Nitrokarburálás

Nitrokarburálás is a specialized surface hardening heat treatment process primarily used to improve the wear resistance, fatigue strength, and corrosion resistance of metal components. The method combines nitriding and carburizing to create a hardened case layer on the surface of ferrous materials, particularly steels. Unlike traditional nitriding, which relies solely on nitrogen diffusion, nitrokarburálás introduces carbon into the process, allowing for higher hardness and better lubrication properties in the treated layer.

The process typically occurs at temperatures between 500–600°C, below the austenitizing range of most steels, preventing dimensional changes. The workpiece is exposed to a nitriding atmosphere containing ammonia (NH₃) and carbon sources such as hydrocarbons or carbon monoxide. The ammonia dissociates into nitrogen and hydrogen, while the carbon diffuses into the surface, forming a compound layer rich in iron nitrides (e.g., ε-phase) and iron carbonitrides. Beneath this layer, a diffusion zone develops, enhancing core strength.

Nitrokarburálás is widely applied in industries requiring durable, low-friction surfaces, such as automotive (e.g., gears, camshafts), aerospace (e.g., bearings, valves), and machinery components. The process offers advantages such as minimal distortion, improved fatigue life, and the ability to treat complex geometries. However, it is generally limited to ferrous alloys, particularly low-alloy steels, and may require post-treatment grinding to achieve precise tolerances.

Compared to nitriding, nitrokarburálás provides a slightly softer but more lubricious surface, making it suitable for applications where reduced friction is critical. The process can be performed in salt baths, gas atmospheres, or plasma (ion) nitriding setups, each offering variations in efficiency and environmental impact. Proper selection of process parameters, such as time, temperature, and gas composition, is essential to achieve optimal case depth and hardness.