Keyword: ball milling

  • Structure transformation in graphite at high-energy ball milling treatment

    Materials Science. Non-Equilibrium Phase Transformations., Vol. 7 (2021), Issue 1, pg(s) 11-13

    The changes in the structure of the crystalline graphite are studied during high-energy ball milling (BM) treatment. It was found by XRD analysis the milling time increasing up to 3.5 h leads to the formation of an amorphous phase in the milling process. After 10 h of ball milling treatment, complete amorphization of graphite takes place. It has been shown by high-resolution electron microscopy the individual particles have complex morphology which depends on the BM time. After 1 h of BM carbon materials characterized by an onion-like structure: the individual particles have a spheroidal shape with a size of ~ 10 nm. However, unlike the previous ones after 10 h of ball milling carbon nanomaterials are characterized by a disordered structure, which is typical for amorphous carbon.

  • MATERIALS

    The effect of ball milling speed on the penetration of Cr and Zr into Cu for production of Cu1CrZr alloy powder

    Machines. Technologies. Materials., Vol. 13 (2019), Issue 8, pg(s) 362-366

    The copper alloys are preferred for their superior mechanical properties combined with high electrical conductivity for contact material applications. These properties should be a very good combination of high mechanical strength and enough electrical conduction properties as well as high thermal conductivity. To establish the electrical and thermal conductivity, the low resistive materials such as copper and their alloys to be chosen is a must. Copper can be alloyed with Cr and Zr in very low
    amounts down to 1 wt% and 0.15 wt%, respectively. These amounts can be found from phase diagrams of interest. The planetary ball milling was chosen as being a unique technique for powder processing to obtain mechanochemical activation and mixing of powders prior to sintering. The ball milling jar was ZrO2 and ball to powder ratio was varied as 1:1, 5:1, and 10:1. The ball milling rotation was ranged from 400 and 500 rpm for different durations to be investigated. The SEM photos showed the Cr and
    Zr penetration onto Cu powders transformed to flakes of different sizes. The elemental composition maps showed the better and finer distribution of alloying elements at 500 rpm than 400 rpm.