Download Laboratory of Electron Spectroscopies

Physical Chemistry of Materials Center
(IPhCh PAS and FMatSci TU Warsaw)
Head of Laboratory:
Prof.dr hab. Maria Janik-Czachor
Tel.: (0 22) 343-3325
Fax: (0 22) 632 52 76
e-mail: [email protected]
Topics:
1. Electrochemical and corrosion properties of metallic glasses
and their components, 2. Dynamic of electrocatalytic
processes, 3. Local phenomena at electrodes, 4. High
resolution characterization of nonhomogeneous functional and
construction materials.
High resolution morphological and microchemical analysis (SEM and SAM)
Characterization of surfaces of new materials including nanomaterials is an important task for both
chemists and material scientists interested in understanding and improving their performance as
functional and/or contruction materials. The most suitable techniques for such an analysis are Scanning
Auger Microanalysis combined with Scanning Electron Microscopy. Chemical analysis of a selected
nano-area or a thin surface film can be performed with the aid of a Scanning Auger Microprobe.
Apparatus
The Physical Chemistry of Materials Center is equipped with the Microlab 350 (Thermo VG Scientific,
UK) which is a high resolution Auger system. Optionally, it is capable of multi-technique analysis and
may be fitted with a range of preparation facilities. Its key features are:
 Spatial resolution: 7 nm SEM-Scanning Electron Microscopy, 12 nm SAM-Scanning Auger
Microscopy
 High sensitivity
 User selectable energy resolution 0.6% - 0.06%
 Multi-technique capability (AES-Auger Electron Spectroscopy, XPS-X-ray Photoelectron
Spectroscopy)
 Avantage, a Windows based data system
Microlab 350 is a high-performance scanning Auger instrument using field emission technology to
provide high spatial resolution. The spherical sector analyzer (SSA), used on Microlab 350, allows the
analysts to select the best combination of energy resolution and sensitivity for each analysis, in common
with most other spectroscopic techniques. Microlab 350 additionally is equipped in:
 X-ray gun (twin anode source: AlKα, MgKα) for XPS measurements (spatial distribution:
average value from all sample surface area); this extends the use of this instrument to (Xray Photoelectron Spectroscopy) dielectric materials,
 ion gun for sputter etching; usually ion gun is used for depth profiling, sample cleaning
and charge compensation.
This instrument is particularly useful to investigate small surface features, thin layers, impurities in
materials as well as to determine their chemical (elemental) composition and chemical state of their
components.
Sample preparation for surface analysis
Samples cannot exceed 10x10 mm surface area and 10 mm thickness. AES technique is limited to
conducting materials: metals and semiconductors of sufficient conductivity. The stability of samples in
the ultra-high vacuum conditions is required (the pressure lower than 10-10 mb).
Restrains
Samples containing elements such as Hg, Te, Cs, K, Na, As, J, Zn, Se, P, S, etc. or their compounds
cannot be analysed because of a possibility of analyser damage. The same concerns the samples which
decompose with emission of compounds such as H2O, HCl and H2S under conditions of ultra-high
vacuum and/or X-ray radiation.
Local chemical analysis.
The following surface information can be obtained:
1. Chemical composition maps of the surface with nano-scale resolution [M.Janik-Czachor, J.Bukowska,
A.Szummer, A.Molnar, P.Mack, S.M.Filipek, P.Kędzierzawski, A.Kudelski, M.Pisarek, M.Dolata,
M.Varga: Modification of Surface Activity of Cu-based Amorphous Alloys by Chemical Processes of
Metal Degradation, Applied Catalysis A, 235 (2002) 157 and 253 (2003) 539, A. Szummer, M. JanikCzachor, P. Mack, M. Pisarek: High resolution electron probe characterization of modified Cu-based
amorphous alloys, Microscopy & Microanalysis Vol. 9 No. 4 (2003) 359],
2. Local information on surface composition and on chemical state of the surface components in nano
areas [Catalytic Activity of Cu-Based Amorphous Alloy Ribbons Modified by Cathodic Hydrogen
Charging by M. Pisarek, M. Janik-Czachor, A. Molnar and K. Hughes, Appl. Catal. A in press 2005].
3. Composition profiles of thin surface films with a depth resolution below a nm [M. Janik-Czachor, A.
Jaskiewicz, M. Dolata, Z.Werner, Passivity and its breakdown in Al-based amorphous alloys,
Materials Chemistry and Physics, in press 2005)].
Electrochemical Microscopy
The Scanning Electrochemical Microscope designed by dr M. Dolata and dr P. Kędzierzawski and built in
the Institute of Physical Chemistry PAS is a scanning probe instrument, which allows to measure a
distribution of some quantity like potential, current or pH over a surface of metal or semiconductor
electrode. The instrument consists of an X-Y stage propelled by stepper motors and used to move a
microsensor near the surface of the electrode, a motor controller, a potentiostat, a low noise and high
input impedance signal conditioning system and a data acquisition system. Both movement of the
microsensor and measurements are computer controlled with a program developed in the Institute. The
Microscope has a step size of 0.3 μm and lateral resolution of the order of μms depending on sensor size,
a distance from the electrode and an electrode roughness.
Application areas.
Local corrosion studies, galvanic and paint coatings studies, corrosion and electrocatalysis studies of
composite materials, electrode mechanisms, microstructure deposition using Scanning Counter Electrode
technique.
Sample limitations.
The instrument will accommodate plain samples of conducting material of the diameter of 8 mm and the
height of 10 mm.
Electrochemical System for Corrosion Studies.
The system consists of an EP-20 potentiostat and an EG-20 function generator from ELPAN, data
acquisition system from Ambex, Poland and a selection of electrochemical cells adapted for various
types of measurements. The measurements are controlled with programs developed in the Institute.
Application areas.
Electrochemical corrosion studies: determination of corrosion rate, polarization curves, local corrosion
studies, electrode mechanism studies.
Information available:
Department of Electrochemistry, Corrosion and Applied Surface Science
Institute of Physical Chemistry
Polish Academy of Sciences
Kasprzaka 44/52
01-224 Warszawa
tel.: +48 (22) 343 3325
fax: +48 (22) 632 52 76
e-mail: [email protected] or [email protected]