Date post: | 16-Jul-2015 |
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Technology |
Upload: | alan-gardner |
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History....
• There is a demand for Black Electroless Nickel coatings, and there has been for decades
• In the past black EN deposits were typically created by using Nitric Acid, but it was never very successful– Inconsistent results were common
– The deposits were smutty, and the color was uneven
– The corrosion resistance of the deposits were very poor
A New Process......NiKlad Eclipse
• NiKlad Eclipse is a new Black ElectrolessNickel process– It is nitric acid free
– Produces an adherent, even black deposit
– Exhibits excellent corrosion performance when combined with a high phosphorous Electroless Nickel and a passivationlayer.
– It is ELV, WEEE and RoHS compliant
– The deposit produced is a complex Ni/P/Oxide. The black
colour of Ni-P coating is due to the unique surface morphology
combined with the formation of the nickel oxides and nickel
phosphate)
• It has been running in major production for over three
years (producing over ¾ of a million connectors for commercial
use)
Typical NiKlad Eclipse Process
• EN Plate in high phosphorus NiKlad process
• EN Plate NiKlad ELV 824 min 8ums.
• Immerse in NiKlad Eclipse solution– R.T.
– 60 – 120 secs
– Gentle agitation
• Dry
• Passivate or topcoat (Optional)
NiKlad Eclipse Deposit Characteristics
Electroless nickel coating (8um thickness Single layer low Ni-P only)
Black oxidised layer (<1µm)
Base material
NiKlad Eclipse Deposit Characteristics.....
• Black measured at 22 on the L.A.B. color space scale – Scale goes from 0 – 100
• 0 = complete black 100 = complete white
• 94-96% absorption rate and 4-6% emissivity
• Deposit has excellent corrosion protection
• Deposit is conductive
• Deposit is UV stable
• Deposit is abrasion resistant
• Color may be lost in corrosion tests unless
passivated
NiKlad Eclipse Performance
• Corrosion resistance of the process is excellent
• Duplex system can easily achieve >1000 hrs NSS on
steel, brass and aluminium
• Passivated deposit electrochemical corrosion
resistance is comparable to EN plating alone
Effect Eclipse and passivation on 824
0
5
10
15
20
25
NiKlad ELV 824 Eclipse Eclipse + Passivation
Process
Ico
rr (
uA
/cm
2)
NiKlad Eclipse 1000 hrs NSS (per ASTM B117)
6061 Al panels
Duplex EN coating
12.5 um High phosphorous
12.5 um NiKlad ELV 824
NiKlad Eclipse
Cathodic passivate
NiKlad Eclipse Deposit Conductivity
Layer 1 Layer 2 Conductivity (mV)
HP 20 ums NiKlad Eclipse 2.25
HP 30 ums NiKlad Eclipse 2.12
MP ELV 20 ums NiKlad Eclipse 2.21
MP 20 ums NiKlad Eclipse 2.34
NiKlad Eclipse Hardness
• Hardness/Abrasion Resistance– As plated the Eclipse is soft, ~ 2B
– Drying over time (3 days) or in the oven
gives ~2H
– Passivation gives >8H (harder than most
lacquers)
Hardness of Black EN
0
100
200
300
400
500
600
700
800
900
Plated 190°C for 2hs Plated 190°C for 2hs
Hard
ness H
v100
NiKlad Eclipse Passivation
• Passivation
– The passivation of NiKlad Eclipse is carried out
using a cathodic hexavalent chrome solution
– Critical factors are
• Voltage
• Time
• Temperature
• Solution movement
• Rinsing
NiKlad Eclipse Passivation
• Surface analysis after passivation– XPS process measures the first 3 – 5 nm of the coating
Sample C O Ni P Cr
NiKlad Eclipse
No Electrotarnil
B
10.6 50.8 20.9 17.7 -
NiKlad Eclipse +
Electrotarnil B
11.5 61.8 3.7 7.0 16.0
NiKlad Eclipse Passivation
• Surface analysis after passivation
NiKlad Eclipse + Electrotarnil B
0 200 400 600 800 1000
Binding Energy / eV
Co
un
ts
C1s
O1s Cr2p
P2p
Ni2p
NiKlad Eclipse Passivated Deposit
• No hexavalent
chrome present– By XPS
– By GM 3045
• A combination of
chrome oxide and
chromium
hydroxide.
• RoHS compliant
deposit
Bright Mid Phos EN
• Brightness range from 140-
110 Gloss Units
• RoHS, ELV and WEEE
compliant
• Wide operating window –
easy to operate
• Consistent plating rate
NiKlad ELV 849
• Plating Rate
– Consistent plating rate for the entire bath life
• 0.75 – 0.6 mil/hr
NiKlad ELV 849
• As plated hardness
– Comparable to conventional Medium Phos EN
• 500 – 600 HK 100 or 50 – 56 Rc
• After heat treatment at 400C for 1 hour
– Comparable to conventional Medium Phos EN
• 850 – 950 HK 100 or 66 - 69 Rc
• As plated wear
– 22 – 26 mg/1000 cycles
• After heat treatment at 400C for 1 hour
– 14 – 18 mg/1000 cycles
NiKlad ELV 849
• Density 8.2 g/cm
• Phosphorus Content 7-9 weight percent
• Hardness: (as plated) 500 - 600 HK100
(heat treated @ 400 C for 1 hour) 850-950 HK100
• Wear Resistance:(as plated) 22-26 TWI *
(heat treated @ 400 C for 1 hour) 14-18 TW* TWI -- “Taber Wear Index” is the weight loss in mg per 1000 cycles
• Magnetic Tendency Slightly Magnetic
• Electrical Resistivity 70-90 cm
• Corrosion Resistance1 >96 hrs 25μm deposit
• Nitric Acid Resistance2 Fail • 1ASTM B117 performed on flat panel.
• 2If the deposit darkens in concentrated nitric acid after 30 seconds it is considered a failure.