Microstructure of carbon blacks in pitch-bonded graphites and structural changes produced by gas—graphite oxidation reactions

Jones, S. S.; Woodruff, E.M.

doi:10.1016/0008-6223(71)90044-3

Cited by 13 publications

(3 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The double circular feature, C in figure 3, has the topography of a co-rotating node. An earlier electron microscopical study of several pitch carbons and polygranular graphites [13] found similar circular structures that were attributed to the graphitization of quinoline insoluble matter.…”

Section: Microstructural Effects Of Oxidationmentioning

confidence: 69%

The coefficient of thermal expansion of nuclear graphite with increasing thermal oxidation

Hacker

Neighbour

McEnaney

2000

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

Two grades of nuclear graphite, an isotropic graphite (GCMB) and an anisotropic graphite (PGA), were thermally oxidized to high weight losses. Average values of the coefficient of thermal expansion (CTE) in the temperature range 20-600 • C for GCMB and PGA in the parallel direction were unaffected by thermal oxidation up to 60% and 50% weight loss, respectively. The average CTE values for the PGA samples in the perpendicular direction were also unaffected by oxidation in the range 10-50% weight loss, although a slight increase in the CTE in the early stages of oxidation was observed. A new model based upon a continuous network of material, able to transmit thermal strains, which persists after oxidation, was proposed to explain the insensitivity of the CTE to oxidation. The transmission of thermal strains in the continuous network model was considered as a percolation phenomenon. Application of percolation theory to the effect of thermal oxidation on electrical conductivity of oxidized GCMB graphite suggests that the percolation threshold occurs at very high levels of oxidation that are in excess of 95% weight loss.

show abstract

Section: Microstructural Effects Of Oxidationmentioning

confidence: 69%

The coefficient of thermal expansion of nuclear graphite with increasing thermal oxidation

Hacker

Neighbour

McEnaney

2000

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

show abstract

“…Notably, agglomeration of small particles with a roughly spherical appearance was observed in the matrix, which has been previously observed in the binder of pitch-bonded graphite and has been referred to as rosettes by Jones et al 37 And they proposed that these rosette particles were part due to the quinoline insoluble (QI) the fraction of the coal tar pitch binder. During C/C composite graphitization process, these particles are formed by graphitize of aromatic molecules, and thereby resulting in the generation of these rosette shaped particles composed of a spiral of graphite strands.…”

Section: Resultsmentioning

confidence: 71%

Irradiation Effects of Fiber and Matrix Induced by He⁺ Ion for High-Performance C/C Composites

Feng

Yang

Xia

et al. 2019

ACS Appl. Nano Mater.

View full text Add to dashboard Cite

To optimize the performance of the carbon fiber reinforced carbon matrix (C/C) composites by controlling the microstructure for more reliable and safety application in thorium molten salt reactor (hereafter, TMSR), we have investigated the irradiation effects of fiber, matrix, and their interfaces in C/C composite induced by He+ ions and further reveal their corresponding micromechanism. Compared with fibers, an obviously fragmented surface morphology in matrix appears and then gradually becomes widespread around the surface of C/C composite with increasing dose of irradiation. This found is attributed to the breakage of crystallites observed by synchrotron-based grazing incidence X-ray diffraction (GIXRD) and the increase of defect state density revealed by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, respectively. Three different microstructure evolutions in fiber, matrix and fiber-matrix interface induced by irradiation damage have been further revealed in detail by transmission electron microscopy (TEM) and high-resolution TEM (HRTEM). It is found that the layered structure gradually loses its initial ordering and the nanostructural degradation in carbon matrix is much more serious than that of the fiber, resulting in breaks and bends in the lattice with increasing dose. Observed by nanoindentation experiment, the enhancement of the hardness and modulus of the matrix is more significant than that in fiber, which can be attributed to the more obviously pinning of basal plane dislocations in the matrix due to lattice defects induced by He+ irradiation. These discoveries are properly contribute to improve the performance of the C/C composites by regulatory microstructure composition, such as fiber and matrix.

show abstract

“…We believe their presence is caused by the spherical structure of rosettes where some thin lamellae incline or are normal to the electron beam. Yamada [31] studied the rosette structure of QIs in detail, showing they are graphitised carbon blacks, which form some of the QIs found in coal-tar pitch binders [32]. The structure of the QI is schematically shown in Figure 7(c).…”

Section: (B) Boundariesmentioning

confidence: 99%

Mesoscopic structure features in synthetic graphite

et al. 2018

View full text Add to dashboard Cite

The mesocopic structure features in the coke fillers and binding carbon regions of a synthetic graphite grade have been examined by high resolution transmission electron microscopy (TEM) and Raman spectroscopy. Within the fillers, the three-dimensional structure is composed of crystal laminae with the basal plane dimensions (La) of hundreds nanometres, and thicknesses (Lc) of tens of nanometres. These laminae have a nearly perfect graphite structure with almost parallel c-axes, but their a-b planes are orientated randomly to form a "crazy paving" structure. A similar structure exists in the binding carbon regions, with a smaller La. Significantly bent laminae are widely seen in quinoline insoluble inclusions and the graphite regions developed around them. The La values measured by TEM are consistent with estimates from the intensity ratios of the D to G Raman peak in these regions. Atomistic modelling finds that the lowest energy interfaces in the crazy paving structure comprise 5, 6 and 7 member carbon rings. The bent laminae tend to maintain the 6 member rings, but are strained elastically. We suggest that a 7 member carbon ring leaves a cavity representing an arm-chair graphite edge contributing to the Raman spectra D peak.

show abstract

Microstructure of carbon blacks in pitch-bonded graphites and structural changes produced by gas—graphite oxidation reactions

Cited by 13 publications

References 3 publications

The coefficient of thermal expansion of nuclear graphite with increasing thermal oxidation

The coefficient of thermal expansion of nuclear graphite with increasing thermal oxidation

Irradiation Effects of Fiber and Matrix Induced by He⁺ Ion for High-Performance C/C Composites

Mesoscopic structure features in synthetic graphite

Contact Info

Product

Resources

About

Microstructure of carbon blacks in pitch-bonded graphites and structural changes produced by gas—graphite oxidation reactions

Cited by 13 publications

References 3 publications

The coefficient of thermal expansion of nuclear graphite with increasing thermal oxidation

The coefficient of thermal expansion of nuclear graphite with increasing thermal oxidation

Irradiation Effects of Fiber and Matrix Induced by He+ Ion for High-Performance C/C Composites

Mesoscopic structure features in synthetic graphite

Contact Info

Product

Resources

About

Irradiation Effects of Fiber and Matrix Induced by He⁺ Ion for High-Performance C/C Composites