TECHNICAL INFORMATION
Frequently Asked Questions about Stress Meter
This page introduces frequently asked questions about our stress meter.
Q. Why need to measure stress?
Basically, there is stress in the plating film. There are two types of stress, “tensile stress” and “compressive stress” (see page 11 for details). Generally, the stress generated differs depending on the type of metal, and relatively high melting point metals (Ni, Co, Fe, Pd, Cr, Cu, etc.) are said to indicate “tensile stress”, and low melting point metals (Zn, Sn, Cd, Pb, Bi, etc.) are said to indicate “compressive stress”.However, since the practical plating actually used is a polycrystalline film, it shows stress related to various factors during plating. As one of the characteristics of the plating bath, it is important to know the stress of the obtained film.
Q. Is it not good if there is stress?
A. Stress may cause cracking or peeling of the film, and recently, the material to be plated is thin like a film, and the stress of the film may affect the substrate. But stress is not necessarily bad. For example, compressive stress for spherical sample, a little compressive stress in case plating film is to be peeled from the mold, in these cases stress may be helpful. Depending on the shape of the sample and the application, a film with some stress may be required. That is why knowing how much stress is caused by plated film is important.
Q. What is the material of the test piece of the stress measuring device?
The spiral contract meter is SUS304, and the strain gauge type stress meter is copper. The spiral type can be custom made from other materials. (Please contact us as it may be difficult to manufacture depending on the desired material.)
Q. Please tell me the rough processing procedure for each test piece.
The procedure for spiral type and strain gauge type is as follows.
[Spiral type] Instrument constant measurement →
degreasing → activation → Ni strike plating → plating (measurement)
[Strain gauge type] Degreasing → activation → plating (measurement)
Q. What kind of graph will the measured values be?
A. Measurement examples are shown below.
Since they are just example, the graph shape may not always be the same.
Vertical axis : Stress (Mpa) / Horizontal axis: Plating time (min)
