Also known as glow nitriding, it is carried out by the principle of glow discharge. The metal workpiece is placed as a cathode in a negative pressure vessel having a nitrogen-containing medium. After being energized, nitrogen and hydrogen atoms in the medium are ionized to form a plasma region between the anode and the cathode.
Hydrocarbons and derivatives thereof mean that organic compounds contain carbon elements such as ethanol, acetic acid, and sucrose, and thus organic compounds are defined as carbon-containing compounds. Generally, organic compounds contain both carbon and hydrogen. From the structural point of view, hydrocarbons can be regarded as the precursor of organic compounds, while other organic compounds are regarded as hydrogen atoms in hydrocarbon molecules by other atoms. Or a derivative obtained by substituting a group, and therefore, an organic compound can also be defined as a hydrocarbon and a derivative thereof.
Therefore, organic chemistry is the study of the chemistry of carbon compounds, or the chemistry of Hydrocarbons And Their Derivatives. Organic compounds are closely related to people's daily life such as clothing, food, housing, and transportation. The main ingredients of food are fat, protein and sugar, which are three important organic compounds; the main components of natural gas and petroleum are organic compounds.
There is also a gas nitriding for the purpose of corrosion resistance, the nitriding temperature is between 550 and 700 ° C, the temperature is maintained for 0.5 to 3 hours, the ammonia decomposition rate is 35 to 70%, and the chemically stable compound layer can be obtained on the surface layer of the workpiece. Prevent the workpiece from being corroded by humid air, superheated steam, gaseous combustion products, and the like.
The normal gas nitriding workpiece has a silver-gray surface. Sometimes, it may be blue or yellow due to oxidation, but generally does not affect the use.
Ion nitriding, also known as glow nitriding, is carried out using the principle of glow discharge. The metal workpiece is placed as a cathode in a negative pressure vessel having a nitrogen-containing medium. After being energized, nitrogen and hydrogen atoms in the medium are ionized to form a plasma region between the anode and the cathode. Under the strong electric field in the plasma region, positive ions of nitrogen and hydrogen bombard the surface of the workpiece at high speed. The high kinetic energy of the ions is converted into heat, which heats the surface of the workpiece to the desired temperature. Due to the bombardment of ions, atomic sputtering occurs on the surface of the workpiece, which is purified, and at the same time, nitrogen enthalpy penetrates into the surface of the workpiece due to adsorption and diffusion.
Compared with general gas nitriding, the characteristics of ion nitriding are: 1 can shorten the nitriding cycle properly; 2 the nitriding layer is less brittle; 3 can save energy and ammonia consumption; 4 can not need nitriding part Shielded to achieve local nitriding; 5 ion bombardment has a purifying surface effect, can remove the passivation film on the surface of the workpiece, can directly nitriding the stainless steel "target=_blank> stainless steel, heat-resistant steel workpiece. 6 thickness and structure of the layer can be controlled Ion nitriding has developed rapidly and has been used in workpieces such as machine screws, gears, and molds.
Nitrocarburizing is also called soft nitriding or low temperature nitrocarburizing, that is, below the iron-nitrogen eutectoid transformation temperature, so that the surface of the workpiece penetrates into the carbon while mainly infiltrating nitrogen. The fine carbide formed after carbon infiltration promotes the diffusion of nitrogen and accelerates the formation of high nitrogen compounds. These high nitrogen compounds in turn increase the solubility of carbon. The mutual promotion of carbon and nitrogen atoms accelerates the rate of infiltration. In addition, carbon can also reduce brittleness in nitrides. The compound layer obtained after nitrocarburizing has good toughness, high hardness, wear resistance, corrosion resistance and seizure resistance.
Commonly used nitrocarburizing methods are liquid method and gas method. The treatment temperature is 530 to 570 ° C, and the holding time is 1 to 3 hours. Early liquid salt baths used cyanide salts, and later appeared in a variety of salt bath formulations. There are two commonly used: neutral salt through ammonia and urea plus carbonate-based salts, but these reaction products are still toxic. The gas medium mainly includes: an endothermic or exothermic gas (see controlled atmosphere) plus ammonia gas; urea thermal decomposition gas; and an Organic Solvent containing carbon and nitrogen, such as formamide or triethanolamine.
Nitrocarburizing can not only improve the fatigue life, wear resistance, corrosion resistance and seizure resistance of the workpiece, but also has simple equipment, low investment, easy operation, short time and small distortion of the workpiece, and sometimes gives the workpiece a beautiful appearance. .
Glow ion ion nitriding one, advantages: short nitriding time, easy to control quality, nitride layer fatigue resistance, high strength, due to nitriding temperature of 520-540, so the workpiece deformation is small, surface diamagnetic high.
Second, the shortcomings: the equipment control is complex, the furnace temperature uniformity is not good.
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Hydrocarbons And Their Derivatives
Ethylene Oxide,Compounds Chloromethyl Ethylene Oxide,Compounds Ethylene Oxide,Chloromethyl And Ethyleneoxide
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