Microstructure and Properties of Copper–Graphite Composites Fabricated by Spark Plasma Sintering Based on Two-Step Mixing

Abstract

The microstructure and properties of Copper-Graphite Composites (CGC) prepared by spark plasma sintering (SPS) based on two-step mixing and wet milling were investigated. The results showed that Cu powders were rolled into Cu flakes during milling, and their size significantly decreased from 23.2 to 10.9 μm when the graphite content increased from 1.0 wt.% to 2.5 wt.%. The oxidation of Cu powder was avoided during two-step mixing and wet milling. After spark plasma sintering, the graphite powders of the composites were mainly distributed at Cu grain boundaries in granular and flake shapes. The mean size of Cu grains was 9.4 um for 1.0 wt.% graphite content and reduced slightly with the increasing of graphite content. Compared with other conventional methods, the composite prepared by two-step mixing and SPS achieved higher relative density, electrical conductivity, and micro-hardness, which, respectively, reduced from 98.78%, 89.7% IACS (International annealed copper standard), and 64 HV (Vickers-hardness) to 96.56%, 81.3% IACS, and 55 HV when the graphite content increased from 1.0 wt.% to 2.5 wt.%. As the graphite content increases, the friction coefficient and wear rate of the composite decreases. When the graphite content of CGC is 1.0 wt.%, the main wear mechanism was plastic deformation, delamination, adhesive, and fatigue wear. The adhesive and fatigue wear disappeared gradually with the increasing of graphite content.

Evaluation of Mechanical and Tribological Aspect of Self-Lubricating Cu-6Gr Composites Reinforced with SiC–WC Hybrid Particles

“…Figure 1 shows SEM graphs of the dust particles used in the experiments. It is known that graphite powders added to copper reduce mechanical properties [27]. To improve the mechanical properties, Cu-6Gr/SiC-WC compacts were prepared by adding SiC and WC reinforcement powders at different rates into Cu-6Gr powders.…”

Prediction of tribological performance of Cu-Gr-TiC composites based on response surface methodology and worn surface analysis

“…The regression equation in first order quadratic form is also determined for the calculation of COF as given in equation (4). With the help of equation, coefficient of friction value can be obtained for any value of input parameters.…”

“…However, in recent times, the copper graphite composites are widely utilized as bushings and bearings in automobile and electrical industries. The graphite reinforced copper composites are developed by several techniques such as stir casting, SPS, and powder metallurgy [1][2][3][4][5]. Out of which, the powder metallurgy is widely used owing to its medium fabrication cost, complex shapes composites and evenly distributed reinforcements within matrix.…”

Effect of Counterbody on Friction and Wear Properties of Copper-MgP-Graphite Composites Prepared by Powder Metallurgy

“…In the preparation of copper-graphite composite materials, many studies [9,[13][14][15][16]] have investigated the effect of the content of graphite added on the properties of the final composites. While this work aims to study the friction properties of composites made of 10 vol% magnesium phosphate treated graphite and copper.…”