The Importance of Thermal Property Testing in Material Development

Thermal property testing is the key to ensuring the proper conductivity and insulating properties of materials in Aerospace, Oil & Gas and Transportation applications.

Whether your material is plastic, rubber or lubricant, it contains a “thermal blueprint” that can be determined by heating and cooling it under controlled conditions. This allows us to measure specific heat capacity, melting point, glass transition temperature, oxidative stability, flammability and other physical and chemical changes.

Conductivity

The Importance of Conductivity Testing in Material Development

Conductivity is a fundamental element of thermal performance testing that provides insight into the properties of materials and products. It is an important factor for assessing heat transfer between a component and surrounding environment, as well as being a useful indicator of how a material may perform under accelerated thermal cycling.

There are many different types of conductivity test methods available, and some of these techniques can be a little complex to understand, but understanding how they work can make a big difference in the success of the testing process.

Another type of conductivity test uses an electrically conductive probe to measure the conductivity of samples with a high level of accuracy.

It is important to note that the crystalline structure of a material, along with temperature and the presence of impurities, will all contribute to conductivity. For example, silver has a conductivity that increases as the temperature of the sample rises. However, if a silver sample has impurities such as iron and copper, then its conductivity will decrease.

In addition, it is a good indication of how well a component will perform under accelerated thermal stress and fatigue.

In general, a good conductivity value for a material indicates that it is likely to be able to transfer a significant amount of heat, but it also implies that it is less likely to become an effective heat sink. For this reason, it is essential to know the conductivity of a material before subjecting it to extreme temperatures or harsh environments.

Conductivity is also an important indicator of water quality and can help to detect sources of pollution. For example, sudden changes in conductivity can be an indicator of sewage leaks or other contaminants in the water.

Specific Heat Capacity

Specific heat capacity is a measurement of the amount of energy it takes to raise the temperature of a sample one Kelvin. It is a critical material property that manufacturers use to select materials for reactors, engines, and cooling systems.

A specific heat capacity measurement is typically done using a differential scanning calorimeter (DSC). Differential scanning DSCs allow rapid, accurate measurements on a variety of materials and are ideal for determining the specific heat capacities of phase change materials, carbon nanomaterials, heating and cooling systems, building materials, proteins, and molten salt-based nanofluids.

To determine the specific heat capacity of a substance, you need to know the amount of thermal energy needed to change its temperature by one Kelvin and the mass of the substance. This is a very intuitive concept that you probably already understand from everyday life. For example, you may be able to tell that oil is less hot than water because it requires a lot less energy to heat up.

But it is not always easy to measure the specific heat capacity of a solid or liquid when they expand under pressure. If you do this, the value of your specific heat capacity will be higher than if you were to measure it under constant volume.

Alternatively, you can also find the specific heat capacity of a material by comparing it to another substance at the same temperature, such as a reference substance like water or ice.

Thermal Expansion

Thermal Expansion is an important property to be aware of for materials that are susceptible to temperature changes. This can be a significant concern when designing products that will experience large temperature fluctuations, such as aircraft and space shuttles.

Thermoplastics, such as polymers, have coefficients of thermal expansion that are typically higher than those found in most metals.

In many cases, the dilatometer will be used to determine the coefficient of linear thermal expansion (also known as a volumetric expansion). This measurement takes into account the change in length per degree of change in temperature that the material undergoes.

This property is important because it is related to other properties of the material. For example, some materials, such as glass, have relatively high coefficients of thermal expansion due to their structure and composition. However, this may not be desirable for a product that needs to be able to expand and contract as the temperature fluctuates.

Crystals, on the other hand, have low coefficients of thermal expansion because their structure is extremely uniform. These characteristics make these materials ideal candidates to use when testing for thermal expansion.

Similarly, metals tend to have relatively low coefficients of thermal expansion because their bonding bonds are very strong and they are less likely to fail under stress from thermal expansion.

For most solids, the coefficient of thermal expansion is a function of the average amplitude of the atoms’ vibrational energy during heating. This increase in amplitude causes the atoms to separate further from each other, causing the body to grow larger and increasing its volume.

Meltability

Thermal property testing is an important element of product development, enabling products to be characterized with regard to their functional characteristics. These can include meltability, stretching, free-oil formation and elasticity.

Meltability is a material’s ability to melt or to liquefy. In addition, a variety of materials have different meltability properties, which can be difficult to assess with a single test.

A temperature increase can also affect other material properties such as electrical resistance, optical emissivity or magnetism.

As with conductivity, it is critical to test the thermal properties of a material under representative testing conditions to get an accurate understanding of its performance.

ACS Material offers a range of thermal property tests to measure conductivity and diffusivity under a variety of conditions.

The ability to accurately and repeatably measure the thermal properties of a product under a wide range of conditions is essential for a wide variety of industrial applications. This can be a challenge due to the complexity of the measurement process and the strict sample requirements. However, at ACS Material we have developed a new thermal property testing system called ThermalSure(r) that can revolutionize the way we measure these properties.

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