A Study on Wear Resistance of Copper- Silica Sand Nanoparticles Based Composites

Pure copper (Cu) and its composites reinforced with silica sand nanoparticles (Si02)
were prepared by powder metallurgy process. These composites are expected to have
high mechanical properties such as high melting point, hardness and good wear
resistance. This study aims to find the compressibility curve for Cu and investigates the
hardness and wear resistance of Cu-Si02 composites with different compositions of
reinforcement of Si02. To create the compressibility curve for Cu, 6 different
compression forces were applied (34MPa, 41MPa, 48MPa, 55MPa, 62MPa, and
69MPa) and the green densities values were measured and plotted. The following
compositions were developed using the compression force that shows highest green
density value: 5 samples of Cu, 5 samples of composites reinforced with 5wt%, 1 Owt%,
15wt% and 20wt% ofSi02nanoparticles. All samples were divided into 5 groups; each
group consists of a sample of Cu, and composites reinforced with 5wt%, 1 Owt%,
15wt% and 20wt% of Si02 nanoparticles. Then the groups were sintered at 550°C,
650°C, 750°C, 850°C and 950°C for 1 hour in argon atmosphere. The green and sintered
densities were measured by following the Archimedes's method. The hardness values of
the Cu-Si02 composites were measured using Vickers Microhardness Tester at constant
load of 300gf and dwelling time of 15 seconds. The resistance test was conducted under
120N load using pin-on-disc apparatus and hardened cast iron was used as the counter
face. It was observed that 41MPa compression force and 750°C of sintering temperature
are the suitable parameters which result in better green and sintered densities. The
additions of Si02 nanoparticlcs up to 20wt"/o appeared to improve the hardness of the
composites. The hardness increased from 38.2HV to 105.0HV. The sliding wear tests
indicated that the composite with 20wt% Si02 nanoparticles exhibits a lower wear loss
and wear rate compared to pure copper. The weight losses decreased from 0.18274g to
0.12824g and wear rate decreased from 5.153xl0.2mm3/s to 2.474153xl 0"2mm3/s.