Superhard WC94Co6 ceramic electrodes enabling long-term reliability in touch-probe sensors

초록

In high-precision machining, touch probe sensors are essential in accurately detecting the starting point of operations. Although the Ag90Ni10 electrode is highly conductive and widely used, it suffers from wear under repeated contact. Repeated fast contacts enlarge the effective contact area and can induce electrical arcing, promoting a sharp increase in electrical contact resistance (ECR), degrading the long-term reliability of the Ag90Ni10 metal electrode. Consequently, for prolonged operation, maintaining a stable resistance value is more critical than achieving a low initial resistance. We adopted a WC94Co6 electrode as an alternative to Ag90Ni10. Owing to its mechanical durability and high melting temperature, WC94Co6 maintains a lower contact resistance after prolonged cycling, making it a suitable electrode for high-precision touch-probe applications. SEM and EDS analyses confirmed a well-maintained surface composition. Even after 30,000 contact cycles, AFM results revealed a low surface roughness (Ra) of only 184.62 nm, indicating superior wear resistance. ECR measurements over 30,000 cycles demonstrated that the resistance of WC94Co6 increased from 13 mΩ to 42 mΩ during the first 15,000 cycles. Beyond 20,000 cycles, however, the resistance stabilized, increasing slightly from 44 mΩ at 20,000 cycles to 46 mΩ at 30,000 cycles. In contrast, Ag90Ni10 maintained 6.5–7 mΩ up to 15,000 cycles but showed a sharp increase thereafter. WC94Co6 is far less susceptible to wear or property degradation under repeated contact, making it a more suitable long-term alternative to Ag90Ni10. © 2026 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

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