Nitriding of steels

Cyanamide, H2NCN, and calcium cyanamide, CaNCN, are used as fertilizers and raw materials. Calcium cyanamide is employed for the desulfurization and nitridation of steel. Inhalation or oral ingestion of cyanamide causes dizziness, lowers blood pressure, and increases rates of pulse and respiration. Calcium cyanamide acts as a primary irritant to the skin and to nose and throat tissues. The major metabolic product of cyanimide is N-acetylcyanamide, which is found in the urine of subjects exposed to cyanamide. 

Application of surface treatments such as shot peening, nitriding of steels and sandblasting of the surface of metal or others producing constraints of compression are beneficial.1... 

Nitriding of steels is not in itself beneficial to bonded film performance, but Kawamura et al showed an interesting synergistic effect of soft nitriding and manganese phosphating on the wear life of a bonded molybdenum disulphide coating on an annealed steel. 

Aluminum nitride EINECS 246-140-8. Used as a semiconductor in electronics, nitriding of steel steel manufacture. Crystals mp 2150-2200° hardness 9 to 10 on Moh s scale. Atomergic Chemetals Carborundum Corp. Mandoval Ltd Sigma-Aldrich Fine Chem. 

Uses As semiconductor in electronics nitriding of steel filler for elastomeric, epoxy, polymeric systems, in coatings integrated circuit housing ceramics... 

Properties Colorless gas or liq., sharp, intensely irritating odor easily liquefied by pressure sol. in water, alcohol, ether m.w. 17.03 sp.gr. 0.682 (-33.4 C) f.p. -77 C b.p. -33.5 C pH 11.6 (IN aq.) Toxicology ACGIH TLV/TWA 25 ppm STEL 35 ppm LD50 (inh., mouse, 1 h) 4837 ppm, (oral, rat) 350 mg/kg (ammonium hydroxide) corrosive inh. of cone, fumes may be fatal irritating to eyes and mucous membranes shown to produce cancer of the skin in human doses of 1000 mg/kg of body wt. TSCA listed Precaution Moderate fire risk caustic Hazardous Decomp. Prods. Exposed to heat, emits toxic fumes of NH3 and NOx NFPA Health 3, Flammability 1, Reactivity 0 Uses Fertilizer refrigerant nitriding of steel condensation catalyst neutralizer extraction... 

Nitrogen nitriding of steel Aluminum nitride Ammonia nitrification inhibitor Etridiazole... 

Gas nitriding of steels (Davis, 2001, 2002 Pye, 2003 Smith, 1993) is a thermochemical treatment that takes place in the presence of ammonia gas which dissociates on the steel surface at the operating temperatures. The atomic nitrogen produced is adsorbed at the steel surface, and depending on the temperature and concentration of nitrogen, iron nitrides form at and bellow the steel surface. The patent for gas nitriding was first applied for by Adolph... 

K. Funatani, "Low-temperature salt bath nitriding of steels". Metal Science and Heat Treatment, 46(7-8), 2004 pp. 277-281. 

Ammonia is also produced in ammonia plants as a raw material for the manufacture of urea and other nitrogen-based fertilizers. Ammonia in synthesis gas at temperatures between 450 and 500 °C causes nitridation of steel components. When synthesis gas is compressed to up to 34.5 MPa (5000 psig) prior to conversion, corrosive ammonium carbonate is formed, requiring various stainless steels for critical components. Condensed ammonia is also corrosive and can cause stress corrosion cracking (SCC) of stressed carbon steel and low-alloy steel components. 

Uses Fertilizer refrigerant nitriding of steel condensation catalyst neutralizer extraction solvent petroleum industry latex preservative explosives taste and odor control agent in water treatment condensate conosion inhibitor buffer in cosmetics foods (processing aid) phamiaceuticals (alkalizing agenL buffer) microbial fermentation nutrient in food-pkg. applies. 

---