Barrier coating of aluminum alloy die-casting base body

Abstract

The invention relates to the technical field of base body protective coatings, and provides a barrier coating of an aluminum alloy die-casting die. The barrier coating comprises a transition layer arranged on the surface of a base body, a reinforcing layer is arranged on the transition layer far away from the base body side, a barrier layer is arranged on the reinforcing layer far away from the transition layer side, and an anti-sticking layer is arranged on the barrier layer far away from the reinforcing layer side. Under the service temperature (650 DEG C) environment, stripping or interlayer micro-cracking of a barrier coating of the die can be avoided, and meanwhile, main cracks formed by accelerated expansion and collection of cracks are avoided, so that base body failure is avoided; and meanwhile, in the multi-layer coating, microcracks cannot be caused in an interlayer interface, reduction of the toughness of the coating is avoided, and the service performance of the coating is improved especially in a high-temperature environment.

Description

technical field [0001] The invention relates to the technical field of substrate protective coatings, in particular to a barrier coating for aluminum alloy die-casting substrates. Background technique [0002] Aluminum alloy die-casting technology is an important forming technology in the automobile manufacturing industry. Its essence is to fill liquid or semi-solid aluminum alloy metal into the die-casting cavity at a high speed under high pressure, and quickly solidify under pressure to obtain castings. a molding method. The characteristics of this process and the intrinsic properties of aluminum endow aluminum alloy die-casting technology with many advantages such as high forming precision, small specific gravity of castings, and strong heat dissipation. However, during the aluminum alloy die-casting process, the surface of the matrix cavity is continuously washed by molten high-temperature aluminum liquid, resulting in periodic thermal, mechanical shock and chemical rea...

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Problems solved by technology

However, the chemical vapor deposition process will cause pollution to the environment, and chemical vapor deposition generally needs to be carried out at high temperatures, resulting in changes in the microstructure and properties of the die-casting substrate, and the coating is generally in a state of tensile stress, which is prone to microcracks, so The use of chemical vapor deposition technology in the protection of die-casting substrates is limited by conditions. At the same time, such high-temperature problems also exist in nitriding / carbon technology and thermal diffusion technology.

[0005] The magnetron sputtering technology in the physical vapor deposition technology has the following problems in the field of die-casting substrates and other high-temperature protection. First, the deposition temperature of the magnetron sputtering process is low. Or the difference in thermal expansion coefficient between the film sub-layers is likely to cause the barrier coating of the mold to peel off or the micro-cracks between the layers. When the molten aluminum fills the micro-cracks, it is easy to cause the cracks to accelerate and expand, thereby forming main cracks and causing matrix failure; Second, in current magnetron multi-layer coatings, the existence of defects and lattice mismatch problems in the interlayer interface will cause microcracks, which will reduce the toughness of the coating, especially in high temperature environments, such interfacial bonding defects will lead to a decrease in the service performance of the coating

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