| 摘要 |
PROBLEM TO BE SOLVED: To provide an electrical contact which is made of a Cd-free Ag alloy having no problem with toxicity, has appropriately controlled welding characteristics and temperature characteristics in a tradeoff relation, and is useful particularly for a contact breaker having a rated current of 10 amperes or more and a breaking current of 1.5 KV or more, and an electromagnetic switch having a rated current of 35 amperes or more. SOLUTION: This electrical contact is made of the Ag alloy which contains 1-9 mass% Sn, and less than 1 mass% Cd of an impurity; and has a central layer 1 and an outer layer 2 having higher hardness than that of the central layer 1, in at least a contacting surface part.The central layer 1 has an average hardness of 135 mHv or higher according to a micro-Vickers method, and the outer layer 2 has a surface area of 32.7 to 96.0% with respect to the whole area of the contacting surface. The outer layer 2 has preferably a thickness of 5μm or thicker on average. COPYRIGHT: (C)2005,JPO&NCIPI
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