Accession Number : AD0757513

Title :   Enhancement of Ablator Performance by Additives,

Corporate Author : UTAH UNIV SALT LAKE CITY COLL OF ENGINEERING

Personal Author(s) : Chidley,J. D. ; Seader,J. D.

Report Date : DEC 1971

Pagination or Media Count : 129

Abstract : The behavior of three additives, chromic oxide, iron, and ferric oxide, incorporated into the resin phase of a typical phenolic- silica charring-ablative material was investigated. An extensive theoretical basis for the prediction of the relative effects of such additive upon the ablative performance is presented. Char-depth reduction in composites exposed to the relatively low (7.7 cal/square cm sec) RADIANT FLUX OF THE ARC-IMAGING FURNACE APPEARED TO BE ACCOMPLISHED BY TWO DIFFERENT MECHANISMS. Chromic oxide and iron appear to block initial penetration of radiant energy into the resin. Ferric oxide appears to be reduced exothermally at first, the reaction then changing to endothermic reduc-tion by carbon. Char samples from ablatives exposed to the hot-gas environment of a hybrid rocket motor were examined by a scanning electron microscope for evidence as to the mechanism of char-depth reduction by the three additives. Composites containing chromic-oxide exhibited the least reduction in char depth relative to the standard composite. The effect of iron upon the overall char depth was a reduction of about ten percent. The largest reduction in the char depth, ranging up to thirty percent, was observed in composites containing ferric oxide. The inclusion of iron or ferric oxide in the ablative composite appears to offer considerable enhancement of ablative-wall performance. (Author, modified-PL)

Descriptors :   (*ABLATION, ADDITIVES), (*HYBRID ROCKET ENGINES, ABLATION), PHENOLIC PLASTICS, SILICON DIOXIDE, CHROMIUM COMPOUNDS, OXIDES, IRON, IRON OXIDES, ELECTRON MICROSCOPY, REINFORCED PLASTICS, CHEMICAL REACTIONS, OXIDATION

Subject Categories : Physical Chemistry
      Rocket Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE