52. Solving a chemistry problem

3. By electrolysis of a hydroboron fluoride electrolyte containing Pb(BF4)2 and Sn(BF4)2, an 8 µm thick coating of a lead-tin alloy (50 wt.% Pb, 50 wt.% Sn) was obtained on the parts. The cathode current density during deposition is 1 A/dm2, the current efficiency of the alloy is close to 100%. Determine the duration of the electrolysis process if the coating density is 8.7 g/cm3.