Why Does a Sapphire Case Still Need DLC? Surface Engineering Behind the 20-Piece G-SHOCK

2026/10/02

Casio has introduced the MRG-D5000, a blue-sapphire G-SHOCK limited to only 20 pieces worldwide. While sapphire provides exceptional scratch resistance and visual depth, the watch still incorporates titanium components treated with DLC—Diamond-Like Carbon.

Hardness Alone Is Not Enough

Sapphire is extremely hard and scratch-resistant, but hardness is different from toughness. Concentrated impact or stress around screw holes may still cause cracking.

To address this issue, Casio developed the MR-G Multi-Guard Structure. The bezel and case consist of multiple components assembled without screws, helping reduce stress concentration and protect the sapphire during impact.

Why Apply DLC to Titanium?

According to Casio’s specifications, DLC is applied to the titanium portions rather than the sapphire surface.

In this composite structure, each material performs a different role:

Sapphire crystal: Scratch resistance and visual appeal
Titanium: Lightweight structural support and impact resistance
DLC coating: Surface protection, wear resistance and a refined dark finish
Multi-component structure: Impact distribution and material protection

DLC coatings are known for high hardness, wear resistance, low friction and chemical stability. However, their actual performance depends on substrate preparation, coating adhesion, film uniformity, internal stress and operating conditions.

Relevance to Creating Nano Technologies

The use of DLC on titanium watch components reflects areas relevant to Creating Nano Technologies Inc., including DLC coating, surface pretreatment, film adhesion, wear protection and decorative surface finishing.

For titanium or complex precision parts, successful DLC application requires more than depositing a hard film. Surface cleanliness, activation, coating uniformity, adhesion and durability must all be evaluated according to the material and product requirements.

There is currently no public information indicating that Creating Nano Technologies participated in the MRG-D5000 project. However, the watch provides a clear example of composite surface engineering: sapphire, titanium and DLC do not replace one another—they work together to balance scratch resistance, structural toughness, surface protection and appearance.

Sources

Creating Nano Technologies, Inc.
59 Alley 21 Lane 279, Chung Cheng Road, Yung Kang City, Tainan, TAIWAN
TEL:886-6-2323927 FAX:886-6-2013306 URL: http://www.creating-nanotech.com

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