Updated definition of glass-ceramics

TLDR

Glass‑ceramics combine unique properties and commercial products, and over the past 60 years new processing routes, compositions, and nano‑microstructures have prompted a review of their definition. The paper proposes a revised definition of glass‑ceramics as inorganic, non‑metallic materials prepared by controlled crystallization of glasses via different processing methods. The authors analyze processing methods—including co‑firing, additive manufacturing, and laser patterning—highlighting that glass‑ceramics contain at least one functional crystalline phase with a residual glass and that the crystallized volume fraction can range from ppm to nearly 100 %.

Abstract

Glass-ceramics are noted for their unusual combination of properties and manifold commercialized products for consumer and specialized markets. Evolution of novel glass and ceramic processing routes, a plethora of new compositions, and unique exotic nano- and microstructures over the past 60 years led us to review the definition of glass-ceramics. Well-established and emerging processing methods, such as co-firing, additive manufacturing, and laser patterning are analyzed concerning the core requirements of processing glass-ceramics and the performance of the final products. In this communication, we propose a revised, updated definition of glass-ceramics, which reads "Glass-ceramics are inorganic, non-metallic materials prepared by controlled crystallization of glasses via different processing methods. They contain at least one type of functional crystalline phase and a residual glass. The volume fraction crystallized may vary from ppm to almost 100%".