Accession Number : AD0819788

Title :   IMPROVEMENT OF PYROLYTIC GRAPHITE COATED NOZZLES FOR SOLID PROPELLANT ROCKET MOTORS.

Descriptive Note : Interim technical rept. no. 1, 1 Jan-15 Aug 67,

Corporate Author : ATLANTIC RESEARCH CORP ALEXANDRIA VA

Personal Author(s) : Batchelor, James D.

Report Date : 05 SEP 1967

Pagination or Media Count : 108

Abstract : This report describes the progress during the first seven and one half months on a program to improve pyrolytic graphite coated nozzles. Based on a detailed survey of candidate materials, a group of about twelve substrate materials were selected and fabricated. Thermal and stress analysis were completed which will guide the experimental work. Shear stresses as well as principal stresses were calculated. Low modulus of elasticity and low expansion coefficient in the axial direction were shown to be of prime importance in providing coating/substrate compatibility. Reduced coating expansion anisotropy was the most powerful means discovered to reduce deposition stresses. Firing stresses were found to be insignificant relative to deposition stresses. Critical duty cycles for restart operation were defined. Four deposition furnace runs were made. Conventional commercial graphites were not suitable for delamination-free coatings, but a coating of good quality on a fibrous substrate was selected for the initial motor test. Erosion prediction studies progressed satisfactorily under subcontract with Aerotherm Corporation. (Author)

Descriptors :   (*SOLID PROPELLANT ROCKET ENGINES, ROCKET NOZZLES), (*ROCKET NOZZLES, REFRACTORY COATINGS), PYROLYTIC GRAPHITE, SUBSTRATES, MANUFACTURING, SHEAR STRESSES, MODULUS OF ELASTICITY, COMPATIBILITY, DEPOSITION, COOLING, THERMAL STRESSES, ANISOTROPY, COMPUTER PROGRAMMING, EROSION, PREDICTIONS, STARTING, CAPTIVE TESTS, REINFORCING MATERIALS, FIBER METALLURGY, THERMAL INSULATION, ABLATION, NONDESTRUCTIVE TESTING, MICROSTRUCTURE.

Subject Categories : Coatings, Colorants and Finishes
      Solid Propellant Rocket Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE