April, April showers. The spring is in the water, the spring is in the air. What will April bring. The manuscript of the first paper is almost ready for dispatch.
New alloys are cast and will be homogenized in order to ensure a uniform distribution of elements.
The work in progress!

Lately I obtained silver thin films deposited by magetron sputtering on silicon vafers.
It was found that nanoislands formation is highly sensitive to annealing conditions.
Attempt of examination of importance of layer thickness revealed that inappropriate annealing leads to fingerlike irregular partilces formation.

Another method of fabrication of plasmonic structure is based on surface charge modification followed by nanoparticels adsorption. Silver Nanoparticles in colloidal solution has negative potential which helps to prevent the aggregation process. Modification is based on creation of negatively charged surface and adsorption of polyelectrolyte molecules to change charge into positive.

In my experiments I prepared glass substrate by immersion in NaOH solution followed by HCL and deionised water. Than PAH (polyallylamine hydrochloride)adsorption. On prepared surface I adsorped sub micron copper particles. On surface without preparation no particles was found, on surface specially prepared particles deposited with concentration depended on immersion time.

Main studies carried out during the month:

- using new equipment – vibration micromill, melt spun ribbons of ternary alloy Al-Mn-Fe were pulverized into powder. Two trials were performed on alumina and tungsten carbide balls and containers
- melt spun ribbons with hafnium addition were annealed to precipitate hafnium from the solid solution which could lead to strengthening of whole sample.
- microstructure of cast alloys (containing five or six elements including molybdenum and zirconium or molybdenum and hafnium) was studied using SEM. All investigated alloys revealed similar microstructure including presence of phases like Al6(Mn,Fe), Al3(Mn,Fe) and Al3(Hf,Zr,Ti).
- using SEM melt spun ribbons pulverized with vibration mill were investigated after different times of milling. In obtained powders two fractions were observed: one with big particles around 200 µm and second one with particles below 20 µm. This indicates that longer time of milling is necessary as well as selection need to be performed to separate different fractions.

This month I have carried out some SEM observations on titanium surface treated by electroerosion machining. Method of electroerosion allows for very precise shaping of material by its removal in a very controlled manner. During the process material submerged in dielectric liquid and high voltage is applied between the material and special electrode. By controlling voltage and space (gap) between material and electrode, electric discharge is created. During the discharge in the gap a plasma tunnel is created that conducts electricity, but also releases high amounts of energy. This energy is turned into temperature (up to 4000 C). During that discharge material is rapidly melted and ablated. After the discharge ends, plasma tunnel breaks down, and rapidly implodes washing away melted material.
This type of machining was chosen as a possibility for producing parts of implant-distractor. Therefore its impact on titanium surface layer properties and morphology is being studied.

During this month I faced some technical problems with the microscope. The sample stage was not working as it was supposed to. Especially, rotation of a sample was often impossible due to encoder errors. This made running of 3D measurements impossible. Meanwhile, I read some literature concerning investigations of the cubic ZrO2 where I found information about methods that other people use for sample preparation and what programs are used for experimental data processing.