Chemi-emission of electrons from metal surfaces in the cutting process due to metal/gas interactions

The exo-electron emission behaviour from Ti, W, Mo, Fe, Al, Ni, Cd, Zn and Pb metals was investigated during and after being cut in O-2 and N-2 gases at a gas pressure of 3 x 10(-2) Pa and in a vacuum of 4 x 10(-4) Pa. The results showed that the emission behaviour of electrons during and after cutting depends on the combination of metal and the surrounding gas species. The emission intensity of electrons while cutting various metals in O-2 gas increased sharply with an increase in the negative value of the heat of formation, Delta H-f of the oxide. The emission intensity in N-2 was also higher at higher negative values of Delta H-f of the metal nitride. Electron emission intensity from the cut metal surface is concluded to be a function of the heat of formation of reaction products of the metal surface with the surrounding gas.