METHOD AND INSTRUMENT FOR MEASURING THERMAL EXPANSION COEFFICIENT OF LONG SIZED SAMPLE

摘要

PURPOSE:To accurately measure the thermal expansion coefficient of a long pized sample by measuring electric resistance between two end points of a sample which does not practically receive the influence of a temperature change and converting the electric resistance into an average temperature change. CONSTITUTION:A laser scanning micrometer 5 contactlessly detects a change in the length of a sample S by detecting the quantity of transmitted light of laser beams which is varied according to the displacement a marker 4. Current terminals a1, a2 for supplying current to the sample S and voltage terminals b1, b2 for detecting the potential difference between both the end parts of the sample S are connected to both the end parts. Both the end parts of the sample S to which respective terminals are connected are set up on positions which are not practically influenced by a temperature change applied by a heating furnace 7. The proper average temperature change of the sample S and the change in the length of the sample are found out from the obtained measurement data and the thermal expansion coefficient is found out from the sample length between both the voltage terminals b1, b2 obtained before the temperature change.