GRAPHITE TECHNOLOGY. Period covered April 1, 1957-September 1958

Technical Report · Mon Sep 15 04:00:00 EDT 1958

OSTI ID:4278028

Bradstreet, S W

The two-fold purpose of this investigation has been to correlate the properties of smalls multicrystalline graphite specimens with the factors believed to influence them, and to assess the probability that graphite can conform to engineering specifications. The technique of differential thermal analysis was found applicable to investigating binder pyrolysis. Three promising binder materials were selected for future work: coal-tar pitchs furfuryl alcohol, and phenolberzaldebyde. The most illuminating properties cf experimental mixtures were found to bei apparent (water immersion) densitys dynamic (sonic) meduluss volume electrical resistance, and flexural strength. Measurements of medulus, strength, and thermal expansion have been carried out to temperatures exceeding the creep threshold of graphites between 2l00 and 2250 C. Solvent mixing techniques for insuring homogeneous distribution of the binder were found to improve repreducibility, in all cases some change in the rheology of the system was observed with time. Maximum density and strength in pitch-bonded coke was achieved after agingss the mix at 125 C under partial vacuum. Maximum density consistent with good thermal shock resistance was obtained by adding Thermax to the coke flour. With 14 per cent by weight of Thermax specimens were made having dcnsities exeeeding 1.8 gm/cc with room-temperature strengths of about 2500 psi. Dynamic flexural moduli were measured for specimens heated and cooled between room tcmperature and 2650-C. Speeimens cut from a block of commercials impregnated, molded graphite increased 175 per cent in flexural strength when heated to 2000 C. Such heating caused a significant permanent change in dimensions modulus, and volume resistance. (auth)

• Research Organization: Illinois Inst. of Tech., Chicago. Armour Research Foundation
• NSA Number: NSA-13-011190
• OSTI ID: 4278028
• Report Number(s): WADC-TR-58-503; AD-208324
• Country of Publication: United States
• Language: English

Related Subjects

ALCOHOLS
ALDEHYDES
ARYL RADICALS
BITUMENS
CASTING
CEMENTS
COAL
COOLING
CREEP
CRYSTALS
DENSITY
DISTRIBUTION
ELECTRIC CONDUCTIVITY
EXPANSION
FURFUROL
GRAPHITE
HIGH TEMPERATURE
MACHINING
MEASURED VALUES
METALLURGY AND CERAMICS
MIXING
PHASE DIAGRAMS
PHENOLS
PLANNING
PYROLYSIS
SAMPLING
SOLVENTS
SOUND
STABILITY
STANDARDS
TEMPERATURE
TENSILE PROPERTIES
THERMAL ANALYSIS
THERMAL STRESSES
THICKNESS
VACUUM
VARIATIONS
WEIGHT