As a materials science expert with a focus on metallurgy, I can provide you with a comprehensive understanding of the compatibility of copper with stainless steel. The interaction between metals is a complex subject that involves considerations of galvanic corrosion, mechanical wear, thermal expansion, and the specific applications in which the metals are used.

Galvanic Corrosion:
When two dissimilar metals come into contact in the presence of an electrolyte (such as water or soil), a galvanic cell can form. This cell can lead to galvanic corrosion, where the more anodic (or negative) metal corrodes preferentially to protect the more cathodic (or positive) metal. In the galvanic series, copper is more noble than stainless steel, which means that if they were to form a galvanic cell, stainless steel would be more likely to corrode than copper. However, the risk of galvanic corrosion is significantly reduced if the environment is dry or if a good barrier to moisture is maintained.

Mechanical Wear:
The hardness of the metals can influence their compatibility. Stainless steel is generally harder than copper, which means that in a mechanical system where the two metals are rubbing against each other, the copper is more likely to wear down. This is not a chemical reaction but a physical one, and it's important to consider when designing mechanical systems.

Thermal Expansion:
Different metals expand at different rates when heated. Copper has a higher coefficient of thermal expansion than stainless steel. If the two metals are joined and subjected to temperature changes, the difference in expansion can cause mechanical stress, leading to potential failure or leaks in systems where they are used together.

Specific Applications:
In certain applications, the use of copper with stainless steel is quite common and not problematic. For example, in plumbing, copper pipes are often connected to stainless steel fixtures. In electrical applications, copper is frequently used as a conductive material, and it may come into contact with stainless steel in various components without issue.

Isolation Concerns:
The statement provided suggests that it is not necessary to isolate copper from lead, tin, or stainless steel under most circumstances. This is generally true for stainless steel, as it is a more stable metal in terms of galvanic reactions. However, the principal metals of concern in terms of direct contact are aluminum and zinc, which are more anodic and can corrode quickly when in contact with copper.

Conclusion:
Copper can be used with stainless steel in many applications without significant issues. However, it is important to consider the environmental conditions, the mechanical stresses, and the thermal expansion characteristics when designing systems that combine these two materials. Proper design and maintenance can prevent potential problems and ensure the longevity and reliability of the system.

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It is not necessary to isolate copper from lead, tin or stainless steel under most circumstances. The principal metals of concern in terms of direct contact are aluminum and zinc. Iron and steel are generally not a problem unless their mass is similar or smaller than that of the copper.read more >>