CDP abrasives are polycrystalline ceramic particles containing nanodiamond. They can be customized through controlling any of the production parameters, which renders CDP more like a tool than a means to produce a specific group of products.
Here are the variables and how they affect properties of the powders that are produced:
- Method of Detonation: Affects amount of carbon produced and diamond yield in the carbon phase
a) Cylindrical: Lower cost per kilogram produced and lower diamond yield
b) Annular: Highest cost per kilogram produced and higher diamond yield
Tip: Cylindrical detonation in an unyielding steel block maximizes diamond yield
- Ratio of dry ice to reducing agents: Affects carbon yield and diamond yield in the carbon phase
a) Stoichiometric (exactly enough dry ice to convert all reducing agents to reducing agent oxides) = highest carbon yield and lowest diamond yield in the carbon phase.
b) Excess Dry Ice: This quenches the heat of detonation, decreases overall carbon yield and optimizes the percentage diamond in the carbon phase. However, this approach produces less material per kilogram of CDP explosive detonated.
Tip: Add graphite powder to customize both the carbon yield and diamond yield upon detonation
- Type of Reducing Agents (Metals): Determines the type of oxides produced, each of which have unique hardnesses
a) Solitary reducing agents like magnesium or aluminum produce magnesium oxide (Mohs hardness of 5.5) and aluminum oxide (Mohs hardness of 9.0) respectively.
b) Combinations of reducing agents produce combinations of each reducing agent’s respective oxides plus new structures based on both reducing agents. Examples: spinel, produced by detonating dry ice, magnesium and aluminum together or mullite, produced by detonating dry ice, aluminum and silicon together.
Tip: Adding tungsten to the detonatable formulation encourages the production of very hard tungsten carbide
- Acid Digestion: Removes magnesium oxide to produce acid-resistant powders that are richer in graphite/diamond and harder oxides such as spinel, silica, and aluminum oxide.
Tip: Acid digestion of magnesium + silicon + dry ice detonation byproducts produces very fine nanodiamond/silica