Filing peaked at 118 records in 2018 and had fallen to 66 by the 2022 midpoint, with the decline continuing through subsequent years. This pattern is typical of a claim space where the core compositional territory has already been staked out by early filers, leaving later entrants to pursue narrower ratio windows or component-specific applications rather than broad new chemistries. It does not mean research interest has disappeared, but that the easiest claims have already been filed. Publication lag also means the very latest year always looks thinner than it will eventually turn out to be.

The corpus is dominated by a small set of Japanese and US-based organisations, including Nippon Steel, Toshiba and its materials affiliate, Hitachi, Alps Alpine, Panasonic, and Metglas-linked entities. Nippon Steel stands out as the only one of these still filing in the most recent tracked year. Historical volume, however, does not equal current activity — several of the largest historical filers show no recent filings at all, so a ranking by total family count and a ranking by recent momentum tell different stories.

In practice the terms overlap heavily in this corpus and are usually treated as synonyms in search strategy, though "bulk metallic glass" typically signals a claim to a three-dimensional, thermoplastically formable alloy rather than a thin ribbon or coating. The representative filing in this dataset, for a Zr-Nb-Cu-Ni-Al bulk metallic glass, illustrates the pattern: claims are written as tight elemental ratio constraints rather than broad open-ended compositions. Distinguishing the two matters mainly when assessing whether a claim covers thin-film or ribbon forms as well as bulk components.

IPC concentration data shows alloy composition (C22C) claims heavily outnumber coating and surface-deposition claims (C23C) and heat-treatment claims (C21D), even though surface chemistry is central to real-world corrosion and oxidation performance. Sub-areas such as surface passivation layer chemistry, post-anneal oxidation barrier treatments, and corrosion-resistant amorphous coatings on crystalline substrates show comparatively thin filing density relative to bulk composition claims. Anyone drafting in this space should search these narrower branches specifically rather than relying on aggregate C22C search results, which will overstate how crowded the coating side actually is.

US20130340897A1, assigned to Crucible Intellectual Property, claims a Zr-Nb-Cu-Ni-Al bulk metallic glass where the Nb-to-Zr ratio stays below roughly 0.040 and the Cu-to-Ni ratio stays below 1.15, improving thermal stability and thermoplastic formability. This is a narrow elemental-ratio claim rather than a broad compositional one, so it blocks filings that fall inside those specific ratio windows within this five-element system but leaves alloys outside the ratios, or built on different element sets entirely, open. Anyone drafting a similar Zr-based system should check their ratios explicitly against this filing before assuming clearance.