Metric Formula  for the Deposit Stress Analyzer System:

CALCULATIONS: (For Thickness)

If the test strip legs are spread outward on the side that has been plated (plated side out and resist side in) the deposit stress is tensile in nature. If the test strip legs are spread inward on the side that has been plated, the deposit stress is compressive in nature. It is necessary to know the total units or increments spread between the plated test strip leg tips from both sides of the center line on the measuring block scale and the average deposit thickness in order to calculate the deposit stress. If the deposit thickness cannot be determined by actual measurement, it can be calculated as follows:

T =              W                   = cm

.               D (7.74 cm²)

T = deposit thickness in cm

W = deposit weight in grams,

D= Density of the plated material, g/cm³ (see page 7 Table of Density Values for the D)

A = surface area in square centimeters. Since the plated surface area on a test strip is 7.74 square centimeters, the formula for nickel thickness can be shortened as follows:

Note: If using x-ray for thickness it would = T after the deposit thickness is known and the number of increments spread between the test strip leg tips has been determined, the deposit stress can be calculated thus:

Calculate the Deposit Stress:

S = UKM÷3T                          where:                 S = kg/cm²

U = number of increments spread (See Table B for conversion),

T = deposit thickness in cm,

K = the test strip calibration constant will be labeled on each lot of test strips,

M= the modulus of elasticity of the deposit ÷ by the modulus of elasticity of the substrate material (See Table A).

TEST STRIP MATERIAL RECOMMENDED PLATING CONDITIONS FOR PLATING See table 2 page 8 of DSA Brochure

Note: If the test conditions cause the test strip leg tips to spread beyond 20 units, reduce the deposition time and the deposit thickness for the test to improve accuracy.

FOR PN: 1194 – COPPER–IRON ALLOY 0.00508 cm thick (deposit stress from 105 to 10194 kg/cm²)

DEPOSIT STRESS M value for nickel plating M = 1.715 The correction factor for the difference in the modulus of elasticity between the deposit and that of the substrate = EDeposit ÷ ESubstrate = 2110813 ÷ 1230797 = 1.715 kg/cm².

FOR PN: 2042B – IRON-NICKEL ALLOY 0.00381 cm thick (deposit stress from 35 to 7030 kg/cm²)

Note: that this test strip material is applicable for tensile stressed deposits only.

DEPOSIT STRESS M value for nickel plating M = 1.4297 The correction factor for the difference in the modulus of elasticity between the deposit and that of the substrate = EDeposit ÷ ESubstrate = 2110813 ÷ 1476446= 1.4297 kg/cm²

 FOR PN: 270NI – PURE COLD ROLLED NICKEL 0.0011 INCH THICK  (deposit stress from 14 to 4218 kg/cm²)

DEPOSIT STRESS M value for nickel plating M = 1.0000 The correction factor for the difference in the modulus of elasticity between the deposit and that of the substrate = E Deposit ÷ E Substrate = 2110813 ÷ 2110813= 1.0000 kg/cm²

TABLE A                                        (Values for M)

Test Strip Material       1194 2042B 270NI
E Substrate 1,230,797 1,476,446 2,110,813
Stock Thickness, cm 0.00508 0.00381 0.002794
Metal    E Deposit Value   M M M
Cadmium 562,883 0.4573 0.3812 0.2667
Cobalt 2,528,896 2.0547 1.7128 1.1981
Chromium 2,151,601 1.7481 1.4573 1.0193
Copper 1,121,688 0.9114 0.7597 0.5314
Gold (Soft) 787,221 0.6396 0.5332 0.3729
Nickel 2,110,813 1.715 1.4297 1.0000
Palladium 1,193,068 0.9693 0.8081 0.5652
Platinum 1,743,715 1.4167 1.181 0.8261
Rhodium 3,660,781 2.9743 2.2763 1.7343
Sliver 774,984 0.6297 0.5249 0.3671
Tin 414,820 0.337 0.2809 0.1965
Zinc 984,026 0.7995 0.6665 0.4662

E Substrate= modulus of elasticity of the substrate material (test strip material).

E Deposit = modulus of elasticity of the plating deposit.

M= modulus of elasticity of the E Deposit ÷ modulus of elasticity of the E Substrate

Table B                    (U factor conversion) (*English is the increments spread on the Deposit Stress Analyzer)

Note:  If the increments spread is 6.25 the Metric would be 0.4394.

English Metric    English Metric    English Metric 
0 0 8.5 0.5977 17 1.2304
0.5 0.0351 9 0.6329 17.5 1.2305
1 0.0702 9.5 0.668 18 1.2657
1.5 0.1054 10 0.7032 18.5 1.301
2 0.1406 10.5 0.7383 19 1.336
2.5 0.1754 11 0.7735 19.5 1.3712
3 0.2109 11.5 0.8087 20 1.4059
3.5 0.2461 12 0.8438 20.5 1.4416
4 0.2812 12.5 0.8788 21 1.4767
4.5 0.3164 13 0.9142 21.5 1.5118
5 0.3513 13.5 0.9493 22 1.5471
5.5 0.3867 14 0.9845 22.5 1.5821
6 0.4218 14.5 1.0196 23 1.6174
6.5 0.4569 15 1.0547 23.5 1.6526
7 0.4923 15.5 1.0899 24 1.6877
7.5 0.5274 16 1.125 24.5 1.7229
8 0.5625 16.5 1.1603 25 1.7581