Effect of Sintering Temperature on the Tribological Behavior of Plasma Assisted Debinded and Sintered MIM Self Lubricating Steels

Solid lubrication and solid lubricants are one of the most promising choices for controlling friction and wear in energy efficient modern systems. The production of self lubrication composites containing second phase particles incorporated into the volume of the material appears to be a promising solution. A new processing route to obtaining a homogeneous dispersion of discrete solid lubricant particles in the volume of sintered steels produced by metal injection molding (MIM) was recently presented. This new route was achieved by in situ formation of graphite nodules due to the dissociation of precursor (SiC particles) mixed with the metallic matrix powders during the feedstock preparation. Nodules of graphite (size ≤ 20μm) presenting a nanostructured stacking of graphite foils a few nanometers thick were obtained. The thermal debinding, as well as the sintering, was performed in a single thermal cycle using a Plasma Assisted Debinding and Sintering (PADS) process. In this work, we present and discuss the effect of sintering temperature on the tribolayer durability and average friction coefficient in the lubricious regime (μ<0.2) of plasma assisted debinded and sintered self lubricating steel produced by metal injection mould technique. Three different temperatures (1100, 1150 and 1200 °C) and six different SiC contents (0–5%) were analyzed. Friction coefficient was little affected by the sintering temperature. However, the durability of the tribo layer formed on the sliding interface was greatly increased (5X) for the lower sintering temperature (1100°C).