Barium Titanate Thin Films Obtained by Screen Printing Technology

Barium titanate thin films have been obtained using screen printing of pastes based on BaTiO3 na-nopowders. Obtained pastes have been characterized by optical microscopy and optical profilometry. De-posit pattern geometry fidelity in regard to screen mask and films thickness and roughness parameter Ra during screen printing parameters changing depended on pastes rheological behavior. In addition, films roughness and thickness were strongly depended on solid and solvent content in pastes. Solvent content rising and BaTiO3 content lowering resulted in films thickness and roughness decreasing. Depending on paste solid and content barium titanate films thickness was changed from 1.56 to 3.18 m, the film rough-ness Ra from 50 to 196 nm and Rz from 160 to 393 nm. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3515

Rheology and Printability of Pastes Based on BaTiO3 Nanopowder Depending on Ethyl Cellulose Viscosity

This paper is about rheology of pastes based on BaTiO3 nanopowder with ethyl cellulose 100 cP (paste P1) and 10 cP (paste P2) as organic binder. It was established, that P1 was pseudoplastic – thixotropic system and P2 was rheopexic - pseudoplastic – thixotropic one. The reduction of EC viscosity led to changing of paste structurization type from pseudoplastic (P1) to plastic one (P2). Structurization of P1 can be explained with excess of polymer in the paste composition and with dominance of the polymer – polymer bonds. Unlike P1, P2 has some elastic properties due to strong structural links because of polymer – nanoparticle bonds. Moreover, the value of initial viscosity of P2 (2.11 Pa∙s) was much less than of P1 (37,5 Pa∙s). It was found, that the viscosity of polymer influences the paste printability. In particular, P2 was more prone to form thinner and smoother prints. Thus, composition of P2 was more promising one for obtaining prints with good quality and subsequent assembly into a multilayer object due to its elastic properties during low deformation

Rheology and Printability of Pastes Based on BaTiO3 Nanopowder Depending on Ethyl Cellulose Viscosity

This paper is about rheology of pastes based on BaTiO3 nanopowder with ethyl cellulose 100 cP (paste P1) and 10 cP (paste P2) as organic binder. It was established, that P1 was pseudoplastic – thixotropic system and P2 was rheopexic - pseudoplastic – thixotropic one. The reduction of EC viscosity led to changing of paste structurization type from pseudoplastic (P1) to plastic one (P2). Structurization of P1 can be explained with excess of polymer in the paste composition and with dominance of the polymer – polymer bonds. Unlike P1, P2 has some elastic properties due to strong structural links because of polymer – nanoparticle bonds. Moreover, the value of initial viscosity of P2 (2.11 Pa∙s) was much less than of P1 (37,5 Pa∙s). It was found, that the viscosity of polymer influences the paste printability. In particular, P2 was more prone to form thinner and smoother prints. Thus, composition of P2 was more promising one for obtaining prints with good quality and subsequent assembly into a multilayer object due to its elastic properties during low deformation

Relationships Between Pore Structure, Free Carbon Content, Particle Size Distribution and Deposition Stage of Ni/NiO Nanopowers

Ni/NiO nanopowders have been prepared by using thermal decomposition of aqua solutions of nickel acetate ammine complexes in air at the annealing temperature range 300 – 500 ºC, time of decomposition from 30 to 180 min. Particle size of powders has been investigated by and scanning electron microscopy (SEM). Powders pore structure has been determinated by low temperature nitrogen adsorption method. Content of free carbon in powders is determitated by stage of decomposition and annealing temperature. Decomposition of hydroxy-containing precursor at occurred in 3 stages: 1) the primary formation of Ni; 2) decomposition of precursors with formation of NiO; 3) afterreduction of NiO to Ni by residuals of organic compounds and ammonia. The first two stages is characterized by highly endothermic effect that can lead to decreasing of acetic acid evaporation rate and resulted in high free carbon content of powders. Increasing of deposition time permits to remove of acetic acid from particle surface and decrease free carbon content in powder

Synthesis of Ni/NiO Nanosize Powders with Different Phase Ratio by Thermal Decomposition of Nickel Acetate Amines

Ni/NiO nanopowders with different phase ratio have been prepared using thermal decomposition of nickel acetate ammine complexes containing various ammonia content in air at the temperature range 300 – 500 °C. Obtained powders have been characterized by IR-spectroscopy, XRD and TG, DTA, DTG, TEM, laser granulometry and adsorption-structural method. Thermal decomposition of nickel ammine complexes occurred with forming nickel hydroxide, carbonate and hydroxocarbonate ammines precursors. Composition of the precursors depended on temperature and ammonia content in initial complex. Mean crystallite size of nickel depended on temperature only. In the temperature range from 350 to 500 °C the crystallite size of nickel has grown from 50 to 55 nm. Mean crystallite size of nickel oxide depended on temperature and ammonia content. In the temperature range from 350 to 500 °C the crystallite size of NiO has grown from 5 to 25 nm. Increasing ammonia content from 3.6 to 14.4 mol/mol Ni led to decreasing NiO crystallite size from 8 – 10 to 5 nm. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3512

Features of Ni / NiO Nanopowder Synthesis by Thermal Decomposition of Nickel Acetate Amines: Effect of Annealing Temperature and Duration and Ammonia Content on Powder Composition and Particle Size

Ni/NiO nanopowders with different metal and oxide phase ratio have been prepared by using thermal decomposition of nickel acetate ammine complexes which contain various ammonia concentrations at the temperature range 300 – 500 ºC in air. Obtained powders have been characterized by IR-spectroscopy, XRD and TG, DTA, DTG, TEM, laser granulometry, adsorption-structural method and layer-by-layer Auger analysis. Thermal decomposition of nickel ammine complexes occurred with formation of crystalline hydroxide containing and amorphous carbonate containing precursors. Changing of precursors composition with different NH3 content and annealing duration and temperature leads to different pore structure, agglomerate size of powders and determinates free and fixed carbon concentrations. Mean crystallite size of nickel depended on temperature only. In the temperature range from 350 to 500 °С the crystallite size of nickel has grown from 50 to 55 nm. Mean crystallite size of nickel oxide depended on temperature and ammonia content. In the temperature range from 350 to 500 °С the crystallite size of NiO has grown from 5 to 25 nm. Increasing ammonia content from 3.6 to 14.4 mol/mol Ni led to decreasing NiO crystallite size from 8–10 to 5 nm

Features of Ni / NiO Nanopowder Synthesis by Thermal Decomposition of Nickel Acetate Amines: Effect of Annealing Temperature and Duration and Ammonia Content on Powder Composition and Particle Size

Ni/NiO nanopowders with different metal and oxide phase ratio have been prepared by using thermal decomposition of nickel acetate ammine complexes which contain various ammonia concentrations at the temperature range 300 – 500 ºC in air. Obtained powders have been characterized by IR-spectroscopy, XRD and TG, DTA, DTG, TEM, laser granulometry, adsorption-structural method and layer-by-layer Auger analysis. Thermal decomposition of nickel ammine complexes occurred with formation of crystalline hydroxide containing and amorphous carbonate containing precursors. Changing of precursors composition with different NH3 content and annealing duration and temperature leads to different pore structure, agglomerate size of powders and determinates free and fixed carbon concentrations. Mean crystallite size of nickel depended on temperature only. In the temperature range from 350 to 500 °С the crystallite size of nickel has grown from 50 to 55 nm. Mean crystallite size of nickel oxide depended on temperature and ammonia content. In the temperature range from 350 to 500 °С the crystallite size of NiO has grown from 5 to 25 nm. Increasing ammonia content from 3.6 to 14.4 mol/mol Ni led to decreasing NiO crystallite size from 8–10 to 5 nm

Inkjet Printing of Thin Dielectric Films Based on BaTiO3

BaTiO3 thin films have been prepared by inkjet depositing of ceramic inks based on barium titanate nanopowder. Formulated inks had good sedimentation stability. The most significant stabilization of the pigment was observed for samples formulated on ethyl and n-butyl alcohols. All prepared inks had dilatant flow with a pronounced minimum viscosity of Newtonian flow. The printing operation was performed using thermal drop-on-demand inkjet printer. Printed films had dense structure and considerable adhesion to the substrate surface. Optical profilometry of the three layer film showed thickness about 400 nm. Due to strong adhesion printed coatings have not separated from the substrate surface. Special method of forming an intermediate polymer film on the substrate surface has been used to separate printed patterns. Aggres-sively dissolving of an intermediate polymer film has been observed during printing on this intermediate layer. After printing of each subsequent layer substrate thickness has been reduced on average 200 nm and took place rising of surface roughness. However, printed layer has been removed from the substrate surface. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3522

Relationships Between Pore Structure, Free Carbon Content, Particle Size Distribution and Deposition Stage of Ni/NiO Nanopowers

Ni/NiO nanopowders have been prepared by using thermal decomposition of aqua solutions of nickel acetate ammine complexes in air at the annealing temperature range 300 – 500 ºC, time of decomposition from 30 to 180 min. Particle size of powders has been investigated by and scanning electron microscopy (SEM). Powders pore structure has been determinated by low temperature nitrogen adsorption method. Content of free carbon in powders is determitated by stage of decomposition and annealing temperature. Decomposition of hydroxy-containing precursor at occurred in 3 stages: 1) the primary formation of Ni; 2) decomposition of precursors with formation of NiO; 3) afterreduction of NiO to Ni by residuals of organic compounds and ammonia. The first two stages is characterized by highly endothermic effect that can lead to decreasing of acetic acid evaporation rate and resulted in high free carbon content of powders. Increasing of deposition time permits to remove of acetic acid from particle surface and decrease free carbon content in powder

Wear-Resistant TiN – Si3N4 Nanocomposites Consolidated By Electric Discharge Sintering

Dense nanocomposites on the basis of silicon nitride with the size of structural elements less than 150 nm have been consolidated by Electric Discharge Sintering. The improvement of materials properties is expected: wearproofness, fracture toughness (~ 5 – 6 MPa м1/2), hardness (~ 22 GPа), bend stress (800- 1100 MPа), stability to the aggressive environments (acids at a room and high temperatures) as compared to traditional materials which now use as frictional unit. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3509