Analysis of organic binder distribution in spray dried granules by ultrasonic-atomic force microscopy

In this paper, ultrasonic-atomic force microscopy (U-AFM) was applied for obtaining qualitative and quantitative information of binder distribution in spray dried ceramic slurries. Embedded granules were mounted on the surface of a transducer generating acoustic waves, 0 to 500KHz. These samples were vibrated at their resonant frequency while surfaces were scanned with a cantilever. Thus, both hardness and topography images were collected simultaneously. Since the contrast of the two materials is related to hardness, the distribution of binder and ceramic can be found immediately from the hardness images. By modeling the cantilever with its deflection vibration, the quantitative modulus of the binder and ceramic mixture was acquired while the sample and cantilever were vibrated at their resonance frequency. From the calibration with an Al₂O₃ sample, those measurements were reconfirmed.