Comparing diamond and tungsten involves assessing two materials known for their exceptional durability. Diamond is widely considered the standard for extreme hardness, while tungsten is recognized for its strength, density, and resistance to high temperatures. Understanding which material is more resistant to damage requires examining how material scientists define and measure hardness. This comparison reveals why each is uniquely suited for specific industrial applications.
How Material Hardness is Measured
Material hardness is defined by a substance’s resistance to permanent deformation, which can manifest as scratching, indentation, or penetration. This property is distinct from strength, which measures a material’s ability to withstand force before breaking. For preliminary comparisons, the Mohs scale of mineral hardness offers a relative ranking based on scratch resistance.
For engineering precision, absolute hardness values are determined using indentation tests. Common methods like the Vickers and Knoop tests press a precisely shaped diamond indenter into the material’s surface under a known load. The size of the resulting indentation is then measured to calculate a specific hardness number, such as the Vickers Hardness (HV), allowing for direct comparison of materials like metals and ceramics.
The Extreme Hardness of Diamond
Diamond holds the distinction of being the hardest naturally occurring material on Earth, scoring a perfect 10 on the Mohs scale. Its extraordinary resistance to scratching and indentation stems from its unique atomic structure. Each carbon atom forms strong, short covalent bonds with four neighbors, creating a dense, three-dimensional tetrahedral lattice.
This crystal arrangement requires immense energy to break or rearrange, resulting in its exceptional hardness. When tested with the Vickers method, diamond exhibits hardness values that can exceed 10,000 HV. This unparalleled resistance to deformation is why diamond is used as the indenter tip in many tools designed to measure the hardness of other materials.
Tungsten and Its Hardness Range
Pure tungsten metal is a dense, high-melting-point element that is significantly harder than many other metals, but it registers only about 7.5 on the Mohs scale. The material most people refer to when discussing extreme tungsten hardness is actually tungsten carbide (WC), a ceramic composite. This compound is formed by combining tungsten and carbon atoms, and is used extensively in industrial wear parts.
Tungsten carbide achieves a Mohs hardness score between 9 and 9.5, placing it just below diamond. Its Vickers hardness falls within the range of 1,500 to 2,500 HV, making it incredibly hard compared to hardened tool steel. The material’s advantage is its balance of high hardness combined with high compressive strength and fracture toughness, resisting cracking better than a material with only maximum hardness.
The Definitive Answer and Practical Uses
The definitive answer to the comparison is clear: diamond is vastly harder than both pure tungsten metal and its hardened form, tungsten carbide. Diamond’s Vickers hardness value is multiple times higher than the best tungsten carbide grades, confirming its superior resistance to scratching and surface deformation. This difference dictates the practical applications for each material in manufacturing and engineering.
Diamond’s maximum hardness makes it the choice for abrasive applications, such as cutting, grinding, and polishing other extremely hard materials like stone or ceramics. Tungsten carbide, while softer than diamond, is preferred where a combination of high hardness, high wear resistance, and good toughness is necessary. This includes heavy-duty drill bits, industrial nozzles, and components in mining and construction machinery that must endure high impact and stress.