Diamond synthesis from carbon nanofibers at low temperature and low pressure.

Chengzhi Luo,Chunxu Pan,Wenge Yang,Xiang Qi

doi:10.1038/srep13879

Abstract

In this article, we report a new route to synthesize diamond by converting “solid” carbon nanofibers with a Spark Plasma Sintering system under low temperature and pressure (even at atmospheric pressure). Well-crystallized diamond crystals are obtained at the tips of the carbon nanofibers after sintering at 1500 °C and atmospheric pressure. Combining with scanning electron microscopy, transmission electron microscopy, electron-energy loss spectroscopy and Raman spectroscopy observations, we propose the conversion mechanism as follows: the disorder “solid” carbon nanofibers → well crystallined carbon nanofibers → bent graphitic sheets → onion-liked rings → diamond single crystal → the bigger congregated diamond crystal. It is believed that the plasma generated by low-voltage, vacuum spark, via a pulsed DC in Spark Plasma Sintering process, plays a critical role in the low temperature and low pressure diamond formation. This Spark Plasma Sintering process may provide a new route for diamond synthesis in an economical way to a large scale.

Highlights

In this article, we report a new route to synthesize diamond by converting “solid” carbon nanofibers with a Spark Plasma Sintering system under low temperature and pressure
Many approaches have been pursued to make diamonds, such as chemical-vapor-deposition (CVD)[2], shock-wave processes[3], plasma activation[4], high pressure[5], exotic precursors[6,7] and explosive mixtures[8], etc., since the first report of diamonds synthesized through high-pressure and high-temperature (HPHT) process[9]
Graphite can be converted to diamond, the high temperature and high pressure are needed or the catalysts are presence

Summary

Introduction

We report a new route to synthesize diamond by converting “solid” carbon nanofibers with a Spark Plasma Sintering system under low temperature and pressure (even at atmospheric pressure). We report a new route to synthesize diamond, which is converted from “solid” carbon nanofibers (CNFs) in a Spark Plasma Sintering (SPS) system under low temperature and low pressure (even at atmospheric pressure) conditions.

Results

Conclusion