MORPHOLOGICAL AND MECHANICAL CHARACTERISTICS OF DENSE POROUS CERAMICS USING CARBON BLACK AND POLYMETHYL METHACRYLATE AS PORE-FORMING AGENTS AT VARYING CONCENTRATIONS

Abstract

Porous ceramics are widely used in high-performance engineering applications due to their unique porosity, mechanical stability, and thermal resistance. However, optimizing the trade-off between porosity and mechanical strength remains a significant challenge, particularly when employing different pore-forming agents. This study investigates the morphological and mechanical characteristics of dense porous ceramics fabricated using carbon black (CB) and polymethyl methacrylate (PMMA) as pore-forming agents at varying concentrations (1–5 wt%). Despite extensive research on individual porogens, a comparative analysis of their influence on microstructure evolution, pore distribution, and mechanical performance in a single ceramic system remains largely unexplored. Ceramic samples were synthesized via a solid-state reaction and subjected to controlled sintering at 1175°C. Microstructural characterization using Field emission scanning electron microscopy (FESEM) revealed that CB generated small, uniformly distributed closed pores, enhancing mechanical integrity, while PMMA introduced larger, interconnected open pores, promoting higher porosity but reducing strength. X-ray diffraction (XRD) analysis confirmed the presence of orthoclase, silicon dioxide, and mullite phases, with variations in crystallinity influenced by porogen type. Mechanical evaluation through three-point flexural testing demonstrated that 3 wt% CB resulted in the highest flexural strength of 49.72 MPa, whereas PMMA incorporation led to a substantial decrease, reaching 14.80 MPa at 5 wt% due to excessive porosity and structural discontinuities. This study provides new insights into porogen selection for tailoring ceramic microstructures, demonstrating that CB is more suitable for applications requiring high mechanical strength, while PMMA is beneficial where enhanced permeability is prioritized. The findings contribute to the development of high-performance porous ceramics for energy-efficient insulation, filtration, and lightweight structural applications, offering a systematic framework for optimizing porosity-mechanical strength relationships in advanced ceramic materials.