Porosity and Its Measurement

Espinal, Laura

doi:10.1002/0471266965.com129

Cited by 37 publications

(28 citation statements)

References 41 publications

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“…An analysis of plasma-spraying characteristics allows adjusting the porosity of coatings and the pore size [28,29]. A number of studies have focused on the theoretical [30,31] and experimental [32][33][34][35][36][37][38][39] research of the relationship between the parameters of the plasma jet and pore-size distribution of the coated material. On the basis of the empirical results obtained in [33], it is possible to figure out that the porosity is a function of the plasma powder particles' dimension:…”

Section: Analysis Of Structural Defectsmentioning

confidence: 99%

Modelling of Temperature Field and Stress–Strain State of the Workpiece with Plasma Coatings during Surface Grinding

Usov

Tonkonogyi

Dašić³

et al. 2019

Machines

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Plasma coatings play a key role in surface tailoring through providing important advantages for tools during their further application. However, grinding these coatings may cause different defects such as grinding burns and cracks, structural changes to the coating material, and the destruction of adhesive contacts between the coating layer and the substrate. The reason for that is the high heat flux generated in the process of abrasive material removal due to the high friction and stresses. In order to define the optimal conditions for grinding plasma coatings, the mathematical model of the temperature thermal field and the stress–strain state during the grinding process is developed. Based on the temperature, strength, and fracture criteria, this mathematical model makes it possible to define the functional relationship between the technological characteristics of the grinding process and the conditions that provide the required quality of surface processing. The role of the structural defects that are generated while coatings are being sprayed, as well as during coating adhesion, is also considered. An algorithm developed to present the results of the modelling process enables checking if the input parameters meet the condition of zero-defect grinding of a workpiece, and determining an expected surface roughness. Input parameters include the grinding wheel geometry, its abrasive properties, the wheel speed, longitudinal and transverse motion, grinding depth, and the use of the cutting fluid. Experimental testing of this study shows the way in which the regime of the grinding process and different grinding wheel parameters influence the physical and mechanical properties of the surface layer.

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Section: Analysis Of Structural Defectsmentioning

confidence: 99%

Modelling of Temperature Field and Stress–Strain State of the Workpiece with Plasma Coatings during Surface Grinding

Usov

Tonkonogyi

Dašić³

et al. 2019

Machines

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“…There are many methods to measure the porosity; the selection criteria should extend beyond the expected poresize range and take into account the suitability of sample preparation and material property [25]. Two of the commonly used methods to measure the apparent porosity in calcium sulphate porous materials are the total free water porosity measurements and mercury intrusion porosimetry (MIP) [26].…”

Section: Introductionmentioning

confidence: 99%

Infiltration tests to assess the permeability and hydraulic conductivity of 3D printed plaster parts under different conditions

Ocaña-Garzón

Santana

Lino

2020

J Braz. Soc. Mech. Sci. Eng.

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In the postprocess of infiltration in the Binder Jetting technology, the permeability (k) and hydraulic conductivity (K) are essential factors in the penetration of the infiltrant within the three-dimensional printing (3DP) model and thus get to improve its mechanical strength. This study experimentally evaluated the influence of 3DP sample thickness, infiltrant type, build orientation, binder saturation and colour of model 3DP on its permeability and hydraulic conductivity. Permeability and hydraulic conductivity were determined based on Darcy's law in a custom-made falling-head permeameter with low-and high-viscosity mineral oils that simulated the infiltrants. In addition, porosity and the pore-size distribution were estimated using the liquid saturation and mercury intrusion porosimetry methods. In decreasing order, the build orientation and binder saturation of the sample showed a statistical significance for k, whereas for K the infiltrant type and build orientation were significant. The cumulative volume curves of intruded/extruded mercury to the 3DP model showed liquid entrapment, and this seems to be related to kinetic effects over mercury extrusion, together with the tortuosity and surface chemistry of the pores in the porous system. More than 90% of the pores detected are macropores (> 0.05 µm); however, the predominance in the absorption of the intruded mercury occurred in pores between 10 and 30 µm.

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“…In this context, porosity is one of the coefficients that affect the elastic constants and other properties of the produced materials. Examples of the industrially porous materials include; catalysts materials, ceramic and construction materials, pharmaceutical products, pigments, membranes, sorbents, sensors, electrodes, fuel cells and active components in batteries, and gas and oil bearing stratum and rocks [2]. Recently, in computer science, some projects have used image analysis to characterize the porosity behavior in different materials [3,4].…”

Section: Introductionmentioning

confidence: 99%

Porosity Measurement of Iron Oxide by Using Computer Vision System

El-Nasr¹,

Saleh²,

Alshennawy³

2020

International Journal of Engineering Research and Technology

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In this work, a proposed Computer Vision System (CVS) has been applied to measure the porosity of iron oxide (Fe 3 O 4) specimens. Measurement of the porosity using CVS reduces time, effort and cost compared to the conventional methods. Fe 3 O 4 was received from iron rolling process in the form of thin layer, and then converted to powder by grinding process and filtering by 200 μm sieve. Fe 3 O 4 specimens were then manufactured by powder metallurgy (PM) technique using steel die subjected to a compression load (300 KN) to form cylindrical discs with 27 mm diameter and 10 mm height. Optical microscope with digital camera has been used in capturing images of the surfaces of Fe 3 O 4 specimens. The proposed CVS uses k-means algorithms, which divide the intended surfaces into distinct regions and by computing the ratio between these regions, the specimen porosity is obtained. Layers of the specimens are removed to measure the average porosity inside the specimens. The average value of porosity of specimens has been obtained for the original specimen and its mean value is ∼26.39%. In comparison, the porosity computed by CVS was very close to that obtained using conventional method, which confirms the efficiency of this technique.

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Porosity and Its Measurement

Cited by 37 publications

References 41 publications

Modelling of Temperature Field and Stress–Strain State of the Workpiece with Plasma Coatings during Surface Grinding

Modelling of Temperature Field and Stress–Strain State of the Workpiece with Plasma Coatings during Surface Grinding

Infiltration tests to assess the permeability and hydraulic conductivity of 3D printed plaster parts under different conditions

Porosity Measurement of Iron Oxide by Using Computer Vision System

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