My research in may:

I made a literature review on sintering of aluminium alloys in different atmospheres. The effectiveness of the sintering atmosphere of most of the aluminum alloys decreases in the order: nitrogen > vacuum >argon > nitrogen+hydrogen = argon+hydrogen. This indicates that the atmosphere plays an active role in the sintering of aluminium. A clue of the beneficial use of nitrogen is the formation of aluminium nitride.

In order to perform sintering in nitrogen and argon atmospheres, I tried to produce green compacts from milled 7475 alloy powder by uniaxial cold pressing at different pressures (200 – 600 MPa). Compacting turned out to be impossible without using a binder. Therefore, I decided to use 1 wt.% of glycerin addition to the powder. The optimal pressure of compacting was 300MPa.

Seminars/meetings:

Fourth meeting of “Local Composite Platform”:
- very interesting lecture on ”Composite layers and regions fabricated by in situ technique in iron and aluminum castings” given by Ewa Olejnik from Faculty of Foundry Engineering, AGH

IMMS seminars:
- “The characteristics of stress-textured areas of heterogeneous structure in selected materials and construction elements” by Sylwia Pawlak,
- “Ultra-thin multilayer polymer films as multifunctional coatings and membranes” by Tomasz Kruk.

Main studies carried out during May:

- Preparation of thin foils from Al91Mn7Fe2 ingot and melt-spun ribbons for further investigation. (The Tenupol-5 double jet electropolisher was used)
- Microscopic observation:
• Transmission Electron Microscopy
- Observation of quasicrystal-aluminium eutectic formation, confirmed by obtained 5-fold diffraction patterns, STEM analysis confirmed that is has similar composition to the quasicrystals with spherical and dendritic shape.
- Investigation of crystallographic orientation relationship between matrix and quasicrystalline phase, as a result relation i5<011>&#945; was observed in the 5-fold diffraction pattern
- Basing on analysis of quasicrystal 2-fold electron diffraction patterns quasilattice constant aR was calculated to be 0.461 nm. (which is in agreement with values obtained for quasicrystals by other researchers )
• Scanning Electron Microscopy:
- Phase and composition analysis of two recently prepared alloys
- In Al91Mn6Fe2Si1 ingot four different phases were observed:
&#945;-Al, Al6Mn, Al3(Mn,Fe) and Al4Mn.
- In Al91Mn6Fe2Zr1 ingot also 4 different phases were formed:
&#945;-Al, Al6Mn, Al3(Mn,Fe) and Al3Zr
- Preparation of melt-spun ribbons from the mentioned alloys by melt-spinning technique.
- An abstract preparation: “TEM study of the quasicrystalline phase transformation in Al-Mn-Fe melt-spun ribbon” for the 10th Multinational Congress on Microscopy (MCM 2011) in Urbino (Italy).
- Participation in seminars
performed by M.Sc. Eng. Sylwia Pawlak and M.Sc. Eng. Tomasz Kruk.

In May I took part in the "12th European Workshop on Modern Development and Applications in Microbeam Analysis" which was held in Angers, France. I presented a poster there, entitled “3D-EBDS investigation of Ni-Mo protective coatings”. An abstract of the poster contribution is given below. Additionally, I was taking part in 3D-EBSD measurements of a severely deformed aluminum alloy and a Ni-Mo deposit. Some results of these investigations were presented during the conference.

Abstract
P. Bobrowski, M. Faryna and A. Bigos

Hard, wear and corrosion resistant chromium coatings are widely used in aerospace, automotive and machinery industry. Despite of their excellent mechanical properties such coatings are to be eliminated from the manufacturing process due to severe toxicity of hexavalent chromium. A promising alternative to hard chromium coatings are Ni-based coatings containing refractory metals, e.g. Mo obtained from environmentally friendly ammonia-citrate electrolyte. This kind of Ni-Mo coating electrodeposited on steel substrates in a system with the rotating disk electrode under galvanostatic conditions at definite current density 4 A/dm2 was chosen for microstructure investigations. Size, shape as well as orientation of Ni-Mo crystals grown on low carbon stainless steel substrate were established in scanning electron microscope (SEM) by use of three-dimensional electron backscatter diffraction (3D EBSD) technique. It combines a regular 2D orientation imaging microscopy (OIM) with focused ion beam (FIB) sputtering. The FIB consecutively removes successive layers of the material being investigated while the EBSD/SEM acquires electron diffraction data. Such measurements were performed on Quanta 3D FEG SEM with geometrical setup employing rotating pre-tilted sample holder. Experimental parameters and measuring conditions for diffraction acquisition from coating with directionally grown Ni and Mo crystals were evaluated and optimized.

1. Attending in seminars:

- M.Sc. Eng. Sylwia Pawlak: 'The characteristics of stress-textured areas of heterogeneous structure in selected materials and construction elements';
- M.Sc. Eng. Tomasz Kruk: 'Ultra-thin multilayer polymer films as multifunctional coatings and membranes';
- Professor Henryk Paul: 'Inhomogeneity of deformation band and their influence on the formation of deformation and recrystallization textures in fcc metals';

- Associate Professor Piotr Ozga: 'Correlation between ceramics microstructure and functional properties'(second and third meeting);
- Professor Pawel Zieba: ‘Mass and charge transport in polycrystalline materials’ (third meeting);
- Associate Professor Lidia Litynska-Dobrzynska: ‘Development of aluminium alloys’ (third meeting).

2. Training of using the scanning electron microscope for creating maps orientation (EBSD).

3. Research

- Pressing by the curved channel angular (ECAP) the samples of aluminum alloy with dimensions 10x10x70mm using a testing machine INSTRON 3382;
- Preparation of samples for observation in the scanning electron microscope - grinding on abrasive papers, polishing and electrolytic etching;
- Preparation of the orientation maps of samples of aluminum after ECAP and recrystallization (T = 270 ° C and t = 1h, 30 min, 5 min, 2 min, 1 min, 0 min);
- Assisting in the round tensile specimens at elevated temperatures (100 ° C, 200 ° C, 300 ° C) on the testing machine INSTRON 6025.

In May 2011 I continue the study of stability of homogeneous Zn(II)-Sn(II)-Mo(VI) citrate solutions and the study of electrochemical properties of citrate complexes presented in examinated solutions.
The electrochemical behavior of citrate complexes was investigated by cyclic voltammetry method. Cyclic voltammetry (CV) is one of the most commonly used electrochemical techniques, and is based on a linear potential waveform; that is, the potential is changed as a linear function of time. It offers a rapid location of redox potentials of the electroactive species. CV can be used to investigate the electrochemical properties of species.
All my electrochemical studies were carried out with PARSTAT 2273 potentiostat. The working electrode was copper disc, the reference electrode was saturated calomel electrode, and the counter electrode was platinum.
I conducted research in different hydrodynamic conditions, in the following solutions:
1) 0,65 M Na3HCit; pH=5;
2) 0,25 M Na3HCit; pH=5;
3) 0,65 M Na3HCit; 0,02 Na2MoO4; pH=5;
4) 0,65 M Na3HCit; 0,05 Na2MoO4; pH=5;
5) 0,65 M Na3HCit; 0,1 Na2MoO4; pH=5;
6) 0,25 M Na3HCit; 0,02 Na2MoO4; pH=5;
7) 0,25 M Na3HCit; 0,05 Na2MoO4; pH=5;
8) 0,25 M Na3HCit; 0,1 Na2MoO4; pH=5;
9) 0,65 M Na3HCit; 0,08 SnSO4; pH=5;
10) 0,65 M Na3HCit; 0,16 ZnSO4; pH=5;
11) 0,65 M Na3HCit; 0,16 ZnSO4; 0,08 SnSO4; pH=5;
12) 0,65 M Na3HCit; 0,02 Na2MoO4; 0,16 ZnSO4; pH=5;
13) 0,65 M Na3HCit; 0,05 Na2MoO4; 0,16 ZnSO4; pH=5;
14) 0,65 M Na3HCit; 0,1 Na2MoO4; 0,16 ZnSO4; pH=5;
15) 0,65 M Na3HCit; 0,15 Na2MoO4; 0,16 ZnSO4; pH=5;
16) 0,65 M Na3HCit; 0,20 Na2MoO4; 0,16 ZnSO4; pH=5;
17) 0,65 M Na3HCit; 0,24 Na2MoO4; 0,16 ZnSO4; pH=5;
18) 0,65 M Na3HCit; 0,30 Na2MoO4; 0,16 ZnSO4; pH=5;
19) 0,25 M Na3HCit; 0,02 Na2MoO4; 0,16 ZnSO4; pH=5;
20) 0,25 M Na3HCit; 0,05 Na2MoO4; 0,16 ZnSO4; pH=5;
21) 0,25 M Na3HCit; 0,1 Na2MoO4; 0,16 ZnSO4; pH=5;
The results of all carried out tests, and plans for further research were discussed in detail with the tutor Prof. Associate. dr hab. Piotr Ozga.
In May I also attended in the following seminars:
-6.05.2011 roku M.Sc. Eng. Sylwia Pawlak „Charakterystyka napr&#281;&#380;eniowo-teksturowa obszarów o niejednorodnej strukturze w wybranych materia&#322;ach i elementach konstrukcyjnych” ;
- 27 maja 2011 M.Sc. Eng.. Tomasz Kruk „Ultracienkie wielowarstwowe filmy polimerowe jako wielofunkcyjne pow&#322;oki i membrany”.