**1. Introduction**

Discovered by Klement et al. in the early 1960s, amorphous metallic glasses have attracted much attention for several decades due to their outstanding properties, such as excellent mechanical properties, good corrosion resistance, and unique physical and chemical characteristics. These metallic materials are suitable for application as a new class of advanced materials [1–3]. However, their tiny size, a result of their limited glass-forming ability (GFA), makes it difficult to use BMG materials in industry.

Therefore, over the past decades, three main directions have been followed in the development of higher-quality BMG materials with better properties. These directions are as follows: (1) new compositions of metallic alloys [4–6], (2) novel processing routes [7–11], and (3) potential application fields [12–15]. In efforts to achieve new bulk metallic glasses (BMG) with high glass-forming ability (GFA), many studies have focused on establishing a relationship between the GFA and the chemical compositions of metallic materials. For example, in the Al-based metallic system, both types of metal elements, transition metal elements, and rare earth metal elements can increase the GFA of Al-based alloys [15, 16]. On the other hand, various processing routes, such as melt spinning [7], magnetron sputtering [8], pulsed laser quenching [9], and liquid splat-quenching [10] have also been developed to overcome the crucial constraint on the size and geometry of metallic glass samples. For instance, a high-throughput strategy, named the combinatorial approach via co-sputtering, has been developed for producing and characterizing substantial compositional libraries at the same time [11]. In addition, several studies have also focused on discovering potential fields of application, such as structural materials [3], hydrogen storage materials [12], soft magnetic materials [13], and biomaterials [14].

Although several research articles concerning metallic glass materials have been published, almost no studies have conducted patent analyses of metallic glass materials, to the author's best knowledge. Patent information is useful because it contains valuable research results for the researcher, business planner, R&D manager, and policymaker [17–20]. The reason is that a patent application is a costly and time-exhausting process; the willingness of the applicant to invest time, money, and effort in the process generally indicates that the patent can provide commercial benefits and technical contributions. Therefore, as pointed out by Daniel Gredel et al., patent documentation is the most comprehensive of all research resources. Nearly 70% of the technical information contained in these documents is not available in any other type of information source, and it can be used for detailed analysis [21]. For instance, patent data can be used to analyze competitors, track the evolution of technology, master crucial technologies, and identify the trends and conditions of patent development in different markets [22].

In the present research, patent data were analyzed to explore the technological development of metallic glass materials. The variations in numerous patents and assignees, technology life cycle, and categories of patents for metallic materials were studied. Furthermore, the top ten patent assignees and the trends of their patents filed, patent families, and patent citations were analyzed. The top five families and five most-cited patents are also explored in the present study.

The article is structured as follows. Section 2 presents the study methodology and the details of the information analysis. Section 3 presents an analysis of amorphous alloys patenting activity and possible explanations for the data. In Section 4, the final section, the implications and conclusions are presented.
