When purchasing graphite plates, there's always a concern that the graphite products might break or shatter during shipping. In reality, some processed graphite products are brittle, while others are not. Therefore, careful handling is crucial during shipping, such as using foam packaging to prevent product damage.
So, are graphite plates brittle or hard?
Pure graphite can be considered hard; the higher the density of the graphite, the harder it is. However, scientifically, graphite is described as very soft. Graphite is made of carbon, and carbon can also form very hard diamonds. This explanation can be confusing for those unfamiliar with graphite.
Actually, there's no contradiction. Graphite is made of carbon, and diamond is also made of carbon. The hardness is comparable to that of ordinary iron and steel. So, the hardness referred to isn't the kind of surface hardness like a rock; it refers to the inherent hardness of the graphite material. However, graphite is also very soft; it can be used like a pencil to write on paper and can be easily milled. Unlike iron and steel, high-purity graphite can be easily cut and milled with ordinary mechanical equipment and cutting tools.
Don't assume that because it's easily milled, graphite isn't hard. In fact, the inherent hardness of graphite causes significant wear on milling and cutting tools. Therefore, high-purity graphite is characterized by being hard, brittle, and also having toughness. Brittleness and toughness seem contradictory, but they're not. Brittleness means that graphite breaks and chips easily, while toughness refers to its elasticity. For example, a small piece of graphite can be bent into an arc by external force, and when the force is released, the graphite piece returns to its original shape without permanent deformation. However, if the force is too strong, it will break easily. So, from this example, it's clear that graphite being both brittle and tough is not a contradiction.