Thermal Shock Behavior of Zircon Based Refractories

N. RENDTORFF; G. SUAREZ; Y. BRUNI; L. GARRIDO; E. AGLIETTI

Advances in Science and Technology

Trans tech publication inc.

Lugar: Zurich; Año: 2010 vol. 70 p. 59 - 64

1662-0356

Abstract: In service refractory materials are submitted to local temperature gradients that originatethermal stresses causing a thermal shock (TS) damage to the material. Practical tests for evaluatingthe thermal shock resistance (TSR) determine the variation or change of some characteristicproperty of the test sample like E (elastic module) or the strength before and after quenching. In thiswork, the microstructure and thermal shock behavior of Zircon based refractories are analyzed.Several compositions (eight), from pure Zircon to 70 % of Zircon were studied. The main structuraland mechanical properties of the refractories were characterized, as modulus of rupture, elasticmodulus, porosity, and microstructure. The dynamic elastic modulus E of the refractories wasmeasured by the excitation technique. The TS behavior was evaluated by measuring the decrease inE and the modulus of rupture, before and after a quenching test. The influence of the presence ofother phases was also analyzed. Refractories showed Zircon as the main crystalline phase. In somematerials, m-ZrO2 appears coming from Zircon dissociation. The thermal shock behavior ofrefractory of high Zircon content is typical of the brittle ceramic materials. Materials showed arelation between elastic module and strength. Dynamic elastic modulus measurements have shownto be suitable for evaluation the TSR for these materials.