Glasses and glass-ceramics in the CaO–MgO–SiO2 system: diopside containing compositions - a brief review

Among different silicate systems, CaO−MgO−SiO2 is the one of the most promising due to abundance of reagents, easier fabrication, improved performance, and wide range of application. Analysis of the current literature sources denotes that phase diagram of CaO−MgO−SiO2 system is regularly used by researchers worldwide as constitutive model for synthesis glass-ceramic materials (GCs) possessing an adequate combination of high chemical durability, mechanical and electrical properties. In recent years, materials from this system attracted extra interest for applications in bone tissue repair owing to their ability to induce hydroxyapatite formation in contact with body fluids and to be resorbed in controllable degradation rate. In this brief review diopside containing compositions are specifically discussed. The main goal is to provide critical analysis of the experimental trials directed on synthesis of GC materials in the CaO−MgO−SiO2 system. Glass compositions were analysed through the standpoint of their location in the relevant region, or phase field, within a phase diagram to guide GC production and to make educated choices of compositions and processing parameters. Apart from Introduction and Conclusions this review comprises five consecutive parts. In the first part, constitution of phase diagram of CaO−MgO−SiO2 system is comprehensively discussed with connection to melts’ crystallization path and crystalline phase formation. In the second part, special attentiveness is drawn towards diopside- containing GCs produced from wastes and non-expensive natural raw materials. In this regard and taking into consideration presence of Al2O3 in the majority types of wastes, cross sections of CaO−MgO−SiO2−Al2O3 system with 10, 15 and 20% of Al2O3 are suggested to utilize when anticipating ultimate crystalline phase(s) formation. The following parts of this review are mostly addressed to recent advancement in producing optimized diopside-containing glass–ceramic biomaterials for bone repair as well as innovative sealants for solid oxide fuel cells (SOFC). Likewise, some other active areas of research and application for diopside containing GC compositions are briefly discussed.publishe

EUROMAT 2019 Symposia on Processing

This issue of JMEP contains invited, peer-reviewed papers presented at the European Congress and Exhibition on Advanced Materials and Processes (EUROMAT 2019), held on September 1–5, 2019, in Stockholm, Sweden, in two symposia from the Area C “Processing”: C6 “Joining,” organized by Anna Zervaki (University of Thessaly, Greece), Ivan Kaban (IFW Dresden, Germany), and C. Sommitsch (Technische Universität Graz, Austria) C8 “Interface Design and Modelling, Wetting, and High-Temperature Capillarity,” organized by Pavel Protsenko (M.V. Lomonosov Moscow State University, Russian Federation), Fabrizio Valenza (CNR—ICMATE, Genoa, Italy), and Simeon Agathopoulos (University of Ioannina, Greece) The research works in the field of joining technologies, presented at the C6 symposium, concerned soldering, brazing, diffusion bonding, resistance spot welding, friction stir welding, and riveting techniques. The symposium C8 covered research topics on grain boundary wetting, surface energy of liquid metals and interfacial phenomena, considering fundamental as well as applied issues related to materials joining, and interface design. We wish to thank the authors for the written contributions and acknowledge the reviewers for their careful reading and evaluation of the manuscripts and valuable suggestions to improve the quality of the papers. We are grateful to the editor-in-chief of JMEP, Dr. Rajiv Asthana, and the ASM journal staff, including Mary Anne Fleming, senior content developer; Kate Doman, content developer (journals); and Vincent Katona, production coordinator; for the opportunity to publish the symposia contributions in this issue and for their professional and friendly support during the entire reviewing and publication process. We hope this collection will stimulate fresh thinking and promote further research on joining and interfacial phenomena

CHARACTERIZATION AND DETERMINATION OF INTERFACIAL PROPERTIES OF BIOCERAMIC OXIDES IN CONTACT WITH BIOLOGICAL LIQUIDS AND LIQUID METALLIC PHASES

THIS STUDY INVOLVES THE CHARACTERIZATION (CERAMOGRAPHY, MICROHARDNESS, THERMAL EXPANSION COEFFICIENT) OF NEW MIXED OXIDES BASED ON AL2O3, ZRO2, SIO2 AND TIO2. IN ORDER TO EVALUATE THEIR BIOCOMPATIBILITY, WETTING EXPERIMENTS WERE CARRIED OUT WITH BIOLOGICAL LIQUIDS, AT 37 C. THUS, THE SURFACE ENERGIES OF THE SOLIDS AND THE LIQUIDS DUE TO DISPERSION AND POLAR FORCES WERE DETERMINED. FORTHE EVALUATION OF THE ADHESION BETWEEN THE OXIDES AND LIQUID METALLIC PHASES, THE CONTACT ANGLE, THE WORK OF ADHESION AND THE INTERFACIAL ENERGY WERE EXPERIMENATALLY DETERMINED. EXPERIMENTAL RESULTS SHOWED THAT IN ALL CASES THE CONTACT ANGLE WAS GREATER THAN 90 C. THE WETTABILITY IS IMPROVED AT HIGHER TEMPERATURES AND IN HIGH MELTING POINT MATALS. FINALLY, A SEMI-EMPIRICAL EQUATION IS PROPOSED TO CALCULATE THE INTERFACIAL ENERGY.ΣΤΗΝ ΜΕΛΕΤΗ ΑΥΤΗ ΧΑΡΑΚΤΗΡΙΣΤΗΚΑΝ (ΚΕΡΑΜΟΓΡΑΦΙΑ, ΜΙΚΡΟΣΚΛΗΡΟΤΗΤΑ, ΣΥΝΤΕΛΕΣΤΗΣ ΘΕΡΜΙΚΗΣ ΔΙΑΣΤΟΛΗΣ) ΝΕΑ ΜΙΚΤΑ ΟΞΕΙΔΙΑ ΜΕ ΒΑΣΗ ΤΑ AL2O3, ZRO2, SIO2 ΚΑΙ TIO2, ΠΟΥ ΠΑΡΑΣΚΕΥΑΣΤΗΚΑΝ ΜΕ ΔΙΑΦΟΡΕΣ ΚΟΝΙΟΜΕΤΑΛΛΟΥΡΓΙΚΕΣ ΤΕΧΝΙΚΕΣ. ΑΠΟ ΠΕΙΡΑΜΑΤΑ ΔΙΑΒΡΟΧΗΣ ΠΡΟΣΔΙΟΡΙΣΤΗΚΕ Η ΣΥΝΑΦΕΙΑ ΤΩΝ ΟΞΕΙΔΙΩΝ ΑΥΤΩΝ ΜΕ ΜΙΑ ΣΕΙΡΑ ΒΙΟΛΟΓΙΚΩΝ ΥΓΡΩΝ ΣΤΟΥΣ 37C, ΩΣ ΜΙΑ IN VITRO ΕΚΤΙΜΗΣΗ ΤΗΣ ΒΙΟΣΥΜΒΑΤΟΤΗΤΑΣ. ΕΤΣΙ ΠΡΟΣΔΙΟΡΙΣΤΗΚΑΝ ΟΙ ΕΠΙΦΑΝΕΙΑΚΕΣ ΕΝΕΡΓΕΙΕΣ ΤΩΝ ΟΞΕΙΔΙΩΝ ΚΑΙ ΤΩΝ ΥΓΡΩΝ ΠΟΥ ΟΦΕΙΛΟΝΤΑΙ ΣΤΗΔΡΑΣΗ ΤΩΝ ΔΥΝΑΜΕΩΝ ΔΙΑΣΠΟΡΑΣ ΚΑΙ ΤΩΝ ΠΟΛΙΚΩΝ ΔΥΝΑΜΕΩΝ. ΓΙΑ ΤΗ ΜΕΛΕΤΗ ΤΗΣ ΠΡΟΣΦΥΣΗΣ ΣΤΗ ΔΙΕΠΙΦΑΝΕΙΑ ΟΞΕΙΔΙΩΝ/ΤΗΓΜΕΝΩΝ ΜΕΤΑΛΛΙΚΩΝ ΦΑΣΕΩΝ, ΠΡΟΣΔΙΟΡΙΣΤΗΚΑΝ ΠΕΙΡΑΜΑΤΙΚΑ Η ΓΩΝΙΑ ΔΙΑΒΡΟΧΗΣ, ΤΟ ΕΡΓΟ ΣΥΝΑΦΕΙΑΣ ΚΑΙ Η ΔΙΕΠΙΦΑΝΕΙΑΚΗ ΕΝΕΡΓΕΙΑ ΚΑΘΩΣ ΚΑΙ Η ΕΠΙΔΡΑΣΗ ΤΗΣ ΘΕΡΜΟΚΡΑΣΙΑΣ ΣΤΑ ΜΕΓΕΘΗ ΑΥΤΑ. ΤΑ ΠΕΙΡΑΜΑΤΙΚΑ ΑΠΟΤΕΛΕΣΜΑΤΑ ΕΔΕΙΞΑΝ ΟΤΙ ΣΕ ΟΛΑ ΤΑ ΣΥΣΤΗΜΑΤΑ ΠΟΥ ΕΞΕΤΑΣΘΗΚΑΝ Η ΓΩΝΙΑ ΕΠΑΦΗΣ ΗΤΑΝ ΜΕΓΑΛΥΤΕΡΗ ΤΩΝ 90 C, ΕΝΩ Η ΔΙΑΒΡΟΧΗ ΒΕΛΤΙΩΝΕΤΑΙ ΑΥΞΑΝΟΜΕΝΗΣ ΤΗΣ ΘΕΡΜΟΚΡΑΣΙΑΣ ΚΑΙΤΟΥ ΣΗΜΕΙΟΥ ΤΗΞΗΣ ΤΟΥ ΜΕΤΑΛΛΟΥ. ΤΕΛΟΣ, ΠΡΟΤΕΙΝΕΤΑΙ ΜΙΑ ΗΜΙΕΜΠΕΙΡΙΚΗ ΣΧΕΣΗ ΠΟΥ ΕΠΙΤΡΕΠΕΙ ΤΟΝ ΥΠΟΛΟΓΙΣΜΟ ΤΗΣ ΔΙΕΠΙΦΑΝΕΙΑΚΗΣ ΕΝΕΡΓΕΙΑΣ

Microstructural features, physicο-mechanical properties, and wear behavior of dental translucent polychromic multilayer zirconia of hybrid composition prepared by milling technology

Objective: The present study determined the mechanical properties and the wearbehavior, as results of the micro(nano)structure, of the enamel, transition, and den-tine layers, which comprise the polychromic multilayer zirconia materials of hybridcomposition fabricated by milling technology.Materials and Methods:Prismatic blocks were fabricated from two commercialpre-sintered dental polychromic multilayer zirconia materials of hybrid composi-tion, IPS e.max ZirCAD Prime (medium andhigh translucency, from the dentineto the incisal layer) and 3D Pro ML (translucency gradient, from the dentine tothe incisal layer) by milling technique, and then, cut into 3 distinct parts to sepa-rate the enamel, transition, and dentine layers. The samples were sintered, ther-mally treated (similarly to the glazing procedure), and polished forcharacterization. Their microstructure, mechanical properties (determined bynanoindentation and microhardness), andwear behavior (evaluated by scratchtest), were examined.Results:The produced materials had a homogeneous and dense nanostructure,where the grain size decreased from the enamel to dentine layer. The mechanicalproperties also decreased from the enamel to dentine layer. However, the threelayers manifested similar dynamic friction coefficient.Conclusion:The differences in the above properties in the three layers negligiblyinfluenced the wear behavior of the entire multilayer zirconia material.Clinical Significance:The properties of dental restorations produced from poly-chromic multilayer zirconia of hybrid composition by milling technology(i.e., strong, non-fragile, and esthetic materials), anticipate good performance inoral cavit

Synthesis of Si, N co-Doped Nano-Sized TiO2 with High Thermal Stability and Photocatalytic Activity by Mechanochemical Method

Τhe photocatalytic activity in the range of visible light wavelengths and the thermal stability of the structure were significantly enhanced in Si, N co-doped nano-sized TiO2, and synthesized through high-energy mechanical milling of TiO2 and SiO2 powders, which was followed by calcination at 600 °C in an ammonia atmosphere. High-energy mechanical milling had a pronounced effect on the mixing and the reaction between the starting powders and greatly favored the transformation of the resultant powder mixture into an amorphous phase that contained a large number of evenly-dispersed nanocrystalline TiO2 particles as anatase seeds. The experimental results suggest that the elements were homogeneously dispersed at an atomic level in this amorphous phase. After calcination, most of the amorphous phase was crystallized, which resulted in a unique nano-sized crystalline-core/disordered-shell morphology. This novel experimental process is simple, template-free, and provides features of high reproducibility in large-scale industrial production

Wollastonite-containing glass-ceramics from the CaO–Al2O3–SiO2 and CaO–MgO–SiO2 ternary systems

Glass-ceramics (GCs) are polycrystalline materials produced from parent glasses by the controlled crystallization that results in crystalline phase(s) embedded in a residual amorphous matrix. Typically, GCs are produced by a conventional glass route with subsequent crystallization for which two heat treatments are usually applied, the former to generate nuclei and the latter being a crystal growth stage. Alternatively, another technically viable route for manufacturing GCs involves sintering of glass-powder compacts followed by crystallization (sinter-crystallization).Wollastonite-containing GCs from the CaO–Al2O3–SiO2 and CaO–MgO–SiO2 systems find a wide variety of uses in different technological fields, including construction, architecture, medical and high-tech fields. For example, a special type of wollastonite-containing GC marketed under the name of Neoparies®, which is stronger and lighter than natural stone, features high resistance to weathering/chemical attack and is manufactured on a large scale for construction and architectural applications. In the biomedical field, the well-known Cerabone® products have been used in bone-contact applications for many years.The main goal of this brief review is to provide a critical analysis of the experimental trials focusing on the synthesis of wollastonite-containing GC materials and to discuss the various fields of their application. Constitution of phase diagram of CaO–Al2O3–SiO2 and CaO–MgO–SiO2 systems are comprehensively discussed with connection to melt crystallization path and crystalline phase formation. Furthermore, special emphasis will be given to the production of wollastonite-containing GCs for construction and architectural purposes from natural raw materials and wastes, as well as to the recent advancement in developing wollastonite-containing GC biomaterials for bone repair