Synthesis of Pyrochlores

The first step in the experimentation process was the synthesis of the pyrochlores used for testing. This involved creating an aqueous solution of the necessary reagents using the following stoichiometric equation:

18HfO(NO3)2+18La(NO3)3+50C2H5NO2->9La2Hf2O7+100CO2+125H2O+70N2

A calculated amount of La(NO3)3 was replaced with Eu(NO3)3 to dope the samples at a 4 mol % level. The equation above was used to synthesize La2Hf2O7:Eu. The reagents were altered as appropriate but following the same general formula in order to synthesize the other pyrochlores. The appropriate amounts of each chemical were measured on the electronic mass scale shown in the first picture. These chemicals were then poured into a crucible shown in the second and third pictures and dissolved in 15 ml of water.

The next step was to heat the hot plate shown in the second picture to 540 degrees Celsius and put the crucible containing the aqueous solution on top. Within 10 minutes the combustion took place as seen in the second picture. A large flame erupted from the crucible and died down in just a few seconds. A large puffy mass also formed at this time as shown in the third picture. This mass was the pyrochlore that was formed. It was ground into a powder in a mortar and pestle and stored in a vial for later analysis and testing.