Benchmarking Transverse-Field-Annealed Nanocrystalline Cores Against Commercial Grades: Theory, Design Constraints and a Pre-Specified Protocol

Status: preprint draft, not peer reviewed. No experiments have been run. Transverse-field annealing of Fe-Cu-Nb-Si-B nanocrystalline ribbon is established and, in published studies, lowers high-frequency core loss; commercial grades already use annealing to shape the B-H loop. This preprint does not claim a new effect. It proposes a fair, reproducible way to compare a laboratory field-annealed core with a named commercial core under identical geometry and excitation, with stated uncertainty. The paper derives four constraints that shape the design: the competition between field-induced and random anisotropy (which scales as the sixth power of grain size), the coupling of permeability to flux penetration in 20 µm ribbon at 100 kHz, the near-collinearity of loss components over 20-100 kHz, and the effect of small phase errors on loss measurement. It then states three falsifiable hypotheses, five testable predictions, a measurement plan adapted from the open MagNet methodology, and decision rules fixed before data collection. Numerical inputs marked as assumed are unverified, and the reference table records what has and has not been checked against full texts. Limitations: the author has no laboratory access, samples or funding, and is seeking a collaborating group with core-loss measurement capability. Parts of the draft were prepared with an AI language model (Claude, Anthropic); the author is responsible for its content, and corrections are welcome.