Influence of electrical current on the contact voltage drop and wear properties of CNTs-Ag-G composites

CNTs-Ag-G composite brushes were fabricated by means of powder metallurgy method. The process included mixing power, pressing at 200 MPa, sintering for 1 h in pure H2 protective atmosphere at 700°C and repressing at 400 MPa. The effect of the electrical current (0-25 A/cm2) on the contact voltage drop and wear properties of CNTs-Ag-G composite was studied. The contact voltage drop was low in the initial stage of wear, then rose to a certain level, finally became stable. With the increase of the electrical current, the temperature of interface rose and the probability of adhesion wear increased. Due to the altering of contact manner, the contact resistance decreased and contact voltage drop increased little. At the same time, the wear mass loss increased rapidly. The wear mass loss and contact voltage drop of traditional electric brush are both larger than those of CNTs-Ag-G composite brush.