Wisher - from what I understand, Silkies are usually recessive white. That means that a chicken has to have two copies of the white gene (ok, so the correct term is "allele") for the bird to be white. A black bird could be carrying a copy of recessive white, but it clearly doesn't have 2 copies, or it would be white. If your black bird is carrying recessive white, then some of the offspring could be white.That much is easy.
The tricky part is that you don't know what genes (other than recessive white) a white Silkie is carrying. They might have the genes to be black, blue, partridge, buff; you can't tell, because the white means that the birds have no pigment in their feathers. Breeding a white Silkie to a bird that isn't white means that at least some of the offspring will get something other than recessive white from that other-color parent, which will let them express whatever genes the white bird isn't expressing. In other words, they (theoretically) could be anything. Apparently, a lot depends on what the black is carrying, too - what you might get is black with leakage, or other less desirable versions of black.
The post was 1121 of the 6th Annual BYC HAL. By Silkue Sensation. It had percentage hatch when breeding nn to silkies and others but not the color. But it may be helpful.
I'm probably wrong - I used to spend a lot of time on silkie and showgirl threads - BUT, I think they said you only need to cross to a turken(naked neck) once to get that feature,and from there on just breed to silkies and showgirls.