subject: The Nature Of Nickel [print this page] Nickel with magnetism, belong to transition metal. Under the low temperature, nickel is still have a good strength and ductility. Silver-white ferromagnetic metal, pertain to family in the periodic table, atomic number is 28, the common valence is +2, +3. Room temperature, the nickel in the humid air formed a dense oxide film on the surface to prevent further oxidation. Nickel can resistant the corrosion of fluorine, alkali, brine, and many organic substances, can slowly dissolve in dilute acid, strong nitric acid can make nickel surface passivation and with resistance. Nickel is the same with the platinum, palladium, can absorb large quantities of hydrogen, the smaller the particle size, the greater amount of absorption. The important salts of nickel are nickel sulfate and nickel chloride.
From the information by metal powder supplier, nickel is widely used, large used in manufacturing various types of stainless steel, soft magnetic alloy and alloy structural steel, used in chemical, petroleum, and machinery manufacturing industry. Nickel with chromium, copper, aluminum, cobalt and other elementals constitutes of the non-iron-base alloy. The nickel base alloy, nickel-chromium-based alloy are the thermostability, antioxidant materials for the manufacture of a jet turbine, resistive, heating elements, high-temperature equipment structural member and so on; aluminum-nickel-cobalt alloy is a good magnetic material, produce electrical equipment. The nickel powder is used as a hydrogenation catalyst for chemical reactions.
Nickel is a silvery-white metal, melting point is 1455 C, the boiling point is 2730 C, the density is 8.90 g / cm 3. with ferromagnetic and ductility, can conduct electricity and heat. Room temperature, nickel in the humid air formed a dense oxide film in the surface, can not only prevent continuing to be oxidized, also can resist the corrosion of alkali and salt solution. The massive nickel will not burn, thin nickel wire is combustible, special fine porous nickel particles in the air may ignite spontaneously. When heated, nickel react with oxygen, sulfur, chlorine, bromine violently. The fine powder of metallic nickel can absorb a considerable amount of hydrogen gas when heated. Nickel slowly dissolved in dilute hydrochloric acid, dilute sulfuric acid, dilute nitric acid, but surface passivation in the fuming nitric acid. Nickels oxidation state is -1, +1, +2, +3, +4, in simple compound, +2 valence is the most stable, the +3 valence nickel salt as the oxidant. Nickel oxide have NiO, and Ni2O3. Nickel hydroxide is a strong alkali, slightly soluble in water, soluble in acid. The nickel sulfate can be formed alum with an alkali metal sulfate. Divalent nickel ion can form a coordination compound. Nickel and carbon monoxide can be formed four nickel carbonyl under pressure, after heating it will also be decomposed into metallic nickel and carbon monoxide.
Electroplating nickel plating is mainly used as protective and decorative coatings. Nickel plating for iron substrate, is a cathode coatings. Its porosity is high, so use copper plating layer as the underlying or multi-layer nickel plating. Nickel plating deposited out from the ordinary nickel plating solution is not bright, but easy to polish. Use certain brighteners mirror-bright can be obtained nickel layer. It is widely used for cars, bicycles, watches, medical equipment, instrumentation and daily Hardware. The sulfate - chloride solution containing part of chloride called Watts nickel plating bath, the most widely used in the production. Use electrochemical action to deposit a layer of nickel on the surface of black metal or non-ferrous workpiece. Can be used as a surface coating, but mainly for the chrome-plated base, to prevent corrosion, increased wear resistance, gloss and beautiful. Widely used in machinery, apparatus, instruments, medical equipment, household appliances and other manufacturing industries. The workpiece as the cathode, pure nickel plate as anode, hanging into the electrolytic solution of nickel sulfate, sodium chloride, and boric acid are dubbed, electroplating. If the plating solution was added a naphthalene disulfonate, saccharin, coumarin brightener, for toluene sulfonamides and other bright agent can be directly obtained bright nickel plating without polishing.
