We’ve helped a few customers in determining the thermal conductivity of thin materials, such as paint and coating, according to ASTM D5930.
In general, the thermal resistance of thin materials is negligible. In case it is necessary to determine the thermal conductivity of paint and coating. A pair of special samples, with thick paint or coating, need to be prepared, as illustrated below.
- Substrate (the blue color part): the substrate needs to be flat and rigid. The substrate type does not affect the measurement result. Typical substrate types include glass, metal plate, and wood plate.
- The preferred substrate size is 50 mm x 50 mm; The minimum size is 30 mm x 30 mm and the maximum size is 100 mm x 100 mm.
- Thick paint or coating (the yellow color part): the paint or coating needs to be applied onto one side of the substrate, with large enough thickness
- The preferred thickness is 3 mm or larger; the minimum thickness is 1 mm.
- Sample quantity: two samples in a pair are needed.
Shown below is the arrangement during testing.
The measurement probe is a thin film (less than 0.1 mm in thickness, the red color part) with a tiny wire inside (refer to our thermal conductivity test page for details). The probe is sandwiched between the two test samples, next to the paint or coating material.
Because the probe is in contact with the paint or coating material and the measurement duration is very short, it is equivalent to insert a tiny wire into a bulk material block made of the paint or coating. Only the thermal conductivity of the paint or coating is measured and the result is not affected by the substrate material.