Direct coating on brass substrate in vacuum chamber

Sir I want to know whether we can do any direct coating on brass component in PVD chamber equivalent to that of Ni-Cr.

The answer depends on what you are trying to achieve. Yes, you can deposit nickel and chrome on brass by PVD processes. But the coatings are not going to be identical to coatings deposited by wet coating processes. For example, residual stresses will be compressive in the PVD deposited coatings, vs tensile in electroplatings. You can't build up very thick coatings easily by PVD because of the high compressive stress. PVD coatings cannot duplicate the "fill" characteristics of electroless nickel. On the other hand, PVD coatings should have better adhesion to the substrate than plated coatings.

As a side note, it might not be viable to coat by PVD brass alloys with high zinc content. Zinc has a high vapor pressure. If the zinc comes out of the alloy, it will contaminate the vacuum chamber.