The Effect of the Heating Rate during Carbonization on the Porosity, Strength, and Electrical Resistivity of Graphite Blocks Using Phenolic Resin as a Binder

Lee, Sang-Hye; Kim, Jae Hyun; Kim, Woo-Seok; Roh, Jae-Seung

doi:10.3390/ma15093259

Cited by 6 publications

(5 citation statements)

References 21 publications

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“…Moisture is released as condensation in the low-temperature range, as CO 2 , CH 4 , and CO in the medium range, and as H 2 in the high range. Gas release occurs rapidly in the medium-temperature range, resulting in the formation of large pores [20,36]. Table 2.…”

Section: Resultsmentioning

confidence: 99%

“…A previous study by our team found that the properties of graphite blocks increased when heating rate during carbonization was adjusted to below 3 • C/min. Graphite blocks prepared at heating rates higher than 5 • C/min had large pores and cracks in their microstructures and exhibited low flexural strength and high electrical resistivity [20].…”

Section: Fabrication Of Graphite Blockmentioning

confidence: 99%

“…Accordingly, this study performed carbonization at a heating rate of 2 • C/min, below the previously reported heating rate of 3 • C/min [20]. To compensate for the increased manufacturing time due to the curing process and to improve the production speed, a faster heating rate of 5 • C/min was applied.…”

Section: Fabrication Of Graphite Blockmentioning

confidence: 99%

“…Figure 7 shows the electrical resistivity and flexural strength of the graphite blocks Our research team reported that a rapid heating rate during carbonization when fabricating graphite blocks with a phenolic resin binder led to low bulk density and high porosity [20]. However, a comparison of C-HR5-G and HR2-G revealed that C-HR5-G has a higher bulk density and lower porosity.…”

Section: Electrical Resistivity and Flexural Strength Of Graphite Blockmentioning

confidence: 99%

“…Our research team, based on extensive experience in manufacturing graphite blocks, has been exploring ways to improve the oxidation resistance of binder phenolic resins without additives [19,20]. One promising method is to inhibit the formation and reduce the size of open pores in the binder phenolic resins.…”

Section: Introductionmentioning

confidence: 99%

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Improved Oxidation Resistance of Graphite Block by Introducing Curing Process of Phenolic Resin

Lee

Roh

2023

Materials

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The purpose of this study is to improve the oxidation resistance of graphite blocks after graphitization at 2800 °C by introducing a curing process of phenolic resin, used as a binder to control the pore size. Using the methylene index obtained from FTIR, the curing temperature was set to 150 °C, the temperature at which cross-linking most highly occurs. Graphite blocks that had undergone curing, and were carbonized with a slow heating rate, showed increased mechanical and electrical properties. Microstructural observation confirmed that the curing process inhibited the formation of large pores in the graphite block. Therefore, the cured graphite block showed better oxidation resistance in air than a non-cured graphite block. Oxidation of the graphite block was caused by pores created by pyrolysis of the phenolic resin binder, which acted as active sites.

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Section: Resultsmentioning

confidence: 99%

Section: Fabrication Of Graphite Blockmentioning

confidence: 99%

Section: Fabrication Of Graphite Blockmentioning

confidence: 99%

Section: Electrical Resistivity and Flexural Strength Of Graphite Blockmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Improved Oxidation Resistance of Graphite Block by Introducing Curing Process of Phenolic Resin

Lee

Roh

2023

Materials

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Changes in Physical Properties with Varying Impregnation Temperatures and Compression Times During Fabrication of Carbon Blocks Using Needle Cokes and Pitch

Youn,

Lee,

Kim

et al. 2024

Korean J. Chem. Eng.

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Impregnation was conducted to decrease the pores formed during the carbonization process after manufacturing carbon blocks using needle cokes and coal tar pitch. This was carried out in the order of heating, subjecting to vacuum, and compression, and changes in mechanical and electrical properties before and after impregnation were analyzed with impregnation temperature and compression time as variables. The impregnation temperatures were 150, 200, and 250°C, and compression times were 30, 60, and 90 min. The optimal impregnation temperature was 200°C, resulting in a 12.5% increase in bulk density and a 26.0% decrease in porosity after impregnation of the carbon blocks. The optimal compression time was 60 min, leading to a 14.3% increase in bulk density and a 24.0% decrease in porosity after impregnation. Under the selected optimal conditions, after three impregnation cycles, the bulk density increased by 33.8% compared to the initial state (0 cycles 1.259 g/cm³ → 3 cycles 1.685 g/cm³), and porosity decreased by 56.8% (0 cycles 39.1% → 3 cycles 16.9%). According to the performance evaluation of carbon blocks, electrical resistivity decreased by 52.0% (72.5 µΩm → 34.8 µΩm) and exural strength increased by 368.3% (6.0 MPa → 28.1 MPa). The substantial increase in exural strength was attributed to the reduction in porosity.

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Feasibility assessment of manufacturing carbonized blocks from rice husk charcoal

Hwang,

Roh,

Nam

2023

Biomass Conv. Bioref.

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Artificial graphite has recently attracted significant interest as a promising carbon material for industrial applications because of its high heat and chemical resistance, excellent electrical conductivity, and low thermal expansion. However, its practical use is severely limited by its high preparation costs and poor cycling stability. In this study, rice husk charcoal (RHC) was prepared from agricultural biowaste using a pyrolysis (heat treatments) method in this study. We investigated the effect of the heat-treatment temperature on rice husk via elemental and thermogravimetric analyses. The results indicated that the rice husk heat treated at 400 °C (RHC 400) was thermally stable with a high carbon content. Its preparation process was also relatively inexpensive. Further, carbonized blocks were prepared using the fabricated RHC and compared their properties with those of artificial graphite scrap (AGS) carbonized blocks. The bulk density, porosity, flexural strength, and electrical resistivity of the RHC carbonized block were 1.14 g/cm3, 24.65%, 52.55 MPa, and 142.93 μΩm, respectively. These results demonstrate that the flexural strength and electrical resistivity of the RHC-prepared block were higher than those of the AGS carbonized block. In contrast, its density was lower than that of the AGS carbonized block.

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The Effect of the Heating Rate during Carbonization on the Porosity, Strength, and Electrical Resistivity of Graphite Blocks Using Phenolic Resin as a Binder

Cited by 6 publications

References 21 publications

Improved Oxidation Resistance of Graphite Block by Introducing Curing Process of Phenolic Resin

Improved Oxidation Resistance of Graphite Block by Introducing Curing Process of Phenolic Resin

Changes in Physical Properties with Varying Impregnation Temperatures and Compression Times During Fabrication of Carbon Blocks Using Needle Cokes and Pitch

Feasibility assessment of manufacturing carbonized blocks from rice husk charcoal

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