Phase Relations in the Systems TiO2-IrO2 and SnO2-IrO2 in Air

C L McDaniel; S J Schneider

doi:10.6028/jres.071A.016

. 1967 Mar-Apr;71A(2):119–123. doi: 10.6028/jres.071A.016

Phase Relations in the Systems TiO₂-IrO₂ and SnO₂-IrO₂ in Air

C L McDaniel ¹, S J Schneider ¹

PMCID: PMC6624694 PMID: 31824035

Abstract

The pseudobinary systems TiO₂–IrO₂ and SnO₂–IrO₂ were studied by x-ray diffraction after treatment at various temperatures in air. Their equilibrium phase diagrams were similar, with no intermediate phases detected in either system. Maximum solid solution of TiO₂ occurs with the addition of about 5 mole percent IrO₂ at 1040 °C. Solid solution of TiO₂ in IrO₂ extends to a maximum of about 12 mole percent TiO₂ at 1040 °C, the dissociation temperature. Limited solid solubility of SnO₂ in IrO₂ exists up to 3 mole percent SnO₂ at the dissociation temperature, 1025 °C. Solid solution in SnO₂ was not detected at temperatures up to 1400 °C.

Keywords: Dissociation, phase relations, SnO₂–IrO₂ system, solid solution, TiO₂–IrO₂ system

1. Introduction

The National Bureau of Standards has initiated a program to obtain accurate melting points of some of the metal oxides [1].¹ As part of this program, it is important to determine the suitability of various refractory metals as container materials. The effects various container materials have upon the oxides can be best established through a study of their equilibrium phase relations. The present work presents the results of an investigation of the phase relations between IrO₂ and TiO₂ and between IrO₂ and SnO₂.

Powdered Ir has a strong tendency to oxidize to IrO₂ when heated in air at moderate temperatures. However, complete oxidation is difficult to achieve. By utilizing IrO₂ rather than Ir metal, the approach to equilibrium could be achieved more readily. The study would still reflect, however, the behavior in air of Ir metal in combination with TiO₂ or SnO₂.

Iridium has a face-centered cubic, copper-type structure with a = 3.8394 Å [2]. The freezing point of Ir, 2443 °C, is given as a secondary reference point on the International Practical Temperature Scale (IPTS)² [3]. Iridium dioxide is similar to TiO₂ in having the tetragonal, rutile structure with a = 4.4983 Å and c= 3.1544 Å [4].

Titanium dioxide occurs in two tetragonal polymorphic forms: anatase; and rutile (a = 4.594 Å, c= 2.958 Å) [5], the stable modification. The unit cell dimensions of SnO₂ (tetragonal) have been reported as a = 4.738 Å, c = 3.188 Å [6]. Several melting points of TiO₂ have been reported, the values ranging from 1820 to 1850 °C in an air environment [1]. Two melting points have been reported for SnO₂, 1630 and 1637 °C [1].

2. Materials

The starting materials used in this study were found by general quantitative spectrochemical analyses³ to have the following impurities:

IrO₂:	0.01−0.1%, Pt;
	0.001−0.01% each Al, Cu, Fe, Pd, and Si;
	0.0001−0.001% Mg; and < 0.0001% Ca
TiO₂:	0.01−0.1% Si;
	0.001−0.01% Mg;
	0.0001−0.001% Cu; and < 0.0001% Ca
SnO₂:	0.01−0.1% each Bi, Co, and Fe;
	0.001−0.01% each Al, Cu, Ni, Pb, and Si;
	< 0.001% each Ag, Ca, In, Mg, and Mn.

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3. Experimental Procedure

Specimens for the studies were prepared from 0.4 g batches of various combinations of the end members. Calculated amounts of each oxide, corrected for ignition loss, were weighed to the nearest milligram. Each batch was thoroughly hand mixed, placed in Vycor tubes (sealed at one end) and fired in a muffle furnace for a minimum of 18 hr at each of the following temperatures, 800, 900, and 1000°C. Succeeding each heat treatment, the materials were thoroughly hand mixed and examined by x-ray diffraction techniques.

Following the preliminary heat treatments, portions of each batch were placed in small Vycor tubes and fired in a platinum alloy wire-wound quench furnace at various temperatures for different periods. The Vycor tube containing the specimen was air quenched by quickly pulling the tube from the furnace. Equilibrium was assumed to have been achieved when the x-ray pattern showed no change after successive heat treatments or when the data were consistent with the results from a previous set of experiments.

As IrO₂ is heated near its dissociation temperature, it becomes somewhat volatile. The problem of volatility of IrO₂ was minimized greatly by reacting the end members at low temperatures. In an attempt to maintain composition and obtain maximum reaction, sealed platinum tubes were employed as specimen containers for the prolonged heat treatments at temperatures below dissociation. The use of Vycor tubes instead of platinum for experiments at the higher temperatures was necessary because Ir, frequently found as a decomposition product, readily reacts with platinum. On the other hand, the Vycor tube did not appear to influence or react with the various oxide samples.

Temperatures in the quench furnace were measured with a 100 percent Pt versus 90 percent Pt-10 percent Rh thermocouple. All reported temperatures pertaining to quench furnace data are considered accurate to within ±5 °C. The precision of the measurements was ±2 °C.

An induction furnace utilizing an iridium crucible as both the susceptor and specimen container was used for the heat treatments above 1400 °C. Temperatures were measured with a calibrated optical pyrometer sighted through a small hole in the crucible cover. The optical pyrometer temperature measurements are estimated to be accurate to within ±25 °C or better.

All specimens were examined by x-ray diffraction at room temperature using a high angle recording Geiger counter diffractometer and Ni-filtered Cu radiation.

4. Results and Discussion

4.1. TiO₂-IrO₂ and SnO₂-IrO₂ Systems in Air

The equilibrium phase diagram for the TiO₂-IrO₂ system in air is given in figure 1. The diagram was constructed from the data listed in table 1. The circles indicate the compositions and temperatures of the experiments. It should be emphasized that figure 1 represents a composite of the systems TiO₂-Ir and TiO₂-IrO₂ in the Ti-Ir-Oxygen ternary system. At the lower temperatures, the oxygen content of the specimens closely conforms to the compositions represented by the pseudobinary TiO₂-IrO₂ system. At the higher temperatures; the compositions of the solid phases change by an apparent oxygen loss to those generally indicated by the TiO₂-Ir join. Considering this dissociation as a type of phase transition in which the vapor phase is ignored, figure 1 is a binary representation of a portion of the ternary system.

Table 1.

Experimental data for compositions in the TiO₂–IrO₂ system

Composition		Heat Treatment^a		X-ray diffraction analyses^b	Remarks
TiO₂	IrO₂	Temp.	Time	X-ray diffraction analyses^b	Remarks
Mole %	Mole %	°C	hr
98	2	900	45	TiO_2ss + IrO_2ss	Very small amount of IrO_2ss.
		^c1000	18	TiO_2ss
		1050	2	TiO_2ss
		1075	3	TiO_2ss
		1125	3	TiO_2ss
		1200	4	TiO_2ss
		1300	3	TiO_2ss
		1400	2	TiO_2ss + Ir
95	5	900	48	TiO_2ss + lrO_2ss
		^c1000	60	TiO_2ss + IrO_2ss	Quenched in ice water.
		^c1000	336	TiO_2ss + IrO_2ss	Furnace cooled.
		1035	2	TiO_2ss + IrO_2ss
		1040	2	TiO_2ss + IrO_2ss + Ir	Nonequilibrium.
		1045	2	TiO_2ss + IrO_2ss + Ir	Nonequilibrium.
90	10	900	48	TiO_2ss + IrO_2ss
		^c1000	60	TiO_2ss + IrO_2ss	Quenched in ice water.
		^c1000	336	TiO_2ss + IrO_2ss	Furnace cooled.
		1035	2	TiO_2ss + IrO_2ss
		1040	2	TiO_2ss + IrO_2ss + Ir	Nonequilibrium.
75	25	900	18	TiO_2ss + IrO_2ss
		^c1000	60	Ti0_2ss + IrO_2ss
		^c1030	504	TiO_2ss + IrO_2ss
		1035	2	TiO_2ss + IrO_2ss
		1040	2	TiO_2ss + IrO_2ss + Ir	Nonequilibrium.
		1300	0.5	TiO_2ss + Ir + IrO_2ss	Nonequilibrium.
		^d1700		TiO₂ + Ir
50	50	500	0.5	TiO_2ss + IrO_2ss	High temperature x-ray data.
		900	20	TiO_2ss+IrO_2ss
		975	0.5	TiO_2ss+IrO_2ss	High temperature x-ray data.
		1000	0.5	TiO_2ss + IrO_2ss	High temperature x-ray data.
		1000	3	TiO_2ss + IrO_2ss	High temperature x-ray data.
		1000	18	TiO_2ss + IrO_2ss
		^c1000	18	TiO_2ss + IrO_2ss	Quenched in ice water.
		^c1000	60	TiO_2ss + IrO_2ss	Furnace cooled.
		1003	64	TiO_2ss + IrO_2ss
		1020	66	TiO_2ss + IrO_2ss
		1025	66	TiO_2ss + IrO_2ss
		1030	3	TiO_2ss + IrO_2ss
		1030	504	TiO_2ss + IrO_2ss
		1035	2	TiO_2ss + IrO_2ss
		1040	2	TiO_2ss + IrO_2ss + Ir	Nonequilibrium.
		1045	2	TiO_2ss + IrO_2ss + Ir	Nonequilibrium.
		1050	2	TiO_2ss + IrO_2ss + Ir	Noneqtiilibrium.
		1055	2	TiO_2ss + IrO_2ss + Ir	Nonequilibrium.
		1100	1.5	TiO_2ss + Ir + IrO_2ss	Nonequilibrium.
		1100	40	TiO_2ss + Ir + IrO_2ss	Nonequilibrium.
		1200	3	TiO_2ss + Ir
		1300	0.5	TiO_2ss + Ir
		^d1700	3	Ir + TiO₂ + IrO₂	Nonequilibrium; IrO₂ probably formed on cooling.
25	75	900	18	IrO_2ss + TiO_2ss
		^c1000	60	IrO_2ss + TiO_2ss
		^c1030	504	IrO_2ss + TiO_2ss
		1035	2	IrO_2ss + TiO_2ss
		1040	2	IrO_2ss + TiO_2ss + Ir	Nonequilibrium.
		1300	0.5	Ir + TiO_2ss
		^d1700	3	Ir + TiO₂ + IrO₂	Nonequilibrium; IrO₂ probably formed on cooling.
15	85	900	20	IrO_2ss + TiO_2ss
		^c1000	18	IrO_2ss + TiO_2ss
		1030	1.5	IrO_2ss + TiO_2ss
		1035	2	IrO_2ss + TiO_2ss
		1040	2	IrO_2ss + TiO_2ss + Ir	Nonequilibrium.
10	90	900	48	IrO_2ss + TiO_2ss
		^c1000	60	IrO_2ss + TiO_2ss	Quenched in ice water.
		^c1000	336	IrO_2ss + TiO_2ss	Furnace cooled.
		1025	2	IrO_2ss
		1030	2	IrO_2ss + Ir
		1065	3	IrO_2ss + Ir + TiO_2ss	Nonequilibrium.
5	95	900	48	IrO_2ss + TiO_2ss	Very small amount of TiO_2ss.
		^c1000	60	IrO_2ss	Quenched in ice water.
		^c1000	336	IrO_2ss	Furnace cooled.
		1020	2	IrO_2ss
		1025	2	IrO_2ss + Ir
		1030	2	IrO_2ss + Ir
		^c1030	504	IrO_2ss + Ir
2	98	900	45	IrO_2ss
		^c1000	18	IrO_2ss
		1025	2	IrO_2ss + Ir
		1040	3	IrO_2ss + Ir
		1050	2	IrO_2ss + Ir + TiO_2ss	Nonequilibrium.
		1075	2.5	IrO_2ss + Ir + TiO_2ss	Nonequilibrium.
		1200	2	Ir + TiO_2ss

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All specimens were heat treated at 800 °C a minimum of 18 hr. Unless otherwise indicated, Vycor tubes (sealed at one end) were used for specimen containers and were air quenched.

The phases identified are given in order of the relative amount present at room temperature.

Sealed platinum tubes were used for specimen containers.

Experiments were conducted in the iridium crucible induction furnace.

It was found in earlier work that IrO₂ dissociates to Ir metal and presumably oxygen at 1020 °C ±5 °C in air at atmospheric pressure [7]. The dissociation is apparently a reversible process. Apparent metastable dissociation occurs when amorphous IrO₂ is used. The data indicated a lowering of the dissociation temperature and was not consistent with the results from previous experiments. However, crystalline IrO₂, characterized by x-ray diffraction patterns after heating at 1000 °C for 18 hr, yielded dissociation data in good agreement with the earlier work [7, 8]. Metastable dissociation was also observed in the oxide-IrO₂ mixtures prior to the preliminary heat treatments.

No intermediate solid solution phases or binary compounds were detected in the TiO₂-IrO₂ system. Solid solution in TiO₂(TiO_2SS) occurs with the addition of up to about 5 mole percent IrO₂ at 1040 °C. At 1400 °C the extent of TiO_2ss decreased to less than 2 mole percent IrO₂, and at 1700 °C it was not detectable. Presumably at temperatures higher than 1400 °C, although not detected, TiO_2ss exists in decreasing amounts to the melting point of TiO₂. Melting was not observed in any of the experiments.

Up to 12 percent TiO₂ in solid solution with IrO₂ (IrO_2SS) was found at the maximum dissociation temperature, 1040 °C. Figure 1 indicates IrO_2SS dissociates to two solid phases, Ir solid solution (Ir_ss) and TiO_2SS. The Ir_ss apparently extends over such a small compositional range, it was not detected in this study. The TiO_2ss and IrO_2ss phases were identified by a shift in the x-ray reflections indicating a change in the unit cell dimensions.

At temperatures above 1040 °C, it could not be determined whether the system under consideration is a pseudo or a true binary system. The uncertainty is due to the inability to identify the type of TiO_2ss that exists above the dissociation temperature. No definite conclusion can be made in this study concerning the presence of IrO₂ or Ir in the TiO₂ss phase. The TiO_2SS may be an oxygen deficient phase at the higher temperatures.

The equilibrium phase diagram for the SnO₂-IrO₂ system in air is given in figure 2. The pertinent data are listed in table 2. The diagram is similar to the TiO₂-IrO₂ system in many respects. No intermediate binary phases were detected. Only limited solid solubility in IrO₂ was found to exist, extending to about 3 mole percent SnO₂ at 1025 °C, where dissociation occurs. Solid solutions in either SnO₂ or Ir were not detected.

Table 2.

Experimental data for compositions in the SnO₂-IrO₂ system

Composition		Heat treatment^a		X-ray diffraction analyses^b	Remarks
SnO₂	IrO₂	Temp.	Time	X-ray diffraction analyses^b	Remarks
Mole %	Mole %	°C	hr
95	5	900	18	SnO₂ + IrO_2ss	Very small amount of IrO₂.
		1000	18	SnO₂ + IrO_2ss
		^c1000	168	SnO₂ + IrO_2ss
		1020	2.5	SnO₂ + IrO_2ss
		1025	2	SnO₂ + IrO_2ss + Ir	Nonequilibrium.
		1030	2.5	SnO₂ + IrO_2ss + Ir	Nonequilibrium.
		1200	2.5	SnO₂ + Ir
		1400	3	SnO₂ + Ir
90	10	900	20	SnO₂ + IrO_2ss
		^c1000	168	SnO₂ + IrO_2ss
		1020	2.5	SnO₂ + IrO_2ss
		1025	2	SnO₂ + IrO_2ss + Ir	Nonequilibrium.
		1030	2	SnO₂ + IrO_2ss + Ir	Nonequilibrium.
75	25	900	20	SnO₂ + IrO_2ss
		^c1000	5.5	SnO₂ + IrO_2ss	Quenched in ice water.
		^c1000	70	SnO₂ + IrO_2ss	Furnace cooled.
		1020	2	SnO₂ + IrO_2ss
		1025	2	SnO₂ + IrO_2ss + Ir	Nonequilibrium.
50	50	900	20	SnO₂ + IrO_2ss
		1000	66	SnO₂ + IrO_2ss
		^c1000	25	SnO₂ + IrO_2ss	Quenched in ice water.
		1020	2	SnO₂ + IrO_2ss
		1025	2	SnO₂ + IrO_2ss + Ir	Nonequilibrium.
		1030	2	SnO₂ + IrO_2ss + Ir	Nonequilibrium.
		1035	2	SnO₂ + IrO_2ss + Ir	Nonequilibrium.
		1040	2	SnO₂ + IrO_2ss + Ir	Nonequilibrium.
		1050	2	SnO₂ + IrO_2ss + Ir	Nonequilibrium.
		1060	20	SnO₂ + Ir
25	75	900	18	IrO_2ss + SnO₂
		^c1000	168	IrO_2ss + SnO₂
		1015	2	IrO_2ss + SnO₂
		1020	2.5	IrO_2ss + SnO₂
		1025	2	IrO_2ss + SnO₂ + Ir	Nonequilibrium.
10	90	900	20	IrO_2ss + SnO₂
		^c1000	168	IrO_2ss + SnO₂
		1015	3	IrO_2ss + SnO₂
		1020	2	IrO_2ss + SnO₂
		1025	2	IrO_2ss + SnO₂ + Ir	Nonequilibrium.
		1030	2.5	IrO_2ss + SnO₂ + Ir	Nonequilibrium.
5	95	900	18	IrO_2ss + SnO₂
		^c1000	168	IrO_2ss + SnO₂
		1015	2	IrO_2ss + SnO₂
		1020	2	IrO_2ss + SnO₂
		1025	2	IrO_2ss + SnO₂ + Ir	Nonequilibrium.
2.5	97.5	900	18	IrO_2ss + SnO₂
		1000	18	IrO_2ss + SnO₂
		^c1000	168	IrO_2ss + SnO₂
		1015	2	IrO_2ss + SnO₂
		1020	2	IrO_2ss + SnO₂
		1025	2	IrO_2ss + SnO₂ + Ir	Nonequilibrium.
		1030	2	IrO_2ss + Sn0₂ + Ir	Nonequilibrium.
1	99	900	18	IrO_2ss + SnO₂	Very small amount of SnO₂.
		1000	18	IrO_2ss
		1015	2	IrO_2ss
		1020	2	IrO_2ss
		1025	3	IrO_2ss + Ir	Nonequilibrium.
		1035	2	IrO_2ss + Ir	Nonequilibrium.
		1050	3	Ir + SnO₂	Very small amount of SnO₂.
		1060	4	Ir + SnO₂	Very small amount of SnO₂.

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All specimens were heat treated at 800 °C a minimum of 18 hr. Unless otherwise indicated, Vycor tubes (sealed at one end) were used for specimen containers and were air quenched.

The phases identified are given in order of the relative amount present at room temperature.

Sealed platinum tubes were used for specimen containers.

Inasmuch as both TiO₂ and IrO₂ have the tetragonal, rutile type structure with similar unit cell dimensions and the same cationic radii (0.68 Å) [10], it was expected that larger regions of solid solubility than observed would exist. Several experiments were conducted in order to establish whether or not the results found in this study were indeed indicative of equilibrium conditions. Every effort was made through thorough mixing and various heating techniques to react the oxides. The data did not differ for long heats (3 weeks) versus short heats (few hours) and for quenched specimens versus furnace cooled specimens. The results were identical for experiments using sealed and unsealed tubes below the dissociation temperatures. Hydrothermal experiments did not indicate any increase in oxide reaction.

It was thought that an unmixing dome might exist such as reported for the TiO₂-SnO₂ system [11]. High temperature x-ray diffraction data indicated that there was no unmixing on cooling in the TiO₂IrO₂ system. The data indicate that the tendency for dissociation is so great that only limited solubility occurs. At higher temperatures and higher oxygen pressures a miscibility range may exist.

Iridium metal seems quite acceptable as a container material for a study of SnO₂ in air above 1025 °C. The oxidation of Ir at low temperatures does not appreciably detract from its use as a container at high temperatures. The fact that TiO_2ss was not detected above 1400 °C, does not eliminate possible problems in the use of Ir as a container material for a study of TiO₂ in air.

4.2. Summary

Equilibrium phase diagrams for the TiO₂-IrO₂ and SnO₂-IrO₂ systems were determined in air. Selected mixtures in the systems were studied by x-ray diffraction after various heat treatments. In the TiO₂-IrO₂ system, solid solution in TiO₂ occurs up to about 5 mole percent IrO₂ at 1040 °C. Solid solution in IrO₂ occurs up to about 12 mole percent TiO₂ at the maximum dissociation temperature of 1040 °C.

The SnO₂-IrO₂ system is similar to TiO₂-IrO₂ system in many respects. Limited solid solubility of IrO₂ was found with the addition of about 3 mole percent SnO₂ at 1025 °C, the temperature at which dissociation occurs.

Footnotes

Figures in brackets indicate the literature references at the end of this paper.

This scale (IPTS) applies to all temperatures listed in this paper.

The spectrochemical analyses were performed by the Spectrochemical Analysis Section of the National Bureau of Standards.

5. References

[1].Schneider S. J., NBS Monograph 68, 31 p. (1963). [Google Scholar]
[2].Swanson H. E., Fuyat R. K., and Ugrinic G. M., NBS Circular 539 4, 9–10 (1963). [Google Scholar]
[3].Stimson H. F., Res J.. NBS 65A (Phys. and Chem.), No. 3 139–45(1960). [DOI] [PMC free article] [PubMed] [Google Scholar]
[4].Swanson H. E., Morris M. C., and Evans E. H., NBS Monograph 25, Sec. 4 (1965). [Google Scholar]
[5].Swanson H. E. and Tatge E., NBS Circular 539, Vol. 1,44(1953). [Google Scholar]
[6].Swanson H. E. and Tatge E., NBS Circular 539, Vol. 1,54(1953). [Google Scholar]
[7].Schneider S. J., Waring J. L., and Tressler R. E., J. Res. NBS 69A (Phys. and Chem.), No. 3, 245–54 (1965). [DOI] [PMC free article] [PubMed] [Google Scholar]
[8].McDaniel C. L. and Schneider S. J., J. Am. Ceram. Soc. 49 [5], 285–86 (1966). [Google Scholar]
[9].Cordfunke E. H. P. and Meyer G., Rec. Trail. Chim. 81, 495–504(1962). [Google Scholar]
[10].Ahrens L. H., Geochim. et Cosmochim. Ada 2, 155–69 (1952). [Google Scholar]
[11].Coughanour L. W., Roth R. S., Marzullo S.. and Sennett F. E., J. Res. NBS 54 [3], 149–62 (1955). [Google Scholar]

[R1] [1].Schneider S. J., NBS Monograph 68, 31 p. (1963). [Google Scholar]

[R2] [2].Swanson H. E., Fuyat R. K., and Ugrinic G. M., NBS Circular 539 4, 9–10 (1963). [Google Scholar]

[R3] [3].Stimson H. F., Res J.. NBS 65A (Phys. and Chem.), No. 3 139–45(1960). [DOI] [PMC free article] [PubMed] [Google Scholar]

[R4] [4].Swanson H. E., Morris M. C., and Evans E. H., NBS Monograph 25, Sec. 4 (1965). [Google Scholar]

[R5] [5].Swanson H. E. and Tatge E., NBS Circular 539, Vol. 1,44(1953). [Google Scholar]

[R6] [6].Swanson H. E. and Tatge E., NBS Circular 539, Vol. 1,54(1953). [Google Scholar]

[R7] [7].Schneider S. J., Waring J. L., and Tressler R. E., J. Res. NBS 69A (Phys. and Chem.), No. 3, 245–54 (1965). [DOI] [PMC free article] [PubMed] [Google Scholar]

[R8] [8].McDaniel C. L. and Schneider S. J., J. Am. Ceram. Soc. 49 [5], 285–86 (1966). [Google Scholar]

[R9] [9].Cordfunke E. H. P. and Meyer G., Rec. Trail. Chim. 81, 495–504(1962). [Google Scholar]

[R10] [10].Ahrens L. H., Geochim. et Cosmochim. Ada 2, 155–69 (1952). [Google Scholar]

[R11] [11].Coughanour L. W., Roth R. S., Marzullo S.. and Sennett F. E., J. Res. NBS 54 [3], 149–62 (1955). [Google Scholar]

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Phase Relations in the Systems TiO₂-IrO₂ and SnO₂-IrO₂ in Air

C L McDaniel

S J Schneider

Abstract

1. Introduction

2. Materials

3. Experimental Procedure

4. Results and Discussion

4.1. TiO₂-IrO₂ and SnO₂-IrO₂ Systems in Air

Figure 1. Phase equilibrium diagram for the TiO₂-IrO₂ system in air.

Table 1.

Figure 2. Phase equilibrium diagram for the SnO₂-IrO₂ system in air.

Table 2.

4.2. Summary

Footnotes

5. References

ACTIONS

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Phase Relations in the Systems TiO2-IrO2 and SnO2-IrO2 in Air

C L McDaniel

S J Schneider

Abstract

1. Introduction

2. Materials

3. Experimental Procedure

4. Results and Discussion

4.1. TiO2-IrO2 and SnO2-IrO2 Systems in Air

Figure 1. Phase equilibrium diagram for the TiO2-IrO2 system in air.

Table 1.

Figure 2. Phase equilibrium diagram for the SnO2-IrO2 system in air.

Table 2.

4.2. Summary

Footnotes

5. References

ACTIONS

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Phase Relations in the Systems TiO₂-IrO₂ and SnO₂-IrO₂ in Air

4.1. TiO₂-IrO₂ and SnO₂-IrO₂ Systems in Air

Figure 1. Phase equilibrium diagram for the TiO₂-IrO₂ system in air.

Figure 2. Phase equilibrium diagram for the SnO₂-IrO₂ system in air.