Ti-Al-Si-N films deposited on WC-Co
substrates by a hybrid coating system was studied by Y. K.
Jeong et al. [1]. The synthesized Ti-Al-Si-N films were
revealed to be composites of solid-solution (Ti,Al,Si)N
crystallites and amorphous Si3N4 by instrumental analyses
such as XRD and HRTEM. The highest micro-hard- ness
value (50 GPa) was obtained from the Ti-Al-Si-N film
having the Si content of 9 at %, the microstructure of
which was characterized by a nano-composite of nc-(Ti,
Al, Si)N/a-Si3N4.
The tool lives of Ti-Al-Si-N coated tool for AISI D2
steel of hardness 62 HRC were studied under various
cutting speeds in high speed machining center. Tool wear
curves with cutting length were presented.
A. Ebrahimi et al. [2] also investigated the machina-
bility of micro-alloyed steel (30 MnVS6) and quenched-
tempered (QT) steels (AISI 1045 and AISI 5140), at dif-
ferent cutting condition. An experimental investigation
was conducted to determine the effects of cutting speed,
feed rate, hardness, and work piece material on the flank
wear land and tool life of coated cemented carbide inserts
in the hard turning process. Chips characteristics and
chip/tool contact length were also investigated. The dif-
ferent sections (shear plane, micro crack, thickness and
edge) of the chip were examined by scanning electron
microscope (SEM). The results showed that the tool life
and machinability of the micro-alloyed steel is better than
the QT steels at identical cutting condition.
Experimentally, the behavior of a CBN tool during hard
turning of 100Cr6-tempered steel have been studied by M.
A. Yallese et al. [3]. Initially, a series of long-duration
wear tests is planned to elucidate the cutting speed effects
on the various tool wear forms. Then, a second set of
experiments is devoted to the study of surface roughness,
cutting forces and temperature changes in both the chip
and the work-piece. The results show that CBN tool offers
a good wear resistance despite the aggressiveness of the
100Cr6 at 60HRC. The optimal productivity of machined
chip was recorded at a speed of 120 m/min for an ac-
ceptable tool flank wear below 0.4 mm. Beyond this lim-
iting speed, roughness (Ra) is stabilized because of a
reduction in the cutting forces at high speeds leading to a
stability of the machining system. Surface quality ob-
tained with CBN tool significantly compared with that of
grinding despite an increase in the advance by a factor of
2.5. A relationship between flank wear (Vb) and rough-
ness (Ra) is deduced from parametric analysis based on
extensive experimental data.
In the present paper, experiment work is reported. This
work relates to the study of the improvement of the me-
chanical properties of the cutting tools on which deposits
of titanium nitride doped with iron (0.7%, 1.4%, 2%, 1%,
2.8%, 3.5%) were carried. After experimentation, the
results obtained showed a remarkable increase in hardness
in an interval of doping out of suitable iron (2.1%) [4].
The cutting tools covered with doped layers with the iron,
subjected to the machine-works on lathe, according to the
model of Taylor, records an improvement of the lifespan,
expressed by a bending of the curves Vb = f(T) towards
the line, on low the, average ones and high cutting speeds.
2. Technique of Development
The basic technique consists at the use of a magnetron
sputtering at plasma whose principle of working (high
vacuum, high voltage, proportions of gases of starting of
plasma), enable to make a material of titanium nitride
doped of iron, starting from one target of titanium, strewn
by small pure iron targets. The layers deposited are ini-
tially intended to wrap the active part of the cutting tools.
2.1. Target Preparation
To obtain the layers of TiN doped in iron, the preparation
of material to depose must be in the form of a target. For
our case, we have produced one target interchangeable of
titanium, shown in Figure 1 in circular form, with 5 cm in
diameter and 0.3 cm for thickness.
For allow obtaining doping, this target was strewn by
small targets (5 mm of diameter and 1mm thickness) of
pure iron. The components ratio (%) TiN-Iron is a func-
tion of the surfaces exposed to plasma and the output of
Copyright © 2011 SciRes. MSA
Improvement Properties of the Cutting Tools Using Technical Plasma Treatment1467
Ti
Fe
Fe
FeTi
Fe
Ti
Fe
Fe
Ti
Fe
FeFeFe
Fe
Ti
Fe
Fe
FeTi
Fe
Ti
Fe
Fe
Ti
Fe
Fe
FeTi
Fe
Ti
Fe
Fe
Ti
Fe
FeFeFe
Fe Ti
Fe
FeFeFe
Fe
Figure 1. The configuration of titanium and iron superposed
targets.
pulverization of each material. The number of secondary
targets is given according to % of doping of iron.
2.2. Coatings Development
The development of these layers of titanium nitride doped
with iron on the cutting tools is carried in accordance with
the usual process [5]. After the preparation of the sput-
tering magnetron with plasma and the adjustment of the
various parameters (distance inter-electrodes, selection of
the high vacuum of work, the high voltage) and the
preparation of the samples (cutting tools), and their in-
stallation on the door substrate, in the enclosure of the
engine, the system of coatings of the cutting tools by
deposition is engaged. The duration of the deposition, is
function of the layer thickness to obtaining.
2.3. Experimental Devices
These deposits of titanium nitride doped with iron, were
realized in the enclosed of the sputtering magnetron with
plasma, show in Figure 2, realized previously—pregnant
of work.
2.4. Layers Disposition
After one scouring of the target by a flow of bombardment,
the protective shield of the target is actuated, and the
operation of deposition of the layers of titanium nitride
doped with iron starts under the conditions and the pa-
rameters of calibration of the starting of plasma.
Coatings of (Ti, Fe) N were deposited using a reactive
magnetron sputter system. Two superposed cathodes
(Titanium and Iron) were used. Iron concentration was
varied by changing the cathode surface ratio-unbiased
tools, and NaCl substrates were employed. The deposition
conditions were: basic pressure = 105 mbar, total pressure
= 102 mbar, nitrogen partial pressure = 5 × 103 mbar,
target to substrate distance 20 cm, DC magnetron power =
200 W/cm2. The deposition rate was 10 um/h. The mi-
crostructure of coatings deposed on NaCl was observed in
transmission electron microscope. The organization of the
various series of deposition of the layers of coating is as
follows, in Table 1.
3. Experimentation of Cutting Tools
Obtained
Once covered by the layer of titanium nitride doped in
Figure 2. Together substrate of the sputtering.
Table 1. Series of cutting tools treatment.
Series Substrates used in this study
1st series 05 cutting tools without treatment
2nd series 05 cutting tools to 0.7% iron
01 substrate NaCl
3rd series 05 cutting tools to 1.4% iron
01 substrate NaCl
4th series 05 cutting tools to 2.1% iron
01 substrate NaCl
5th series 05 cutting tools to 2.8% iron
01 substrate NaCl
6th series 05 cutting tools to 3.5% iron
01 substrate NaCl
iron for the different concentrations (0.7%, 1.4%, 2.1%,
2.8% and 3.5%), the cutting tools was subjected to the
tests determination of hardness and the machining opera-
tions on lathe EMCO. A beach of selection cutting speeds
without lubrication was adopted.
Compared to the use of the ordinary cutting tools, we
recorded a net improvement of the principal mechanical
properties of these tools.
4. Results and Discussion
After experimentation of the cutting tools whose the ac-
tive parts were covered by this material with various
percentages of doping of iron, the results obtained, made it
possible, to release from the broad point of view the study
for certain parameters characteristic, as for the perform-
ances of the cutting tools. Among the required main me-
chanical properties in mechanical engineering, the hard-
ness, the characteristic of the tribological contact tool of
cutting-piece to be machined and its wear resistance under
the cutting pressure. This significant characteristic results
in defining, in a direct way to the determination of the
endurance and the lifespan of the cutting tool.
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Improvement Properties of the Cutting Tools Using Technical Plasma Treatment
1468
4.1. Evaluation of Hardness Obtained
The micro-hardness (Hv) was determined using a Vickers
indentor.
Comparatively to the value of the initial hardness of the
cutting tool, the tools subjected to the treatments of coat-
ing by plasma, present a net increase in hardness. The
curve, the doping is to 2.1%, reveals significantly that, the
evolution of the hardness depends essentially to the % of
doping of iron, up to a value of saturation estimated at
2.8% of iron Fi gure 3.
4.2. Analyze Structure of Material Worked by
Plasma
The microstructure of coatings deposed on NaCl was
observed in transmission electron microscope (MET).
Figure 4 show an analysis by STEM equipped with a
system of analysis EDAX, of a layer of TiN-Fe (120.000),
were obtained. For more investigation, images bottom in
clearly and in black bottom were taken Figure 5. The
1150
1650
2150
2650
3150
3650
050100 150 200 250
Load [gf]
Micro Hardness [Hv ]
doping 0% Fe
doping 0.7% Fe
doping 1.4% Fe
doping 2.1% Fe
doping 2.8% Fe
doping 3.5 % Fe
Figure 3. Micro-hardness obtained with coating Titanium
nitrite.
Figure 4. Micrographic in MET of one TiN-Fe layer.
image in bottom black shown in Figure 6 confirms the
existence of a kind of black precipitate at black spots form
within the clear phase.
An electronic diagram of diffraction on the precipitate—
p—was realized Figure 7. The conclusions obtained of
P
-
>
Figure 5. Image structure (backgro und in blac k).
P
>
Figure 6. Image structure (background in clear).
Figure 7. Electronic diffraction diagram of the precip itate: p.
Copyright © 2011 SciRes. MSA
Improvement Properties of the Cutting Tools Using Technical Plasma Treatment1469
these analyses, support the alternative of a probability,
that, iron is in the solid solution or in the form of very fine
precipitates in the matrix.
4.3. Evaluation of the Wear Vb (mm)
At the time of their submission at the machining on lathe,
the cutting tools treated by plasma have a good behavior at
wear.
The tests of machining on lathe EMCO, realized in
agreement with the parameters of cut, such as they are
defined by the standard ISO [11], and are based on the
laws of the mathematical models governing the study of
the lifespan from the cutting tools, show a remarkable
improvement of the tribological process of the tool and the
piece to machining.
The evolution gradual from the initial endurance of the
tools without coating (Figure 8) shows an improvement
of the endurance. The curves obtained in the stadium of
low and average speeds, present a collective displacement
Vb = f(T) curves towards the line, which, explains the
considerable reduction of the effect of the wear of the
Figure 8. Curves of wear of tool without plasma treatment
for the different speeds.
Figure 9. Curves of wear of tool with doped at 2.1% iron, for
the different speeds.
Figure 10. Curves of wear of tools with doped at 2.8% iron
for the different speeds.
Figure 11. Comparison of wear of tool with doped at 0%,
2.1% and 2.8% iron for speed V = 80 m/mn.
cutting tools. One records during the machining operation
a decreasing evolution of wear. The minimal value of Vb
carried, is found with the doping of 2.1% iron (Figures
9-10) show a decreasing evolution of wear after saturation
at 2.8% iron. At the Figure 11, curve at first position
(2.1% iron) show a net improvement of wear.
5. Conclusions
The study of the influence of the effects of the technique
of plasmas as physical phenomenon of the ionization of
gases under the effect of an electric field for making a
material of titanium nitride coating doped at the different
percentages of iron, on the mechanical properties of the
cutting tools, subjected to the hardness tests, and after for
the works on lathe, shows that the contribution of these
coatings obtained by plasma, improves considerably the
principal mechanical characteristics of the cutting tools.
The evolution of the hardness as recorded on the curves,
show a net improvement of the initial hardness of the
cutting tool (basic heat treatment), also show a rise of the
Copyright © 2011 SciRes. MSA
Improvement Properties of the Cutting Tools Using Technical Plasma Treatment
Copyright © 2011 SciRes. MSA
1470
hardness of this material, obtained by plasma.
That starting from the doping of 0.7% of iron, 1.4%, to
reach a maximum (peak) of hardness to 2.1% of iron. At
the end, one records a reduction in this same hardness
starting at 2.8% of iron. This increase in hardness is the
consequence of a whole of phenomena certainly related to
the bombardment of the layers during their growth, as
well as the mechanisms leading to the increase in the yield
stress. In the case of the titanium nitride coatings, the
analyses carried suppose the formation of very strong
distortions of the crystal lattice. one can however think
that it is the existence of these distortions (micro—de-
formations) which is at the origin of the increase in the
yield stress, which leads to the hardening of these layers
deposited (physical phenomenon of hardness).
In addition, like the phase of titanium nitrides (Chock)
the structure NaCl [12] has, gradual evolution of hardness
and its relapse with a percentage of doping equal to 2.8%
of iron, can be explained by the phenomenon of saturation
according to the various percentages of iron doping of the
crystalline structure in sites of substitution or insertion.
Concerning this structure, it was observed that the addi-
tion of iron to the TiN during the deposition by plasma
appreciably increases the hardness of the layers deposited.
This increase of the hardness [13] generates an im-
provement of the principal mechanical characteristics, in
particular the friction resistance. This aptitude of materials
for the friction resistance in the field of mechanics in
means of working tools, is exploited in term of wear re-
sistance, from where improvement of the endurance and
the lifespan of the cutting tools. In the extreme connection
with the results of the hardness obtained, the comparative
study of the tests of machining by turning, obtained with
various percentages of doping of iron, show a net im-
provement of the longevity of the working life of the
cutting tools. This variation compared with the initial
tools (without coatings and doping), is characterized ac-
cording to two stadiums selective of speed of machining.
During these tests of turning carried according to the
law of Taylor, and in accordance with the conditions of
standard ISO 3685, the curves obtained in the stadium of
low and average speeds, present a collective displacement
Vb = f(T) curves towards the line, which, explains the
considerable reduction of the effect of the wear of the
cutting tools. One records during the machining operation
a decreasing evolution of wear. The minimal value of Vb
carried, is found with the doping of 2.1% iron.
6. Acknowledgements
The authors would like to acknowledge the encourage-
ment and support of this research by Professor Achour S.
Research Unit in Materials Physics and Applications,
niversity of Constantine, Algeria. U
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