Di Wang

CrN coatings prepared by physical vapor deposition may fail prematurely in localized regions during machining due to stress and high temperature. To address this problem, three groups of CrN coatings with different bias voltages were deposited on cemented carbide tools using cathodic arc ion plating. The influence of coating microstructure on cutting performance was investigated. The surface and cross-sectional morphologies of the coatings were observed using scanning electron microscopy. The crystal structures of the coatings were characterized using X-ray diffraction. The nanohardness values and elastic moduli of the coatings were measured using nanoindentation, and the coating–substrate adhesion was evaluated using a scratch tester. The residual stresses of the coatings were determined using the substrate bending method. The cutting performance of the coated tool was tested using a Computer Numerical Control (CNC) machine tool. The cutting process using coated tools was simulated using ABAQUS 6.14 software. The results indicated that, as the bias voltage increased, the droplets on the surface of the CrN coating became smaller and the structure became denser, but the thickness gradually decreased. The hardness increased from 18.59 GPa at 100 V to 24.57 GPa at 200 V, the bonding force increased from 72.6 N to 78.5 N, and the residual stress also increased to −2.22 GPa. Cutting tests showed that the cutting performance of the 200V-CrN coating was nearly twice that of the 100V-CrN coating. According to the microstructure and finite element simulation results after cutting, the 200V-CrN coating with a dense structure and higher residual compressive stress exhibited better stress-absorption capacity and was less susceptible to wear or fracture during the cutting process, thereby extending tool life.

To enhance the surface protection of exposed moving parts made from magnesium alloys, this study focuses on developing high-performance micro-arc composite (MCC) coatings on AZ80 wrought magnesium alloy substrate. AZ80 alloys were fabricated through forging at different temperatures (250 °C, 350 °C, and 450 °C) to investigate the influence of thermal deformation on substrate properties. Subsequently, micro-arc oxidation (MAO) coatings and MCC coatings were applied to the forged alloys. Comprehensive analyses—including microstructural characterization, salt spray corrosion tests, and stress corrosion cracking (SCC) evaluations—were conducted under both static and stress conditions. Among the forging temperatures, 250 °C produced substrates with refined grains and a favorable distribution of β-Mg₁₇Al₁₂ precipitates, resulting in improved baseline corrosion resistance. MAO coatings offered moderate protection, primarily delaying corrosion initiation and crack propagation under stress environments. Building upon this foundation, MCC coatings—fabricated by electrostatic spraying to form an inner-embedded and outer-wrapped structure over the MAO layer—demonstrated significantly superior protective performance. Under both static and stress corrosion scenarios, the MCC coatings effectively suppressed SCC initiation and progression, highlighting their potential for robust surface protection in demanding service environments.

To enhance the surface protection of exposed moving parts made from magnesium alloys, this study focuses on developing high-performance micro-arc composite (MCC) coatings on AZ80 wrought magnesium alloy substrate. AZ80 alloys were fabricated through forging at different temperatures (250℃, 350℃, and 450℃) to investigate the influence of thermal deformation on substrate properties. Subsequently, micro-arc oxidation (MAO) coatings and MCC coatings were applied to the forged alloys. Comprehensive analyses—including microstructural characterization, salt spray corrosion tests, and stress corrosion cracking (SCC) evaluations—were conducted under both static and stress conditions. Among the forging temperatures, 250℃ produced substrates with refined grains and a favorable distribution of β-Mg17Al12 precipitates, resulting in improved baseline corrosion resistance. MAO coatings offered moderate protection, primarily delaying corrosion initiation and crack propagation under stress environments. Building upon this foundation, MCC coatings—fabricated by electrostatic spraying to form an inner-embedded and outer-wrapped structure over the MAO layer—demonstrated significantly superior protective performance. Under both static and stress corrosion scenarios, the MCC coatings effectively suppressed SCC initiation and progression, highlighting their potential for robust surface protection in demanding service environments.

When military helicopters and transport aircraft take off and land forcibly on desert or simple runway, sand and dust will cause solid particle erosion damage to aircraft blades, leading to compressor performance degradation and structural integrity damage, which seriously affects the reliability of the engine. For the field of erosion protection, this book introduces the following six aspects, including erosion mechanism, influencing factors, protection methods, preparation methods, coating systems and structures, and the application status of erosion resistant coatings. The research and development direction of erosion resistant coating technology in the future was clarified, which laid a foundation for further research and application of erosion resistant coating technology.

Ammunition damage effect is an important basis for system simulation and ammunition power analysis. To solve the problem of ammunition damage effect analysis, it is necessary to collect relevant data, model, simulate and analyze ammunition. Based on the theoretical formula and test data, this paper proposes a typical ammunition modeling, power field analysis and damage effect analysis method, and constructs the corresponding typical ammunition damage effect analysis software, which includes database, parametric modeling module, power field analysis module, three dimensional visualization module. Compared with the corresponding test data, the credibility of the method and the availability of the software are verified.

The effect of deposition pressure on the microstructure and ablation behavior of ZrB2 coatings deposited by very low pressure plasma spraying is investigated. The results show that under a chamber pressure less than 50 kPa, as the spray chamber pressure decreases, the porosity of the coating deposited at the same distance decreases, and the coating prepared under 100 Pa presents the lowest porosity of 1.79 %. Furthermore, among the ZrB2 coatings deposited at 100 Pa, 5 kPa, 10 kPa and 50 kPa, the dense coating deposited at 100 Pa showed the lowest ablation rate of 0.33 μm/s, 0.75±0.08 mg/s.