Nickel sulfamate is an excellent electroplating main salt, is dark green transparent liquid, at high temperature or low pH is susceptible to hydrolysis. Soluble in water, liquid ammonia, ethanol, slightly soluble in acetone, aqueous solution is acidic, hygroscopic, in moist air deliquescence quickly. In dry air slowly weathering, will lose four molecules of water upon heating, begins to decompose and form base salts at temperatures above 110℃, continued to heat and generate the mixture of brown-black nickel oxide and green nickel oxide. Because of its coating with low internal stress, fast plating speed, high solubility, no pollution, becomes one kind of rapidly developed electroplating main salt on the international in recent years, has been widely used in industries such as precision electroplating, electronics, printed circuit board plating, automotive, aerospace, weapons, coinage, metallurgy, nickel screen, radio, nickel-plated, colored metal, nickel catalysts, ceramics brown pigment, and color aluminum alloy.
Nickel sulfamate provides the desired nickel metal ion for nickel plating and plays the role as a conductive salt, nickel salt content is high, can use a higher cathode current density, deposition speed is fast, commonly used for high-speed thick nickel-plated. But the too high concentration will reduce the polarization of cathode, poor dispersion ability, and plating solution with a large loss. Low nickel salt content has low deposition rate, but good dispersing ability, can obtain fine crystal and bright coating. But stability of Nickel sulfamate is poor, the cost is relatively high.
sulfamic acid is a sulfuric acid derivative, has an amino functional group and a sulfonic acid functional group, can be performed chemical reaction with a variety of substances, an aqueous solution has equivalent of a strong acidity of hydrochloric acid and sulfuric acid, also known as a solid sulfuric acid, having characteristics of non-volatile, not absorb moisture, no odor and minimal human toxicity. But the skin cannot be contact with an amino acid for long time, even more cannot enter the eye. When at the ambient temperature is very stable and can be maintained unchanged for several years; when the temperature reaches 209 ℃, begins to decompose. Soluble in water and liquid ammonia, slightly soluble in methanol, insoluble in alcohol, ether, hydrocarbons and carbon disulfide. Although its solution is strongly acidic, but corrosivity to metal is small than mineral acid, the effect on iron corrosion products is slow, can add some sodium chloride, to make it slow to produce hydrochloric acid, which can effectively dissolve iron dirty. Also can remove scale and corrosion products of the surface of the devices such as iron, steel, copper and stainless steel. It is the only useful as cleaning acid for galvanized metal surface. When the use of sulfamic acid aqueous solution to clean, the temperature is controlled not to exceed 66 ℃ (to prevent decomposition of sulfamic acid), concentration does not exceed 10%.
The above information is edited by the chemicalbook of Liu Yujie.
Green crystal. Deliquescent. Soluble in water.
1. For electroplating of precision instruments.
2. For the electronics industry.
3. Mainly used for precision electroplating, the advantages of plating are low internal stress and fast deposition rate.
Synthesis method is that sulfamic acid reacts with nickel hydroxide to generate Nickel sulfamate, followed by concentrated, crystallization, centrifugation, to obtain finished products of nickel sulfamate.
2H2NSO3H+Ni(OH)2→Ni(NH2SO3)2+2H20
The 150 kg sulfamic acid was added into a reaction vessel, added hot distilled water and stirred to dissolve. 100 kg of nickel carbonate was added, stirred at reflux state and reaction for several hours, until the no CO2 released, reaction was completed. The reaction mixture was infiltrated into the thin film evaporator, cooled and crystallization, filtration, centrifugal dewatering, dry to obtain finished products.
Nickel plating Nickel(II) sulfamate is used for electroplating and as a surface treating agent. It finds application in metal coloring and casting.
Nickel sulfamate is used as an electrolyte in nickel electroplating systems.
Nickel sulfamate is prepared by heating an aqueous solution of sulfamic acid, H2NSO3H, with fine nickel powder or black nickel oxide under controlled conditions:2H2NSO3H + NiO → Ni(SO3NH2)2 + H2O
At ordinary temperatures, sulfamic acid hydrolyzes slowly forming ammonium bisulfite. However, when heated it hydrolyzes rapidly forming sulfuric acid. Therefore nickel sulfamate should be prepared rapidly before any sulfamic acid hydrolysis occurs due to longer contact time with water.
Nickel sulfamate also can be prepared by the action of sodium sulfamate on nickel carbonate: 2H2NSO3Na + NiCO3 → Ni(SO3NH2)2 + Na2CO3
Nickel sulfamate is usually not isolated from its product mixtures. The product solution is sold for commercial applications.
Flammability and Explosibility
Non flammable
Confirmed human
carcinogen. Poison by intraperitoneal route.
When heated to decomposition it emits very
toxic fumes of SOx and NOx. See also
NICKEL COMPOUNDS.
