Patricia Popoola

By Api Popoola, OE Olorunniwo and OO Ige

Part of the book: Developments in Corrosion Protection

By Olanrewaju Adesina, Patricia Popoola and Olawale Fatoba

Over the years, engineering materials are being developed due to the need for better service performance. Wear, a common phenomenon in applications requiring surface interaction, leads to catastrophic failure of materials in the industry. Hence, preventing this form of degradation requires the selection of an appropriate surface modification technique. Laser surface modification techniques have been established by researchers to improve mechanical and tribological properties of materials. In this chapter, adequate knowledge about laser surface cladding and its processing parameters coupled with the oxidation, wear and corrosion performances of laser-modified titanium has been reviewed.

Part of the book: Fiber Laser

By Patricia Popoola, Gabriel Farotade, Olawale Fatoba and Olawale Popoola

Modern aero engine components are subjected to extreme conditions were high wear rate, excessive fatigue cycles, and severe thermal attack are inevitable. These aggressive conditions reduce the service life of components. Its generic effect is magnified in the light of understanding the fact that aero engine parts are highly sensitive to functional and dimensional precision; therefore, repair and replacement are great factors that promote downtime during operation. Hard thermal barrier coatings have been used in recent times due to their optimized properties for maximum load bearing proficiency with high temperature capability to meet performance and durability required. Nevertheless, less emphasis is being given to the coating-substrate interaction. Functionally graded structures have better synergy and flexibility in composition than coatings, giving rise to controlled microstructure and improved properties in withstanding acute state of affairs. Such materials can be fabricated using Laser Engineered Net Shaping (LENS™), a laser-based additive manufacturing technique. LENS™ offers a great deal in rapid prototyping, repair, and fabrication of three-dimensional dense structures with superior properties in comparison with traditionally fabricated structures. The manufacture of aero engine components with functionally graded materials, using LENS™, can absolutely mitigate the nuisance of buy-to-fly ratio, lost time in repair and maintenance, and maximize controlled dimension and multi-geometric properties, enhanced wear resistance, and high temperature strength. This review presents an extensive contribution in terms of insightful understanding of processing parameters and their interactions on fabrication of functionally graded stainless steel, which definitely influence the final product quality.

Part of the book: Fiber Laser

By Gabriel A. Farotade, Patricia A. I. Popoola and Olawale M. Popoola

The financial prudence of the global world is shaken due to the vigor induced by corrosion as the degradation of essential assets, namely, oil and gas platforms and marine machineries, appears as a red-flagged situation. The exacerbation created by chemical degradation of these assets is as a result of the presence of saltwater, and the highly dominating activity of salt in the atmosphere poses a critical influence in selecting the mode of corrosion prevention to be integrated. As the hunger for longer term service and cost effectiveness of protection increases, studies are clustered in the search of new corrosion-resistant coatings while adhering to the increasing stringent environmental code of practice. Porosity is a key factor which is considered in the development of corrosion-resistant coatings, stimulating localized forms of corrosion, such as galvanic and crevice corrosion. Nevertheless, researches have been implemented to coin this challenge by acquiring full understanding of effective parameters of salt bath conditions, their interactions, and influence on the degree of uniform electrodeposition. A significant contribution is presented in the light of reviewing the possibility of computational analysis of system and design parameters in optimizing the deposition rate and quality.

Part of the book: Applied Studies of Coastal and Marine Environments

By Olawale S. Fatoba, Patricia A.I. Popoola, Sisa L. Pityana and Olanrewaju S. Adesina

Laser surface alloying (LSA) is a material processing technique that utilizes the high power density available from defocused laser beam to melt both reinforcement powders and a part of the underlying substrate. Because melting occurs solitary at the surface, large temperature gradients exist across the boundary between the underlying solid substrate and the melted surface region, which results in rapid self-quenching and resolidifications. Reinforcement powders are deposited in the molten pool of the substrate to produce corrosion-resistant coatings. These processes influence the structure and properties of the alloyed region. A 3D mathematical model is developed to obtain insights on the behavior of laser melted pools subjected to various process parameters. It is expected that the melt pool flow, thermal and solidification characteristics will have a profound effect on the microstructure of the solidified region.

Part of the book: Fiber Laser

By Peter Odetola, Patricia Popoola, Olawale Popoola and David Delport

The issue of corrosion and degradation has been evaluated as one of the major sources of concern in the history and trend of materials development and their applications in engineering. Design, process, and production consideration of materials hinge on the motive of built-to-last technology in their lifetime applications. The “World Corrosion Organization” has calculated that the direct cost of corrosion worldwide is over 3% of global gross domestic product (GDP)—approximately US$2.2 trillion—every year.

Part of the book: Electrodeposition of Composite Materials

By Nicholus Malatji and Patricia A.I. Popoola

The inclusion of second-phase particles in nickel-based matrix to fabricate composite coatings presents a promising solution to combating corrosion and wear deterioration of materials during service. Composite coatings possess better surface properties such as wear resistance, high microhardness, thermal stability, and corrosion resistance than the traditional nickel coatings. Their excellent properties enable them to be used in advanced industrial applications where they will be constantly exposed to severe and degrading environments. There are various surface modification techniques that are employed to produce these coatings and electrodeposition has received wide range of use in fabrication of nickel matrix composites. This technique is associated with low cost, simplicity of operation, versatility, high production rates, and few size and shape limitations. To produce advanced electrodeposits with better performance during application, the optimization and further developments of the process remain vital. Therefore, this chapter aims to review the electrofabrication and properties of nickel composite/nanocomposite coatings for corrosion and wear applications.

Part of the book: Electrodeposition of Composite Materials

By Patricia A.I. Popoola, Nicholus Malatji and Ojo Sunday Fayomi

Deterioration of metals and alloys during service due to corrosion and wear phenomena shortens materials’ life span and structural integrity particularly in aggressive environments such as coastal and marine. This degradation also limits the use of these materials in most industrial applications. Therefore, the improvement of the quality of these materials in order to combat these challenges in industry remains critical. Surface modification techniques are employed to enhance materials’ properties to enable better performance and to extend their applications in demanding environments. Electrodeposition has been a useful method developed to improve the corrosion and mechanical properties of materials. In the present contribution, ample knowledge about electrodeposition of Zn composite/nanocomposite coatings and their characteristics are reviewed to address coastal and marine degradation of metals and alloys.

Part of the book: Applied Studies of Coastal and Marine Environments

By Peter Odetola, Patricia Popoola, Olawale Popoola and David Delport

Nowadays, synergy of the attractive properties of materials while avoiding limitations of their use in isolation is a major driver for flexibility in design and manufacture. This allows tailoring of materials’ properties to meet specifications. Composite technology utilizes an excellent combination of properties: strength, stiffness, light weight, wear, chemical, corrosion, and temperature resistance, which transcend those of the constituent materials. Engineering structures, equipment, and vessels in key industries that are material-dependent are susceptible to deterioration process and damage over time in their service conditions. Composite coatings through electro-deposition offer a reliable cost-effective means of impacting special surface properties for corrosion protection, better appearance, and mechanical properties’ enhancement. The properties of the composite coatings can be optimized by varying the type, size, amount and distribution of the particles content incorporated among others.

Part of the book: Electrodeposition of Composite Materials

By Oluranti Agboola, Maurice Steven Onyango, Patricia Popoola and Opeyemi Alice Oyewo

A fractal is an object or a structure that is self‐similar in all length scales. Fractal geometry is an excellent mathematical tool used in the study of irregular geometric objects. The concept of the fractal dimension, D, as a measure of complexity is defined. The concept of fractal geometry is closely linked to scale invariance, and it provides a framework for the analysis of natural phenomena in various scientific and engineering domains. The relevance of the power law scaling relationships is discussed. Fractal characteristics of porous media and the characteristic method of the porous media are also discussed. Different methods of analysis on the permeability of porous media are discussed in this chapter.

Part of the book: Fractal Analysis