Characteristics of yttrium stabilized zirconia ceramics for preventing low-temperature aging

Characteristics of yttrium stabilized zirconia ceramics for preventing low-temperature aging

Yttrium stabilized zirconia ceramics have excellent mechanical properties such as high strength, high fracture performance, and wear resistance. However, its long-term use at 100 to 400 ℃, especially in humid environments, can lead to a significant decrease in mechanical properties, accompanied by micro or macro cracks on its surface. This is the low-temperature aging phenomenon of zirconia ceramics.

Numerous studies have shown that the grain size and stabilizer content in materials largely determine the stability of the tetragonal phase, which in turn affects the low-temperature aging resistance of the material. Both decreasing the grain size and increasing the content of Yttrium(III) oxide can effectively inhibit the occurrence of tetragonal monoclinic phase transformation. The sintered body with grain size lower than the critical grain size is difficult to undergo aging phenomenon. The critical grain size for low-temperature aging is 0.3μ M to 0.5μ M.

According to the influencing factors of aging formation and the different application scenarios of materials, the measures to prevent low-temperature aging of yttrium stabilized zirconia vary, roughly divided into overall method and surface method:

1. Control the grain size of tetragonal yttrium stabilized zirconia and the content of stabilizer Yttrium(III) oxide.

2. Add high elastic modulus second phase dispersed particles, such as alumina particles, to the yttrium stabilized zirconia material.

3. Add other oxides into yttrium stabilized zirconia materials, the most common of which is CeO2, which is the most common stabilizer and can effectively enhance Fracture toughness.

Surface method:

Since low temperature aging starts from the surface, it is also an effective anti-aging measure to treat the surface of materials to prevent the aging phenomenon from expanding inward. Heat treatment of yttrium stabilized zirconia ceramic sintered body in nitrogen gas forms a nitrogen ion stable oxide layer on the material surface, effectively preventing low-temperature aging phenomenon.

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