Electroless Nickel Alloy calculation of stress using the DSA formula for the strip PN: 270NI
E Deposit = 7977000 PSI the Modulus of Elasticity for the plated alloy deposit.
In the Deposit Stress Analyzer formula, S = UKM divided by 3T.
M = the Modulus of Elasticity of the deposit,
EDeposit, divided by the Modulus of Elasticity of the substrate, ESubstrate. Thus, M = 7977000 PSI divided by 30,000,500, the Modulus of Elasticity of the nickel test strip. If pure nickel would be plated over the pure nickel test strip, PN: 270NI, M would equal 1.0.
In this case of nickel phosphorus alloy, however, M becomes 0.2659 and the actual internal stress of the deposit is 0.2659 times greater than that of a pure nickel deposit applied under similar conditions.
Frequently, the increase that the Modulus of Elasticity effects on the internal deposit stress of electroless applied alloy coatings is not recognized. Numerous formulas for calculating the internal deposit stress of metallic deposits do not include a correction for the difference of the Modulus of Elasticity between the deposit and the substrate material. In such cases, the calculated result can be far from the actual value.