Jong Rok Ahn
材料科学技术（英文）
Four oxide nanoparticles, such as yttrium oxide, lanthanum oxide, cerium oxide and zirconium oxide were coated on rhenium filaments by an electrophoretic deposition method. The oxide coatings were examined by scanning electron microscopy, and electron emission characteristics of the oxide-coated rhenium were studied to find alternative oxide materials for replacing the hazardous thorium oxide. Among four oxides tested in this work, yttrium oxide and lanthanum oxide coated rhenium showed enhanced electron emission compared with an uncoated rhenium. However, lanthanum oxide coating evaporated too quickly in a vacuum chamber, and hence yttrium oxide was found to be the only alternative material for use in a routine mass spectrometry. An optimum coating thickness of the yttrium oxide and lanthanum oxide was around 20 μm.
关键词:
Electrophoretic deposition
,
Oxide nanoparticles
,
SEM
,
Electron emission
Onder Albayrak
材料科学技术（英文）
A new method for the production of the coating surface consisting of tricalcium phosphate (TCP) and titanium dioxide (TiO2) on titanium (Ti) substrates by using electrophoretic deposition (EPD) method has been developed. Crack occurrence on coating surface and hydroxyapatite (HA) decomposition into TCP, which are commonly encountered in EPD method, were used as an advantage in this study. HA nano-powders synthesized by acid-base method were used as the coating material. They were deposited on Ti substrates with different voltages and durations. Cracks on the deposited surface were observed by scanning electron microscopy (SEM). Samples were sintered in air atmosphere to allow TiO2 growth from the Ti substrate to fill the cracks. SEM observation and X-ray diffraction (XRD) analysis proved the occurrence of complete decomposition of HA into TCP, TiO2 growth between cracks, and coalescence of TCP/TiO2 on coating surface. This type of coating surface is expected to increase the coating strength because of TiO2 growth in the cracks and its coalescence with TCP.
关键词:
Electrophoretic deposition
,
Hydroxyapatite
,
Bioceramics
,
Microstructure.
Shaohua ZHANG
,
C.C.Sorrel
,
F.Y.Li
材料科学技术（英文）
Electrophoretic deposition (EPD) is receiving great interests because of its advantages of versatility, easy scaling-up, low cost and variety of shapes. This review covers the theory, application, suspension preparation, and process parameter selection of electrophoretic deposition. Besides traditional DLVA theory, new theories and model have been put forward to explain the mechanism of EPD. Its applications include SOFC, fibre reinforced and graded ceramic composites, nanostructured materials and a variety of advanced films and coating. An effective suspension requires appropriate selection of solvent, binder, dispersant and other ionic additives. A good conbination of process parameters will lead to the good formation of electrophoretic deposition.
关键词:
Electrophoretic deposition
,
null
Lihong Xue Youwei Yan
材料科学技术（英文）
Highly oriented barium titanate (BaTiO3) thin films on Pt substrate were fabricated by combination of electrophoretic deposition with hydrothermal treatment. The structure and morphology of thin films were characterized by X-ray diffraction and field-emission scanning electron microscopy. It is found that the titania precursor film, Ba(OH)2 oncentration and hydrothermal temperature play crucial roles in the film morphology and orientation. The BaTiO3 thin films with highly (110) preferred orientation can be formed on polycrystalline Pt substrate by appropriate adjustment of the reaction conditions. The orientation parameter f of highly oriented BaTiO3 films was up to 1.00. The films exhibited a smooth and crack-free surface and remained in the layered structure. In situ topotactic transformation and dissolution-crystallization mechanisms were proposed to explain the morphology and orientation of BaTiO3 films during hydrothermal treatment.
关键词:
Barium titanate
,
Preferred orientation
,
Electrophoretic deposition
,
Hydrothermal treatment
Zude FENG
,
Qishen SU
,
Zuochen LI
材料科学技术（英文）
Hydroxyapatite (HAP) coatings were deposited onto titanium substrates by electrophoretic deposition (EPD) from ethanol. The results indicated that the addition of very small amount of HCl resulted in a decrease in the aging time as well as the suspension concentration required to obtain a coating. In addition, the results revealed the existence of a critical saturated voltage (Vsat), which had significant effect on the quality of deposition. The mean interfacial shear strengths of HAP coatings after sintering were found to be greater than 13MPa.
关键词:
Hydroxyapatite
,
null
,
null
