How much sample is required for STA, and what are the requirements for sample form?

Sample Quantity and Mass Specifications

For Simultaneous Thermal Analysis, which typically combines Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC), the ideal sample mass ranges from 5 to 50 milligrams for most applications. This relatively small sample size ensures optimal thermal transfer and accurate measurement resolution while maintaining signal quality. The precise mass required depends on the material's thermal characteristics and the specific information sought. For highly energetic materials or those with significant thermal transitions, smaller masses (5-15 mg) are preferable. In contrast, materials with subtle transitions may require larger samples (20-50 mg) to achieve sufficient detection sensitivity.

Critical Sample Form and Preparation Requirements

Physical Form Specifications

STA requires samples in specific physical forms to ensure reliable results:

• Powdered samples should be finely ground with particle sizes typically below 100 micrometers to ensure homogeneous packing and thermal conductivity

• Solid pieces must be cut to fit into the crucible with dimensions not exceeding 5mm in any direction

• Fibers or films should be cut into small pieces to ensure proper contact with the crucible base

• Liquids or pastes require special hermetic crucibles and are typically limited to 10-20 mg to prevent spillage during analysis

Sample Preparation Protocols

Proper sample preparation is essential for accurate STA results. Materials must be representative of the bulk material and free from contamination. For hygroscopic materials, including some Ceramic precursors or certain Plastics, careful drying before analysis is critical. Samples should be homogeneous, particularly when analyzing materials produced through Powder Bed Fusion or Binder Jetting processes, to ensure the measured thermal properties accurately represent the material.

Application-Specific Considerations

Additive Manufacturing Materials

When analyzing materials used in additive manufacturing, such as metal powders for Aluminum Alloys or polymer filaments, the as-received powder or filament form is typically ideal for STA. For printed parts, a representative section must be carefully extracted to avoid altering thermal properties through Heat Treatment effects during cutting. This approach helps characterize the thermal behavior of processes such as Hot Isostatic Pressing (HIP) optimization or post-processing parameter development.

Specialized Material Considerations

Different material categories require specific preparation approaches:

• For Superalloy powders, ensure complete removal of any organic processing aids

• For Titanium Alloy components, use inert atmosphere crucibles to prevent oxidation during analysis

• For Resins and photopolymers, protect from premature light exposure that could initiate cross-linking

• For composite materials, maintain the representative fiber-matrix distribution in the sampled portion