IPC-TM-650 EN 2022 试验方法.pdf - 第173页
IPC-23241-1 Figure 1 Porosity T est Schematic mA VM P ower Supply o-1 a DC o-10 V - + - + T eflon® Gold Clad Plate Photographic P aper , Silver Halide Free Sample Under T est T eflon® IPC-TM-650 Number 2.3.24.1 Subject P…
After
saturating the photographic paper with electrolyte, press
the paper between two paper towels to ensure any excess
electrolyte is removed from the photographic paper.
5.6
Assemble
the sample being tested for porosity and the
photographic paper of 5.5 in the electrographic clamp-press
as explained in 5.6.1 through 5.6.6.
5.6.1 Place
a piece of Teflon or equivalent insulating mate-
rial on the platform of the compression spring and piston
device on the clamp-press.
5.6.2 Place
the back of the sample or area of sample being
tested on top of and in contact with the Teflon.
5.6.3
Place
the silver halide-free photographic paper satu-
rated with electrolyte in 5.5 on top of and in contact with the
face of the sample or area of the sample being tested. The
emulsion side of the paper should be in contact with the test
sample.
5.6.4
Place
a piece of pure gold or gold-clad copper on top
of the photographic paper so the gold surface is in contact
with the photographic paper.
The gold or gold-clad material placed on the photographic
paper is to have the same maximum dimensions as that part
of the sample being porosity tested. The minimum dimensions
of the gold or gold-clad material is to be not more than
0.79375 mm shorter than the dimensions of the area being
tested in any one direction. Attach a lead wire to the gold or
gold-clad material in order to make electrical contact.
5.6.5
Place
a piece of Teflon or equivalent insulating mate-
rial on the back of the gold or gold-clad material.
5.6.6
Lower
the screw of the clamping and screw the
device until the pressure end of the screw is just in contact
with the back of the Teflon and holds the assembly in place.
Do not apply force at this time. See 5.11 for a schematic dia-
gram of assembly.
5.7
Compress
the spring of the clamp-press by tightening
the screw device until a pressure is exerted on the assembly
as in 5.6.6.
5.8
Connect
a DC power source so the positive (+) voltage
contacts the sample being tested and the negative (-) voltage
is connected to the lead of the gold or gold-clad material of
5.6.6. Apply a current, such that the current density is 250 mA
± 50 mA per square inch of surface in contact with the pho-
tographic paper. Applied voltage should not exceed 10 volts.
If the current density of 250 ± 50 mA/sq. in. cannot be
obtained at ≤10 volts, then the time of current flow should be
increased while holding the potential at 10 volts. The
increased time of current flow can be calculated by the follow-
ing formula.
Time of current flow (sec) =
250 mA/sq. in. of surface in contact with paper
Current
density in mA/sq. in. at 10 volts
x 60 sec
The time of the current flow should be 60 ± 1 sec.
5.9
Unclamp
the assembly and remove the silver halide-free
photographic paper.
5.10
Apply
one to two drops of the indiicator solution from
5.2. to the photographic paper.
5.11
Develop
the photographic paper containing indicator
solution by holding the paper over an ammonium hydroxide
solution.
5.12
Dry
the photographic paper to which indicator solution
was added and read the test results.
5.13
Observe
the porosity test schematic, as shown in Fig-
ure 1.
5.14
Test Results
5.15
Nickel
exposure through the gold will show up on the
indicating photographic paper as a red stain. Copper expo-
sure will show up as green stains. This exposure is caused by
pores, cracking, or unplated areas. These stains should be
examined under 10X min, 15X max.
5.15.1
Pores
Pores
will show up as fine dots.
5.15.2
Cracking
Cracks
will show up as continuous fine
lines.
5.15.3
Unplated Areas
Unplated
areas will show up as
large blots or red lines.
IPC-TM-650
Number
2.3.24.1
Subject
Porosity
Testing of Gold Electrodeposited on a Nickel Plated Copper
Substrate Electrographic Method
Date
10/85
Revision
P
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IPC-23241-1
Figure
1 Porosity Test Schematic
mA
VM
Power Supply
o-1 a DC
o-10 V
-
+
-
+
T
eflon®
Gold Clad Plate
Photographic Paper, Silver Halide Free
Sample Under Test
Teflon®
IPC-TM-650
Number
2.3.24.1
Subject
Porosity
Testing of Gold Electrodeposited on a Nickel Plated Copper
Substrate Electrographic Method
Date
10/85
Revision
P
age3of3
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1.0
Outline for Methods
The
part is exposed to an atmo-
sphere that is corrosive to the basis metal. Where there is
porosity, the reagent attacks the basis metal and generates
corrosion products. The part is examined for corrosion prod-
ucts.
1.1
Method 1 (Nitric Acid Vapor-Gold on Copper)
This
method
applies only to gold coatings on copper and copper-
base alloys.
1.2
Method 2 (Extended Nitric Acid Vapor)
This
method
applies only to gold coatings on copper and copper-base
alloys.
1.3
Method 3 (Nitric Acid Vapor - Gold on Nickel)
This
method
applies to gold coatings on copper, copper-base
alloys, and nickel.
2.0
Nitric Acid Vapor - Gold on Copper
2.1 Apparatus
Methods
1, 2, and 3.
2.1.1
Collimated Incandescent Lamp
No.
31-33-53,
Bausch and Lomb Co., or No. 359, American Optical Co., or
equivalent.
2.1.2
Desiccator (Glass)
Fisher
Scientific Co. Series
8-595 or 8-624 or equivalent. The size of the desiccator shall
be chosen so that no more than 164 cm
3
of
air space exists
for 6.45 cm
2
of
nitric acid surface area when approximately
301 ml of acid are placed in the bottom.
Caution:
No sealant (e.g., stopcock grease, etc.) shall be
applied to the mating surfaces of the desiccator cover or
bottom. Sealants may cause these to stick together, and any
method employed to release a stuck cover is likely to be
extremely hazardous.
2.1.3
Part Support
A
supporting structure made of glass
or other material not attached by nitric acid vapors to hold the
parts under test in the upper part of the desiccator.
2.1.4
Oven
An
oven capable of drying parts at 125°C.
2.1.5
Pressure Sensitive Polytetrafluoroethylene Tape
with Silicone Adhesive Backing
Connecticut
Hard Rubber
Company TFE Type HM225 or equivalent.
2.2
Reagents
Methods
1 and 2. Nitric Acid, 69, 0 to 71.0
Percent HNO
3
.
3.0
Procedure
3.1 Method 1 (Nitric Acid Vapor-Gold on Copper)
Caution:
Perform all work in hood, since the vapors given off
are toxic. Chemical goggles, completely closing the eyes,
should be worn and eyewash facilities should be readily
available.
To
minimize and tendency for the cover to stick, press a mini-
mum of three strips of the pressure polytetrafluoroethylene
tape (adhesive side down) at equal intervals around the mat-
ting surface of the bottom of the desiccator. Place approxi-
mately 300 ml of nitric acid in the bottom of the desiccator.
Cover the desiccator and allow about 30 minutes for equilib-
rium to be established before starting the test. This equilibrium
is necessary only when the nitric acid is first placed in the
desiccator.
Clean the part with 1,1,1-trichloroethane or toluene or other
suitable solvent and dry with filtered dry air (gage pressure
less than 207 kPa (30 psi)).
Inspect the cleaned part at 10 power magnification for evi-
dence or particulate matter of the surface. If any remains,
reclean the solvent or use a clean soft brush to remove it prior
to the start of the porosity test.
Place the clean part on the support so that adequate space
exists to allow circulation of acid vapor and air around it.
Carefully remove the desiccator cover, place the support in
the desiccator and immediately replace the cover to prevent
an excessive loss of vapors that would disrupt the equilibrium
previously established. The test shall be performed at a tem-
perature of 24 ± 3°C and a maximum relative humidity of 60
percent. Unless otherwise specified, the time of exposure to
the reagent vapor shall be one hour.
2215
Sanders Road
Northbrook, IL 60062-6135
IPC-TM-650
TEST
METHODS MANUAL
Number
2.3.24.2
Subject
Porosity
of Metallic Coatings on Copper-Base
Alloys and Nickel (Nitric Acid Vapor Test)
Date
8/97
Revision
A
Originating Task Group
N/A
Material
in this Test Methods Manual was voluntarily established by Technical Committees of the IPC. This material is advisory only
and its use or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to the use, application, or adaptation of this
material. Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement.
Equipment referenced is for the convenience of the user and does not imply endorsement by the IPC.
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