Fabrication of SiC Dense-Porous Laminates by Electrophoretic Deposition Process

2008 ◽  
Vol 368-372 ◽  
pp. 1841-1843
Author(s):  
Yuan Li ◽  
Ji Qiang Gao ◽  
Jian Feng Yang ◽  
Hong Jie Wang ◽  
Guan Jun Qiao
Keyword(s):  
Electrophoretic Deposition ◽  
Deposition Process ◽  
Green Body ◽  
Sintering Process ◽  
Laminated Structure ◽  
Porous Layers ◽  
Sic Ceramics ◽  
Vacuum Atmosphere ◽  
One Step ◽  
Pore Fraction

In order to obtain dense-porous laminated structure in green bodies of SiC ceramics, rapid aqueous electrophoretic deposition (EPD) was introduced. The suspension for the electrophoretic deposition was prepared using silicon carbide, silicon and carbon powders as the starting materials. During the electrophoretic deposition process, the intending dense and porous layers were deposited alternately to form the green body. After drying, the green bodies were reaction-bonded at 1550°C in vacuum atmosphere. Pore fraction of the porous layers could be adjusted by changing process preferences of EPD and suspension composition. Pore size and size distribution could be controlled by using different sized starting powders. Using this process, no additional substance is necessary to generate the pores via burnt-off, and the dense/porous laminated structure can be obtained by one-step sintering process.

Pulse Electric Fields for EPD of Thermal Barrier Coatings

2012 ◽  
Vol 507 ◽  
pp. 21-25 ◽  
Author(s):  
Heather McCrabb ◽  
Joseph Kell ◽  
Binod Kumar
Keyword(s):  
Thermal Barrier Coatings ◽  
Electric Fields ◽  
Electrophoretic Deposition ◽  
Deposition Process ◽  
Thermal Barrier ◽  
Sintering Process ◽  
Barrier Coatings ◽  
Coating Roughness ◽  
Deposition Processes ◽  
Pulse Electric

Conventional electrophoretic deposition is being combined with pulse electric fields to deposit yttria stabilized zirconia from ethanol based suspensions onto bondcoated turbine alloys for thermal barrier coatings. The addition of the pulse electric fields to the electrophoretic process has demonstrated the capability to decrease the coating roughness, minimize hydrolysis, and decrease coating edge effects commonly encountered in electrokinetic and electrochemical deposition processes. Subsequent to the electrophoretic deposition process the green body coatings were subjected to a combined binder burnout and sintering process for further coating densification. The coatings have been qualified in terms of surface roughness as well as microstructure and experiments have been performed to show that the pulse EPD process can deposit TBC materials onto turbine components.

scholarly journals Improvement of mechanical properties of HfB2-based composites by incorporating in situ SiC reinforcement through pressureless sintering

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Ghadami ◽  
E. Taheri-Nassaj ◽  
H. R. Baharvandi ◽  
F. Ghadami
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Relative Density ◽  
Pressureless Sintering ◽  
Sintering Process ◽  
Vacuum Atmosphere ◽  
Sic Reinforcement ◽  
Microstructural Studies ◽  
Composite Samples

AbstractHfB2, Si, and activated carbon powders were selected to fabricate 0–30 vol% SiC reinforced HfB2-based composite. Pressureless sintering process was performed at 2050 °C for 4 h under a vacuum atmosphere. Microstructural studies revealed that in situ SiC reinforcement was formed and distributed in the composite according to the following reaction: Si + C = SiC. A maximum relative density of 98% was measured for the 20 vol% SiC containing HfB2 composite. Mechanical investigations showed that the hardness and the fracture toughness of these composites were increased and reached up to 21.2 GPa for HfB2-30 vol% SiC and 4.9 MPa.m1/2 for HfB2-20 vol% SiC, respectively. Results showed that alpha-SiC reinforcements were created jagged, irregular, and elongated in shape which were in situ formed between HfB2 grains and filled the porosities. Formation of alpha-SiC contributed to improving the relative density and mechanical properties of the composite samples. By increasing SiC content, an enhanced trend of thermal conductivity was observed as well as a reduced trend for electrical conductivity.

Electrophoretic Deposition of 10B Nano/Micro Particles in Deep Silicon Trenches for the Fabrication of Solid State Thermal Neutron Detectors

2018 ◽  
Vol 27 (01n02) ◽  
pp. 1840002 ◽  
Author(s):  
Machhindra Koirala ◽  
Jia Woei Wu ◽  
Adam Weltz ◽  
Rajendra Dahal ◽  
Yaron Danon ◽  
...  
Keyword(s):  
Solid State ◽  
Thermal Neutron ◽  
Electrophoretic Deposition ◽  
Detection Efficiency ◽  
Chemical Vapor ◽  
Cost Effective ◽  
Deposition Process ◽  
Neutron Detectors ◽  
Micro Particles ◽  
Silicon Trenches

We present a cost effective and scalable approach to fabricate solid state thermal neutron detectors. Electrophoretic deposition technique is used to fill deep silicon trenches with 10B nanoparticles instead of conventional chemical vapor deposition process. Deep silicon trenches with width of 5-6 μm and depth of 60-65 μm were fabricated in a p-type Si (110) wafer using wet chemical etching method instead of DRIE method. These silicon trenches were converted into continuous p-n junction by the standard phosphorus diffusion process. 10B micro/nano particle suspension in ethyl alcohol was used for electrophoretic deposition of particles in deep trenches and iodine was used to change the zeta potential of the particles. The measured effective boron nanoparticles density inside the trenches was estimated to be 0.7 gm cm-3. Under the self-biased condition, the fabricated device showed the intrinsic thermal neutron detection efficiency of 20.9% for a 2.5 × 2.5 mm2 device area.

One-step anodization-electrophoretic deposition of titanium nanotubes-graphene nanoribbon framework for water oxidation

2021 ◽  
pp. 115802
Author(s):  
Thiago A.S. Soares ◽  
Johan R. González-Moya ◽  
Yearin Byun ◽  
Anderson Thesing ◽  
Christopher Dares ◽  
...  
Keyword(s):  
Electrophoretic Deposition ◽  
Water Oxidation ◽  
Graphene Nanoribbon ◽  
One Step

scholarly journals Pressureless sinterability study of ZrB2–SiC composites containing hexagonal BN and phenolic resin additives

2021 ◽  
Vol 1 (2) ◽  
pp. 99-104
Author(s):  
Iman FarahBakhsh ◽  
Riccarda Antiochia ◽  
Ho Won Jang
Keyword(s):  
Phenolic Resin ◽  
Vacuum Furnace ◽  
Sintering Process ◽  
Powder Mixtures ◽  
Cold Pressing ◽  
X Ray ◽  
Sic Ceramics ◽  
Sic Composites ◽  
By Products

This research is dedicated to the role of different amounts of hexagonal BN (hBN: 0, 1.5, 3, and 4.5 wt%) on the pressureless sinterability of ZrB2–25 vol% SiC ceramics. Phenolic resin (5 wt%) with a carbon yield of ~40 % was incorporated as a binder to the powder mixtures and after initial cold pressing, the final sintering process was performed at 1900 °C for 100 min in a vacuum furnace. The as-sintered specimens were characterized by X-ray diffractometry, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The results disclosed that the incorporation of 1.5 wt% hBN could increase the relative density to ~92%, while the sample with zero hBN content just reached ~81% of full densification. Appropriate hBN content not only facilitated the particle rearrangement during the cold pressing, but also removed the harmful oxide impurities during the final sintering. Nevertheless, the addition of higher amounts of hBN remarkably lessened the densification because of more delamination of the non-reacted hBN flakes and release and entrapment of more gaseous by-products induced by the reacted hBN phases.

How Electrophoretic Deposition with Ligand-Free Platinum Nanoparticles Affects Contact Angle

2015 ◽  
Vol 654 ◽  
pp. 218-223 ◽  
Author(s):  
Alexander Heinemann ◽  
Sven Koenen ◽  
Kerstin Schwabe ◽  
Christoph Rehbock ◽  
Stephan Barcikowski
Keyword(s):  
Contact Angle ◽  
Electrophoretic Deposition ◽  
Platinum Nanoparticles ◽  
Deposition Time ◽  
Deposition Process ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Ligand Free ◽  
Vital Parameters ◽  
Scanning Electron

Electrophoretic deposition of ligand-free platinum nanoparticles has been studied to elucidate how wettability, indicated by contact angle measurements, is linked to vital parameters of the electrophoretic deposition process. These parameters, namely the colloid concentration, electric field strength and deposition time, have been systematically varied in order to determine their influence on the contact angle. Additionally, scanning electron microscopy has been used to confirm the homogeneity of the achieved coatings.

scholarly journals Superhydrophilic Coating with Antibacterial and Oil-Repellent Properties via NaIO4-Triggered Polydopamine/Sulfobetaine Methacrylate Polymerization

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2008
Author(s):  
Hsiu-Wen Chien ◽  
Hong-Yu Lin ◽  
Chau-Yi Tsai ◽  
Tai-Yu Chen ◽  
Wei-Nian Chen
Keyword(s):  
Surface Modification ◽  
Photoelectron Spectroscopy ◽  
Deposition Process ◽  
Water Contact ◽  
Water Separation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Oil Water Separation ◽  
One Step ◽  
Oil Repellent

Superhydrophilic coatings have been widely used for the surface modification of membranes or biomedical devices owing to their excellent antifouling properties. However, simplifying the modification processes of such materials remains challenging. In this study, we developed a simple and rapid one-step co-deposition process using an oxidant trigger to fabricate superhydrophilic surfaces based on dopamine chemistry with sulfobetaine methacrylate (SBMA). We studied the effect of different oxidants and SBMA concentrations on surface modification in detail using UV–VIS spectrophotometry, dynamic light scattering, atomic force microscopy, X-ray photoelectron spectroscopy, and surface plasmon resonance. We found that NaIO4 could trigger the rate of polymerization and the optimum ratio of dopamine to SBMA is 1:25 by weight. This makes the surface superhydrophilic (water contact angle < 10°) and antifouling. The superhydrophilic coating, when introduced to polyester membranes, showed great potential for oil/water separation. Our study provides a complete description of the simple and fast preparation of superhydrophilic coatings for surface modification based on mussel-inspired chemistry.

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