Evaluation of mechanical properties of porous alumina ceramics obtained using rice husk as a porogenic agent

Ribeiro, Guilherme Cunha; Fortes, B. A.; Silva, L. da; Castro, José Adilson de; Ribeiro, Stella Rodrigues Ferreira Lima

doi:10.1590/0366-6913201965s12604

Cited by 11 publications

(10 citation statements)

References 19 publications

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“…The pore structures contain tiny and big pores and can prevent the content of the polymer powders to recognize the accurate control of the permeability of the final product. The schematic representation of the pore-forming agent method for porous ceramic production (Ribeiro et al 2019) is shown in Fig. 4.…”

Section: Powdersmentioning

confidence: 99%

Porous Ceramic Properties and Its Different Fabrication Process

Uthaman¹,

Lal²,

Thomas³

2021

Engineering Materials

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The unique compositions and outstanding properties of porous ceramic products make them useful in various application fields such as high-temperature thermal insulation, filtration, and catalytic reactions. This chapter aims to review the porous ceramics properties, classifications, and the different types of fabrication methods of porous ceramics. The readers can get a profound view of porous ceramic materials and their different fabrication methods such as particle stacking sintering, the addition of foaming, gel casting, sol-gel process, polymeric sponge, and freezedrying method. The fabrication process of porous ceramics can influence the quality of the final products.Recently, the utilization of porous ceramics has become great consideration due to its outstanding mechanical strength, chemical, abrasion resistance, etc. (Eom et al. 2013;Colombo 2008). Some benefits of porous ceramics are illustrated in Fig. 1. The broadly considering porous ceramics are silica, alumina, titania, magnesium oxide, zirconia, etc. (Colombo 2002). The pore structure, morphology, pore size, pore wall, porosity, the density of the pore strut, and interconnection of pores have a significant role in the properties of porous ceramics (Sakka 2005; Liu and Chen 2014). The particle size distribution of ceramic powders, the concentration of binder, types of binders, fabrication, etc., can influence the porosity and pore size (Ohji and Fukushima 2012). Typically, the particle size of raw ceramic powder is about two to five times greater than pores, for acquiring the needed pore size. And, the greatest service temperature of porous ceramics is around 1000-2000 °C. The pores are

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Section: Powdersmentioning

confidence: 99%

Porous Ceramic Properties and Its Different Fabrication Process

Uthaman¹,

Lal²,

Thomas³

2021

Engineering Materials

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“…where: m RH : initial mass of rice husk; and m SiO2 : final mass of silicon dioxide obtained from rice husk. Thus, following the present methodology, 100 g of in natura rice husks generate around 20 g of resulting material, which is associated with a high content of silicon dioxide [4,6,20]. Despite its low market value, it is acceptable due to the rice husk be an abundant waste in the South Region of Brazil [26].…”

Section: Resultsmentioning

confidence: 96%

“…The silicon dioxide can be obtained from rice husk by thermal treating, which can be enhanced by a previous acid/alkaline leaching process [5]. Due to the high content of silicon dioxide found on in natura rice husk [6], the resulting material has silicon dioxide content varying between 96% to 99% [7], strongly dependent on chosen processes, e.g., the parameters used in the leaching process (acid/base concentration, mixing time,…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of SrO-containing bioglass-ceramic from rice husk silicon dioxide

et al. 2020

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Rice husk is an abundant waste at the Rio Grande do Sul, Brazil, and it can be used to produce pure silicon dioxide, which is the main component of bioglass-ceramics. The addition of compounds, such as SrO, can improve the biocompatibility of these biomaterials. Therefore, the goal of this paper was to use rice husk silicon dioxide as a cheap precursor to obtaining bioglass-ceramics of the system 50%SiO2-25%Na2O-(25-x)%CaO-x%SrO (mol%) by sol-gel and investigate its potential use as a biomaterial. Two samples (BGC blank and BGC-5%Sr) were synthesized and characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and elemental carbon analysis by the combustion method. Scanning electron microscopy (SEM) was used to investigate the morphology of the bioglass-ceramics, while MTT assay of cell viability was used for in vitro characterization. The obtained silicon dioxide was amorphous and presented a small carbon content. Also, the bioglass-ceramics showed main phases with Si, Ca, Na, and Sr on their structure. Both samples were not cytotoxic against peripheral blood mononuclear cells (PBMC), and the incorporation of 5% SrO improved biocompatibility.

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“…The 40 wt.% starch sample doped with niobium retained a maximum porosity of 57% and a compressive strength of 60 MPa. Ribeiro et al [22] used the rice husk as a pore-forming agent to prepare porous alumina ceramic membranes with a total porosity ranging from 24% to 54%. In Ref.…”

Section: Introductionmentioning

confidence: 99%

Rational Design and Porosity of Porous Alumina Ceramic Membrane for Air Bearing

Xiao

et al. 2021

Membranes

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Air bearing has been widely applied in ultra-precision machine tools, aerospace and other fields. The restrictor of the porous material is the key component in air bearings, but its performance is limited by the machining accuracy. A combination of optimization design and material modification of the porous alumina ceramic membrane is proposed to improve performance within an air bearing. Porous alumina ceramics were prepared by adding a pore-forming agent and performing solid-phase sintering at 1600 °C for 3 h, using 95-Al2O3 as raw material and polystyrene microspheres with different particle sizes as the pore-forming agent. With 20 wt.% of PS50, the optimum porous alumina ceramic membranes achieved a density of 3.2 g/cm3, a porosity of 11.8% and a bending strength of 150.4 MPa. Then, the sintered samples were processed into restrictors with a diameter of 40 mm and a thickness of 5 mm. After the restrictors were bonded to aluminum shells for the air bearing, both experimental and simulation work was carried out to verify the designed air bearing. Simulation results showed that the load capacity increased from 94 N to 523 N when the porosity increased from 5% to 25% at a fixed gas supply pressure of 0.5 MPa and a fixed gas film thickness of 25 μm. When the gas film thickness and porosity were fixed at 100 μm and 11.8%, respectively, the load capacity increased from 8.6 N to 40.8 N with the gas supply pressure having been increased from 0.1 MPa to 0.5 MPa. Both experimental and simulation results successfully demonstrated the stability and effectiveness of the proposed method. The porosity is an important factor for improving the performance of an air bearing, and it can be optimized to enhance the bearing’s stability and load capacity.

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Evaluation of mechanical properties of porous alumina ceramics obtained using rice husk as a porogenic agent

Cited by 11 publications

References 19 publications

Porous Ceramic Properties and Its Different Fabrication Process

Porous Ceramic Properties and Its Different Fabrication Process

Synthesis and characterization of SrO-containing bioglass-ceramic from rice husk silicon dioxide

Rational Design and Porosity of Porous Alumina Ceramic Membrane for Air Bearing

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