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Item type:Publication, Access status: without files , Novel technique for measurement of coating layer thickness of fine and porous particles using focused ion beam(2019-02-01); ; ; ; A novel technique for the measurement of the coating layer thickness of fine particles was developed in this work based on cross-sectioning of micrometre-sized single coated particles using focused ion beam (FIB) milling. This technique was tested on two batches of aerogel particles coated with thin coatings in a spouted bed. The FIB milling procedure consisted of two steps. First, the desired part of the coated particle was removed using a high ion beam current. The resulting cross-sectioned area was then polished using a lower ion beam current to make the cross-section clearly visible. The FIB milling process was controlled with simultaneous scanning electron microscopy (SEM). Afterwards, the coating layer thickness was evaluated using the SEM images. The coating layer was successfully applied on the porous aerogel microparticles in the spouted bed. The coating uniformity of the highly porous particles increased with increasing sprayed coating solution amount, with up to 91% of the particle pores being covered. The FIB-cross-sectioning technique using an ion beam of 2.50 nA for the first milling and 0.43 nA for polishing of the surface resulted in successful generation of cross-sections of representative particles with a visible particle core and coating layer. A coating layer thickness of approximately 700 nm was achieved on particles with sizes of below 45 μm.Publicationtype: Journal Article262 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Coating of fine Aerogel particles using spouted bed technologyAerogels are porous and light-weighting materials with high inner surface area. Their properties enable to use them in many fields, e.g. as acoustic and thermal insulation materials, catalyst, adsorber or drug carriers. However, open pore structure does not allow their application in different areas because of change of the structure caused by liquid-contact. Therefore there is a protective layer on their surface needed, which provides new fields of application, e.g. in food products. In this work coating of the protein-based aerogel microspheres (dP < 100 μm) with shellac using spouted bed technology was performed. This method enables applying of dense, uniform and thin coating layer on fine particles. To improve the uniformity of the coating layer the specific surface area before and after the coating procedure was measured and showed clear decrease after longest coating time. To investigate the behavior ofaerogels in water containing medias the particles were exposed to water drops using sessile drop protocol. The coating protects the aerogel particles from water influence.Publicationtype: Conference Paper168 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Coating of protein-based aerogels using spouted-bed technology(Wiley-VCH, 2016-08-29); ; ; ; Publicationtype: Journal Article102