Accession Number : ADA154269


Title :   Thermodynamics of High Temperature Materials.


Descriptive Note : Annual rept. 1 Oct 83-30 Sep 84,


Corporate Author : NATIONAL BUREAU OF STANDARDS GAITHERSBURG MD CENTER FOR CHEMICAL PHYSICS


Personal Author(s) : Abramowitz,S


Full Text : http://www.dtic.mil/dtic/tr/fulltext/u2/a154269.pdf


Report Date : 15 Mar 1985


Pagination or Media Count : 256


Abstract : This research encompasses six tasks each of which treats, from either an experimental or theoretical base, the measurement or interpretation of the high-temperature thermophysical behavior of model systems which show potential applications to environmental resistant materials and the spacecraft survivability programs. Topics include: the heat capacity, electrical resistivity and hemispherical total emittance of graphite in the range of 1500-3000 K. The heat capacity and electrical resistivity of nickel in the range 1300-1700K. Determination of the melting point of nickel. Determination of the specific heat of both hexagonal and cubic boron nitride in the range of 273.15-1200 K. The heat capacity of aluminum has been calculated using several theoretical models. The thermodynamic effects of elastic and inelastic collisions have been determined. The problem of how to treat polyatomic molecules having highly distorted vibrational states, as can be expected after laser irradiation, has been addressed. High temperature equilibria have been modelled using a square well potential. A program for evaluation of the classical partition function and resultant thermodynamic quantities for molecules at high temperatures has been developed. An efficient computer code has been developed which allows calculation of the equilibrium configuration of the symmetric carbon structures present in graphite-like layers. Experiments have been initiated to test the predictions of this code. The gas phase ionic reactions leading to the build up of unsaturated hydrogen deficient carbon chain hydrocarbons has been studied.


Descriptors :   *THERMODYNAMICS , *GRAPHITE , *REFRACTORY MATERIALS , *HEAT RESISTANT METALS , COMPUTER PROGRAMS , SPACECRAFT , SURVIVABILITY , MODELS , HIGH TEMPERATURE , CARBON , LASERS , EMITTANCE , ALUMINUM , HYDROCARBONS , MOLECULAR STRUCTURE , NICKEL , ELECTRICAL RESISTANCE , THERMODYNAMIC PROPERTIES , MELTING POINT , SPECIFIC HEAT , BORON NITRIDES , THERMOPHYSICAL PROPERTIES


Subject Categories : Ceramics, Refractories and Glass
      Metallurgy and Metallography
      Miscellaneous Materials
      Thermodynamics


Distribution Statement : APPROVED FOR PUBLIC RELEASE