Ultrasonic velocity for estimating density of structural ceramics

The feasibility of using ultrasonic velocity as a measure of bulk density of sintered alpha silicon carbide was investigated. The material studied was either in the as-sintered condition or hot isostatically pressed in the temperature range from 1850/sup 0/ to 2050/sup 0/C. Densities varied from approximately 2.8 to 3.2 g/cm/sup 3/. Results show that the bulk, nominal density of structural-grade silicon carbide articles can be estimated from ultrasonic velocity measurements to within 1% using 20 MHz longitudinal waves and a commercially available ultrasonic time intervalometer. The ultrasonic velocity measurement technique shows promise for screening out material with unacceptably low density levels.