Preparation method of low-cost hollow spherical YSZ powder for plasma spraying

Abstract

The invention provides a preparation method of a low-cost hollow spherical YSZ powder for plasma spraying, comprising the following steps: 1, adding yttrium salt and zircon salt in proportion into deionized water and stirring until yttrium salt and zircon salt are completely dissolved so as to obtain a mixed solution; 2, carrying out coprecipitation treatment, filtering and drying so as to obtain a solid mixture; 3, carrying out a hydrothermal reaction to obtain a hydrothermal reaction product; 4, successively carrying out filtration, washing and drying on the hydrothermal reaction product, and carrying out ball-milling on the hydrothermal reaction product, deionized water, a binder and a dispersant and uniformly mixing to obtain a slurry; 5, adjusting pH value and carrying out spray-drying treatment to obtain aggregates; and 6, sintering and screening to obtain the low-cost hollow spherical YSZ powder for plasma spraying. According to the invention, preparation of the hollow spherical powder is realized by controlling dispersibility of the slurry for spray drying. The YSZ powder prepared by the above method has a hollow spherical structure with a full tetragonal phase, has excellent performance, has low cost and has remarkable popularization value.

Description

technical field [0001] The invention belongs to the technical field of YSZ ceramic material processing, and in particular relates to a method for preparing low-cost hollow spherical YSZ powder for plasma spraying. Background technique [0002] Yttrium stabilized zirconia (hereinafter referred to as YSZ) coating has high melting point, high creep temperature and extremely low thermal conductivity (about ~1w / m·k), and is widely used in rocket engine nozzles, aeroengines and gas turbine blades The heat-insulating protective coating of high-temperature alloy parts, using YSZ coating can reduce the working temperature of the parts and prolong the service life of the parts. At the same time, it can also increase the working temperature of aero-engines or gas turbines, thereby increasing the thrust-to-weight ratio of aero-engines or gas turbines thermal efficiency. [0003] The particle structure and phase structure of YSZ powder are important factors affecting the microstructure ...

AI Technical Summary

Problems solved by technology

[0004] The phase structure of the YSZ powder determines the phase structure of the coating. The YSZ powder is composed of yttrium oxide and zirconia. When the yttrium oxide is uniformly distributed and all form a "solid solution alloy" with the zirconia, the zirconia is stabilized as a tetragonal At this time, the powder and coating are all composed of tetragonal phase. On the contrary, when the distribution of yttrium oxide in the powder is not uniform or all of them do not form a "solid solution alloy" with zirconia, the powder and coating are composed of tetragonal phase and monoclinic phase. The mixture of phase composition, the coating will undergo a reversible phase transition between monoclinic phase and tetragonal phase during use, causing volume changes and stress, resulting in cracking failure and reducing the service life of the coating

[0005] The traditional way of preparing YSZ hollow spraying powder, such as U.S. Patent US4450184, uses mechanical means to mix micron or submicron yttrium oxide and zirconia powder, and then uses spray drying, granulation and sintering to make a porous powder with a particle size of 10um ~ 120um, and finally The powder is fed into the high-temperature flame flow generated by the plasma or flame spray gun to melt it and "capture" the air in the powder. The molten droplets containing air bubbles form hollow spherical powder after cooling. Since the initial powder is yttrium oxide and zirconium oxide Mechanical mixture, it is difficult to achieve uniform distribution of yttrium oxide, and the final powder contains a certain amount of monoclinic phase, which affects the service life of the coating. Low (2kg / h~5kg / h), high cost of powder preparation

[0006] Therefore, there is an urgent need to develop a method for the preparation of low-cost hollow spherical YSZ powder for plasma spraying, to solve the problem of low production efficiency, high production cost and powder in the traditional preparation process. Problems with monoclinic phase

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