TY - RPRT
T1 - A "Green" Passivation of Zinc containing surfaces as an
alternative to chromate
AU - Montgomery, Melanie
AU - Maahn, Ernst emanuel
AU - Møller, Per
AU - Hyttel, H.
AU - Andersen, S.
AU - Andersen, K.
AU - Larsen, L.
AU - Linnemann, H.
AU - Witt, R.
N1 - MUP Project
PY - 1996
Y1 - 1996
N2 - With view to a replacement for chromate passivation, Molyphos was
developed under the Danish Materials Programme I (MUP I). In the
Danish Materials Programme II(MUP II), the further development of
Molyphos a molybdate phosphate conversion coating has been
undertaken by application of a sealer to give added protection
against white rust formation of zinc coated components. Various
coating systems have been investigated: The types of zinc plated
coating include acid zinc, cyanide zinc, and Zn/Fe. Many types of
sealer have been employed both water and solvent based. The
coating systems have been exposed in salt spray tests, humidity
tests, prohesion tests and field tests. The results show that a)
barrel plated acid zinc specimens coated with Molyphos + sealer
give comparable performance to chromate in field tests and b) a
Zn/Fe substrate and Molyphos coating (plus selected sealer) gives
comparable performance to chromate in the prohesion test. However
no combination in the Molyphos system could compare with the
performance of yellow chromate in the neutral salt spray test or
humidity test, although Molyphos performs very well in the
prohesion test. Welding tests have shown that components coated
with sealers cause equipment problems during welding.
AB - With view to a replacement for chromate passivation, Molyphos was
developed under the Danish Materials Programme I (MUP I). In the
Danish Materials Programme II(MUP II), the further development of
Molyphos a molybdate phosphate conversion coating has been
undertaken by application of a sealer to give added protection
against white rust formation of zinc coated components. Various
coating systems have been investigated: The types of zinc plated
coating include acid zinc, cyanide zinc, and Zn/Fe. Many types of
sealer have been employed both water and solvent based. The
coating systems have been exposed in salt spray tests, humidity
tests, prohesion tests and field tests. The results show that a)
barrel plated acid zinc specimens coated with Molyphos + sealer
give comparable performance to chromate in field tests and b) a
Zn/Fe substrate and Molyphos coating (plus selected sealer) gives
comparable performance to chromate in the prohesion test. However
no combination in the Molyphos system could compare with the
performance of yellow chromate in the neutral salt spray test or
humidity test, although Molyphos performs very well in the
prohesion test. Welding tests have shown that components coated
with sealers cause equipment problems during welding.
M3 - Report
BT - A "Green" Passivation of Zinc containing surfaces as an
alternative to chromate
ER -