Accession Number : ADA193708


Title :   Erosion of Metals Exposed to Hot, Dense Gases


Descriptive Note : Final rept. 16 Jun 1984-15 Jun 1988


Corporate Author : PORTLAND STATE UNIV OR DEPT OF PHYSICS


Personal Author(s) : Takeo, Makoto


Full Text : http://www.dtic.mil/dtic/tr/fulltext/u2/a193708.pdf


Report Date : Feb 1988


Pagination or Media Count : 39


Abstract : Metal foils were exposed in a ballistic compressor to a mixture of argon and hydrogen. Behavior of hydrogen is unpredictable. When pure iron foil was exposed to a mixture of Ar with 16% H2 (by volume) at 120 atmospheres and 1400 C about a millisecond, precipitate particles of similar size (500 angstroms x 1000 angstroms) occurred, oriented in the same direction in entanglement of matrix dislocations. The electron microdiffraction pattern indicates a distorted tetragonal structure, which seems to be Fe16H2. The diffraction pattern of the matrix shows a distorted bcc. A nitrogen-proton nuclear reaction confirmed the presence of hydrogen in the exposed foil and supports the predicted structure. When pure chromium foil was exposed, streaks appeared in the electron diffraction pattern, possibly related to generation of lattice displacement waves. Using a CCD video camera, a video digitizer, and a microcomputer, a device is constructed for analyzing electron diffraction patterns. This system can help to reduce the measurement time to one third when compared with conventional manual methods and produces results with better accuracy and less operator fatigue.


Descriptors :   *EROSION , *HOT GASES , *FOILS(MATERIALS) , *DENSE GASES , METALS , MEASUREMENT , HYDRIDES , CORROSION , HIGH TEMPERATURE , ACCURACY , IRON COMPOUNDS , HYDROGEN , MIXTURES , TIME , ELECTRONS , PARTICLES , DIFFRACTION , CAMERAS , PATTERNS , MANUAL OPERATION , BEHAVIOR , MICROCOMPUTERS , COMPRESSORS , ANALOG TO DIGITAL CONVERTERS , ARGON , ELECTRON DIFFRACTION , DISTORTION , PRECIPITATES


Subject Categories : Properties of Metals and Alloys


Distribution Statement : APPROVED FOR PUBLIC RELEASE