Session: AM9.1 - Materials for (strategic sectors) Aerospace and Defense applications

Paper Number: 189887

189887 - Synthesis of Diamond Reinforced Hybrid Reaction Bonded Silicon Carbide 

Abstract

Advanced defence, aerospace, and precision manufacturing sectors demand structural materials capable of simultaneously delivering ultra-high hardness, superior wear resistance, thermal stability, and enhanced impact energy absorption. Reaction Bonded Silicon Carbide (RBSiC) is widely recognized for its excellent mechanical strength, oxidation resistance, low density, and high-temperature performance. However, conventional RBSiC ceramics suffer from inherent brittleness, low fracture toughness, and limited ballistic energy-dissipation capability, restricting their performance in extreme wear and protective armour applications. This research proposes the development of a diamond-reinforced hybrid RBSiC.

Diamond powder (Grit size »160 mm) was uniformly mixed with structural matrix material SiC powder (Grit size »10 mm), and porous silicon carbide preforms were produced. The composite structure was synthesized using a vacuum-assisted molten silicon infiltration process applied to engineered porous silicon carbide preforms containing uniformly dispersed diamond. Coke and graphite were added to the premix to facilitate the formation of secondary SiC during the Si infiltration process. This approach was expected to improve densification, reduce residual free silicon content, and preserve reinforcement integrity during processing.

Experimental results demonstrated significant improvement in the mechanical and structural performance of the developed composite system. Diamond-reinforced RBSiC composites exhibit Rockwell hardness values in the range of HRA (Rockwell Hardness A) 93–95, indicating superior hardness compared to conventional RBSiC materials. Ultrasonic evaluation reveals a sonic velocity of approximately 12 km/s, suggesting high elastic modulus, excellent densification, and strong interfacial bonding within the composite structure. X-ray diffraction analysis confirmed the retention and successful detection of the diamond phase after infiltration processing, demonstrating effective protection of diamond particles during high-temperature fabrication. The densification analysis indicated near-zero residual porosity (≈0%), confirming complete silicon infiltration and highly compact microstructural development. Thermal stability and oxidation resistance are also being examined to validate performance in extreme environmental conditions. The proposed hybrid reinforcement architecture generates synergistic strengthening mechanisms through multi-phase interfacial reactions and reinforcement interaction, resulting in improved wear resistance, fracture toughness, and ballistic performance compared to conventional RBSiC materials.

Presenting Author: R Vivek Sriram INDIAN INSTITUTE OF TECHNOLOGY MADRAS

Presenting Author Biography: Vivek Sriram R is a research scholar specializing in advanced ceramic composites and superabrasive-reinforced materials. His work focuses on developing diamond, cBN, and boron carbide reinforced Reaction Bonded Silicon Carbide (RBSiC) composites for high-wear and ballistic protection applications. His research interests include vacuum silicon infiltration, interfacial coating engineering, and microstructural characterization using SEM, XRD, and Raman spectroscopy. He aims to pursue doctoral research at IIT Madras and contribute to next-generation defense and industrial material technologies.