OREANDA-NEWS. December 27, 2011. Furukawa Electric Co., Ltd. has developed high-strength copper Corson alloy strip EFCUBE-ST, as an electrical contact material (terminal material) used for ultra-compact connectors mounted on thin electronic devices.
 The product adopts a high-density Corson alloy (note 1) that meets needs for high springing properties, and features high bending workability and a low Young's modulus (note 2) made possible by Furukawa Electric's proprietary metal structure control technologies.
 Samples are already being shipped to major connector manufacturers. Monthly production of 300 tons is targeted in fiscal 2013, combined with EFCUBE-820(C64775) and other Corson alloy products already being mass produced.
 
Background of development

With connectors mounted on smartphones, tablets and other thin mobile electronic devices, smaller sizes, reduced height, and multipolar structures are demanded. Copper alloy strips for connectors used on these devices need to possess contradictory properties, namely high springing properties and favorable bending workability. In addition, favorable elasticity (a low Young's modulus) that resists permanent deformation and high electrical conductivity are demanded, in line with the decrease in length and the cross-section area of terminals. Conventional high-strength copper alloys (titanium-copper alloy and beryllium-copper alloy) only offer insufficient electrical conductivity and elasticity, and also pose issues in terms of costs.
Features of developed product

Furukawa Electric has developed the high-strength alloy strip EFCUBE-ST, to replace existing titanium-copper alloy strips. The developed product features high strength based on high-concentration Corson alloy, with significantly improved bending workability, something that had been an issue with high-strength Corson alloy strips. These properties have been made possible by applying the proprietary metal structure control technologies.
 By aligning crystal orientations in a direction effective for improving their properties, favorable bending workability (minimum bendable radius (note 3): 1t) has been realized, in addition to high strength (yield strength: 900MPa) and a Young's modulus as low as that of phosphor bronze (110GPa). Consequently, the product helps to boost the connection reliability (note 4) of connectors. With roughly triple the electrical conductivity (35% IACS) of phosphor bronze and titanium-copper alloys combined with high thermal resistance (stress relaxation properties), the product is also ideal for connectors used with advanced devices and batteries and other power source systems loaded with large electrical currents.
 EFCUBE-ST is an alloy made by precipitation of Ni-Si compounds at a high concentration. Using the cutting-edge facilities newly introduced to Copper Strips Division (Nikko), stable structure control has become possible, enabling groundbreaking copper alloys strip to be developed.
 Also, industry-leading plate thickness accuracy and surface quality have been achieved using production technologies cultivated with lead frame materials and other products.
 EFCUBE-ST has been developed to meet needs for more advanced functions than those provided by EFCUBE-820, developed last year, and is set to contribute to further reductions in the dimensions of thin mobile electronic devices.