Diamond is known as the hardest substance on Earth, and it's widely used as a cutting tool in various fields. However, there are still certain materials that cannot be cut by a diamond cutting tool. These materials are incredibly rare and have some of the most robust structures in the world.
One of the most challenging materials to cut is cubic boron nitride (CBN). CBN is a synthetic material that has similar properties to diamond, including exceptional hardness and thermal conductivity. It's often used in manufacturing industries to make cutting tools, but it requires a different kind of cutting tool for the cutting process. Although diamond tools work exceptionally well on most materials, CBN is one of the very few materials that challenge them.
Another material that's difficult to cut is tungsten carbide. Tungsten carbide is incredibly hard and has a high abrasion resistance. Like CBN, this material is frequently used in industrial applications to fabricate cutting tools, molds, and wear-resistant parts. However, diamond tools are not ideal for cutting tungsten carbide, and specialized tools such as ceramic-based tools and abrasive water jet cutting are used instead.
Diamond tools are also not suitable for cutting metals that have a high reactivity with carbon at high temperatures. For instance, chromium, titanium, and cobalt alloys are not suitable for diamond cutting tools due to the tendency of these metals to react with carbon at high temperatures, which can cause the diamond cutting tool to degrade.
Moreover, there are materials that can't be cut by diamond tools, not because of their hardness but because of their physical properties. For example, materials that are soft and pliable, such as rubber, are tough to cut because they 'smear' and 'gum up' the diamond blade, making it useless.
In conclusion, diamond cutting tools are incredibly versatile and useful in cutting a vast range of materials. However, there are materials that pose challenges to diamond cutting tools. These materials include cubic boron nitride, tungsten carbide, and highly reactive metals such as chromium, titanium, and cobalt alloys. So, it's essential to use the appropriate tool for the material to achieve the best results.
