CALCULATION AND PLOTTING OF STANDARD FREE ENERGY CHANGES AND EQUILIBRIUM CONSTANTS FOR CVD HARD COATINGS REACTIONS

Abstract

CVD (chemical vapor deposition) coatings such as TiC , TiN , Al 2 O 3 and so on are widely used as tools' surface preserved materials with corrosion resistance and wear resistance. Standard Gibbs free energy changes for reactions are widely used to approximately analyze the trends of substance reactions and phase transitions in chemical reactions, metallurgy processes, materials synthesis and processing. Hard coatings and thin films can be prepared by CVD process. Accurate calculation and plotting of the standard free energy changes and equilibrium constants for CVD TiC , TiN , Al 2 O 3 coatings reactions are realized using the developed general computer program. Only inputting the basic thermodynamic data tabulated in data books into the computer program, the relationships of the standard free energy changes and equilibrium constants for most reactions with the temperatures can be gained in the same diagrams.