Compressibility curves are widely used to describe the compaction behavior of powders. The friction between the powder and the wall of the mold during compaction results in over-estimation of the compaction force. This paper presents a method to correct this effect and obtain a 'friction-free' compressibility curve. The method is based on the friction force distribution theory. By eliminating the effects of wall friction force and specimen geometry, it is possible to determine the real compaction behavior of powders. A series of uniaxial compaction tests were conducted to establish the validity of the friction-free compaction concept. The data obtained from tests for various aspect ratios and lubrication conditions are shown to tend towards a unique friction-free compressibility curve, once results have been corrected for frictional effects.
- Bentonite block
- Friction-free compressibility curve
- Uniaxial compaction
- Wall friction