Preparation And Tribological Performances Of Nickel Based Composites

A gigantic portion of rice husk（RH）has not been used so far across the globe although it is considered as a value-added by-product.For the reason of having distinctive features like high silicon content,hardness,small bulk density,and so on,proper utilization has been a significant challenge.Neither it can be easily decomposed nor directly fed to animals as a result it is causing a serious environmental and human health risk.Thus the proper utilization of RH is mandatory.Using RH as an additive in matrix composites could be one of the best solutions.During fabrication of metal-matrix composites（MMC）rice husk can be one of the promising additive because of its phenomenal properties.This study investigates the contribution of rice husk ceramic（RHC）in improving the tribological properties of Ni-MMC（Nickel metal-matrix composite）.RHC was obtained by heating the mixture of RH and phenol resin in a 1:3 ratio at 900^oC under nitrogen atmospheric conditions for2 hours.Thus obtained RHC powder has a particle size of 500 nm.Further characterization of RHC particle along with inorganic additives graphite and Mo S₂ was done via SEM,XRD,Raman,FTIR,and TG.Nickel composites were fabricated with RHC along with metal additives aluminum and copper,and inorganic additives graphite and Mo S₂ in different content via powder metallurgy method.After weighing and sintering the powder in desired amount pressure of 30MPa was employed for 5 minutes at room temperature in order to fabricate the composite discs.Thus fabricated discs were heated in a furnace at 500^oC for 2 hours under nitrogen atmospheric conditions.At room and 400^oC temperature with ball on disc tribometer the tribological characteristics of Ni-MMC were studied.The wear properties,reinforcement distribution,and microstructural phases of the composite discs were investigated using SEM/EDS and an optical microscope,respectively.Addition of RHC particles to Ni-MMC shows the improvement of wear and friction properties.The lowest wear rate and coefficient of friction was resulted with the inclusion of 3 wt%RHC.It was found that with the expansion of Mo S₂ and graphite with 3wt%RHC wear rate and the coefficient of friction were reduced.Meanwhile,the content of aluminum and copper in MMCs determined wear rate and coefficient of friction value.