Effects of pressure carbonization in the CC composite process

Hosomura, T.; Okamoto, Hiroyuki

doi:10.1016/0921-5093(91)90741-5

Cited by 14 publications

(7 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another HIPIC process does not use a can, but simply applies an isostatic gas pressure on the surface of molten pitch, which seals the workpiece [190]. HIPIC increases the carbon yield of pitch, especially when the molecular size of the pitch is small.…”

Section: Fabricationmentioning

confidence: 99%

“…HIPIC increases the carbon yield of pitch, especially when the molecular size of the pitch is small. Moreover, as the pressure rises, the pores in the carbonized matrices become smaller in size and more spherical in shape [190]. The increase in pressure causes the carbon yield to increase dramatically for pitch A (low molecular weight), but only slightly for pitch C (high molecular weight).…”

Section: Fabricationmentioning

confidence: 99%

See 1 more Smart Citation

Science of composite materials

Chung

2003

Engineering Materials and Processes

View full text Add to dashboard Cite

Composite materials are those containing more than one phase such that the different phases are artificially blended together. They are not multiphase materials in which the different phases are formed naturally by reactions, phase transformations or other phenomena.A composite material typically consists of one or more fillers (fibrous or particulate) in a certain matrix. A carbon fiber composite is one in which at least one of the fJ.llers is composed of carbon fibers, either short or continuous, unidirectional or multidirectional, woven or non-woven. The matrix is usually a polymer, a metal, a carbon, a ceramic or a combination of different materials. Except for sandwich composites, the matrix is three-dimensionally continuous, whereas the fJ.ller can be three-dimensionally discontinuous or continuous. Carbon fiber fJ.llers are usually three-dimensionally discontinuous, unless the fibers are three-dimensionally interconnected by weaving or by the use of a binder such as carbon.The high strength and modulus of carbon fibers make them useful as a reinforcement for polymers, metals, carbons and ceramics, even though they are brittle. Effective reinforcement requires good bonding between the fibers and the matrix, especially for short fibers. For an ideally unidirectional composite (i.e., one containing continuous fibers all in the same direction) containing fibers of much higher modulus than that of the matrix, the longitudinal tensile strength is quite independent of the fiber-matrix bonding, but the transverse tensile strength and the flexural strength (for bending in longitudinal or transverse directions) increase with increasing fiber-matrix bonding. On the other hand, excessive fiber-matrix bonding can cause a composite with a brittle matrix (e.g., carbon and ceramics) to become more brittle, as the strong fiber-matrix bonding causes cracks to propagate in a straight line in a direction perpendicular to the fiber-matrix interface, without being deflected to propagate along this interface. In the case of a composite with a ductile matrix (e.g., metals and polymers), a crack initiating in the brittle fiber tends to be blunted when it reaches the ductile matrix, even when the fiber-matrix bonding is strong. Therefore, an optimum degree of fiber-matrix bonding (i.e., not too strong and not too weak) is needed for brittle-matrix composites, whereas a high degree of fiber-matrix bonding is preferred for ductile-matrix composites.The mechanisms of fiber-matrix bonding include chemical bonding, interdiffusion, van der Waals bonding and mechanical interlocking. Chemical

show abstract

Section: Fabricationmentioning

confidence: 99%

Section: Fabricationmentioning

confidence: 99%

Science of composite materials

Chung

2003

Engineering Materials and Processes

View full text Add to dashboard Cite

show abstract

“…In a previous study, the effect of pressure during the densification was examined (Oh et al, 1999;Matzinos et al, 2000). Highpressure carbonization, carried out with Hot Isostatic Press (HIP) equipment, is an attractive route to high-performance C/C composites, exploiting the high carbon yields obtained from pitches (Hosomura and Okamoto, 2003). For such carbonization, expensive equipment is needed to improve the carbon yield, which increases production costs.…”

Section: Introductionmentioning

confidence: 99%

The effect of modification of matrix on densification efficiency of pitch based carbon composites

Mohammad

Ali

Amir

et al. 2010

J Coal Sci Eng China

View full text Add to dashboard Cite

Using coal tar pitch as a matrix precursor to prepare carbon materials is widely used by impregnation/carbonization processing technology. Four different grades of coal tar pitch and a natural pitch were characterized in terms of carbon yield, density, viscosity, and fractionation with solvents, as well as by thermal analysis methods. The suitability of these commercially available matrices for densification of 3 dimensional carbon-carbon composites was examined. The theoretical results compared with experimental results. The highest density after impregnation was obtained using one of the coal tar pitches. The predicted results are in reasonable agreement with experiment data. The significance of this research is that a special heat treatment regime was conducted. The effects of modification temperature on the densification efficiency of composites were investigated and then structure and characteristics of the composites were determined by scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and X-Ray Diffraction (XRD).

show abstract

“…The HIPIC process increases, significantly, the carbon yield of pitches with small molecular weight. However, it does not have appreciable effect on the yield of pitches with higher molecular weight because they already have a very high carbon yield [4,5]. Furthermore, much work has been done using this method, and over many years, this practice has emerged as a reliable approach for fabrication of C/C composites in mass production.…”

Section: Preparation Of C/c Compactsmentioning

confidence: 99%

“…Hosomura [5] determined that pitches with high molecular weight reached the saturation limit at a pressure of around 10 MPa. Mesophase pitch exhibits a high molecular weight, softens at a high temperature, and has high viscosity as a result of the process by which it is synthesized.…”

Section: Introductionmentioning

confidence: 99%

Influence of hot-pressing pressure on the densification of short-carbon-fiber-reinforced, randomly oriented carbon/carbon composite

Raunija¹

2015

Carbon letters

View full text Add to dashboard Cite

The prime objective of this research was to study the influence of hot-pressing pressure and matrix-to-reinforcement ratio on the densification of short-carbon-fiber-reinforced, randomly oriented carbon/carbon-composite. Secondary objectives included determination of the physical and mechanical properties of the resulting composite. The 'hybrid carbon-fiberreinforced mesophase-pitch-derived carbon-matrix' composite was fabricated by hot pressing. During hot pressing, pressure was varied from 5 to 20 MPa, and reinforcement wt% from 30 to 70. Densification of all the compacts was carried at low impregnation pressure with phenolic resin. The effect of the impregnation cycles was determined using measurements of microstructure and density. The results showed that effective densification strongly depended on the hot-pressing pressure and reinforcement wt%. Furthermore, results showed that compacts processed at lower hot-pressing pressure, and at higher reinforcement wt%, gained density gradually during three densification cycles and showed the symptoms of further gains with additional densification cycles. In contrast, samples that were hot-pressed at moderate pressure and at moderate reinforcement wt%, achieved maximum density within three densification cycles. Furthermore, examination of microstructure revealed the formation of cracks in samples processed at lower pressure and with low reinforcement wt%.

show abstract

Effects of pressure carbonization in the CC composite process

Cited by 14 publications

References 3 publications

Science of composite materials

Science of composite materials

The effect of modification of matrix on densification efficiency of pitch based carbon composites

Influence of hot-pressing pressure on the densification of short-carbon-fiber-reinforced, randomly oriented carbon/carbon composite

Contact Info

Product

Resources

About