The use of advanced ceramics, composites and coatings constantly grows in different industrial areas, such as mining, mineral and fuel production and processing, refinery, petrochemical and chemical processes, power generation, engineering, biomedical applications and many others. In these applications, the materials should possess high integrity in various wear, corrosion and synergistic wear-corrosion conditions. The application processes require optimisation of the existing advanced materials and their technologies specifically to obtain necessary designs. The development of new materials, including oxide and non-oxide ceramics, ceramic-ceramic and ceramic-metal composites and protective coatings on metallic components, with improved properties and their technologies may be also required according to harsh service conditions. The gradual deterioration and failure mechanisms of the ceramic and coating materials under wear and corrosion application conditions should be paid significant attention, and the routes of materials’ wear and corrosion resistance enhancement need to be considered for the products reliability, processes efficiency and service longevity. This special issue combines the results of recent developments in advanced materials and their testing or service results under wear, corrosion and wear-corrosion-related conditions for different applications, and/or it reviews the achievements in these areas. The special issue covers the following aspects:
Development and processing of ceramics, composites (e.g., ceramic-ceramic and ceramic-metal) and coatings and their evaluation in wear and corrosion application conditions;
Relationship of composition-structure-application properties (wear and corrosion resistance) for ceramics, composites and coatings;
Ceramic components design, technology and installation features for industrial wear and corrosion applications;
Case studies and examples of applications of industrial components for mining and mineral processing, power generation, engineering and biomedical applications, chemical and petrochemical industry and other situations where corrosion and wear are serious issues;
Deterioration and failure mechanisms of ceramics and coatings depending on specific application/ service conditions under wear (e.g., abrasion, erosion, cavitation, fretting and friction) and corrosion (gaseous or liquids, including acidic and basic environments, brines, molten salts and metals, of different chemistries and concentrations, various flow parameters, elevated temperatures and pressures, etc.);
Methods of testing and evaluation of ceramics and coatings in different wear and corrosion environments;
Trends and paths of advanced materials development and manufacturing for wear and corrosion applications and new potential service areas.
All 14 papers of the special issue were prepared according to the personal invitation by the guest editor. The authors, which represent different countries from North America, Europe and Asia, are recognised specialists in the area of advanced materials for wear and corrosion applications. The results in some selected articles have been presented at international ceramic or advanced materials conferences, while some articles describe absolutely new results.
The special issue’s articles encompass wear and corrosion studies of different advanced materials with different compositions and structures, which were obtained by different processing routes. In the majority of the articles, new materials or technologies have been developed and tested. The conducted studies demonstrated the importance of the appropriate selection of the materials’ composition, dense structure and surface quality. The necessity to consider and apply certain processing routes to obtain the desirable components’ design and the importance of the testing and evaluation methods are also demonstrated and emphasised. Moreover, the paths to obtain the materials with enhanced properties through the creation of the desirable structure and by proper technology were proposed or outlined in the majority of articles.
The paper by D. Wolfe et al. reviewed advanced engineered ceramic coatings (e.g., based on oxides and non-oxides) with enhanced wear and corrosion resistance and integrity at high temperatures mostly for power generation. The authors highlighted many critical aspects, including coating functionalities, design features and architectures, processing influences, and provided future directions for engineering high-performance ceramic coatings. S. Ueno and T. Ohji reviewed the environmental barrier coatings (EBC) for non-oxide ceramics, specifically for Si3N4- and SiC-based ceramics, also for power generation. The developed and described oxide-based EBC with selected eutectic compositions can successfully withstand high temperature, highly oxidising environments and protect non-oxide ceramics for the gas turbine components.
High-entropy ceramic materials, such as metal carbides and borides, are reliable candidates for wear resistance applications due to their superior hardness and toughness and ability to withstand high temperatures where the components may serve. Thus, A. Naughton-Duszova et al. demonstrated high performance of the dual-phase (Ti-Zr-Nb-Hf-Ta)-carbide-boride ceramics under friction-induced wear conditions and described possible wear mechanism under the mentioned conditions for these materials. Alumina, zirconia and alumina-zirconia ceramics are highly reliable materials for various wear and corrosion-related applications. Highly homogeneous structures consisting micron- and sub-micron grains obtained through the optimised processing are the critical factors to reach high application properties of these advanced ceramics. L. Curkovic et al. and M. Grabowy et al. demonstrated a high level of wear and corrosion resistance of these materials in selected harsh environments.
Appropriate advanced coatings provide necessary and superior protection of metallic components in various industries, such as mining and mineral processing, oil & gas production, power generation and many other industrial situations, especially when bulk ceramic or composite components are difficult or impossible to produce because of their designs and/or dimensions. The coatings may be based on ceramics, glassy, composites or intermetallides, and their compositions and technologies are selected based on specific application and service conditions, on design of the components, which need to be protected, on metallic substrates, and many other factors. Thus, enamel (glassy) coatings on low-cost carbon steels significantly outperformed bare steels, including stainless steels, in various corrosion service environments, such as high temperature – high pressure steams containing acid gases (H2S, CO2 and CO), concentrated acids and brines, related to downhole oil & gas and geothermal production, and refinery, chemical and petrochemical processing. The proposed technology can be scaled-up for various shapes and dimensional components, including for the protection of inner and/or outer surface steels piping systems. Tungsten carbide-based composite overlays developed and prepared by G. Fisher and D. Diaz demonstrated high wear resistance (in both abrasion and erosion environments), and the obtained materials have high potential in various mining and oil sand processing applications. Composite materials based on ceramic ingredients in the metallic matrix may be good options for different wear-related applications not only in mineral processing and engineering applications, but also for aircraft and marine engineering components, specifically where repairing is regularly required. W. Jibran et al. developed the metal matrix composite (MMC) coatings based on Al alloys with embedded Al2O3 grains and demonstrated high performance in abrasion conditions and high tensile strength of these MMC. Specifically, the Al2O3-Al MMC coatings, which were obtained by two-step process including cold spraying and friction stir processing, demonstrated higher application properties compared to the single-step process due to attained superior structural homogeneity and higher consolidation of the coating. The copper-chromium spinel CuCr2O4 synthesised through the Pechini and the modified Pechini sol-gel methods is proposed as the potential coating material on stainless steels for concentrated solar power applications. J. Billman et al. studied the processing routes’ features, calcination temperatures, and the influence of these processing factors on the ceramic phase composition, grain sizes and morphology; the spinel particles of sub-micron sizes have been obtained. The chromising technology was proposed to enhance wear resistance of carbon and tool steels. The authors evaluated chromide-based coatings’ performance through structural analysis, indentation and nano-indentation techniques and tribological studies, depending on steel composition, and they proposed, which steels are better suited for chromising to reach more reliable performance.
Advanced coatings for biomedical applications were prepared to improve the corrosion and tribo-corrosion resistance of implants. Z. Wang and I. Zhitomirsky developed the technology of polymer-diamond composite coatings (films) on stainless steels with multi-layered architectures, which can be managed. The obtained coatings containing diamond nano-particles demonstrated promising results according to the electrochemical characterisation. The carbide-derived carbon (CDC) coatings on Ti-based alloys developed by Y. Sun et al. also had superior tribo-corrosion resistance. These CDC coatings significantly outperformed bare Ti6Al4 V widely employed as the implant material based on the electrochemical and pin-on-disk tribo-corrosion testing. Clinical implications with these coatings are proposed.
A new method of rapid evaluation of wear resistance of ceramics, composites and coatings has been proposed by P. Mechnich and G. Alkan. In their work, the authors employed the resonant acoustic mixer with zirconia media, i.e. erosion resistance of various materials could be evaluated under different conditions. The authors tested dense alumina ceramics, plasma spray-Al2O3 coating and WHIPOX Al2O3/Al2O3 ceramic matrix composite without and with reaction-bonded Al2O3 coating.
As the guest editor, I am grateful to all the authors who contributed their manuscripts to this special issue of the Journal of Advances in Applied Ceramics and their efforts to prepare the manuscripts in time. I am also grateful to all reviewers for their work and advice, which definitely helped to improve the papers for publication. I hope that this special issue will be interesting and useful for many ceramic specialists from academia and industry who work with the development, manufacturing and evaluation of advanced ceramics and coatings, specifically for wear- and corrosion-related applications, as well as for the specialists who use advanced materials in modern devices and technologies in the mentioned applications.