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Austenitic stainless steels represent an important class of materials which possess excellent cryogenic properties and good high-temperature strength. Their mechanical properties are comparable to those of mild steels but offer an excellent general corrosion resistance in the atmosphere, in many aqueous media and oxidizing acids. Particularly, the addition of molybdenum in type 316L provides pitting resistance in phosphoric and acetic acids and chloride solutions, as well as corrosion resistance in sulphurous acid. However, in general, stainless steels are characterized as having relatively poor wear resistance. This fact has led to the development of a number of surface treatments in order to improve their tribological performance without compromising their corrosion resistance, such as nitriding by ion implantation, pulsed plasma nitriding and plasma immersion ion implantation, boronizing. Also, it has been well documented that it is possible to extend the service life of many different parts and components, made of relatively soft substrates, subjected to corrosion and wear, by means of the use of thin hard films such as oxides, nitrides and carbides applied onto their surfaces. However, since such parts could also be subjected to cyclic loading during service, it is of almost importance to evaluate the effect of such hard films on the fatigue properties of the coated substrate, an area which has become an important research topic in the past few years. Mainly, AISI 316 L type steels are used in biomedical applications, automotive industry, ship industry, HVAC (heat ventilation air condition climate) systems and pressure vessel systems. Different superficial hardening processes are commonly applied to metals. Those are generally limited by the metal's original chemical composition as well as the required mechanical properties. Thermochemical methods, for which the superficial composition is locally modified, can produce microstructures and mechanical properties that are completely different from those of the basic metal. atoms and those of the basic metal leads to the formation of new compounds in the superficial layer. Boriding or boronizing is a thermochemical surface hardening technique used for boridetype coating that can be applied to a large range of materials (ferrous metals, non-ferrous metals and cermets). Boriding can be performed in numerous ways, including gas boriding, molten salt boriding, with and without electrolysis, and pack boriding. The produced layers provide an extremely high hardness, good tribological properties and anti-corrosion resistance of the treated surfaces. It is a surface treatment process in which boron atoms are diffused into the material surface between 800 and 1100 °C. A boride layer with hardness (HV) of 1600-2000 forms by penetrating and diffusing boron to the surface. Boronizing is a prominent choice for a wide range of tribological applications where the control of friction and wear is of primary concern. Boronizing being a thermochemical diffusion treatment can be applied to a wide range of steel alloys including carbon steel, low alloy steel, tool steel and stainless steel. Borides are non-oxide ceramics and could be very brittle. The aim of this study is to clarify the improvement of surface properties of AISI 316 L type stainless steel by thermo-chemical boronizing technique. In this study, boronizing bath was consisting of mixing of the silicon carbide, borax and boric acid in the salt bath. Boronizing process were performed different temperature and time. After the boronizing process, the various tests to determine the properties of boride layer were done. The results of this investigation can be summarized as follows, a) Thickness of boride layer on the surface of boronized AISI 316 L stainless steel increased as a parabolic with increasing temperature and time, b) The boride layers of boronized samples show continuity the surface. The surface structure of boride layer is more homogeneous and more density,c) The basic phase for the boride layer occurred with boronizing technique was Fe2B. The FeB did not occur, d)Activation energy of boride layer occurred with boronizing was 231.886 kJ/mol, e)The surface roughness values of boronized samples increased both the increasing additive ratio and increasing boronizing temperature. There is not affair to the effect on the roughness of the boronizing time and the type of the additives, The residual stress of boride layer increased with increasing temperature. [ABSTRACT FROM AUTHOR]