reaction mass of cerium(IV)oxide, praseodymium(III,IV)oxide and zirconium (IV)oxide

Melting point / freezing point

Link to relevant study record(s)

Reference

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25 July 2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

no guideline followed

Principles of method if other than guideline:

The method aims to investigate the temperature behaviour of the reaction mass of cerium dioxide, praseodymium oxide and zirconium dioxide. A thermogravimetric (TG) analyser together with a Differential Thermal Analysis (DTA) was used for this.

GLP compliance:

not specified

Type of method:

thermal analysis

Key result

Melting / freezing pt.:

> 800 °C

Atm. press.:

101.325 kPa

Decomposition:

no

Remarks:

only loss of physisorbed water was observed

Sublimation:

no

Remarks on result:

other: a yellow to brown powder was obtained after the experiment

Results:

1. A total weight loss of 4.12% is recorded up to 750°C with no thermal event being assigned to a melting process.

2. The main loss between room temperature and 415°C accounts for 3.19 wt% and corresponds to an exothermic event with a maximum at 65°C.

3. The second weight loss occurring between 415 and 760°C is measured to be 0.93 wt% and is accompanied by a shallow endotherm.

The mass loss can be attributed to loss of physisorbed water from the powder surface.

Conclusions:

TG/DTA scan proves that the reaction mass of cerium dioxide, praseodymium oxide and zirconium dioxide does not melt when heated from room temperature up to 800°C, the final product being a yellow to brown powder. The mass loss (4.12% in total) can be attributed to loss of physisorbed water from the powder surface.

Description of key information

Based on the TG/DTA (Dvininov, 2017; Klimisch 2) it can be concluded that the reaction mass of cerium dioxide, praseodymium oxide and zirconium dioxide does not melt when heated from room temperature up to 800°C, the final product being a yellow to brown powder. The mass loss (4.12% in total) can be attributed to loss of physisorbed water from the powder surface.