Most of the month was spend on holidays, however I am not going to describe it in details here. The rest of August I was reading scientific articles. It is quite quiet in the institute during holidays season so it is easier to focus on reading and learning.

Main studies carried out during August:

- preparation of ribbons samples with vanadium, molybdenum, titanium and chromium addition for observation with Scanning Electron Microscopy by embedding in resin, polishing, sputtering with thin carbon layer. The best results from microscopy investigation, concerning homogeneity of ribbon’s microstructure were obtained for ribbons with molybdenum addition

- observation of ingots (with Cr and Mo addition) microstructure, determination of chemical composition of observed phases with SEM

- TEM investigations of Al-Mn-Fe of crystallographic relationships between phases occurring in ribbons microstructure in as-cast state and after annealing

- preparation of poster for MCM 2011 - 10th Multinational Congress on Microscopy
in Urbino, Italy with the title: ‘TEM study of the quasicrystalline phase transformation
in Al-Mn-Fe melt-spun ribbon’.

- participation in seminar about magnesium alloys with rare earth elements addition given by prof. Lazar L. Rokhlin from Moscow

Main studies carried out during July:

- preparation of ribbons with zirconium addition for observation with Scanning Electron Microscopy by embedding in resin, polishing, sputtering with thin carbon layer. As a result of microscopy investigation inhomogeneous structure of obtained ribbons was observed (as in previous obtained ribbons)
- preparation of new alloys with addition of the following elements: V, Ti, Mo, Cr
- observation of prepared ingots microstructure, determination of chemical composition of observed phases with SEM
- obtaining ribbons from prepared ingots by melt-spinning technique
- TEM investigations of Al-Mn-Fe ribbon in as-cast state and after annealing
-preparation of the article for 39th School in Material Science in Krynica, Poland (26-30 September): “Microstructure, mechanical properties and thermal stability of Al-Mn-Fe melt-spun ribbons” and an abstract: „Characterization of Al-Mn-Fe melt-spun ribbon” for publication in “Archives of Metallurgy and Materials”.

My research in July:

Investigation of samples of 7475 alloy powder sintered in argon or nitrogen atmosphere at different temperatures (600 deg.C, 620 deg.C, 630 deg.C, 640 deg.C, 650 deg.C were used for argon atmosphere and 540 deg.C, 570 deg.C, 590 deg.C for nitrogen atmosphere).
Before sintering, green compacts of milled AA7475 powder (with 1% of glycerin addition) were prepared by uniaxial cold pressing at 300 and 400 MPa.
Metallographic specimens from cross-sections of sintered samples were prepared by mechanical grinding and polishing using 3 µm, 1 µm and 1/4 µm diamond suspensions.
Microstructure observations of prepared samples were carried out using metallographic microscope.

TEM observation of AlN nano-powder used for new 7475/AlN composites preparation by powder metallurgy technique.

Preparation for the exams in following subjects:
“Introduction to materials science”
“Thermodynamics - engineering approach”.

In july I mainly focused on studying the Electrochemical Impedance Spectroscopy (EIS). EIS is a method of characterizing electrochemical systems. This technique measures the impedance of a system over a range of frequencies, and therefore the frequency response of the system, including the energy storage and dissipation properties, is revealed. Often, data obtained by EIS is expressed graphically in a Bode plot or a Nyquist plot. EIS is universal and commonly used method used to studying the rate and the mechanisms of electrode processes and to determine the characteristic of interface electrode/electrolyte. I could use this method to study the processes of electrodeposition of metals, electrochemical characteristic of alloy layers and to study of the corrosion processes.

I participate in „Theory and Practice of Elektrochemical Impedance Spectroscopy” summer school in Bath University (19th -22nd July 2011).

On the training I listened the following lectures:

-Network analysis. An introduction to Linear Ciruit Analysis and Circuit Elements”; Dr Frank Marken (University of Bath);
-“Frequency response analysis”; Professor Laurie Peter (University of Bath);
-“Introduction to Electrochemical Instrumentation”; Dr John Harper (Solartron Analytical);
-“Electrical Properties of Materials”; Dr Jason Riley (Imperial College London);
-“Impedance of Electrochemical Systems”; Dr Toby Jenkins (University of Bath);
-“Spectroelectrochemical Impedance”; Dr David Fermin (University of Bristol);
-“Solartron Systems: Extreme Impedance”; Dr John Harper (Solartron Analytical);
-“The uses of equivalent circuits”; Professor Stephen Fletcher (Loughborough University);

and I also attended in the following lab sessions:

• "Seeing those sine waves”
• "Getting to know the equipment”
• „Fitting the software"
• "The impedance properties of a simple redox reaction: the ferri/ferrocyanide couple"
• "Characterisation of a lead-acid battery by EIS"
• Studying corrosion by EIS" (part I)
• Studying corrosion by EIS" (part II) "Practical Impedance Spectroscopy: measurement of polymer film porosity and corrosion"
• "Studying the dye sensitized solar cell (DSC) by Impedance spectroscopy"
• "The impedance Characteristic of Polyaniline
• Studying of Porous Electrodes and Supercapacitors by EIS".