鎳磷、鈷磷與鎳鈷磷合金電鍍之研究
Date Issued
2003
Date
2003
Author(s)
DOI
912216E002040
Abstract
The effects of electrolyte composition and
electroplating parameters on the phosphorus
content, deposit hardness, internal stress
and cathodic current efficiency for Ni-P and
Co-P electrodeposits were investigated so
as to develop a process for
micro-electroforming the mechanic
elements for high-temperature applications.
Experimental results indicate that with
increasing the bath phosphorous acid
concentration, the grain structure of the
Ni-P and Co-P alloys, plated at a current
density of 8 A/dm2, was refined as
compared to the coarse columnar structure
associated with pure Ni and Co coatings,
and hence their hardness was markedly
increased, whereas the cathodic current
efficiency monotonously decreased with the
phosphorus acid concentration.
Conversely, the efficiency was enhanced by
means of pulse current. TEM further
revealed the coatings plated from the bath
with 40 g l-1 phosphorus acid consisted of
nano grains. When annealed at
temperatures less than 400 ℃, the hardness
of the alloy coatings increased due to the
precipitation of P-bearing intermetallic
compounds. However, the hardness of the
alloy coatings dropped after 1 h of
annealing at temperatures exceeding 500
℃ because of the recrystallization and
grain growth of the nickel matrix. Finally,
the Co-P alloys had larger high-temperature
strength than the Ni-P alloys.
electroplating parameters on the phosphorus
content, deposit hardness, internal stress
and cathodic current efficiency for Ni-P and
Co-P electrodeposits were investigated so
as to develop a process for
micro-electroforming the mechanic
elements for high-temperature applications.
Experimental results indicate that with
increasing the bath phosphorous acid
concentration, the grain structure of the
Ni-P and Co-P alloys, plated at a current
density of 8 A/dm2, was refined as
compared to the coarse columnar structure
associated with pure Ni and Co coatings,
and hence their hardness was markedly
increased, whereas the cathodic current
efficiency monotonously decreased with the
phosphorus acid concentration.
Conversely, the efficiency was enhanced by
means of pulse current. TEM further
revealed the coatings plated from the bath
with 40 g l-1 phosphorus acid consisted of
nano grains. When annealed at
temperatures less than 400 ℃, the hardness
of the alloy coatings increased due to the
precipitation of P-bearing intermetallic
compounds. However, the hardness of the
alloy coatings dropped after 1 h of
annealing at temperatures exceeding 500
℃ because of the recrystallization and
grain growth of the nickel matrix. Finally,
the Co-P alloys had larger high-temperature
strength than the Ni-P alloys.
Subjects
Nickel sulfamate bath
Ni-P electrodeposit
Co-P
electrodeposit
electrodeposit
nano grain
Publisher
臺北市:國立臺灣大學材料科學與工程學研究所
Type
report
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