The coarsening parameter K=(r 3 -r 0 3 )/t has been measured for Al 2 O 3 in Al-9Ti-6O-1Mg-0.35Li-1.25C (wt.%) at 600 o C for comparison with measurements for Al 4 C 3 , Al 3 Ti, Al 1 3 Fe 4 , Al 1 2 (Fe,V) 3 Si and Al 3 Ni in aluminium-based matrices at 600 o C. Measured values of K follow the same sequence as theoretical values, but observed values are typically an order of magnitude smaller than calculated values assuming that one `unit' of the coarsening phase is added each time an atom of the slowest diffusing, least soluble, solute becomes attached.