nitridálással

Nitridálás is a surface hardening process used to improve the wear resistance and hardness of steel. It involves diffusing nitrogen into the surface layer of the steel, typically at elevated temperatures. This diffusion creates a hard, brittle layer of iron nitrides or alloy nitrides on the surface. The process can be carried out in several ways, including gas nitriding, salt bath nitriding, and plasma nitriding.

Gas nitriding is performed in a furnace containing an ammonia atmosphere. At temperatures between 500 and 570 degrees Celsius, ammonia decomposes, releasing nitrogen atoms that diffuse into the steel surface. Salt bath nitriding uses molten salt baths containing nitrogen-bearing compounds, offering a faster process. Plasma nitriding, also known as ion nitriding, uses a glow discharge to create a plasma of nitrogen ions, which then bombard the steel surface and diffuse into it.

The depth and hardness of the nitrided layer depend on factors such as the base material composition, temperature, time, and the specific nitriding method used. Nitriding is particularly effective for medium and high carbon steels, as well as alloy steels containing elements like chromium, molybdenum, and aluminum, which readily form stable nitrides. The process is advantageous as it results in minimal distortion of the workpiece, and the nitrided layer is very hard, leading to excellent wear resistance, improved fatigue strength, and enhanced corrosion resistance in some cases. It is widely applied to components such as gears, camshafts, crankshafts, and extrusion dies.