Mercury intrusion porosimetry of plasma-sprayed ceramic

Abstract

Limitations and corrections for the application of mercury intrusion porosimetry (MIP) in measuring plasma-sprayed ceramic (alumina-titania) deposits are studied. The data reduction procedures of the MIP technique are discussed; the importance of which changes between different machines and samples. Thus, it is proposed that each published result should be accompanied by the specific data reduction procedures and assumptions used so that data may be compared. Preparation of plasma-sprayed ceramic samples has a significant influence on the MIP result. Sample fragmentation into irregular pieces (below about 1.2 mm effective diameter) prior to the MIP measurement resulted in an increase of surface effects such that the surface roughness dominated the MIP data and the measured porosity volume increased. Variation in sample thickness between 0.8 and 4.7 mm did not change the measured porosity. Orientation (parallel or perpendicular to the substrate) of the flat surface did not have a measurable effect on the MIP results.