Thermogravimetric Analysis (TGA) 2D: Furnace Cross-Section

Sample & Method

Sample material

Heating rate β 10 °C/min

Furnace atmosphere

Live Readout

Temperature

25.0 °C

Mass remaining

100.0 %

DTG (decomposition rate)

0.00 %/min

Press Start to begin the heating ramp.

How it works

This is the 2D cross-section companion to the 3D thermogravimetric-analysis simulator: the same balance-and-furnace rig drawn here as a flat side-view slice you can pan and zoom instead of orbit. It heats a sample at a controlled rate β (°C/min) inside a furnace on a microbalance and records mass m(T) continuously. Each decomposition event — dehydration, gas release, oxidation — is modelled as its own single-step Arrhenius process:

dα/dt = A · exp(−E_a / R·T) · (1 − α)
T(t)  = T₀ + β·t
m(T)  = m₀ − Σᵢ wᵢ·αᵢ(T)

α is the extent of reaction (0→1) for a step, A the pre-exponential (attempt) frequency, E_a the activation energy, R the gas constant and wᵢ the mass fraction that step releases. The instrument's second output, the DTG curve, is simply −dm/dt — its peaks mark the temperature of fastest mass loss for each step.

Sample material — picks a real multi-step reference: calcium oxalate monohydrate (3 steps: loses H₂O, then CO, then CO₂, leaving CaO), pure calcium carbonate (1 step: CaCO₃ → CaO + CO₂) or PVC (dehydrochlorination then char decomposition).
Heating rate β — a higher β shifts every step to a higher apparent onset temperature, exactly as kinetic theory predicts: less time is spent at any given T before the sample is hotter, so the same conversion α needs a higher T to reach the same rate.
Furnace atmosphere — PVC's residual carbon char is stable up to 900 °C in inert N₂ but combusts away in oxidizing air, adding a fourth mass-loss step (this has no effect on the two purely inorganic samples).
The crucible cross-section empties grain by grain in real time as α advances for each active step; the TGA (mass %) and DTG (rate) curves trace the same run on the strip-chart below.
Drag to pan, scroll/pinch to zoom — inspect the coils or crucible up close; the underlying kinetics keep running regardless of view.

Real-world relevance: this is the exact method (ASTM E1131) used to certify polymer filler content, characterize hydrate/carbonate minerals, and set safe processing temperatures for thermally sensitive materials.

Sample mass Furnace coil

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