Magnesium zirconium oxide

Melting point / freezing point

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

melting point/freezing point

Type of information:

not specified

Adequacy of study:

weight of evidence

Study period:

not specified

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Data from SDS of manufacturer. Original report not available.

Principles of method if other than guideline:

No data (original source not available).

GLP compliance:

not specified

Type of method:

other: no data

Melting / freezing pt.:

ca. 2 500 °C

Conclusions:

The melting point was reported to be ca. 2500°C. The original source is not available.

Reference 2

Endpoint:

melting point/freezing point

Type of information:

not specified

Adequacy of study:

weight of evidence

Study period:

not specified

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Data from SDS of manufacturer. Original report not available.

Principles of method if other than guideline:

No data (original source not available).

GLP compliance:

not specified

Type of method:

other: no data

Melting / freezing pt.:

ca. 2 700 °C

Conclusions:

The melting point was reported to be ca. 2700 °C. The original source is not available.

Reference 3

Endpoint:

melting point/freezing point

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Read across based on the available handbook data for MgO and ZrO2. The read across justification document is attached in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Key result

Remarks on result:

other: Based on handbook data for the melting point of MgO and ZrO2, it can be concluded that magnesium zirconium oxide has an equally high melting point (> 2500°C). No precise value could be derived from the read across data.

Reference 4

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

no data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Principles of method if other than guideline:

Data were obtained from the CRC handbook.

GLP compliance:

not specified

Type of method:

other: no data

Melting / freezing pt.:

2 825 °C

Atm. press.:

101.325 kPa

Conclusions:

According to the reference, magnesium oxide has a melting point of 2825°C.

Reference 5

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

no data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Principles of method if other than guideline:

Data were obtained from the Merck index.

GLP compliance:

not specified

Type of method:

other: no data

Melting / freezing pt.:

2 800 °C

Atm. press.:

101.325 kPa

Conclusions:

According to the reference, magnesium oxide has a melting point of 2800°C.

Reference 6

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

no data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Principles of method if other than guideline:

Data in this peer-reviewed publication were taken from many sources, including both compilations and primary literature. Where conflicts were found, the value deemed most reliable was chosen for inclusion in the handbook. Reference sources were not provided for this parameter, nor were the experimental methods.

GLP compliance:

not specified

Type of method:

other: no data

Melting / freezing pt.:

ca. 2 710 °C

Conclusions:

The melting point of zirconium dioxide was reported to be 2710°C.

Reference 7

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

no data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Principles of method if other than guideline:

Data in this peer-reviewed publication were taken from many sources, including both compilations and primary literature. Where conflicts were found, the value deemed most reliable was chosen for inclusion in the handbook. Reference sources were not provided for this parameter, nor were the experimental methods.

GLP compliance:

not specified

Type of method:

other: no data

Melting / freezing pt.:

2 680 °C

Conclusions:

The melting point was reported to be 2680°C.

Description of key information

Based on melting point data available for the individual substances ZrO2 and MgO and based on supporting data from two manufacturers on magnesium zirconium oxide (Safety Data Sheets), the substance magnesium zirconium oxide can be concluded to have a high melting point (at least 2500 °C). 

Additional information

1. Information on zirconium dioxide

Although only two values are available from peer reviewed handbooks, it can be safely concluded that the melting point of zirconium dioxide is approximately 2700°C, making it environmentally irrelevant. The differences in results are assumed to be caused by the error of measurement at high melting temperatures and it is concluded that the melting point of zirconium dioxide is around 2700°C.

2. Information on magnesium oxide

Two values for the melting point of the substance were obtained from peer reviewed handbooks. The melting point of the substance was reported to be 2825°C and 2800°C, depending on the handbook. It can therefore be concluded that the melting point of magnesium oxide is around 2800°C.

3. Information on magnesium zirconium oxide

Supporting data on the substance itself were obtained from the safety data sheets of two manufacturers (Saint-Gobain, 2012; Imerys, 2015). The melting point of the substance was reported to be ca. 2700°C and ca. 2500°C, respectively. The original reports were however not available (i.e., the information was assigned a Klimisch 4 score).

 

4. Conclusion on magnesium zirconium oxide

Based on information on the individual components of the substance, i.e. zirconium dioxide and magnesium oxide, the melting point of magnesium zirconium oxide could also be expected to be very high. This was supported by the melting point values of ca. 2700°C and ca. 2500°C mentioned in the SDS of two manufacturers of magnesium zirconium oxide. All data were used in a weight of evidence approach to cover the endpoint.