Rg. Munro et al., VARIANCES IN THE MEASUREMENT OF CERAMIC POWDER PROPERTIES, Journal of research of the National Institute of Standards and Technology, 100(1), 1995, pp. 51-60
Variances in the measurement of properties used to characterize cerami
c powders are discussed in the context of the International Energy Age
ncy's study, Annex II, Subtask 2, which includes chemical and physical
measurements for five powders: two grades of silicon nitride, and one
grade each of silicon carbide, silicon, and zirconia. The analysis pr
esented here includes results for 39 properties reported by 25 laborat
ories using approximately 700 samples of the powders. Measurement unce
rtainties are discussed in the contexts of measurement variations with
in given laboratories (within-laboratory variance, sometimes called re
peatability), among different laboratories (between-laboratory varianc
e, also called reproducibility), and among different measurement techn
iques (between-methods variance). The analysis shows that the between-
laboratory variance tends to be significantly greater than either the
within-laboratory or the between-methods variances. The implication of
this result is that the most important improvements in powder charact
erization measurements may be achieved through the standardization of
the measurement methodologies.