COBARION®

COBARION development began in 2001 in Iwate Prefecture’s Kamaishi, which is known as the City of Steel. Recognizing the potential of cobalt alloys in industrial applications, Akihiko Chiba, then a professor at Iwate University, began research to develop a material for medical use. In 2012, he completed a prototype for use in artificial joints. This groundbreaking new material, COBARION, was revolutionary in the medical field, thanks to hypoallergenic properties that made it gentle on the body and its outstanding strength and resistance to both abrasion and corrosion.

Then, in 2017, MR-G, the flagship brand of G-SHOCK timepieces, adopted the material. Takehiro Sasaki explains, “Up until then, we had been producing COBARION for larger things like artificial joints. Working with MR-G, though, required making the material in thinner, more compact forms that would make it easier to process during timepiece production. We engaged in so many processes of trial and error to attain a thinner form while maintaining its hardness.”

As with ordinary metals, the COBARION production process involves the three stages of melting, in which the constituent elements are heated to the melting point and fused together; forging, where this material is pressed and shaped to increase its hardness; and rolling, in which the metal is shaped thinner to make it easier to process. After extensively experimenting with the number of melting processes to apply, and adjusting melting temperatures, Sasaki eventually hit upon the ideal production process. Additionally, the final stage of rolling ended up making the material even harder. It was quite a struggle, Sasaki says, however, with surface breakage and cracks sometimes appearing when the material was rolled out thinly. Furthermore, the COBARION was actually so hard that it would sometimes damage the rolling equipment itself, making it even more challenging to process. Nonetheless, when the trial and error work was finally complete so that the rolling worked, Sasaki discovered that the new ratio of original to post-process thickness yielded an even harder final product.

At the same time, cobalt alloys also have the property of increasing in hardness when nitrogen, which was traditionally considered an impurity, is injected during the melting stage. This makes it similar to the deep-layer hardening process applied to pure titanium for use in MR-G timepieces.

Chiba explains, “In my research on cobalt alloys, I found that incorporating nitrogen dramatically increased their hardness. The material is rigid and increases in hardness when pressed at high temperatures. It is non-magnetic and also has a high elongation rate when heated. This combination of properties is so exceedingly rare in metals that it would be more accurate to say this alloy exists in a whole new class of its own.”

The corrosion resistance of COBARION offered another unexpected benefit as well: a gleam comparable to platinum. As Chiba describes it, “A dense, robust, ultrathin passivating oxide film that forms on the surface beautifully reflects light without diffusion,” creating a gleam that is soft, white, and profound.

The impressive scratch resistance of COBARION also ensures that this gleam stays true for the long-term, which is one of the reasons why the material is so well suited for crafting watch bezels and other fine items like jewelry. COBARION offers a hardness exceeding that of both stainless steel and titanium, as well as a beauty comparable to platinum. A material befitting MR-G timepieces, echoing both their total toughness and their captivating beauty, COBARION brings an unmistakable gleam to every lucky wrist with an MR-G.