الفهرس 
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Abstract
In the present investigation , the mechanical characteristics, typically,hardness and compression strenth, as well as the tribological behavior of epoxy resins reinforced with both micro-and nano-sized ceramic particulates were
investigated. The tribological behavior of such epoxy-based polymeric matrix composited (PMCs) was extnsiveley investigated under both dry and water iubricated condition against a 316 stainless steel disc.
The effect of the applied load, sliding velocity and sliding distance (sliding time) on the coefficient of friction (COF)
and the wear rate (WR) of the expoxy PMCs were also investigated.
The worn surfaces of both nano- and micro- PMCs were investigated using scanning electron microscope (SEM).
A comparison between the effect of the nano- and mocro-sized additives on the mechanical and tribological and epoxy PMCs was carried out.
Epoxy (EP) matrix was reinforced with low volume fraction (2and4%vol.-%) of several micro-and nano-sized ceramic particulates, typically, G,SiC and Al2O3 particulates.
It is believed that the addition of such low volume fractions can improve both the tribological as well as the mechanical properties such as hardnees and compression strength of the PMCs without or with limited
alternation of other mechanical properties such as toughness, which is one of the serious problems of the epoxy. Since , it is well known that thermoset polymeric materials, such as epoxy and polyamides, suffer from low toughness when compared with thermoplastic materials such as polyesters and polyethylene.
Micro-sized G, SiC and AI2O3 particulates having average size of 70 and 100 um were used as micro additves. While nano additives of the aforementioned ceramic particulates having size range varying between 50 and 70 nm were used.The results revealed that, at low volume fraction of ceramic particulates up to 4%, the dispersion of nano-particulates inside the epoxy matrix is more effective in improving the mechanical and tribological properties of the composited than the dispersion of micro-particulates.
The nano-composites exhibited both higher hardness and compression strengh when compared with micro- composites.
For example, hardness of composites containing 4vol.-%of SiC oarticulates having 70um and other containing 4vol.-% of SiC particulates having 60nm are 26 and 31VHN, respectively.
The hardness and compression strength were found to increase by increasing the volume ffraction of the ceramic particulates.