Key Takeaways & Executive Findings
- •• The AlCrSiN/AlCrN/CrN/Cr multilayer coating achieved a critical load of 87.8 N, indicating excellent adhesion. • Silicon doping induced nanocrystallization and amorphization, increasing hardness to 26 GPa. • A nanoscale Cr-rich (Cr,Al)2O3 layer formed at high temperatures, effectively inhibiting oxygen diffusion. • AIMD simulations revealed that Cr atoms have higher oxygen-capture capability than Al, and Si atoms act as diffusion barriers, enhancing oxidation resistance.
Abstract
An advanced AlCrSiN/AlCrN/CrN/Cr multilayer coating was developed via hybrid multiarc ion plating and high-power impulse magnetron sputtering. The multilayer design enhanced the substrate–coating compatibility, achieving a critical load of 87.8 N. Silicon doping induced nanocrystallization and amorphization, increasing the hardness to 26 GPa. At high temperatures, a nanoscale Cr-rich (Cr,Al)2O3 layer was formed, effectively inhibiting oxygen diffusion. The coating underwent unique phase transformations, during which Cr2N and amorphous Si3N4 were converted into dispersed SiCr3 nanoparticles, which stabilized Cr atoms and suppressed their outward diffusion. Ab initio molecular dynamics simulations revealed that Cr atoms exhibited higher chemical activity and oxygen-capture capability than Al atoms and Si atoms served as diffusion barriers by pinning onto the oxidized surface, considerably improving the oxidation resistance of the coating.
1. Introduction
Mold-forming technology plays a pivotal role in modern industrial manufacturing, particularly in hot forging and stamping processes, during which molds are subjected to extreme thermomechanical stresses. Under these conditions, molds are subjected to severe impact loading [1], abrasive wear [2], and thermal fatigue failure [3], necessitating advanced surface protection strategies. Physical vapor deposition has emerged as a transformative surface engineering approach [4,5], and AlCrN coatings are being widely adopted because of their exceptional hardness [6,7], high oxidation resistance [6,8], and excellent tribological properties [7,9]. However, the application of conventional AlCrN coatings on emerging advanced difficult-to-form materials remains limited, prompting the development of enhanced protective solutions [10−12].
Recent studies have demonstrated that Si doping with AlCrN coatings induces a unique nanocomposite structure in which amorphous Si3N4 phases are interwoven with nanocrystalline (Al,Cr)N networks [13,14]. The optimal incorporation of Si (3−5 at.%) considerably enhances the coating performance, achieving simultaneous improvements in hardness [15], wear resistance [16], and oxidation resistance [17] while maintaining adequate fracture toughness [15,18,19]. The performance enhancement results from the synergistic nanocrystalline-strengthening and amorphous-phase reinforcement mechanisms.
Despite these advancements, coating–substrate adhesion remains a critical challenge. Although Si doping increases the coating hardness [15,17], it may intensify interfacial stresses owing to the disparity between the physicochemical properties, potentially causing premature spalling [20]. Multilayer architectures featuring gradient transition designs can effectively address the aforementioned issues [2,10,17]. Such designs enhance interfacial compatibility via controlled gradients in the chemical composition, stress distribution, mechanical properties, and thermal expansion coefficients [21,22]. Furthermore, multiple interfaces in these coatings serve as barriers to crack propagation [23,24].
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Ji-yuan LIU, Shu-bing HU, Bo PENG, Jing-jing TIAN, Si-qi ZENG, Hai-xin CHANG, Hong-ya LI, Jin-ke YU, Fei GUO (2025). Multiscale investigation of oxidation mechanism in AlCrSiN multilayer coatings via experiments and ab initio molecular dynamics. SinoTechIntel Verified Research. https://doi.org/10.1016/S1003-6326(25)66981-0
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Frequently Asked Questions
What is the critical load achieved by the AlCrSiN multilayer coating?
The AlCrSiN/AlCrN/CrN/Cr multilayer coating achieved a critical load of 87.8 N, indicating excellent adhesion to the substrate.
How does silicon doping affect the hardness of AlCrN coatings?
Silicon doping induces nanocrystallization and amorphization, which increases the hardness of the coating to 26 GPa.
What role does the Cr-rich oxide layer play in oxidation resistance?
At high temperatures, a nanoscale Cr-rich (Cr,Al)2O3 layer forms, which effectively inhibits oxygen diffusion and enhances oxidation resistance.
What did ab initio molecular dynamics simulations reveal about the oxidation mechanism?
The simulations revealed that Cr atoms exhibit higher chemical activity and oxygen-capture capability than Al atoms, while Si atoms act as diffusion barriers by pinning onto the oxidized surface, thereby improving oxidation resistance.
What is the significance of the multilayer architecture in this coating?
The multilayer architecture with gradient transitions enhances interfacial compatibility, reduces interfacial stresses, and provides multiple interfaces that act as barriers to crack propagation, improving overall performance.
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