Diamond is now considered the hardest natural material, known for its exceptional hardness and widespread use in jewelry and industry. However, when it comes to hardness, is diamond truly the hardest substance on Earth? Let's delve deeper into this question and unravel the mysteries behind hardness.
Why is diamond nature's hardest substance?
- Mohs hardness of 10, microhardness of 10000 kg/mm2 (1000 times higher than quartz, 150 times higher than corundum).
- Due to its high hardness and thermal conductivity, it has significant industrial applications in cutting and high-pressure fields.
Table 1. Classification and properties of diamonds
Item | ⅠType Diamond | ⅡType Diamond | ||||
Ⅰa | Ⅰb | Ⅱa | Ⅱb | |||
Content in nature | ~98% | ~0.1% | 1-2% | ~0% | ||
Synthetic diamond |
| Little single crystal | Large single crystal | Single crystal | ||
Impurity | Nitrogen (ppm) | ~2×103 (aggregated state | 102~103 | 1~102 | ~1 (High purity) | ~1 |
diffuse state | ||||||
Other impurity (ppm) |
| Metal inclusion 104~105 |
|
| B ~100 | |
Color | colorless~yellow | Green~brown | yellow | colorless | Blue | |
Electrical resistivity (Ω·cm) | 104~1016 | 1016 | 1016 | 101~104 | ||
Insulator | P-type semiconductor | |||||
What substances have a hardness higher than that of diamond?
Boron Nitride
- Cubic Boron Nitride (cBN): Cubic boron nitride is commonly used in cutting tools and high-pressure high-temperature experiments, second only to natural diamonds in hardness.
- Wurtzite Boron Nitride: The latest simulations show it can form a unique tetrahedral crystal lattice structure, with a hardness 18% higher than diamond.
- Hexagonal Boron Nitride (hBN): It is hard but typically softer than diamond. Yet, in extreme conditions like high temperature and pressure, hBN can convert to cubic boron nitride (cBN) with diamond-like hardness.
AM-III (New Type Glass Material)
Researchers have created a novel glass material with a Vickers hardness of 113 GPa, exceeding that of diamond (70-100 GPa). It is an amorphous material without a fixed melting point and functions as a high-efficiency semiconductor material.
Humanity's pursuit of harder, more scratch-resistant, lighter, and stronger materials is never-ending. With technology advancing continuously, we are confident in discovering and promoting the application of even more amazing materials in the future.
Heeger Materials is a reputable supplier offering various kinds of high-quality Refractory Metals, Rear Earth Materials, and High-purity Materials products at competitive prices, which are widely used in research and science fields. If you're interested, feel free to contact us at [email protected] for a quote, and we guarantee a response within 24 hours.