Material Properties: Alumina, Platinum, and Boron Nitride?

Using the wrong material leads to sample contamination, cracking, or failed experiments. Labs see lower yields and increased downtime just from ignoring crucible composition.

Three main materials stand out for reusable crucibles: alumina for general use, platinum for sensitive or reactive analysis, and boron nitride for high-temperature, high-conductivity needs.

 

Comparison of Crucible Materials

Material	Key Property	Application	Weakness	Reference
Alumina	High thermal stability	General thermal analysis	Not for strong acids	Lab standard
Platinum	Chemical inertness, temp up to 1700°C	API testing, pharma, reactivity studies	High cost, softness	Pharma R&D
Boron nitride	High thermal conductivity, inert	High-temp, non-stick R&D	Brittle, needs care	Ceramics research

I have tested all three materials with demanding samples. Most labs pick alumina for price, platinum for purity, and boron nitride when heat conduction or no sticking is essential.

 

Thermal Conductivity and Temperature Resistance?

Thermal analysis data can fail when a crucible cannot handle required heat flow or peak temperatures. This leads to baseline drift or even sample loss.

Check each material’s highest working temperature and its ability to transfer heat. For precise DSC or TGA methods, reliable temperature performance means sharper peaks and trusted measurements every time.

 

Thermal Properties by Material

Material	Max Temperature	Conductivity (W/m·K)	Good For	See More
Alumina	up to 1600°C	~30	Organic, polymer, basic ceramics	Conductivity
Platinum	up to 1700°C	72	Pharma, reactive or oxidizing samples	Platinum details
Boron nitride	up to 2000°C	60-80	Non-oxide ceramics, molten metals	Boron nitride

I pick boron nitride for tasks where extremely high conductivity or resistance is required. Labs should review method protocols and confirm the actual test range in their routine runs before choosing a material.

 

Size, Shape, and Volume Considerations?

Poor crucible sizing causes handling errors, bad heat transfer, and sample waste. Many users struggle with mismatched sizes or poorly fitting lids.

Crucible size, shape, and volume must match the instrument’s slots and the typical sample mass. Deep or shallow shapes affect evaporation rate and peak sharpness. Matching volume is critical for credible results.

 

Crucible Dimensions and Effect on Applications

Shape	Volume Range	Key Use	Effect	Further Reading
Flat bottom	20-100 μL	DSC	Improves contact, sharp peaks	DSC detail
Deep well	50-1000 μL	TGA/R&D	For larger masses, slow loss	TGA info
Custom/special	Any	Non-standard samples	Matches unique workflow	Instrument manual

I follow instrument guides and method sheets when choosing my crucible volume and shape. Consult the supplier if uncertain, especially for custom or multi-step thermal analysis.

 

Cleaning and Maintenance Requirements?

Improper maintenance leads to surface residue, cross-contamination, or short crucible lifespan. Many labs overlook cleaning needs until quality issues happen.

Most reusable crucibles require gentle cleaning using approved solutions. Material guides advise which chemical or thermal cleaning technique applies. Regular upkeep keeps results consistent and extends equipment value.

 

Maintenance Steps and Material Notes

Material	Routine Cleaning	Avoid	Extra Care	Read More
Alumina	Soak in dilute acid, rinse	Strong bases/abrasives	Air dry completely	Alumina
Platinum	Acid clean, polish as needed	Scratching, base attack	Store apart from steel	Platinum
Boron nitride	Gentle rinse, no scrub	Harsh chemicals, ultrasonic	Avoid impacts, handle with care	Boron nitride

I log cleaning cycles and only use chemicals that match the supplier guide. Consistent practice helps avoid costly mistakes and supports valid lab records for regulatory audits.