Bone grafting or bone implant is a typical procedure in surgery in which a missing or broken bone is replaced in order to treat bone fractures that pose a significant health risk to the patients. Several research works have been carried out in the past few years regarding various composite materials used in bone implants, their fabrication methods, and evaluation of their physical, mechanical, chemical, and thermal properties. The use of ceramic powders and ceramic-based composites in biomedical applications are steadily increasing over years mainly due to their advantages like high compressive strength, excellent hardness, etc. In this research work, organic ceramic matrix composites with varying proportions of conch shell and sea sponge are fabricated using powder metallurgy technique and their physicomechanical properties such as density, porosity, water absorption, and micro-hardness are evaluated. Finally, optimization of process parameters is done using multi-objective optimization based on ratio analysis (MOORA) to select the best possible specimen of CMCs.
TopIntroduction
The term Composite is now widely used in manufacturing and processing industries. It is described as the combination of two or more materials joined together at flexible proportions. It is generally construed to be having two phases viz., matrix, the major constituent and reinforcement, the minor constituent. The matrix or outer cover may be metals, ceramics or polymers. The reinforcement may be inducted into the matrix in the form of powders, whiskers, short or continuous fibres.
Ceramic Matrix Composites (CMCs) have ceramic powders as major constituents. The CMCs are having increased applications in structural, aviation, marine and medical industries such as engine cylinder blocks, piston heads, combustion passages, etc. due to their high hardness, high compressive strength, good toughness, excellent thermal stability, better electrical insulation and superior corrosion and wear resistance. More specifically, a number of ceramic bio materials and their associated composites such as Alumina, Zirconia, Silica and Tri Calcium Phosphate (TCP) enjoy immense usage in the field of medical sciences, thanks to their bio-compatibility, resistance to organic solvents, bio- inertness and good crack growth initiation. Zirconia toughened Alumina is used abundantly in anthroplasty (Roualdes et al., 2010). Applications of these bio ceramics range from artificial teeth, filling the gap between teeth, orthopedic implants, prosthesis to hip bone replacement, maxillo-facial figuration, plastic surgery and so on. Goswami et al. assessed the physico-mechanical and surface wear properties of Magnesium oxide filled ceramic composites for hip implant applications. In their review paper, they explained the advantages of using ceramic based composites over conventional metal inserts (Goswami et al., 2019). Afzal and Adeel in their survey paper, reviewed various implantable zirconia based bio ceramics for bone repair and replacement (Afzal & Adeel, 2014). To be more precise, CMCs are on the verge of replacing conventional metals, which are traditionally used to join broken bones, exponentially. Nag and Banerjee in their book chapter, explained the properties, processing techniques, development and failure modes of various medical implant materials as well as the responsiveness of host materials to those implants (Nag & Banerjee, 2012). So, the biomaterials can be natural, synthetic or organic ceramics and their composites.
Organic ceramics are a promising variety of bio materials, which are extensively used nowadays to replace broken or disfigured femoral, collar or hip bones. Bone tissues resemble Hydroxy Apatite (HA) structure. Hence, organic ceramics, which are rich in HA can be used in artificial prostheses (Rivera-Muñoz, 2011). Usage of body parts of dead marine organisms for bone tissue engineering is encouraged by Clarke et al. in their review paper (Clarke et al., 2011). They also briefed about the merits of using conch shell in broken human bone replacement. As these organic ceramics are processed from animal body parts, particularly the shells and bones of dead sea organisms like oysters, sea sponges, conches, crabs, snails and cuttlefish, they are less expensive, more environmentally friendly, have more calcium content and provide good adhesion, when more than one such ceramics are used together (Organic CMCs). The advantages of obtaining high crack growth initiation, cell attachment and development in scaffolds, when a sea sponge based artificial fiber skeleton is used are clearly elaborated by Green et al. in their study (Green et al., 2003). Due to their attractive attributes, their usage is phenomenally increasing in bone restructuring and allied activities.
When two or more conflicting or contrasting characteristics, subjected to certain constraints are optimized simultaneously, that particular optimization process is called multi-objective optimization or multi-attribute optimization. Multi Objective Optimization based on Ratio Analysis (MOORA) is one of the novel and recent analytical Multi Criteria Decision Making (MCDM) techniques used in conditions where multi objective parametric optimization is required to select the best set of process parameters and properties among various alternatives. Gadakh indicated the applicability, versatility and flexibility of MOORA, while solving various complex decision-making problems in recent manufacturing scenario (Gadakh, 2011). Karande and Chakraborty observed that, as far as MOORA method is concerned, it is very simple to understand, easy to implement and provide precise ranking to the alternatives, when investigating a problem, that deals with selection of materials (Karande & Chakraborty, 2012).