There is an increasing use of physically based modelling in the simulation of manufacturing processes in order to improve productivity through lower energy costs, lower scrap, improved quality and greater product consistency. An important element in the success of these models is the quality of the thermophysical property data available. However these measurements are often difficult due to the high temperatures required and the reactivity of samples with containers and atmosphere conditions.

Examples of the properties required are:

• Enthalpy and heat capacity
• Density
• Thermal diffusivity and thermal conductivity
• Thermal expansion coefficient
• Viscosity
• Surface tension

High Temperature Facilities

NPL has significant expertise in a number of techniques that can be used to measure these properties at the high temperatures that are needed to simulate industrial processes.

Differential Scanning Calorimetry (DSC)
A relatively fast and reliable method for measuring the enthalpy and heat capacity at temperatures up to 1450 °C.

Levitated drop calorimetry
Provides enthalpy values for highly reactive liquid alloys, such as titanium, up to temperatures approaching 2000 °C

Laser flash
Enables measurement of the thermal diffusivity of liquid and solid materials up to high temperatures

Single Pan Calorimetry
A technique that allows an accurate determination of transition temperatures and a more accurate measurement of heat capacity during solid and liquid/solid transitions than DSC.

High Temperature Dilatometry
Thermal expansion measurements from sub ambient to 1400°C. A cell may be used to observe the melting behaviour of some metals and alloys

Oscillating Cup Viscometry
Provides viscosity measurements from room temperature to 1600°C in the range 1-100 mPa.s

For more information: Rob Brooks