I. Visit to Institute of Physical Chemistry, Polish Academy of Sciences:
Name : Nitin Bagkar
Period : 08/26/2006 to 09/18/2006
Arrived at Poland on 26th August and joined in Institute of Physical Chemistry, Polish Academy of Science, Warsaw, Poland on 28th August for training in high pressure synthesis with Prof. S. M. Filipek.
A. Learning the operation of high pressure apparatus:
The basic operation of high pressure equipment was demonstrated by Prof.
Filipek including the cleaning procedures and safety measures in detail during the first week of training. The typical setup used for high pressure is shown in figure 1 (a) and 1 (b). The various parts of equipment contain hydrogen source (commercially available hydrogen cylinder), multiplicator and high pressure reactor. Hydrogen cylinder was connected to multiplicator where the hydrogen gas was compressed to very high pressures through heavy copper capillary tube which can withstand very high pressures of the order of 15 GPa. All joints of the capillary were connected with metallic ferrules and rubber sealing to avoid pressure leakages during reaction. The output of the multipilcator was connected to the reactor multiplicator through the capillary. The reactor multiplicator was connected to vacuum line, reactor and the pressure gauge. The reactor is made up of heavy steel tube into which samples were loaded in small steel samples containers. One side of the steel tube is closed with threaded stopper and the other end is connected to multiplcator. Hydrogen inlet capillary is connected through small threaded hole near multiplicator. Steel tube is surrounded by external electric heating coil to get desired reaction temperature. The assembly of the high pressure was protected with the toughened glass windows as a safety measure.
B. Experiments carried out during Poland visit
It was planned to prepare manganese hydride and their Laves phase hydride with ErHx under high pressure. The samples of manganese powder and Erbium lumps were loaded into small steel containers and placed into the heavy steel reactor tube.
One side of the tube was connected to the vacuum pump through multiplicator.
Hydrogen inlet copper tube is connected through a small threaded hole near multiplicator. The samples were then evacuated with vacuum pump for three hours and hydrogen pressure was slowly increased from atmospheric pressure to 7000 atm.
The temperature is slowly increased to 125°C. Samples were left inside the reaction vessel for about 20 hrs. Then the temperature was reduced to room temperature by cooling the steel tube with liquid hydrogen and after complete cooling of the system the hydrogen pressure was slowly reduced to the atmospheric pressure. The samples were taken out of the vessel and used for further characterization using X-ray diffraction.
A. Pressure gauge B. Multiplicator C. Capillary D. External heater E. Cooling water circulation
Figure 1a. Experimental setup for high pressure synthesis
A. Copper capillary to reactor B. Copper capillary from hydrogen cylinder C. protecting shield D.
Piston E. Pressure Gauge
Figure 1b. Multiplicator assembly to increase hydrogen pressure
A B
C
D
E
A B
E C
D
C. Results and Discussions
X ray diffraction pattern for erbium hydride samples was shown in figure 1. The sample contains he oxide impurities as evident from the diffraction pattern. It also showed the formation of ErH3 hydride having cubic phase. However for the manganese hydride the peak positions were not shifted as compared to peak positions of pure Mn powder. Powder XRD pattern of pure Mn powder and hydrogenated samples of Mn powder was shown in the figure 2. Thus there was very low amount of manganese hydride formation under present experimental conditions. This was due to low temperature used during hydrogenation indicating that higher temperature is required for the hydride formation in the case of MnHxwith higher hydrogen content.
Figure 1. XRD pattern of ErHx
Figure 2. XRD pattern of ErHx
Figure 2. XRD pattern of MnHx
20 30 40 50 60 70
2(Degree)
MnH0.0703(JCPDS)
Mn powder MnH from powder MnH from crashed powder
II. Conference report:
Prof. Ru-Shi Liu attended Internationalsymposium on “E-MRS Fall Meeting 2006”
from 3rd to 7th September in Warsaw, Poland. The conference was organized in Warsaw Institute Technology, Poland and he presented the poster on "The Study of Growth Mechanism of Gold Nanorods".
(i) Overview of the symposium:
Symposium was organized into ten sections like nanostructured composite films, nanomaterials in catalysis, doped nanomaterials and it also included Fall school on thermal analysis, Thin layered materials workshop, exhibitors and technology commercialization market place. About 850 delegates from all over the world were participated in the E-MRS meet of which 14 delegates were from Taiwan. There were 29 planery sessions and approximately 10 invited talks in each section. During the conference Prof. Ru-Shi Liu attended important lectures and oral presentations related to our area of research through out the symposium. He had good interaction with participants and developed some good ideas based on the new developments for our future work. The Fall meeting was particularly useful in developing good understanding of the structural features, magnetic properties and thermal properties of technologically advanced materials.
(ii) Our contribution in the conference:
Prof. Ru-Shi Liu has presented a poster on “The Study of Growth Mechanism of Gold nanorods". In his poster he presented a novel approach to fabricate long length of gold nanorods by controlling the volume of growth solution. The essence of poster lies in the demonstration of growth mechanism of gold nanorods by X-ray absorption spectroscopy. Because of which his poster attracted good number of participants and bagged the award of the best poster for the symposium. The abstract of the poster was given at the end.
III. Comments:
(i) Visit to the Institute of Physical Chemistry by Dr. Nitin Bagkar:
I was impressed by the hospitality of Prof. Filipek with a warm welcome at Warsaw airport followed by a good guidance and instruction throughout my stay in Institute of Physical Chemistry, Polish Academy of Sciences. I was fortunate to interact with his group members, who helped me a lot during my stay at the institutes in all aspects. I learnt a lot from Prof. Filipek, especially the synthesis of novel hydride materials by high pressure technique and controlling the reaction conditions (temperature and pressure) which is very crucial for the synthesis of metal hydrides.
(ii) Discussions with Prof. R. S. Liu and Prof Filipek:
The Poland visit by Prof. Ru-Shi Liu and Dr. Nitin Bagakar was very productive from the point of view of the discussion regarding the continuation of project with Prof. Filipek. During the discussions we acquired a very good knowledge in the advance developments of high pressure synthesis and novel metal hydrogen systems.
Moreover, we discussed the status of our project with Prof. Filipek during our visit.
Prof. Ru-Shi Liu also planned the new proposal for submitting to the National Science Council and finalized the project with Prof. Filipek. Altogether visit to Poland was very fruitful in terms of the implementation of good synthetic methods based on the training in Poland and interactions in the conference for the future work in Taiwan.
IV. Materials brought back from Poland:
The proceeding of the Symposium on “E-MRS Fall Meeting 2006”
Group photo: Dr. Bagkar, Prof. Filipek and Prof. Liu outside the Institute of Physical Sciences, Warsaw, Poland. (12/09/2006)
Poster at E-MRS Fall Meeting 2006, Symposium B,