Effect Of Powder Content Research Articles

Experimental study on the effect of particle gradation on dewatering performance of geotubes

To clarify the effect of particle gradation of filling soil on the dewatering and consolidation performance of geotubes, the content of four-particle size classes (powder, fine, medium, and coarse) which are commonly used in engineering as the research object was taken. The dewatering rate, soil infiltration and solid-liquid mixing pressure in the bag with time when filling soil with different particles were studied, and the soil loss of the hanging bag was analyzed from the perspective of seepage soil gradation. The research results show that the dewatering process could be divided into the quick dewatering stage, silting stage, and stable stage according to the dewatering rate. According to the performance of soil conservation, it could be divided into the loss stage and reverse filtration stage. Further, based on the effects of powder content, non-uniformity coefficient, and curvature coefficient of soil on the dewatering rate of the hanging bag, a formula for calculating the dewatering rate of geotubes is summarized.

Fabrication and properties of alumina ceramics shaped by digital light processing as an additive manufacturing technology

AbstractCeramic slurries with different contents of Al2O3 were formulated and alumina ceramic parts with promising surface morphology were fabricated by using digital light processing photopolymerization‐based additive manufacturing technology. The factors influencing curing depth of the slurries were studied, while the effects of powder content on shrinkage of the green bodies and microstructure, density, and hardness of the sintered bodies were evaluated. Although the curing depth was decreased with increasing content of Al2O3, all the five groups of slurries could be well cured, as the exposure time was set to be 16 s. According to TG‐DTG curves, the weight loss of the samples was completed at about 580°C. Samples from the slurries with 70 and 75 wt.% Al2O3 had dense microstructure, without obvious cracks at both the macro‐ and micro‐scales. Furthermore, with increasing content of Al2O3 in slurries, the bulk density and hardness of sintered bodies were increased. It is believed that our results could be used as a reference for the fabrication of alumina ceramics through additive manufacturing technology.

Optimizing hydride-dehydride Ti-6Al-4V feedstock composition for titanium powder injection moulding

Titanium is used in biomedical applications because it is bio-compatible, has high specific strength and high resistance to corrosion. Powder injection moulding (PIM) produces near-net shaped intricate parts, minimizes secondary operations and makes titanium products more cost effective. Feedstocks with 50–65 vol% powder content were manufactured from commercially available hydride-dehydride titanium alloy powder (HDH Ti-6Al-4V; d10 = 12.8, d50 = 51.8 and d90 = 117.7 μm) and polyvinyl butyral (PVB) based binder. The effect of powder content on mixing torque, feedstock density and viscosity were investigated. Critical powder loadings (CPL) were determined from feedstock density, mixing torque, and viscosity analyses. A new rheological parameter is proposed for predicting CPL based on feedstock flow behaviour. The CPL increased with polyethylene glycol (PEG) content in the binder system. Optimal powder content for HDH Ti-6Al-4V powder was comparable to those reported using small, spherical GA Ti-6Al-4V powder. The HDH Ti-6Al-4V feedstocks exhibited the lowest distribution slope parameter among the published work suggesting it is a cost-effective material for manufacturing parts for biomedical applications.

Preparation of plasticized wheat gluten/olive pomace powder biocomposite: Effect of powder content and chemical modifications

Abstract During the last decades, a lot of interest was given to the biocomposites development, due to the low cost and degradability of waste food industries. In this study, biocomposites were developed from Wheat Gluten plasticized by 35% of glycerol, containing 0–20% of Clean Olive Pomace (COP), Esterified Clean Olive Pomace (ECOP), or Mercerized Clean Olive Pomace (MCOP) powders, which were prepared by conventional blending. Chemical modifications of the powders were characterized by Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), and thermogravimetric analysis (TGA). Mechanical properties, water absorption, mass loss and thermal properties of biocomposites were detailed. It was found that thermal stability of powder was improved after mercerization. Incorporation of COP powder (20%) in plasticized wheat gluten (WG) improved significantly Young's modulus compared to that of WG films. Water absorption was decreased significantly at 20% of reinforcement and was 29% less than that of WG films. Young's modulus and tensile strength decreased at 5% of ECOP powder, contrary to MCOP biocomposite Elongation at break of biocomposites was decreased with increasing powder content. Incorporation of COP powder (20%) decreased thermal stability of the biocomposite, nevertheless chemical changes did not affect the thermal stability of the ECOP and MCOP biocomposites.

粉末含量和激光功率对熔覆涂层裂纹敏感性的影响

粉末含量和激光功率对熔覆涂层裂纹敏感性的影响

粉末含量和激光功率对熔覆涂层裂纹敏感性的影响

粉末含量和激光功率对熔覆涂层裂纹敏感性的影响

Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) feedstock development and optimization for thermoplastic forming of thin planar and tubular oxygen separation membranes

This paper presents the processing steps for producing thin planar and tubular oxygen separation membranes by thermoplastic forming of Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) with polystyrene (PS) and stearic acid (SA) as binder. The influence of powder content on the shape stability of thin membranes (tubular and planar structures) during the thermoplastic processing route was investigated. The effect of powder content on mixing torque and the rheological behavior were investigated. The effect of the powder content could be analytically described using the model proposed by Frankel and Acrivos. The deformation of free standing green bodies was investigated using disks. The result showed that increasing the powder content is remarkably effective to minimize the deformation of the membrane during the thermal debinding step. By using a high powder content (60vol%) and a multicomponent binder system composed of PS, SA and paraffin wax (PW), it was possible to achieve disks and thin wall tubular structures without deformation after sintering. Using capillary rheometer an unexpected decrease in the total extrusion pressure was measured for the feedstock containing PW. The change in apparent activation energy between 800–1000°C was not related to the membrane properties.

Mineral powder concrete – effects of powder content on concrete properties

The effects of partial replacement of Portland cement with non-pozzolanic mineral powders on normal-strength concretes were studied. The observed concrete properties were workability, pumpability, compressive strength and microstructure. Superplasticisers were used in every test concrete. With the addition of mineral powders, the water requirement of the concrete mixes decreased and the compressive strength of the mineral powder concretes was kept at the same level as in a reference mix by using on average a 75 kg/m3 lower cement amount. Studies of the microstructure of the concretes were made using resin-impregnated and polished specimens that were prepared from three concretes, each containing a different mineral powder. In the environmental scanning electron microscopy study, the specimens showed densification of the interfacial transition zone when mineral powders were used. The effects of the mineral powders on the workability, water requirement and compressive strength values of the concretes were evaluated in relation to grading curves.

Superposed flow properties of ceramic powder‐filled polymer melts

AbstractComplicated shape products from ceramic composite materials are nowadays intensively processed via flow molding technologies. Rheological properties of these materials are essential for the clarification of the deformation behavior through channels under various conditions. In this article, ceramic powder (zirconia) was mixed (10–50 vol%) with polypropylene, paraffin, and stearic acid in an elastic extruder. Parallel superposed steady and oscillatory shear flows were measured on a cone‐plate rheometer. Flow properties at high shear rates were evaluated on a capillary rheometer. The effects of powder content, shear rate/angular frequency, and temperature were clarified. The studied filled systems showed highly non‐Newtonian behavior and apparent yield stress; their viscoelastic properties were influenced remarkably under the superposed shear flow at low shear rate and angular frequency, and they showed significantly different behavior from unfilled and fiber‐filled systems. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

Fabrication of barrier ribs of PDP via powder injection molding

In this paper, an attempt was made to explore a possibility of powder micro injection molding process in manufacturing ceramic microstructures such as barrier ribs of plasma display panel. The barrier ribs are glass matrix composites with ceramic powder (alumina and/or titania) filler. In this molding process, a thermosetting paste was molded into polydimethlsilosane soft molds prepared by replication of thick film resist (SU-8) molds. The SU-8 mold was patterned with UV-lithography. The effects of powder content in the paste on paste viscosity and sintering characteristics of molded samples were examined. In addition, effect of molding speed on pore trapping in the microstructure was studied. These results indicated that the powder micro injection molding process at ambient temperature has merits of low-pressure injection molding process with superior mold release characteristics.

Barrier Ribs of PDP by Injection Molding

Barrier ribs of plasma display panel (PDP) were prepared via injection molding of thermally curable paste. The paste composition was optimized by considering the effects of powder content, binder type and content on the viscosity of paste. Various types of molds including stripe, honeycomb, and meander were prepared using UV lithography. In this study, main causes ofdimensional change during sintering of meander type barrier ribs produced by injection molding process were investigated by changing powder content in the paste. The results indicated that sintering stress generated in the barrier rib is not balanced at the points where the ribs are curved, causing dimensional change in the ribs.