Excellent adhesion to subsequently applied paint or elastomer is obtained
by coating a metal substrate with a phosphate conversion coating by
contact with a liquid phosphating solution that contains zinc cations,
phosphate anions, and at least one adhesion promoter selected from (i)
film-forming organic substances, (ii) polymers of vinyl phenols modified
by substitution of substituted aminomethyl moieties on their aromatic
rings, (iii) inorganic oxides of one of the elements silicon, aluminum,
titanium, and zirconium. Preferably, the phosphating solution also
contains manganese and nickel cations and either iron cations or
hydroxylamine. If adhesion to paint is desired, the adhesion promoter
preferably is an acrylic film-forming substance, while if adhesion to
elastomers is desired, the adhesion promoter preferably is a polymer of
vinyl phenol and the phosphating solution preferably also contains calcium
cations.