RI 7142 Development Of A High-Temperature Interferometric Dilatometer Using A Laser Light Source

A design for a laser-powered optical interferometer, using a specimen whose thermal expansion is to be measured as part of the optical system, was conceived and applied in a prototype dilatometer. The object of thin work was the development of an absolute dilatometer capable of use at elevated temperature, particularly above 1,000° C. The prototype has been operated at temperatures exceeding 1,510° C. Results obtained with this device agree within 2.5 percent with the published data for the coefficient of expansion of columbium.