In this dataset all three are searched together because they share the same core claim structure: propelling particles at a substrate to build a coating, differing mainly in how the particles are heated and accelerated. Plasma spray and thermal spray claims tend to center on particle melting and deposition temperature, while cold spray claims focus on high-velocity solid-state bonding without melting the feedstock. Patent classification does not always separate them cleanly, which is why searches combining all three terms under IPC C23C4, C23C24 and B05B7 return a fuller picture than searching any one term alone.

Activity in this corpus concentrates among a small group of established industrial gas-turbine, semiconductor-equipment and materials companies that have filed steadily since before 2017, rather than being spread evenly across many entrants. Several of these established names show zero filings in the most recent tracked year, meaning their portfolios are largely settled rather than growing. A full ranking by family count is rendered in the assignee table on this page rather than summarized here, since the relative order shifts as new publications are added.

Filing fell from a peak of 52 families in 2017 to 24 at the 2022 midpoint and to 2 in the most recent partial year, a pattern consistent with a technology area where the core process and composition claims have already been substantially staked out. Declining filing volume does not indicate declining industrial use; thermal spray coatings remain widely used in turbine, semiconductor and wear-resistant applications. It more likely reflects that incremental improvements are harder to patent distinctly once the foundational composition and deposition claims are already covered, and remember the most recent year is always undercounted due to publication lag.

The IPC composition shows C23C coating and deposition claims present in 866 of 889 records, far outweighing spraying equipment (B05B, 103) and powder metallurgy (B22F, 48). That imbalance suggests spray equipment design, powder feedstock blends that cross into powder metallurgy, and in-situ process monitoring such as residual stress measurement during deposition are comparatively under-claimed relative to the coating composition itself. A first claim in one of these branches would likely center on a specific feedstock blend or monitoring method rather than a broad coating composition, which is already dense prior art.

CA1298147C, assigned to Union Carbide, claims a method of thermal spray coating that heats particles to a relatively higher temperature before impingement specifically to achieve improved adherence, low residual stress and resistance to spalling. Anyone using a similar two-stage particle heating approach to reduce residual stress in a sprayed coating should review this filing's claim scope carefully, particularly the specific temperature-staging step. Because it dates to 1992, its term has very likely expired, but it remains foundational prior art that later, still-active filings may build on or narrow around, so it is worth checking downstream citing patents rather than relying on the original filing's status alone.