Theses silver spheres are also known as precision spheres. The spheres are used as a calibre or as a size reference. Laser experimentation benefit from silver spheres due to the precise and repeatable reflection that they offer. Precision balls are also used in critical aeronautical bearings, as guidance system balls for space and military applications, precision valves, automotive bearings and other applications where higher precision is necessary. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.
These spheres are defined by grade-the lower the number of the grade, the more precision to which the ball is manufactured. The better the grade of ball the closer to a perfect sphere a ball is made. Precision balls are required to have limited surface defects effecting the rotation of the ball as it passes through the bearing or other application. The better the surface finish, the less “noise” from vibration will occur during bearing rotation. The better the grade of ball, the tighter the ball diameter tolerance, this is critical for quiet bearings.
Silver spheres can be used as an additive in paints, polymers and adhesives to effect electrical conductivity. In this case they are called conductospheres. They are used to coat structures and components where it is important to dissipate electrostatic charge build-up. This property is of obvious importance in the aerospace industry, where protection of sensitive components and dissipation of lightning strikes is important. However, solid silver is a particularly dense material, and so the amount used has to be balanced against the increase in weight. A further issue with the use of solid silver particles for these types of application is the cost.
Using a particle coating technology, these density and cost issues can be addressed simultaneously. The use of a low density core material, such as hollow glass or polymer, as support for a nanometer thin coating of metal, reduces both the density of the final composite and the amount of metal needed.