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» Effect of Al and Iradditions on surface morphology and topography of FeCrNi coatings
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Barbara Kucharska 
The magnetron sputtering deposition (MSD) method belongs to the
basic and the most important methods of depositing coatings in vacuum
conditions, PVD [1÷3]. A very valuable advantage of this method
is the possibility of depositing coatings, particularly those of complex
chemical composition, in a broad range of thicknesses, starting from
several angstroms. This method is successfully used for depositing
coatings based on steels, also heat-resistant grades, which include
310S steel. In the chemical composition of this steel are the additions
of Ni (~20%) and Cr (~25%) [4÷6]. For better resistance the chemical
composition are enriched by addition of high melting elements [7, 8].
The properties of magnetron coatings depend on the sputtering
process parameters, which influence the microstructure and
the grain size of coatings [9, 10]. The essential purpose of applying
coatings is to protect the substrate or to modify the properties
of surface. This function can only be fulfilled by coatings that are
tight and exhibit good adhesion to the substrate [11]. These conditions
are applicable in particular to coatings intended for protection
against corrosion in liquid solutions, as well as in high-temperature
oxidation conditions [12÷15]. Also, in corrosion protection, surface
smoothness plays an important role. Low surface roughness and the
absence of surface defects inhibit the build-up of aggressive ions
and deposits that might initiate pit corrosion [16].
The paper presents the investigation of the surface topography of
magnetron coatings based on heat-resisting steel of 310S enriched
Al and Ru additions. The AFM (Atomic Force Microscope), SEM
(Scanning Electron Microscope), and profilometric techniques were
used in the investigation.
material
Coatings of the composition of 310S heat-resisting steel, deposited
on a substrate of the same steel by the magnetron sputtering method,
were examined. The magnetron targets were two discs, eac[...]
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INŻYNIERIA MATERIAŁOWA 2010/3
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» The effect of structure on the stability of Al-Si coatings under salt mist conditions
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Joanna Wróbel Barbara Kucharska Zygmunt Nitkiewicz
The high corrosion resistance of Al alloys, as well as their sufficient
heat resistance, have contributed to the use of these alloys for
anodic protective coatings being applied on steels intended for, e.g.,
exhaust system elements. Developing coatings that would meet the
ever-increasing operation parameters of cars is the subject of continuous
research work. The new customer demands, technological
solutions, and increasing car performance parameters are all urging
the designers to use increasingly expensive steel grades with bettered
mechanical parameters. However, a significant limitation on
the wide application of stainless steels is the fact that, in spite of the
absence of visible corrosion products, in acidified oxidizing media
containing some anions, these steels undergo spontaneous, often localized
dissolution. Due to the weight and economy of product, the
basic element used for protective coatings in the automotive industry
still remains to be aluminium [1÷4]. The problem of properly
selected protective coatings is crucial in the manufacture of car exhaust
silencers, because the whole exhaust system, in addition to
mechanical damage during service, is exposed to aggressive chemical
agents that accelerate the steel corrosion processes. At present,
steels of a chromium content above 10% with an aluminium-silicon
hot-dip coating applied are used for the manufacture of car exhaust
systems. Exhaust system elements are formed in a stamping process.
The main technological problem during their production from
aluminium-coated steel sheet is to maintain the integrity of the coating.
This problem has been partially solved by using silicon as an
alloying element. However, it has been demonstrated in the author’s
studies, that such coatings often exhibit an uneven arrangement
and size of silicon crystals (as a result of the trade-off between the
technical capabilities to produce a coating by the hot-dip coating
method and th[...]
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INŻYNIERIA MATERIAŁOWA 2010/3
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