ENAMELLING OF, OR APPLYING A VITREOUS LAYER TO, METALS

Description

C23D encompasses the application of vitreous (glass-like) coatings to metallic surfaces through enamelling processes. This subclass covers the chemical composition of enamel materials, application techniques, firing methods, and surface preparation procedures specific to creating durable ceramic coatings on metals such as steel, copper, and aluminum. The classification includes ground coat formulations, cover coat systems, and specialized enamels for functional applications (e.g., cookware, sanitaryware, industrial equipment). C23D excludes other metallic coatings and non-vitreous surface treatments, which fall under different C23 divisions.

Filing statistics

CPC subclass C23D recorded 1,358 patent applications worldwide between 2013 and 2023. Annual filings grew from 59 in 2013 to 93 in 2023 (+58%), peaking at 184 applications in 2020. The most active applicants in class C23 are APPLIED MATERIALS (10,596 applications), TOKYO ELECTRON (5,229 applications) and LAM RESEARCH CORPORATION (3,622 applications).

Source: EPO PATSTAT, worldwide filings