Metallic glass lacks the crystalline grain structure of conventional alloys, so it has no grain boundaries or dislocations for corrosive attack to concentrate on. This gives it more uniform passivation behavior and typically better pitting resistance. The patent record reflects this: the largest single category of claims (C22C, 3,852 records) targets alloy composition directly, because the corrosion benefit is largely a property of the amorphous structure itself rather than an added coating.

Filing activity in this corpus is concentrated among a group of Japanese electronics and materials companies alongside university and research institution filers, with co-assignee links typically connecting a parent company to its own materials subsidiary. Several of the most historically active filers show no filings in the latest tracked year, which is worth checking against their wider patent portfolios rather than assuming exit from the field. Ranking detail for specific assignees is shown in the tables on this page rather than repeated here.

No — filing peaked in 2019 at 202 records and has declined in most years since, reaching around 138 at the 2022 midpoint and continuing down toward the present. That decline pattern, combined with heavy concentration in C22C alloy composition claims, suggests the core chemistry space is well-occupied. Remember that the most recent one to two years are always understated in any patent trend because publication typically lags filing by about 18 months.

The clearest gaps sit in processing and coating routes rather than bulk alloy chemistry: C23C coating and deposition claims run at less than a third the volume of C22C alloy claims, and B22F powder metallurgy, B22D casting and C21D heat treatment routes are thinner still. A claim built around a passivation coating or a specific heat-treatment step applied to an existing amorphous substrate composition is likely to face less crowded prior art than a new bulk alloy chemistry claim.

Citation counts are useful for identifying which patents shaped later filings, but they structurally favor older records simply because they have had more years to accumulate citations. The top-cited record in this corpus, at 760 citations, dates to a 1990s beryllium-bearing alloy patent — influential, but not necessarily the most commercially relevant filing today. Use citation rank to find foundational prior art to clear, not as a proxy for current market importance.