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The post-deposition annealing of AlCrN films was conducted in an atmospheric environment for 2 h, with annealing temperatures ranging from 25 to 1000 °C. The microstructure, mechanical, and tribological properties were systematically investigated as a function of the annealing temperature. The results show that the AlN phase in the film began to oxidize at 600 °C, resulting in deterioration of the film's toughness and resistance to plastic deformation. Subsequently, the wear resistance also deteriorated, with the wear rate being nearly 16 times that of the as-deposited film. At 800 °C, the AlN obviously underwent oxidization to form Al2O3. The high temperature annealing promoted the coalescence of Cr on the film surface and caused a reaction with the Al2O3to form a replacement solid solution of Cr–O–Al, thereby improving the mechanical properties of the annealed films. At the same time, the tribological properties of the films were not significantly deteriorated by annealing at temperatures other than 600 °C, similar to those of the films without any annealing treatment.

The non-isothermal crystallization behaviors of a detonation sprayed Fe-based amorphous coating (AMC) was systematically investigated through differential scanning calorimetry, X-ray diffraction and transmission electron microscopy. The crystallization mechanism of the Fe-based AMC is analyzed and discussed in detail using a combination of the Kissinger-Akahira-Sunose and Ozawa-Flynn-Wall approaches, as well as the local Avrami exponent. The results indicate that the crystallization process of the Fe-based AMC is affected by the non-isothermal heating rate with a significantly higher initial crystallization activation energy (917.7 kJ mol−1) and first peak activation energy (479.6 kJ mol−1), indicating excellent thermal stability. After four stages of amorphous crystallization and phase transformation, the crystallization products of the equilibrium state were primarily composed of 78.5%, 11.3%, and 5.8% (Cr, Fe)23(C, B)6, α-Fe phases, and FeMo2B2phases, respectively.

In this study, the spreading morphologies and deposition behaviors of molten droplet in a single detonation sprayed shot under different oxygen-fuel ratio conditions are characterized in detail to reveal the formation mechanism of Fe-based amorphous coatings. Additionally, the porosities, micro-hardness, amorphous phase content and wear behavior of the coatings were also carefully evaluated to correlate the relationship between preparation process parameters, particle deposition behavior, spreading morphology, and mechanical properties. The results indicate that the spraying oxygen-fuel ratio (OF) parameter can determine the microstructure change of the coating, which is considered to be a reflection of the molten state of the sprayed particles. The low OF reduces the combustion efficiency, making the coating particles deposited in a form similar to cold spraying, resulting in uneven coating structure. In the case of medium OF (2.00), amorphous particles can form completely melted droplets and spread well on the substrate, and produce a good metallurgical bond with the substrate. Thanks to the good spread of the amorphous droplets, the OF-2.00 coating displays a very uniform and dense structure and uniformly distributed microhardness, which also makes its wear resistance (0.63 × 10−6 mm3 N−1 m−1) increased by about 8 times compared with OF-1.43 coating.

Fe-based amorphous coatings (AMCs) were deposited using detonation spraying technology to investigate its performance in high-temperature wear conditions. The results indicate that the detonation-sprayed Fe-based AMC possesses a dense structure, low porosity, high amorphous phase content. At 300 °C, the coating has a maximum wear rate of 6.53 × 10−6mm3N−1m−1, which is almost three times that at room temperature. The main wear mechanisms are oxidative wear, accompanied by fatigue stripping wear and adhesive wear. At 500 °C, the wear scar surface demonstrates increased toughness, resisting plastic deformation due to high-temperature softening. Additionally, partial crystallisation occurs, leading to an overall increase in the hardness of coating. Combined, these factors reduce the wear rate of the coating.