Increased Graphite Powder Density
The present invention relates to a process for producing increased bulk density graphite powders. The process comprises: a) applying a mechanical surface treatment to graphite powder particles; b) accelerating fluidized graphite powder particles in a gas environment; c) changing the surface structures of the graphite powder particles; d) modifying the structural parameters of the graphite particles and their density; e) enhancing the compressibility of the graphite powders. This process can be used for producing mouldings.
For example, an electrode with a density of 1.8 g/cc and a porosity of 52% was prepared. It was then air dried and measured. At the same time, the electrodes were made into 2325 coin cells.
These tests were performed with synthetic and natural graphite powders. The experiments were performed using a dilatometer. Graphite with higher ash content tends to have a higher density.
During the sintering of ferrous PM parts, graphite almost completely reacts. The sintering time is a crucial parameter. If the sintering time is too short, there is a risk of incomplete carbon diffusion. Therefore, the sintering time should be sufficiently long to ensure complete carbon diffusion.
In the case of a medium density high carbon part, it may be advantageous to mix natural and synthetic graphite. This mixture can be used for producing metallic sintering materials, such as duryplastic graphite-polymer composites. Moreover, it is possible to increase the solids content of liquid carbon dispersions by more than 5% to more than 30%.
