Chemical Properties

Resistance to molten metals

Metals Temperature (C) Holding time (Hr) Remarks
Al 800`1,000 950 No attack
Pb 400 144 No attack
Sn 300 144 No attack
Zn 550 500 No attack
Mg 750 20 No attack
Cu 1,150 7 No attack
Ni-Cu alloy 1,250 5 No attack
Fe 1,600 10 No attack

Resistance to chemicals

Chemicals that do not attack them Chemicals that attack them
20% HCI boiling 50% NaOh boiling, in 115hr
65% HNO3 boiling NaOH molten at 450C in 5hr
10%, 77%, 85% H2SO4 48% HF at 70C in 3hr
HPO3, H4P2O7 3% HF + 10% HNO3 at 70C in 116hr
25% NaOH NaCl + KCl salt bath at 900C in 144hr
Cl2 wet gas at 30`900C NaB(SiO3)2 + V2O5 at 1100C in 4hr
H2 S at 1000C NaF + ZeF4 at 800C in 100hr
Conc H2SO4 boiling  
Conc H2SO4 + CuSO4 + KHSO4  
NaNO3 + NaNO2 salt bath at 350C  
NaCl + KCl salt bath at 790C  

Resistance to atmosphere

Atmosphere Temperature(C) Time (Hr) Wt.Change(%) + Change in composition
H2 1,200 10 0.12 No change
Cracked gas (NH3) 1,200 10 0.11 No change
Ar 1,200 10 0.16 No change
Cl2 700 200 -0.48 No change
CO2 1,200 10 5.68 -crystbalite produced
Air 1,200 100 2.04 -crystbalite produced
Air 1,400 5 0.62 -crystbalite produced
Vacuum(10-3 Torr) 1,200 5 -0.65 No change
Vacuum(10-3 Torr) 1,400 5 -2.15 Decomposition

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