Charge

Powders and granular materials can acquire electrical charge on the surface of their particles due to contact and movement against handling equipment and containers. They can also acquire charge due to contact and movement of particles within the material itself. This process is called tribocharging. Tribocharging is caused by electrons moving from one surface to another when different materials come in contact with each other. One material will become positive and the other will become negative. The amount of charge developed depends on the nature of the materials in contact, the pressure of the contact, the relative velocity of the contact surfaces, and the friction between the contact surfaces.

Measuring the charge acquisition properties of powders and granular materials is important because charge acquisition leads to problems and unstable behavior. Charged materials stick to processing equipment and containers. Charged materials can become airborne more easily. Charge materials flow in different ways than materials with no charge. In fact, many research believe that material electrical properties are the most important contributors to powder flow behavior.

Mercury Scientific Inc offers the ION Charge Module to measure the charge acquisition properties of powders and granular materials. The ION module can be added to the Volution Powder Flow Tester or The Revolution Powder Analyzer. Both options allow test samples of powder and granular materials to be charged with contact surfaces of various materials including stainless steel, glass, aluminum, or plastic. Custom materials are also available and users can create their own contact surfaces like paper or coated materials.