The overall goal of this procedure is to simulate the planetary interior differentiation process. This is accomplished by first mixing olive silicate iron powder, and iron sulfide homogenously. The second step is to load the mixture into a high pressure cell assembly.
Next, the assembly is pressurized to six giga pascal and heated to 1, 800 degrees Celsius in a multi anvil device. The final step is to recover the sample and prepare it for 3D imaging. Ultimately, the 3D image used to visualize the distribution of silicone and molten metal and determine if the liquid metal can percolate through the crystalline silicone to form a core.
This method can help answer key questions in planetary science such as planetary core formations through percolations. Begin by preparing materials for the simulation of the percolation process. In core formation, make about a gram of a mixture of natural silicate, olive and metallic iron powder with 10 weight percent sulfur in an agate mortar.
Under ethanol grind, the starting material to find mixed powder for one hour. Once this is done, dry the materials at 100 degrees Celsius for one hour, retrieve the dried material, and once they're cool, begin preparations For the multi anvil experiments. Load the starting material into a CI aluminum oxide capsule, approximately 1.5 millimeters in diameter and 1.5 millimeters in length.
Next place the capsule in a high pressure cell assembly that has an electrical resistance sample heater. The cell is now ready for the multi anvil high pressure apparatus. Mount the cell assembly in the apparatus, pressurize the sample to the target pressure here, six giga pascals based on a fixed point pressure calibration curve.
Also, use the electrical resistance heater to bring the sample to 1, 800 degrees Celsius. The target temperature. For this experiment, maintain the pressure and temperature for 12 hours.
Once the experiment is completed, quench the sample to room temperature by turning off the heater power and release the pressure slowly over six hours by opening the hydraulic oil valve. Finally, recover the high pressure assembly and the sample analysis of the sample makes use of a focused ion beam scanning electron microscope. Prepare the sample for use in the instrument by mounting and polishing it and carbon coating its surface.
Then load it into the sample chamber of the instrument. Align the sample to the coincident point of the focused ion beam and the scanning electron microscope at a working distance of five millimeters. Premil the sample to expose a volume of 15 by 20 by 20 cubic micrometers.
Then continue to use the ion beam to mill layers 25 nanometers in depth. After each layer is removed, take a scanning electron microscope image of the exposed surface After the milling is complete, input the image data files into visualization software, and create 3D images for visualization. This 3D reconstruction is for a quench sample that was heated to 1, 800 degrees Celsius at six giga pascals.
The highlighted volume represents iron and iron sulfide melt. The remainder of the volume is occupied by ine. The volume is approximately five by six by seven cubic micrometers.
The image shows the metallic melt pockets were trapped at the silicate grain corners because of the large dedal angles measured to be above 100 degrees as seen here. This new imaging technique provides a powerful tool to precisely determine the true dedal angle. By monitoring the change in melt distribution across the critical angle, it can be used to pinpoint the transition from non-connected to connected networks in a small composition and pressure interval.
The method also provides a quantitative measure of the volume fraction and connectivity. These 3D images are of the quenched sample with different metal silicate ratios below a volume fraction of 5%The liquid metal forms isolated pockets at higher volume. Fractions and interconnected network is formed After its development.
This technique paves the way for research in the field of experiment, petr and planetary science to explore planetary core formation process through experimental simulation combined with the visualizations.
