US 5,288,645 A · 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.

Claims15

Dependent claims

A method for determining the amount of a selected gas that evolves from a specimen of a selected material, the probable source of that gas and the concentration of a selected element in the evolved gas, the method comprising the steps of:

inserting a specimen into the interior of an evacuable chamber and evacuating the chamber to a selected evacuation pressure;
increasing the specimen temperature T to at least one selected temperature and monitoring the pressure of any gas that appears in the chamber interior at the selected temperature;
and
determining the amount of a gas evolved in the chamber at temperatures near the selected specimen temperature by analyzing changes in the monitored pressure as the chamber temperature is increased.

1 more element

inserting a first test specimen into the interior of a first evacuable chamber and evacuating the first chamber to a selected evacuation pressure;
inserting a second test specimen into the interior of a second evacuable chamber and evacuating the second chamber to the selected evacuation pressure;
heating the first chamber to remove residual gases from the first chamber and the first test specimen;
determining one or more peak evolution temperatures at which the thermal derivative of a gas pressure p1 evolved in the first chamber by heating the first chamber achieves a local maximum;
heating the second chamber to remove residual gases from the second chamber and the second test specimen, wherein during the second chamber heating step, the second chamber temperature is increased to at least one of said peak evolution temperatures and held at such temperature for a period of time;
monitoring the pressure of any gases evolved in the first and second chambers during a selected time interval;
and
determining the amount of a gas evolved from the specimen at temperatures near the peak temperature by distinguishing changes in the monitored pressure as the chamber temperature is increased.

5 more elements

Dependencies are inferred from the claim text.

Hydrogen evolution analyzer

Life of this patent

Hydrogen evolution analyzer

Life of this patent

Abstract

Claims15