The assignee ranking in this dataset covers 90 companies across 240 records, and it is led by a single assignee holding 70 of those records — far ahead of the rest of the field. The top five assignees combined hold 47.9% of all 240 records, and the top ten hold 61.3%, so ownership is concentrated at the top with a long tail of smaller filers below it. This pattern is typical of a mature materials field where a few established refractory and steelmaking manufacturers built the core composition claims early and everyone else files around the edges.

The representative filing in this dataset, US20150353426A1, illustrates the common claim structure: a specific mass ratio of graphite to magnesia raw material tied to a measured performance outcome, in that case apparent porosity of 7.8% or less after a defined firing regime. Claims in this field generally combine a composition range (magnesia purity, graphite loading, antioxidant addition) with a measurable performance threshold (porosity, slag penetration depth, thermal shock cycles survived) rather than claiming a material in the abstract. That composition-plus-performance pattern is what makes many of these claims narrow enough to design around with a different ratio or additive package.

Among receiving offices tracked in this dataset, China leads with 88 records, followed by Japan at 48, the United States at 27, India at 21, the European Patent Office at 15 and Australia at 12. This distribution tracks steelmaking production capacity closely, since magnesia carbon and basic refractory bricks are consumables for steel ladles and converters. A filer targeting global protection should weigh China and Japan coverage most heavily given where the bulk of prior art already sits.