Anti-sticking coating, carbon-based boat and preparation method thereof

Abstract

The invention discloses an anti-sticking coating, a carbon-based boat and a preparation method thereof. The anti-sticking coating comprises a transition layer and a working layer, wherein the transition layer comprises chromium group elements, and the working layer is arranged on at least one part of the transition layer and comprises at least one of aluminum oxide, zirconium oxide and rare earthoxide. Therefore, the bonding strength between the anti-sticking coating and the boat can be improved, and the isolation capacity of the coating is enhanced. When the anti-sticking coating is appliedto the surface of the carbon-based boat for hard alloy sintering, the transition layer in the anti-sticking coating and a carbon-based boat base body have good bonding strength, mismatching of thermalexpansion coefficients between a carbon substrate and the working layer can be improved, the element mutual diffusion effect between the carbon-based boat base body- coating-hard alloy products is inhibited, and the thermal stability of the anti-sticking coating is improved, so that the phenomena of coating peeling and sintering deformation, carburization and decarburization of the hard alloy products caused by the fact that the hard alloy products are stuck to the surface of the boat can be avoided, and the service life of the anti-sticking coating is greatly prolonged.

Description

technical field [0001] The invention belongs to the technical field of cemented carbide sintering processing, and in particular relates to an anti-adhesive coating, a carbon-based boat and a preparation method thereof. Background technique [0002] Cemented carbide is prepared by powder metallurgy and is composed of refractory metal compounds (WC, TaC, NbC, TiC, etc.) and bonding metals (Co, Ni, Fe, etc.), and is an engineering compound with hardness, strength and toughness Material. Widely used in petroleum exploration, aerospace, rail transit, energy and industry and other fields. Cemented carbide sintering usually uses carbon-based boats, and the sintering temperature is usually between 1380°C and 1500°C. As the content of metal binders such as iron, cobalt, and nickel in the alloy composition increases and the sintering temperature increases, the amount of liquid phase in the alloy also increases, which intensifies the diffusion reaction between the cemented carbide pr...

AI Technical Summary

Problems solved by technology

[0003] Disposable coatings are usually used in the prior art, mainly composed of alumina, zirconia, and rare earth oxides, and chemical raw materials such as Tween, formaldehyde, PEG, carbon black, etc. are added. This type of coating has the following disadvantages: (1) The composition is complex, pollutes the environment and has a certain degree of harm to the human body. It is used only once during the sintering process. It needs special personnel to paint, and the thickness of the paint is not easy to control, and the labor cost is high; (2) The charcoal in the paint Black is easily adsorbed on the surface of the electrode in the sintering furnace during the sintering process, reducing the service life of the sintering furnace; (3) carbon black in traditional anti-stick coatings can easily cause carburization at the bottom of the cemented carbide product, resulting in sticking and deformation , affecting product quality

At the same time, when this kind of coating is sintered with high binder phase products, the phenomenon of coating sticking, carburization and product dimensional deformation is more obvious, resulting in a low product qualification rate

[0004] Patents such as Chinese patent CN201010546928.1 and CN109332689A have disclosed that the boat surface coating has been optimized, and the anti-sticking effect is better, but these coatings all contain complex chemical raw materials such as carbon black, Tween, and PEG, and are all disposable. use, cannot solve the problem of reuse

However, the coating made of silicon carbide and alumina has a high porosity and is prone to micro-cracks, making graphite easy to penetrate into the working layer, and sticking boats will also appear after long-term use

And the impurity sulfur element in the graphite will penetrate into the working layer to produce yttrium oxysulfide, causing the coating to fall off, which in turn affects the service life of the boat

[0005] Therefore, the existing anti-sticking coating for cemented carbide sintering needs to be improved

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