A preparation method of nickel-coated hexagonal boron nitride nanosheet composite powder

Abstract

The invention relates to a preparation method of nickel-coated hexagonal boron nitride nano-sheet composite powder. The method comprises the steps of dispersion, sensitization, activation, electrolessplating and post-treatment of BNNS powder to obtain the nickel-coated hexagonal boron nitride nano-sheet composite powder. The chemical plating process is carried out in two stages, namely the 85-90DEG C high temperature stage and the 50-60 DEG C Low temperature stage. Hydrazine hydrate required for chemical plating is added in two times. Ni particles in the BNNS@Ni composite powder prepared bythe preparation method are consistent in size, are uniformly coat the surface of BNNS, and have high binding force with the BNNS. The preparation method is simple and convenient to operate and low incost. Neither high temperature heating or calcination in hazardous gases is required, no radioactive substances are generated, and the operational safety is high.

Description

technical field [0001] The invention relates to a preparation method of nickel-coated hexagonal boron nitride nanosheet composite powder, which belongs to the technical field of inorganic nanometer materials. Background technique [0002] Since the discovery of graphene in 2004, the research on two-dimensional layered inorganic materials has risen rapidly and made rapid progress. In view of the excellent properties that the corresponding three-dimensional bulk materials cannot match, two-dimensional materials have been widely used in more and more fields. Hexagonal boron nitride nanosheets are graphene-like two-dimensional materials, that is, single-layer or few-layer hexagonal boron nitride. Due to the small size effect of hexagonal boron nitride nanosheets in the thickness direction, its mechanical properties are significantly better than those of traditional hexagonal boron nitride, and it has good high temperature oxidation resistance and high chemical stability. Prope...

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Problems solved by technology

These two aspects will damage the mechanical properties and friction and wear properties of composite materials

(2) For ceramic-based solid self-lubricating composite materials, since hexagonal boron nitride is a covalent bond compound, the solid phase diffusion coefficient at high temperature is low (see Journal of Ceramics, 1998, 26 (2): 265- 269), so direct addition of hexagonal boron nitride nanosheets tends to result in low bonding strength with the ceramic matrix, and it is difficult to sinter densely, which in turn leads to a decrease in the mechanical properties and friction and wear properties of the composite.

The disadvantage of this method is that the contact between gold nanoclusters and boron nitride nanosheets is mainly physical adsorption, and the binding force between the two is low.

The problem with this method is that radioactive gamma rays are used, which poses a safety hazard to the health of the operator.

The disadvantage of this method is that high-temperature heating is required, the price of the rare gas used is relatively high, and the reduction of NiO to Ni particles using graphene as a carbon source will affect the surface structure of graphene.

The disadvantage of this method is that the process is cumbersome, and it needs to be calcined at high temperature in hydrogen, and there is a certain risk of operation.

[0005] Chinese patent document CN106623908A provides a method for preparing nickel-coated hexagonal boron nitride composite powder, but this method is suitable for coating micron-sized hexagonal boron nitride, not suitable for coating hexagonal boron nitride nanosheets, mainly The problem is: (1) The specific surface area of ​​hexagonal boron nitride nanosheets is much larger than that of hexagonal boron nitride powder, and it is not easy to disperse, so it needs to be sensitized for a long time under ultrasonic conditions, which will lead to sensitization in the sensitization solution. sn 2+ The ions are oxidized, and then lose the sensitization effect; (2) long-term plating of hexagonal boron nitride nanosheets with a large specific surface area under the conditions of high pH and high temperature can easily cause the plating speed to surge out of control, resulting in The plating solution decomposes and fails, resulting in the failure of electroless plating; (3) plating at a higher temperature, the evaporation of water in the plating solution increases, resulting in a significant reduction in the volume of the plating solution and an increase in the concentration of hexagonal boron nitride nanosheets , easy to cause agglomeration, and then affect the coating effect; (4) Plating at a higher temperature, the decomposition tendency of hydrazine hydrate in the plating solution increases, and the volatilization increases, which makes the stability of the plating solution decrease and endangers the operating environment.

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