Field-emission investigation of composite adsorption layers of hydrogen and hydrogen sulphide on tungsten

Abstract EN

The interaction of H2 and H2S with tungsten, and of H2S with hydrogen-covered tungsten, has been investigated in the field emission microscope.

A number of chemisorbed states with varying heats of adsorption have been identified throughout H2 adsorption at a pressure of 5-10 Nm-2 and 78 K on tungsten.

When H2S was adsorbed at 295K and gas pressure of Nm-15-10 on clean tungsten surface a preferential interaction occurred along Th (111) zones.

An increase in the average work function of 0.3 V has been found for the process.

Desorption of hydrogen, resulting from H2S adsorption, began at 1270 K.

Migration of the remaining sulphuric began at 1400 K while desorption occurred above 1500 K and was complete at 1870 K.

Activation energies for the desorption of hydrogen and sulphuric have been estimated.

The effect of increasing H2S pressure on the emission patterns of tungsten has also been studies.

Addition of H2 had no influence on the emission characteristics and subsequently was heated at.

1700 K