Surface lubrication of graphite fabric reinforced epoxy composites with nano- and micro-sized hexagonal boron nitride

• Published in: Wear Vol. 301; no. 1-2; pp. 802 - 809
• Main Authors: Kadiyala, Ajay Kumar, Bijwe, Jayashree
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2013; Elsevier
• Subjects: Anti-friction material; Applied sciences; Boron nitride; Composites; Disks; Epoxy; Exact sciences and technology; Forms of application and semi-finished materials; Graphite; Hexagonal boron nitride; Mechanical properties; Micro-Raman spectroscopy; Nanocomposites; Nanomaterials; Nanostructure; Physical properties; Polymer industry, paints, wood; Polymer matrix composites; Properties and testing; Reinforcement; Solid lubrication; Technology of polymers; Solid lubrication; Composites; Hexagonal boron nitride; Epoxy; Anti-friction material; Micro-Raman spectroscopy; Solid lubricant; Scanning electron microscopy; Particle size; Adhesive wear; Hexagonal shape; Nanoparticle; Fiber reinforced material; Epoxy resin; Antifriction material; Composite material; Surface treatment; Wear rate; Graphite; Microparticle; Lubrication; Raman spectrum
• ISSN: 0043-1648; 1873-2577
• DOI: 10.1016/j.wear.2012.11.069

In this work graphite fabric (GrF) as a reinforcement and epoxy matrix with high thermal stability (315°C) as a binder were selected for developing high performance composites. Fibers of carbon or graphite are known to be inert with the matrices and hence possibility of composites with weaker interface always exists. Hence these are expected to be treated prior to the use as reinforcement. In this work GrF was treated with HNO3 as per standard practice. The composites with modified and unmodified GrF were developed using a solution impregnation technique followed by compression molding. Two more composites were developed with surface modification technique using these treated GrF. For surface designing a solid lubricant, hexagonal boron nitride-hBN also known as white graphite was used in two sizes {micron (≈1.5μm) and nano-meter (≈70nm)} in different amounts. These composites were evaluated for adhesive wear performance under selected loads and speed by sliding against a mild steel disc (Ra≈0.1μm). It was observed that the μ and specific wear rate (K0) of a composite without modified GrF and without solid lubricated surfaces showed higher values as compared to composites with treated GrF and solid lubricated surfaces. Surface modification by nano-hBN proved most effective leading to a very low μ and K0. Overall, μ and K0 as low as 0.04 and 3×10−16m3/Nm were reported when tested under severe conditions which are treated as extremely good for antifriction materials. The thermo-mechanical stresses incurred in the fibers were examined using Raman spectroscopy by conducting long duration experiments. The film transfer on the disc which was responsible for this performance was studied using SEM–EDAX.