Nano-ceramic composite spraying powder and preparation method for same

Abstract

The invention discloses a nano-ceramic composite spraying powder and a preparation method for the same. The nano-ceramic composite spraying powder comprises MCrAlTaY with definite components, nano-aluminium oxide and / or nano-yttrium oxide, and nano-titanium diboride, wherein in MCrAlTaY, M is Ni, Co or Ni-Co alloy; the MCrAlTaY and the nano-aluminium oxide and / or nano-yttrium oxide form an alloy oxide ceramic composite powder; and nano-titanium diboride is nano-metal ceramic powder. The preparation method comprises the following steps of: conveying the composite powder in a ball mill; adding a ball-milling medium and an organic adhesive; starting the ball mill and uniformly mixing; adding the ceramic powder; and starting the ball mill again until all the ceramic powder is uniformly wrapped on the particle surface of the composite powder, taking out the wet material and drying, and then obtaining the nano-ceramic composite spraying powder. The spraying powder is good in resistance to high-temperature oxidation and resistance to thermal corrosion, thus enhancing the toughness and the resistance to thermal fatigue strength of a coating; and the prepared powder is uniform and complete in coating shape and good in flowability, thus reducing spraying difficulty.

Description

technical field [0001] The invention relates to a nano-ceramic composite spray powder and a preparation method thereof. Background technique [0002] In the continuous annealing process of cold-rolled strip steel, the movement of the strip steel is driven by the rotation of the furnace roll, and the temperature in the high-temperature section of the furnace reaches about 1000 ° C. The surface state of the furnace roll has an important influence on the surface quality of the strip steel. Therefore, the furnace In addition to high temperature oxidation resistance, the surface of the roll also needs to have high temperature hardness, high temperature wear resistance and nodulation resistance. In order to solve the problems of heat resistance, wear resistance and anti-nodulation on the surface of the furnace roller, it is necessary to coat the furnace roller with a coating containing composite cermet powder. [0003] The selection of the coated composite cermet powder and the c...

AI Technical Summary

Problems solved by technology

The production of this kind of composite metal-ceramic powder is to mix the metal powder and the ceramic powder mechanically. Due to the difference in the specific gravity of the two powders, component segregation will occur. During the spraying process, due to the small specific gravity of the ceramic powder, it will cause splash loss, which will reduce the deposition rate of the ceramic powder in the coating and reduce the coating performance.

In addition, the melting point of the above-mentioned ceramic hard phase is relatively high, which is quite different from the melting point of the metal phase, so it is only suitable for high-temperature explosive spraying or plasma spraying. , it is often difficult to fully soften the ceramic particles, the ceramic content in the coating is extremely low or even the existence of the ceramic phase is almost undetectable, and the purpose of strengthening the coating cannot be achieved

[0004] In order to solve the demand for composite powders suitable for supersonic spraying methods, recently, there is also a method of adding oxide ceramic particles during the melting process of metal alloy materials, and forming composite powders through atomization and granulation. However, due to the difference in specific gravity between molten metal and ceramics Larger, the two are incompatible with each other, and the uniformity of the formed mixed substance is poor. At the same time, the composite powder particles are mixed with ceramic components, and the thermal conductivity is not good. The metal phase on the surface of the composite particles is easy to produce localized Over-melting will cause sticking gun to block the gun barrel, making it difficult to optimize the setting of spraying process parameters, which greatly affects the actual performance of the coating