Tribological characterization of sponge gourd outer skin fiber-reinforced epoxy composite with <i>Tamarindus indica</i> seed filler addition using the Box–Behnken method

<jats:title>Abstract</jats:title>
<jats:p>The tribological properties of the sponge gourd outer skin fiber (SGOSF)-reinforced epoxy composites filled with tamarind seed powder were investigated using a pin-on-disc dry sliding wear testing machine. The fiber and filler contents were kept constant (30 and 7.5 wt%). The fibers were treated with sodium hydroxide (NaOH), which increases the bonding strength that has been identified by scanning electron microscope (SEM). A filler content of 7.5 wt% has better hardness due to the embedment of filler with treated fiber and epoxy. Therefore, the SGOSFs/epoxy with 7.5 wt% tamarind filler was chosen for the study of tribological characterization. The lowest specific wear rate of 2.565 × 10<jats:sup>−4</jats:sup> mm<jats:sup>3</jats:sup>·N m<jats:sup>−1</jats:sup> was obtained using the design of expert optimization technique for the control factors such as a load of 44.99 N, a sliding distance of 1,701.39 m, and a sliding velocity of 3.36 m·s<jats:sup>−1</jats:sup> using a ramp plot at the desirable level of 1. For the gripping material application, the highest coefficient of friction value of 0.51 was obtained by maintaining the specified input parameters, such as a load of 42.15 N, a sliding distance of 1,874.86 m, and a sliding velocity of 4.99 m·s<jats:sup>−1</jats:sup> using a ramp plot at the desirable level of 0.927. SEM images were used to investigate the failure mechanism of the worn surfaces, which substantiates the failure of the pure matrix layer on the surface even at low load, followed by the formation of a rarely breakable adhesive layer.</jats:p>