Let's Make Diamonds!
Project WISE - Spring, 1998


Group.gif (64005 bytes) The Spring, 1998 Project WISE Team


Project Wise

HighPressureLaboratory.gif (41695 bytes)WISE (Women in Science and Engineering) , funded by the National Science Foundation (NSF), is a program that encourages women to pursue degrees in the math, science, and engineering fields. They provide monetary assistance the first year as well tutoring services. They offer support and encouragement throughout all four years of undergraduate school. They keep us well informed of scholarship and research opportunities as well as cutting edge technology.All first year students are required to take the course WISE 187. This course was designed to introduce us to the many aspects of research available to us. We will be participating in four labs and doing research in several disciplines such as math, science, and engineering. Our first experiment was Let's Make Diamonds!. The team was composed of Lana Mansfield, Daniele Zimmerman, Maryellen Higgins, Winnie Mok, Kim Guilfoy, and Magaly Lainez.

Introduction

KennedyPress.gif (37104 bytes)Pyrite.gif (17604 bytes)In this experiment, we attempted to make diamond from graphite.  Using the Kennedy Press from the Center for High Pressure Research, we tried  imitate the conditions in which diamonds are naturally formed.  These conditions exist in the Earth's upper mantle where the pressure is 58K and the temperature is 1350 C.

Background

BigGarnet.gif (12405 bytes)We know that carbon exists in different forms at diiferent pressures and temperatures within the earth.  Our goal was to use high pressures and temperatures to physically change carbon as it exists naturally on earth's surface from its graphite form to diamond.

    The increase in pressure will compress the atomic bonds in the graphite to coordinate them into a more stable matrix such as that of diamond.  The bond length between atoms will actually increase from 1.4 Angstroms in graphite to 1.5 Angstroms in diamond.

    The increase in temperature is what speeds up the reaction by melting the catalyst.  The catalyst we used was a mixture of nickel and manganese.   This allows for the change in form to occur over a

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CubesWithPlastic.gif (32700 bytes)Procedure

The process of converting graphite to diamonds involves a series of simple operations.

Saw 6 short and 6 long pyrophyllite gaskets and 12 Teflon gaskets into a trapezoidal shape. Number 8 tungsten carbide cubic anvils from 1 to 8.

Glue the pyrophyllite gaskets on the truncated corners of the #2, #4, #6, and #8 cubes. Then glue the Teflon gaskets behind the pyrophyllite gaskets. To each of side of the cube directly in contact with the gaskets, glue 2 spacers on each and tape these sides with Teflon tape.

Drill a hole in the octahedron pressure medium (MgO sample cup).

Place 3 graphite disks and Nickel-Manganese powdered catalyst inside a Zirconia cylinder.

Cap off each end with a Zirconia disk.

Slip the cylinder into the hole of the MgO octahedron.

Set up the cubes by placing #1, #2, #3, and #4 on the bottom. Place the MgO octahedron in to the octahedral cavity. Put theSawingGasket.gif (24186 bytes) rest of the cubes on top forming a bigger cube.

Crazy glue a square shaped laminated plastic sheet on each side of the big cube.

Now it is ready to be placed in the Kennedy press. Adjust the temperature and pressure to the desired numbers. Once set allow the machine to run for 20 minutes.

Turn off the heat and bring down the pressure.

Remove the cube and inside the Zirconia cylinder should be a small diamond.

Results

Our experiment appeared successful even before the graphite sample was removed from the press. The Kennedy Press achieved optimal temperature and pressure for converting graphite into diamonds. When the sample was removed, we were proven correct.

Diamonds1.gif (65583 bytes)Looking at the sample under the microscope, we could see shiny areas. These areas are what we believed to be the diamonds. When these "diamonds" were pressed firmly across the tungsten carbide cubes, scratches were made- proving that we had indeed made diamonds. Diamonds are stronger than tungsten; graphite is not. Though not all of the graphite was converted into diamonds, much of it was.

These diamonds that we made appear very different from the polished, cut, clear diamonds we know. However, they were still diamonds: dark, shiny, and oddly shaped.

We have proved that under the proper pressure and temperature, graphite can be converted to diamonds.

Discussion

Diamonds2.gif (52905 bytes)Our group's attempts to create diamonds proved successful. After our examination of the Carbon phase diagram, we were able to make an accurate estimation of the conditions needed. The tremendous pressure and temperature used, simulates the conditions in the upper mantle of the earth. These findings help in our understanding of the internal environment where these beautiful minerals are formed.