Ceramic (Zirconia Toughened (ZTA) Powder)

Zirconia toughened alumina ceramic (ZTA) powder is a composite ceramic material with alumina as the matrix and zirconia as the toughening phase. Its preparation process and performance parameters are as follows: 1、 Powder composition and characteristics

1. Zirconia content: usually 10% -40% (volume fraction), and when it exceeds 30%, the toughening mechanism shifts from phase transformation toughening to microcrack toughening.

2. Phase composition: Tetrahedral zirconia (t-ZrO ₂) needs to be stabilized at room temperature with stabilizers (such as Y ₂ O3, CeO ₂) to trigger stress-induced phase transformation toughening.

3. Particle size control: The optimal size of zirconia particles is 150-250nm, as being too coarse or too fine can lead to a decrease in toughening effect. 2、 Preparation process

1. Powder synthesis method: Mechanical mixing method: Directly mixing alumina and zirconia powders, with a simple process but poor dispersibility.  Sol gel method: nanometer level evenly dispersed composite powder can be prepared, and the grain size can be controlled at about 10nm.  Coprecipitation method: molecular level mixing is achieved through spray drying of zirconium/aluminum oxalate precursor to inhibit zirconia crystal growth.

2. Key parameters: The calcination temperature should be controlled between 900-1100 ℃ to avoid premature crystallization of zirconia. 3、 Performance optimization direction

1. Toughening mechanism: Through phase transformation toughening (volume expansion of 3-5%) and microcrack toughening, the fracture toughness of ZTA ceramics can be synergistically improved. The fracture toughness of ZTA ceramics can reach 2.5-4.5 MPa · m ¹/², which is 47-72% higher than that of pure alumina.

2. High temperature stability: When the temperature exceeds 800 ℃, the phase transition mechanism fails and needs to be resolved through stabilizer optimization or matrix modification. 4、 Application

1. Application areas: artificial joints, semiconductor packaging substrates, wear-resistant mechanical components, etc.