Wet ball milling method for preparation of high efficiency micro-nano composite powder applicable to direct powder feeding

Abstract

The invention discloses a wet ball milling method for preparation of high efficiency micro-nano composite powder applicable to direct powder feeding. The method is characterized by comprising the following steps: carrying out ball milling pretreatment on micrometer raw powder and then sieving the micrometer raw powder after ball milling pretreatment so as to obtain pretreated micrometer powder; dispersing nanometer powder in ethanol or in a mixed solution of ethanol and deionized water to prepare stably dispersed nanometer suspension; mixing the pretreated micrometer powder and the stably dispersed nanometer suspension in a ball milling pot, adding grinding balls and carrying out continuous stirring or intermittent stirring on the powder in the ball milling pot during the process of ball milling compounding; and taking micro-nano composite powder prepared through ball milling out from the ball milling pot and drying the micro-nano composite powder in a drying box so as to obtain the high efficiency micro-nano composite powder applicable to direct powder feeding. The micro-nano composite powder prepared by using the method provided in the invention both has composite effects and can satisfy requirements for direct powder feeding in thermal spraying and laser cladding, having good engineering values and application prospects.

Description

technical field [0001] The present invention relates to a preparation method of micro-nano composite powder, especially a preparation method of wet ball milling of micro-nano composite powder, specifically a high-efficiency wet ball mill of micro-nano composite powder that can directly feed powder Preparation. Background technique [0002] In recent years, a technology for constructing mesoscopic (micro-nano-level) new substances --- micro-nano particle composite technology has attracted the attention of experts and scholars at home and abroad. Micro-nano particle composite technology is a technology that coats nanoparticles on the surface of micro-particles or disperses them in micro-particles to prepare micro-nano composite powders with micro-nano synergistic multifunctional effects. [0003] The preparation methods of micro-nano composite powder can be divided into four categories: mechanical method, gas phase method, liquid phase method and solid phase method. Among th...

AI Technical Summary

Problems solved by technology

In 2007, Wang Hongyu and others disclosed a mechanical preparation method of nano-ceramic / micro-metal composite powder (ZL 200710024996.X). "Micro-nano composite powder", which better solves the problem that the nano-powder is easy to agglomerate and the dispersion of nanoparticles in the micro-nano composite powder is poor, which causes the actual use effect of the micro-nano composite powder.

If these commercially available micron raw powders are directly used for ball milling compounding, a large number of fine particles will fall off from the micron raw powders under the action of ball milling during the ball milling compounding process, and the nanoparticles in the nano-suspension will preferentially compound with the fallen fine particles, resulting in the main body There are fewer nanoparticles actually compounded on the surface of the micron powder; on the other hand, there are problems such as the fact that the micron powder is easy to settle during the ball milling compounding process, resulting in a low probability of the micron powder participating in the compounding, which leads to the inability of the nanoparticles in the nanosuspension to fully contact with the micron powder And other issues

It is precisely because of the above two reasons that the micro-nano composite powder prepared by this method cannot meet the requirements of both the composite effect and the direct powder delivery.

If in order to ensure the reinforcement effect of the introduced nanoparticles, the prepared micro-nano composite powder will easily block the powder pipe during the powder feeding process due to the existence of a large number of fine particles, and it is difficult to meet the requirements of thermal spraying, laser cladding and other technologies for direct powder feeding. , can only adopt methods such as bonded powder coating or mold pressing preset, which has poor engineering practicability and the quality of the prepared coating is not ideal; If the particles are sieved and used again, because the actual composite nanoparticles on the surface of the main micropowder are less, the reinforcement effect of the introduced nanoparticles is insufficient.

[0004]In May 2012, Wang Hongyu and others proposed a ball mill tank with stirring function for preparing micro-nano composite powder (application number: 201210131290.4), which solved the problem of The problem that the micron powder is easy to settle during the ball milling process causes the problem that the probability of the micron powder participating in the composite is low, but it does not involve the problem caused by the diversity of the micron powder morphology

At the same time, a large number of experiments have shown that the additional stirring during the ball milling compounding process reduces the phenomenon that the micron powder is easy to settle and improves the probability of the micron powder participating in the compounding; however, the additional stirring in this case further promotes the nano-suspension The combination of medium nanoparticles and fine particles falling off from the original micron powder will cause the coating of nanoparticles on the surface of the main micron powder to decrease instead of increase.

Therefore, the problem that the prepared micro-nano composite powder cannot meet the requirements of both the composite effect and the direct powder delivery has not been resolved.

[0005]Therefore, so far, there is no high-composite effect micro-nano composite powder that can directly feed powder (referred to as high-efficiency micro-nano composite powder, the same below) The wet ball milling preparation method is available, which greatly restricts the wide application of micro-nano composite powders in surface engineering and other fields

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