Accession Number : ADD007714

Title :   Conductance Method for Determining the Mechanical Properties of Propellants.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE ARMY WASHINGTON DC

Personal Author(s) : Sayles,David C

Report Date : 11 Sep 1979

Pagination or Media Count : 6

Abstract : A solid propellant grain is converted from a non-conductive filled elastomer into a highly-conductive filled elastomer by introducing an effective amount of an alkali metal tungstate or the analogous ammonium salt which, in addition to imparting electrical conductance characteristics, also functions as an oxidizer in the propellant composition. When sodium tungstates, known as tungsten bronzes, or the analogous ammonium salt, are used to replace from 1 to 3 parts of the ammonium perchlorate oxidizer in the propellant formulation, it changes the grain to a highly-conductive grain, and, thereby, permits measuring the continuity of the propellant grain by means of electrical conductance measurements. These conductance measurements provide means of assessing the changes which take place in the solid propellant grain, such as, the physical and chemical changes (which affect mechanical properties) which the grain has undergone during storage or aging or when the grain is subjected to different load conditions, such as, acceleration, blast, shock, etc. In addition to the benefit of the reliable means for assessing such changes, the propellant grains employing the tungstates show an unpredicted increase in the propellant burning rate. The propellant density also increased due to the high density of the tungsten bronzes, and this is another benefit. (Author)

Descriptors :   *Patents, *Solid propellants, *Mechanical properties, *Test methods, *Electrical conductivity, *Measurement, Elastomers, Alkali metals, Tungsten alloys, Ammonium compounds, Salts, Sodium compounds, Solid rocket oxidizers, Ammonium perchlorate, Storage, Aging(Materials), Loads(Forces), Tungstates, Accelerated testing, Burning rate, Propellant grains

Subject Categories : Electricity and Magnetism
      Mechanics
      Solid Rocket Propellants

Distribution Statement : APPROVED FOR PUBLIC RELEASE