[Publication] Vacuum evaporation and expansion of pure metals at high temperature: application to titanium and zirconium

The net flux of evaporation must then be accurately predicted i.e. the deviation from the Langmuir law because of the recondensation flux of the metallic vapour on the molten bath.

The objective of this study is an experimental and theoretical evaluation of the net evaporation rate in the case of two reactive metals at high temperature, one (Zr) with a low vapour pressure whereas the second (Ti) exhibits a relatively higher vapor pressure.

An experimental device has been set up in order to measure under usual industrial conditions (10-2 Pa) the evaporation fluxes as well as the expansion of the metallic vapor.

In parallel, a particle simulation of the experiments compares the behaviour of the vapour for weak (Zr) and medium (Ti) collisional regimes.

Experimental and numerical results testify to the validity of the Knudsen cosine evaporation law with an exponent equal to 1 for Zr and 2 for Ti.
 

References:

Title: Vacuum evaporation and expansion of pure metals at high temperature: application to titanium and zirconium

Authors: Thomas Poullain, Jean-Pierre Bellot, Julien Jourdan, Isabelle Crassous, Alain Jardy

Journal: Vacuum

Date of publication (online): June 2022

Link: https://doi.org/10.1016/j.vacuum.2022.111209

Caption image: Map of the simulated atomic density of Ti vapour above the liquid bath