PROPERTIES
of NICKELSHIELD®
| Summary
of Physical Properties |
|
| |
|
| Specific Gravity |
7.85 approximate |
| Melting Point |
1635 Farenheit,
890 Celsius |
| Electrical Resistance |
60 micro-ohms/cm/cm
squared |
| Coeffient of
Thermal Expansion |
13 x 10-6
cm/cm/per degree C -or-
7.22 x 10-6 in/in/per degree F
|
| Thermal Conductivity |
0.0105 to 0.0135
cal/cm/sec/degree C |
| As-plated Hardness |
49-50 Rockwell
C
500 to 600 Vickers |
| Maximum Hardness |
70 Rockwell
C
1000 Vickers |
| Chemical Analysis |
Nickel 90-92%
Phosphorus 8 - 10%
Carbon 0.04%
Oxygen 0.0023%
Nitrogen 0.0047%
Hydrogen 0.0016% |
UNIFORMITY AND POROSITY
Unlike electroplated
nickel and other metals, NICKELSHIELD is deposited uniformly over all
surfaces, no matter what the contours. There is no excessive build-up
on threads and sharp edges or in blank areas, holes, and recesses. The
chemical reaction deposits the nickel evenly over all surfaces with
which the solution comes in contact.
In the as-plated condition, NICKELSHIELD has the structure of a
super-cooled liquid. Therefore, it is non-crystalline and is virtually
non-porous.
CORROSION RESISTANCE
NICKELSHIELD shows
superior corrosion resistance to many chemicals, and in particular,
chemicals of an alkaline nature.
Coatings of one mil (.001 in.) on cold rolled plate have withstood 100
hours or more of the salt spray test ASTM-B-117-49T. When the rust pits
do appear, there seems to be no tendency for them to spread, even when
the part is left in the salt spray chamber.
Corrosion resistance is dependent upon complete coverage; and while
NICKELSHIELD is innately non-porous, the cleanliness and surface finish
of the part have a great bearing upon the quality of the finished product.
A clean, smooth surface results in better corrosion resistance than
a porous, rough surface.
ADHESION
The adhesion of NICKELSHIELD
to the base metal is excellent. Values for the bond strength are in
the range of 30,000 to 60,000 psi although there is no standard test
method. NICKELSHIELD will pass the adhesion test called for in the specifications
MIL-C-26074C- This test requires a 180° bend on 2 mil and 4 mil
samples without flaking. The cracking that does appear parallel to the
axis of the bend is due to exceeding the elastic limit of the NICKELSHIELD.
Microscopic examination of the compression side of the bend will reveal
that sometimes there is flaking in the coating itself, but not between
the coating and the base metal.
HARDNESS AND DUCTILITY
The hardness of as-plated
NICKELSHIELD averages 49- 50 Rockwell C. or 500 Vickers. Subsequent
heat treating above 375°F (190°C.) causes the as-plated amorphous
structure to start to change into a crystalline structure with a resulting
increase in hardness. The maximum hardness of 70 Rockwell C or 1000
Vickers is obtained at 750°F (400°C.) for one hour.
The elastic strain of as-plated NICKELSHIELD is 2%. This can be increased
to 6% by heat treating at 750°F for one-quarter hour, and even more
by heat treating at 1550°F.