Limiting role of the mass transfer of gases in laser thermochemical reactions on the surface of solids

Emil N. Sobol

doi:10.1117/12.23726

1 October 1990 Limiting role of the mass transfer of gases in laser thermochemical reactions on the surface of solids

Emil N. Sobol

Proceedings Volume 1352, 1st Intl School on Laser Surface Microprocessing; (1990) https://doi.org/10.1117/12.23726
Event: International School on Laser Surface Microprocessing, 1989, Tashkent, Uzbekistan

Abstract

Growth kinetics of porous layers produced by gas-transfer controlled thermochemical reactions is described. The analysis of heat and mass-transfer problem allows to find the optimal regimes of laser treatment of solids. 1. GROWTH KINETICS OF SURFACE LAYERS The limiting role of gas transfer is characteristic of various processes in volved in the growth of solid layers of a new phase on the exposed surface'' in the course of laser oxidation and reduction of metals and laser synthesis and decomposition of nitrides and other compounds high-temperature superconductors included. When analyzing laser thermochemical reactions taking place in solids and involving the uptake or release of gases the absorbed energy flux q will be considered constant the thermooptical effects2 being disregarded. Let laser radiation incident on the surface of the original substance A give rise to a layer of a new phase B with a thickness of s through which a gas C migrates. We write the pertinent chemical decomposition and synthesis reactions in the form A 4 B + C and A + C ) B respectively. The direction of the reaction is determined by the sign of the Gibbs thermodynamic potential tG /H + TM where tH and tS are the changes of the enthalpy and entropy of the system respectively. According to the chemical equilibrium theory the pressure at the chemical reaction front is related to temperature by the Arrenius law:

Citation Download Citation

Emil N. Sobol "Limiting role of the mass transfer of gases in laser thermochemical reactions on the surface of solids", Proc. SPIE 1352, 1st Intl School on Laser Surface Microprocessing, (1 October 1990); https://doi.org/10.1117/12.23726

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
7 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Solids

Gases

Calcite

Chemical reactions

Gas lasers

Fusion energy

Diffusion

Show All Keywords

Keywords/Phrases

Search In:

Publication Years