Nano Powder Metal Technology: How Mizutani's University of Tokyo Partnership Changed Steel

Mizutani Scissors occupies a unique position in the professional scissors industry: a manufacturer that has invested in genuine materials science research rather than simply selecting from available commercial steel grades. Their Nano Powder Metal technology, developed through a research collaboration with the University of Tokyo, represents one of the most significant proprietary advances in scissors steel.

The HIP Process

Nano Powder Metal is a registered trademark of Mizutani, and the steel is produced using Hot Isostatic Pressing (HIP / ホットアイソスタティックプレッシング). In this process, fine metal powder is subjected to extremely high temperatures and pressures simultaneously, applied uniformly from all directions using an inert gas medium.

The result is a steel with a remarkably uniform microstructure. Traditional steelmaking — even high-quality Japanese production — produces some variation in carbide distribution and grain size. HIP processing eliminates most of this variation by consolidating the powder into a fully dense material without the directional grain structures that conventional forging and rolling create.

The University of Tokyo Collaboration

The research was led by a physicist at the University of Tokyo, bringing academic metallurgical expertise to a practical manufacturing application. According to Mizutani, the resulting steel is “free of impurities when looked at under a microscope” and demonstrates “extraordinary resistance to abrasion.”

These are strong claims, but the underlying science supports them. Powder metallurgy steels genuinely achieve finer, more evenly distributed carbide structures than conventionally processed steels. Finer carbides mean a smoother, more consistent cutting edge at the microscopic level — directly relevant to scissors performance.

CMC: The Damascus Core Steel

Alongside Nano Powder Metal, Mizutani developed CMC — a patented micropowder metal formulation with higher molybdenum content than standard compositions. CMC is used specifically as the core steel in Mizutani’s Damascus series, where it provides the actual cutting edge while the layered Damascus cladding forms the blade body.

The elevated molybdenum content improves the steel’s resistance to pitting corrosion and enhances its response to heat treatment. For a cutting tool used in wet salon environments and exposed to chemical treatments, this is a practical benefit rather than a theoretical one.

Extramarise Heat Treatment

Mizutani’s proprietary technologies extend beyond the steel itself to its processing. Their Extramarise heat treatment incorporates sub-zero processing (サブゼロ処理 / sabuzero shori), cooling the steel well below freezing as part of the hardening cycle.

Sub-zero processing converts retained austenite — a softer phase that can persist after conventional quenching — into martensite, the hard phase responsible for edge retention. The result is a more completely hardened steel with improved dimensional stability. The blade is less likely to develop subtle warps or shifts over time, maintaining its geometry through years of use and repeated sharpening cycles.

Why It Matters

Mizutani’s investment in materials science is notable because it moves beyond the industry norm of selecting from commercially available steel grades. By developing proprietary steels and processing methods through academic research partnerships, they have created genuine differentiation — not through marketing, but through metallurgy.