Measurement of Cyclic Stresses in High Temperature Range Using Nickel Electroplating : 1st Report, Plating Conditions and Calibration Tests

Abstract

By using an electroplated nickel, a fundamental research for measurement of cyclic stresses in high temperature range is carried out. The plating used consists of two layers, namely, a preliminary deposit of alkaline copper in a copper cyanide bath and a dull nickel deposit in a Watts bath. It is suitable for the present purpose that the current density of nickel deposits is taken to be below 0.5 mA/mm². In the high temperature range up to 200°C, grains of deposited nickel grow large when the deposits are subjected to a cyclic shearing strain of more than a certain magnitude. As a result of examination of the relation between the shearing strain with which grains begin to grow and the number of cycles, it is found under the plating conditions tested that the available testing temperature for the method is within the range of 100 ∼230 °C.