Sintered body material processing of zirconia ceramics

Zirconia ceramic is a ceramic material with high processing performance. It is a high temperature resistant ceramic with high hardness, wear resistance and other excellent properties. The following Kezhong Ceramic Factory briefly introduces the processing of sintered body materials of zirconia ceramics.

Structural ceramics are superior to metals in terms of chemical corrosion resistance, high hardness and wear resistance, high melting point temperature and high temperature strength, but the toughening of structural ceramics has always been the most challenging issue in the field of ceramics, and structural ceramics have good properties at room temperature. The ability of plastic deformation has been the dream of scientists for many years. 3Y-TZP ceramics are polycrystalline ceramics composed entirely of tetragonal ZO2. Under stress induction, a martensitic phase transformation from tetragonal ZrO2(t) to monoclinic ZrO(m) will occur.

There is no diffusion during the phase transition and accompanied by 3% to 5% volume expansion and shear stress, which leads to cracking of the grain boundary and disperses the strain energy of the crack tip; in addition, the phase transition zone induced by the crack tip stress strongly hinders the crack growth. The dual effects of phase transformation toughening and microcrack toughening are superimposed here.

As we all know, one of the methods to promote the superplastic deformation of ceramics at lower temperature or stress is to refine the grain size, and nano-peripheral ceramics use the volume fraction of disordered grain boundaries to increase after the grain size is reduced. As the magnitude increases, it is possible that room temperature brittle ceramics will become ductile. The purpose of this study is to explore the possible behavior and mechanism of the cyclic deformation of nano-ceramics at room temperature. Firstly, a block material of 4mmX64mm×64mm was prepared by hot pressing method (Fujidempace400kN hot pressing furnace), and then processed into a 14mm gauge length Samples, their geometry and dimensions are shown in Figure 3-17.

The cyclic fatigue test is carried out on a computer-controlled servo hydraulic fatigue test machine (Instron100kN8501), equipped with a 10kN sensor, the test frequency is 0.1Hz (sine wave), the stress ratio R is 0.1, and the load control (room temperature) has a 10mm The long axial extensometer is clamped to the center of the sample and has a maximum extension of ±1 mm.

The samples were subjected to a series of saturated cyclic stress/strain loading experiments, and 100 cycles were performed under each stage of tensile stress to achieve a stable cumulative strain. The loading interval for nanomaterials (about 100nm) is 1MPa, and for submicron materials (350nm) is 50MPa. Until the maximum cyclic stress of nanomaterials reaches 60MPa, and that of sub-micrometer materials reaches 250MPa, fatigue failure occurs in all samples. The total number of cycles is more than 500 cycles.

Zirconia ceramics are one of the promising ceramic materials with higher fracture toughness and strength values than other ceramics. Zirconia ceramics are commonly used to make bearings or knives and scissors. The performance of precision ceramic parts depends to a large extent on its processing. In order to study the superplasticity of ceramic materials, a large number of tensile tests have to be done in recent years, so how to prepare tensile test pieces is very critical. The precision grinding experiment is carried out on the M7120 type surface grinder with horizontal axis and rectangular table. The abrasive products used in the experiment include: diamond second wheel, silicon carbide grinding wheel and electric diamond sample block.

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