A design of an alkali metal generator with a working substance in the
form of intermetallic compound A(n)Me(m) the surface of which is cover
ed by a protective layer Me (A - alkali metal, Me - an element, the va
pour pressure of which under the deposition temperatures is similar or
equal to 10(8) and more times lower than the vapour pressure of the c
omponent A) is suggested For this kind of a system a one-dimensional p
roblem of diffusion of a volatile component and its evaporation into v
acuum is solved. It is shown that, in due course, the evaporation stre
am asymptotically approaches a constant value.