High loading of nanostructured ceramics in polymer composite thick films by aerosol deposition

Abstract

Low temperature fabrication of Al2O3-polyimide composite substrates was carried out by an aerosol deposition process using a mixture of Al2O3 and polyimide starting powders. The microstructures and dielectric properties of the composite thick films in relation to their Al2O3 contents were characterized by X-ray diffraction analysis. As a result, the crystallite size of α-Al2O3 calculated from Scherrer's formula was increased from 26 to 52 nm as the polyimide ratio in the starting powders increased from 4 to 12 vol.% due to the crushing of the Al2O3 powder being reduced by the shock-absorbing effect of the polyimide powder. The Al2O3-polyimide composite thick films showed a high loss tangent with a large frequency dependence when a mixed powder of 12 vol.% polyimide was used due to the nonuniform microstructure with a rough surface. The Al2O3-polyimide composite thick films showed uniform composite structures with a low loss tangent of less than 0.01 at 1 MHz and a high Al2O3 content of more than 75 vol.% when a mixed powder of 8 vol.% polyimide was used. Moreover, the Al2O3-polyimide composite thick films had extremely high Al2O3 contents of 95 vol.% and showed a dense microstructure close to that of the Al2O3 thick films when a mixed powder of 4 vol.% polyimide was used.

A Comparative Study on the Influence of Nano and Micro Particles on the Workability and Mechanical Properties of Mortar Supplemented with Fly Ash

“…Moreover, the characterization results of MA and NA by XRD are shown in Figure 4. The XRD patterns for both Al2O3 particles were similar and agreed with the previous study [21]. Notable peaks were at angles of (2θ) 35°, 40°-45° and 55°-60°, which confirmed the α-Al2O3 phase of aluminum oxide.…”

“…Notable peaks were at angles of (2θ) 35°, 40°-45° and 55°-60°, which confirmed the α-Al2O3 phase of aluminum oxide. The intensity of the peaks was higher with NA compared with MA, which was due to the presence of nanocrystallites generated by the crushing of particles during deposition [21]. Figure 5 shows the XRD characteristic spectra of FA.…”

Controlled Nanoconfinement of Polyimide Networks in Mesoporous γ-Alumina Membranes for the Molecular Separation of Organic Dyes

“…The absence of diffraction peaks correlated with the γ-alumina phase where the polyimide network is confined can be explained by the nanosized nature of this layer. Kim and Nam 38 described a decrease in the diffraction peaks of the α-alumina phase when different polyimide/α-alumina film composites were prepared using an amorphous polymer. Interestingly, the diffraction peaks of the α-alumina phase were identical with our pristine support, thus suggesting either small amounts or even the absence of the PI network in the α-alumina pores.…”

Percolative BaTiO3/Carbon-Nanotube Composite Films Employing Aerosol Deposition

“…An aerosol deposition (AD) process can be an alternative fabrication process to solve the problems with current methods. The AD process, which can be used to fabricate ceramic, [16][17][18][19][20][21][22][23][24] metal, 25) and composite [26][27][28][29][30][31] films at room temperature, is based on shock-loading solidification due to the impact of ultrafine particles accelerated through a nozzle by carrier gases, as described elsewhere. [32][33][34] In this work, we present BaTiO 3 /multiwalled carbon nanotube (MWNT) composite thick films fabricated by the AD process at room temperature.…”