Ultra-precision lapping of machinable ceramic Si3N4-BN by in-process electrolytic dressing

Lee, E. S.; Won, Jong Koo; Chun, Young‐Jin; Cho, Myeong-Woo; Cho, W. S.; Lee, J. H.

doi:10.1007/s00170-005-0293-5

Cited by 7 publications

(7 citation statements)

References 1 publication

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“…For pure bentonite mixture, use 𝐵 = 1. 𝛾 𝑠𝑎𝑛𝑑 is the particle density of sand and 𝜌 𝑑 corresponds to the dry density of the mixture. It is an enhanced formulationdoes not depend on the water content or the water density-of similar expressions found in [4,[10][11]. The proposed expression fits better with the compaction process application where, usually, the control variable is the dry density.…”

Section: Hypothesis Of Sand Effect In the Mixturementioning

confidence: 57%

Impact of sand on the water retention properties of a bentonite/sand mixture by NMR characterization

Eizaguirre

Tang²,

Maillet³

et al. 2023

E3S Web of Conf.

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Blocks of compacted bentonite/sand mixture, with a 40/60 proportion in dry mass, are being studied as an elementary component in the construction of seals in the French concept for high-levelradioactive waste disposal. In the disposal, the seal will be subjected to water infiltration from the host rock. Water retention behaviour in the mixture is governed by bentonite. Nevertheless, the impact of the sand fraction, especially at high concentrations, is still unclear. The water retention curve is found experimentally for the wetting path by using vapour equilibrium technique. Moreover, NMR relaxometry tests executed atfull saturation state are presented. As a result of the comparison with experimental data reported in the past, for different mixtures -ranging from pure bentonite to 20/80 bentonite/sand mixtures-, it is concluded that all porosity in the mixture can be correctly attributed to bentonite. This conclusion simplifies mixtures to equivalent pure bentonite specimens with a dry density equal to the bentonite dry density (𝜌𝑑,𝑏) of the mixture. Moreover, an original method to compare NMR relaxation times for different bentonite/sand -or pure bentonite- mixtures is proposed. It provides the longitudinal relaxation time (T1) in saturated mixtures as a function of 𝜌𝑑,𝑏 and the montmorillonite concentration in bentonite.

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Section: Hypothesis Of Sand Effect In the Mixturementioning

confidence: 57%

Impact of sand on the water retention properties of a bentonite/sand mixture by NMR characterization

Eizaguirre

Tang²,

Maillet³

et al. 2023

E3S Web of Conf.

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“…As the lapping wheel speed is increased, material removal by one abrasive is reduced and it helps to draw chips off. And the lapping resistance is decreased more than case of correlatively low wheel speed [8,12]. Most of the high surface quality was obtained with 60rpm wheel speed during the lapping process.…”

Section: Surface Roughness Characteristicsmentioning

confidence: 99%

“…Here, c is half value of the crack length and a is half value of the diagonal length [8]. The measured value was K IC = 5.68 MPam 1/2 .…”

Section: Y 2 O 3 (Yttria) Ceramicmentioning

confidence: 99%

Evaluation of Y2O3 surface machinability using ultra-precision lapping process with IED

2009

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Prospects of Y 2 O 3 have been more extended as a great promising and creditable material for optical, electronic and mechanical purposes. Y 2 O 3 has been more observed as a fine ceramic which has great material properties: high light transparency, excellent thermal resistance and chemical inertness. But in terms of effective application of Y 2 O 3 , its hard and brittle nature needs to be overcome during the surface machining process. Therefore, the surface machining control of Y 2 O 3 should be conducted carefully. The evaluation for stable and continuous machining should also be investigated in various industrial fields as there are only limited studies on the subject. The lapping process with in-process electrolytic dressing (IED) is widely used for surface machining of hard and brittle materials. In this study, Y 2 O 3 surface machinability was evaluated by using the ultra-precision lapping process with IED method by changing three major variables: applied force, wheel speed and machining time. The most suitable value of Ra 92nm surface roughness was acquired with smooth surface quality from the following machining condition: 7kg of applied force, 60rpm of wheel speed and 30minutes of machining time. After the lapping process, the machining tendency and surface characteristics were analyzed with fracture toughness and Vickers hardness for the evaluation of Y 2 O 3 surface machinability.

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“…Although nano-ceramic materials can be processed by the ultra-precision machining technology, the theoretical basis of research on ultra-precision machining of the hard and brittle material technology in China is relatively weak. It is still a long process from industrialization [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Removal mechanism of ultrasonic vibration and ELID composite plane grinding based on ultrasonic vibration of nano-ceramic workpiece

Shao¹,

Zhao²,

Bian³

2018

J. vibroeng.

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To realize the high efficiency mirror surface grinding of hard brittle materials (such as nano-ceramic material), this work firstly constructs an experimental platform for workpiece ultrasonic vibration and ELID combined plane grinding according to the processing mechanism of ultrasonic vibration assisted grinding and ELID grinding; then, based on the removal mechanism of hard brittle material, this work analyzes the kinematics of single abrasive grit with workpiece ultrasonic vibration plane grinding, and studies the effect of ELID plane grinding on the grinding depth; finally, based on the above work, this work proposes the mathematical model of material removal rate for the workpiece ultrasonic vibration and ELID combined plane grinding. Experimental results show that the material removal rate of combined plane grinding increases with the increase of the cutting depth and workpiece speed, the material removal rate of ultrasonic vibration and ELID combined grinding is higher than that of ELID grinding under the same conditions.

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Ultra-precision lapping of machinable ceramic Si3N4-BN by in-process electrolytic dressing

Cited by 7 publications

References 1 publication

Impact of sand on the water retention properties of a bentonite/sand mixture by NMR characterization

Impact of sand on the water retention properties of a bentonite/sand mixture by NMR characterization

Evaluation of Y2O3 surface machinability using ultra-precision lapping process with IED

Removal mechanism of ultrasonic vibration and ELID composite plane grinding based on ultrasonic vibration of nano-ceramic workpiece

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