Study of influence of metal spraying on the membrane pump performances

Effect of fine (approximately 1 μm) films made of Ni, Cr, Ti, Nb on the hydrogen pumping-out rate by palladium pump is studied. Coatings have been applied by plasma-arc method in the atmosphere of argon at pressure of about 1 Pa. The character of the dependence of pumping-out rate on pressure is different for different coatings: in a case of hydrogen pumping-out by pure palladium the dependence is close to Psup(-1/2), during the Ti and Ni films application this dependence is weaker and for Nb and Cr coatings it is practically absent. Activation energy changes in the range of 2.7-9.6 kkal/mol, and relative rate of pumping-out constitutes 10-54%. Sputting of very different metals results in the decrease of the quickness of pumping- out of membrane pump, which is especially sufficient in the case of Nb and Cr films sputtering on the Pd surface