Hydrogen evolution analyzer

Abstract

Method for determining temperature ranges at which a selected gas evolves from a specimen of a selected material, bulk or surface of a metal, semiconductor, or insulator, and the probable source of that gas in each such temperature range. A specimen is placed in an evacuated and baked-out tube, and the specimen temperature T is increased according to a selected time-dependent temperature pattern over a temperature range. As temperature T(t) increases, pressure p(t) of any gas evolving in the tube is measured for a sequence of times t. A total pressure derivative, dp/dT=(dp/dt)(dT/dt).sup.-1, is determined, identifying one or more peak temperatures, each having a peak temperature range corresponding to specimen emission of at least one gas by breaking a bond containing an atom or molecule of that emitted gas. Partial pressure rises in the tube at each peak temperature are monitored and converted to an equivalent gas concentration. In a second embodiment, two tubes, with only one containing a specimen, are used for analyzing the differential pressure .DELTA.p=p1- p2 and differential pressure derivative d(.DELTA.p)/dT. In a third embodiment, both tubes contain specimens, and one or more peak temperatures are identified. In each embodiment, composition, partial pressures and concentrations of gases evolved at a peak temperature are optionally determined by residual gas analysis of another specimen in another tube, heated to and held at a peak temperature.