You mean the father would be a White silkie and the mother a Buff Orpington, right?This might have already been asked, but would the offspring a white silkie over buff orpington be sexlinked?
There are several kinds of sexlinks. Most of them will not work with those chickens, but one or two might.
Gold/silver sexlinks requrie a gold father and a silver mother-- not possible with a Buff Orpington mother.
Barred/not-barred sexlinks require a not-barred father and a barred mother-- also not possible with a Buff Orpington mother.
Skin-color sexlinks might be possible. They require a dark-legged father (most Silkies have dark legs) and a light-legged mother (Buff Orpingtons have white legs, which are fine for this.) If that works, the daughters will have dark legs (like Silkies) and the sons will have light legs (like their mother.) Other genes can affect whether the leg color is obvious enough to be useful, so I can't be entirely sure whether it would work or not.
Feather-sexlinks require a fast-feathered father and a slow-feathered mother. If you do not know the feathering speed of the parents, you won't know if they can produce that kind of sexlinks. (When it works, the daughters are fast-feathering like their father, and the sons are slow-feathering like their mother.)