During the past several years, ECM carried out a large trade-off project with the objective of comparing CTEmeasurements
of samples of our Cesic® MF ceramic material performed by laboratories in Europe, USA, and Japan.
Our focus was on CTE measurements in the cryo-environment down to less than 20 K.
From past experience, we realized that we needed to pay particular attention to making the samples sufficiently large to
obtain realistic measurement results that relate to actual applications, especially for temperatures below that of LN2.
Thus, we made the samples as large as allowed by the size limitations of the test equipment at the different laboratories,
namely, from 15 mm to 250 mm in length.
The scatter in the test data obtained by the different laboratories was so large that the results were unreliable and not very
useful, which we interpreted to be principally due to the large length range of the samples.
Based on these results, we selected Mitsubishi Electric Corporation (MELCO), Japan, for follow-up cryo-measurements
because they were able to test 250-mm long samples down to < 10 K. More recently MELCO enlarged their cryo-test
equipment to sample sizes as large as 500 mm and with the rather high measurement accuracy of 0.1 ppm/K.
In this paper we present the CTE measurement data obtained by the different laboratories and describe the new cryo-test
facility at MELCO.