An experimental investigation on the effect of the MHD interaction with the plasma of the shock layer above a wedge immersed into a hypersonic argon flow was carried out with the Mach 6, partially ionized flow obtained from the high-enthalpy arc-heated wind tunnel of Alta-CPR (Pisa). The tests were conducted with total pressures of 0.65, 0.85, and 1 bar, and magnetic fields in the range of 0.15-0.35 T. The diagnostics included electrostatic probes on the model surface, an optical multi-channel analyser, and a fast shutter CCD camera. Due to the MHD interaction an increase of the shock distance from the body surface was observed, although the MHD interaction effect was reduced by the low conductivity of the plasma in the boundary layer above the test body surface.