Chinese Scientists Synthesize Hexagonal Diamond Harder Than Natural Diamond
Chinese researchers have successfully synthesized a pure hexagonal diamond, exhibiting greater hardness and thermal stability than natural diamonds.
Chinese scientists have successfully synthesized a pure hexagonal diamond, a form of carbon that surpasses natural diamonds in hardness and thermal stability. This achievement, detailed in a recent study published in Nature, marks a significant advancement in materials science.
The research team, led by scientists from Zhengzhou University, transformed highly oriented graphite into hexagonal diamond by subjecting it to extreme pressures of approximately 20 gigapascals and temperatures between 1,300 and 1,900 degrees Celsius. This process resulted in millimeter-sized crystals of hexagonal diamond, also known as lonsdaleite, which were confirmed to be structurally pure through X-ray diffraction and atomic-resolution electron microscopy.
Mechanical testing revealed that the synthesized hexagonal diamond exhibits a Vickers hardness of around 114 gigapascals, slightly exceeding the typical 110 gigapascals of natural diamonds. Additionally, the material demonstrated high thermal stability, maintaining its structural integrity at temperatures up to 1,100 degrees Celsius.
The successful creation of this ultra-hard material opens new possibilities for industrial applications, particularly in fields requiring materials with exceptional hardness and heat resistance, such as cutting tools, abrasives, and high-performance electronics. The researchers noted that their findings provide valuable insights into the graphite-to-diamond conversion process under elevated pressure and temperature, offering opportunities for the fabrication and application of this unique material.