Recently, many customers have asked whether we can make ceramic products with 5 mol yttria-stabilized zirconia or 8 mol yttria-stabilized zirconia. The editor received a question with a question mark on his face. The common differences in zirconia we see are yttrium-stabilized zirconia and magnesium-stabilized zirconia. I didn't know that there are so many classifications according to the content of yttrium-stabilized zirconia. What are the differences between different moles of yttria-stabilized zirconia? Let's take a look!
Zirconium oxide is a widely used type of ceramic material. That is, it has three phases: monoclinic phase, tetragonal phase, and cubic phase, which can have a greater impact on zirconia ceramic materials. On performance. The most common material at present is yttrium-stabilized zirconia material. Among them, 3Y-TZP (3% (mole fraction) Y2O3) material is the most commonly used zirconia ceramic material at present, and has a wide range of applications in various industries such as chemical industry, machinery, industry, etc. The properties of 3Y-TZP manufactured by various methods are significantly different. In order to obtain zirconia ceramic materials with higher mechanical properties, sintering temperature control, doping, etc. can be used. Adding additives can also change the particle size and phase composition of the material to some extent. The particle size and phase composition have a significant influence on the physical properties of ceramic materials. Therefore, studying the effects of particle shape and phase composition on ceramic materials is of great significance in exploring the overall performance improvement of zirconia materials.
1. Effect of yttrium content on relative density
The mole fraction of yttrium oxide corresponding to the maximum densification is 3%, and the relative density reaches 98.113%. Before the critical point, the density of the sample gradually increases with the increase of yttrium oxide content, and gradually decreases after the critical point. Obviously, the relative density of the sintered body with the mole fraction of yttrium oxide of 3% is larger than that of other groups, indicating that Y2O3 can promote the densification of zirconia during sintering. This is because the radius of Y3+ (1.06A) is larger than that of Zr4+ (0.87A). This is because when Y2O3 and ZrO2 form an alternative solid solution, the main crystal phase lattice of ZrO2 is distorted and defects increase, making it easy to move. It can reduce the structural unit and promote sintering to obtain a higher density. When the content of yttrium oxide exceeds the critical value, the role of Y2O3 in the zirconia matrix is weakened, and if Y2O3 is excessive, it hinders crystallization during the zirconia sintering process, so that the relative density gradually decreases. In addition, the X-ray photoelectron spectroscopy (XPS) analysis results showed that Y3+ was segregated at the grain boundaries, which strongly inhibited the movement of the grain boundaries and prevented or delayed the separation of pores and grain boundaries, thereby promoting the densification process. It can proceed to the later stage of sintering. When the yttrium oxide content is 3% (mole fraction), this effect is maximized, so the density of the zirconia ceramic material reaches its maximum at around 3% (mole fraction).
2. Effect of yttrium oxide content on the mechanical properties of zirconia ceramics
As the mole fraction of yttrium oxide increases, the flexural strength of zirconia ceramics increases rapidly, and the maximum strength value is obtained when the yttrium oxide content is 3% (mole fraction). It does not increase any further and gradually decreases.
As the yttrium mole fraction increases, the hardness of the zirconia ceramic material increases, reaching a maximum value at 3%, and then gradually decreasing as the yttrium content increases.
When the yttrium content is 3% (mole fraction), the particle size of yttrium-stabilized zirconia is the smallest and the density of zirconia is high. When the mole fraction of yttrium is 3%, a certain amount of elongated crystals appear in the microstructure of zirconia, and these elongated crystals act as a solidification bridge between the fine zirconia particles and the bulk, which further bonds the zirconia material. Hardness, higher bonding force are obtained, which is also the reason why the hardness of the ceramic is higher when the yttrium content is 3%. Mingrui Ceramics mainly provides non-standard customization of alumina and zirconia (3mol yttria-stabilized zirconia) ceramic products. Welcome to inquire for quotation!
