Intercomparison of thermal expansion etalons.

Project Description

The knowledge of the thermal expansion of length standards is a requirement for reaching highest accuracy in length measurements. This was highlighted by EUROMET Project 275 for slip gauges up to length of 100 mm. A general survey in 1995 showed a wide interest in widening such a comparison of rod-shaped artifacts up to length of 500 mm. The measuring equipment of the interested partners are very different and sometimes designed for certain artifacts. Therefore, we have selected for the comparison different types of artifacts, but all with a basic length of 500 mm. These etalons are:

• Gauge blocks of steel (9 x 35)
• Gauge block of ceramics (9 x 35)
• Gauge block of zerodure (30 x 40)
• Line standard of steel
• Rod of aluminium (20 x 20)
   

We are able to determine with our measuring equipment the thermal expansion coefficient of all suggested etalons with nearly the appropriate measurement uncertainty which will ensure the comparability of all measurement result.

Every institution select from these etalons the suitable to their measuring devices.