Hello, In your research related to friction stir processing (FSP) with nano-particle reinforcement, it is important to understand the differences between bulk density and particle density to make the right choice.

Bulk density refers to the mass of a particulate material (including voids and spaces between particles) divided by the total volume it occupies. On the other hand, particle density refers to the mass of an individual particle divided by its volume, without considering voids or spaces.

When computing volume percentage of nano-particle reinforcing agent in a composite material, you should consider particle density. This is because particle density represents the true material property of the individual particles, which is crucial for understanding how the reinforcement affects the composite's overall properties.

Using particle density will give you a more accurate representation of the nano-particle reinforcement within the matrix material. This information can help you better understand the interactions between the reinforcement and the matrix material, as well as how the overall properties of the composite are influenced by the nano-particles.

To compute the volume percentage of the nano-particle reinforcing agent, you can use the following formula:

Volume percentage = (mass of reinforcing agent / particle density of reinforcing agent) / (total volume of composite) x 100

Keep in mind that when calculating the total volume of the composite, you should account for the volume of both the matrix material and the reinforcing agent.

Regards,