# Thermal conductivity with plating

• kmaryan
In summary, the effective thermal conductivity from the heat source to the ambient air will increase in the X and Y case compared to the X only case due to the addition of the coating, but the exact amount of increase will depend on the thickness and thermal conductivity ratio of the coating.
kmaryan
This relates to design of a heat spreader. My intuition is failing me and I'm not familiar with this area of thermodynamics/heat flow.

Assume I have a heat source, attached to a large flat surface used as a heat spreader/sink. The size of the source is negligible w.r.t. the surface area (A) of the heat spreader. Consider that the heat spreader is made from a material with thermal conductivity X. Now consider an alternative where the heat spreader has a thin coating (metal plating) with heat conductivity Y on top of the material with conductivity X. How does the effective thermal conductivity from the heat source to the ambient air change in the X and Y vs. the X only case?

I'm probably missing information, but I'm not sure what's relevant here. Let me know if anything else is relevant in coming up with at least a first order approximation of how the heat flow changes.

Thanks,

Chris

The first order approximation of how the heat flow changes depends on a few factors. First, you need to consider the thickness (t) of the coating and the thermal conductivity ratio (Y/X) of the coating relative to the substrate material. Assuming that the thickness of the coating is much smaller than the thickness of the substrate material, then the effective thermal conductivity (K) can be approximated by: K = X + (Y-X)*(t/A), where A is the area of the heat spreader. This equation assumes that the coating is homogeneous and isothermal. If the coating is not homogeneous or isothermic, then the equation will need to be modified accordingly.

## 1. What is thermal conductivity with plating?

Thermal conductivity with plating refers to the ability of a material to conduct heat while having a thin layer of another material, called a plating, on its surface. This plating can affect the overall thermal conductivity of the material.

## 2. How is thermal conductivity with plating measured?

Thermal conductivity with plating is typically measured using a technique called the hot disk method. This involves placing a hot disk sensor between two samples, one with the plating and one without, and measuring the heat flow through the samples.

## 3. What factors affect thermal conductivity with plating?

Several factors can affect thermal conductivity with plating, including the thickness and type of plating material, the type of base material, and the temperature of the system. The presence of any impurities or defects in the plating or base material can also impact thermal conductivity.

## 4. How does thermal conductivity with plating impact heat transfer?

Thermal conductivity with plating plays a significant role in heat transfer. A material with high thermal conductivity will transfer heat more efficiently, while a material with low thermal conductivity will hinder heat transfer. Plating can either enhance or reduce the thermal conductivity of a material, depending on the properties of the plating material and its thickness.

## 5. What are some practical applications of thermal conductivity with plating?

Thermal conductivity with plating is crucial in various industries, including electronics, automotive, and aerospace. It is used to improve the thermal management of electronic devices, reduce energy loss in heat exchangers, and enhance the durability of materials in extreme temperature conditions.

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