Gear Coating via Cold Gas Spraying for Load-Bearing Capacity

The patent replaces the thermal diffusion process (carburizing) with a mechanical deposition process (cold gas spraying). Particles are accelerated to supersonic speeds and deposited directly onto the gear surface, forming a dense coating with controlled carbon content gradient. This mechanical approach eliminates the lengthy thermal diffusion process while achieving the desired carbon profile and material properties.

The coating materials are pre-prepared with specific carbon contents before application. By selecting powders with different carbon contents and applying them in a controlled sequence (higher carbon content first, then lower carbon content), the desired carbon profile is achieved in a single coating process rather than through prolonged thermal diffusion.

The patent replaces thermal hardening processes with mechanical particle deposition. The cold gas spraying process uses kinetic energy of accelerated particles to form the coating without significant thermal input. The particles are accelerated to supersonic speeds and deposited on the gear surface, achieving hardening through mechanical impact and plastic deformation rather than thermal treatment.

The patent changes the fundamental parameter from thermal energy to kinetic energy. Instead of heating the gear to achieve carburizing and hardening, the process uses mechanically accelerated particles with kinetic energies corresponding to temperatures of 800-1100°C equivalent, but without actual thermal contact. This preserves the gear's base temperature and toughness while achieving the desired surface hardness.

The patent divides the coating process into multiple stages, each applying a layer with specific carbon content. The first layer uses powder with higher carbon content (e.g., 2.0-4.0% C), and the second layer uses powder with lower carbon content (e.g., 0.1-1.0% C). This segmentation creates a controlled carbon gradient that simulates the natural carbon profile achieved through case hardening, with each layer contributing to different depth zones of the final coating.

The patent uses composite coating structures with multiple layers of different materials (powders with different carbon contents). By combining materials with varying carbon concentrations in a layered configuration, the coating achieves a gradient structure that provides both high surface hardness (from the carbon-rich outer layer) and core toughness (from the carbon-poor inner layer), mimicking the properties of case-hardened steel.