Stability of structural materials based on ZrO2

Abstract

The thermal and mechanical stability of some high-strength ceramic materials from partially stabilized ZrO2 manufactured from various domestic and imported powders, including coprecipitated, sol-gel, and hydrothermal ones, with the use of CIP and sintering is considered. The thermal stability is tested under conditions close to the operating ones, i.e., under long-duration holds at 1000 and 1550°C and in water quenching. The mechanical stability is determined in impact-erosion wear and under combined loads of high pressure and multiple indentations by solid particles. It is shown that all the materials undergo degradation of various degrees but those most durable under normal conditions (hydrothermal and sol-gel materials, ceramics manufactured from imported press powders) are least stable. They have widely fluctuating properties under cyclic high-temperature loads, endure 900-1400°C, and withstand a pressure of at most 1.0-2.0 GPa in an abrasive, just like standard corundum ceramics; however, they are characterized by maximum wear resistance. At the same time, an original material from commercial coprecipitated PSZ powder has quite different features; its thermal stability allows it to withstand repeated quenchings from 1550°C in water, and the mechanical strength can attain 2.6-2.8 GPa, exceeding the strength of quenched tool steels in similar situations. Due to its refractoriness (2700°C) and chemical stability this material is the most versatile in operating under extreme conditions.