Sulfamate nickel

Nickel Sulfamate. Nickel sulfamate [13770-89-3] Ni(S02NH2)2 4H2O, commonly is used as an electrolyte ia nickel electroforming systems, where low stress deposits are required. As a crystalline entity for commercial purposes, nickel sulfamate never is isolated from its reaction mixture. It is prepared by the reaction of fine nickel powder or black nickel oxide with sulfamic acid ia hot water solution. Care must be exercised ia its preparation, and the reaction should be completed rapidly because sulfamic acid hydrolyzes readily to form sulfuric acid (57). 

Cadmium, cobalt, copper, and nickel sulfamates react with lower aHphatic aldehydes. These stable compositions are suitable for use ia electroplating solutions for deposition of the respective metal (see Electroplating). 

Ammonium sulfamate is also produced and commercially available in Japan. It is packed in 25-kg net weight paper bags and 500-kg resinous dexible containers. The tmddoad price (fob Japan) is 1.5— 3/kg. Other sulfamates, eg, nickel sulfamate and aluminum sulfamate, are commercially available. The primary salts manufactured from sulfamic acid in the United States are the ammonium and nickel sulfamates. These salts of sulfamic acid are used mainly in electroplating. 

Soluble anode materials are not always a pure metal. In acid, low chloride nickel solutions, pure nickel does not corrode well, and small amounts of specific impurities are added to make the nickel more active, allowing more efficient dissolution. For example, since the early 1960s, nickel anode material containing a small amount of nickel sulfide [16812-54-7] NiS, has been commercially available and important in nickel sulfamate [13770-85-3] Ni(H2N02S)2, plating baths. These anodes corrode at a lower potential then pure nickel or other nickel anode materials (see Nickel and nickel alloys). 

Nickel sulfamate is more soluble than the sulfate salt, and baths can be operated using higher nickel concentrations and higher currents. Sulfamate baths have been found to have superior microthrowing power, the abiUty to deposit in small cracks or crevices. Using one nickel salt, only a hydrometer and pH paper are needed to control the bath. A small amount of chloride salt was added as a proprietary. Highly purified nickel sulfamate concentrates are commercially available that can be used to make up new plating baths without further purification. 

Palladium and Palladium Alloys. Palladium is used in telephone equipment and in electronics appHcations as a substitute for gold in specific areas. Palladium is plated from ammoniacal and acid baths available along with chelated variations as proprietary processes. One typical alkaline bath uses 8 g/L diammine-dinitropalladium, 100 g/L ammonium nitrate, and 10 g/L sodium nitrite. The pH is adjusted to 9—10 using ammonium hydroxide, and the bath is operated at 100 A/m at 50° C. If ammonium sulfamate, 100 g/L, is used in some baths to replace the nitrate and sodium nitrite salts, the bath is mn at lower temperature, 25—35°C, and a pH of 7.5—8.5. A palladium—nickel alloy, 75% Pd, is plated from a bath having 6 g/L palladium from the same salt, 3 g/L nickel from nickel sulfamate concentrate, and 90 g/L ammonium hydroxide. The bath is operated at 20—40°C with 50-100 A/m/... 

Plating solutions used in nickel electroforming are primarily the Watts bath and the nickel sulfamate bath. Watts baths exhibit higher stress and require additives for stress control, which may affect other properties. Sulfamate baths produce much lower stress and are preferred where purer nickel or nickel—cobalt deposits ate needed. ASTM specifications are available that describe the mandrels and plating solutions (116,162). 

The composition of the codeposition bath is defined not only by the concentration and type of electrolyte used for depositing the matrix metal, but also by the particle loading in suspension, the pH, the temperature, and the additives used. A variety of electrolytes have been used for the electrocodeposition process including simple metal sulfate or acidic metal sulfate baths to form a metal matrix of copper, iron, nickel, cobalt, or chromium, or their alloys. Deposition of a nickel matrix has also been conducted using a Watts bath which consists of nickel sulfate, nickel chloride and boric acid, and electrolyte baths based on nickel fluoborate or nickel sulfamate. Although many of the bath chemistries used provide high current efficiency, the effect of hydrogen evolution on electrocodeposition is not discussed in the literature. 

Nickel sulfamate, 17 112 Nickel sulfate, 17 108-109, 125 Nickel sulfides, 17 89, 112 Nickel tetracarbonyl, 16 66... 

A comparative smdy of great practical value has been carried out between several Ni-based diffusion barrier properties. Those were produced by means of electroless deposition from nickel sulfate and nickel sulfamate deposition solutions (73). It was concluded on the basis of Auger depth profiling (see Section 13.3) that Ni(P) sulfamate has much better diffusion barrier properties than Ni(P) sulfate. This conclusion is a telling example of the influence of anions on the physical properties of electro-chemically deposited metals. 

Low current densities tend, in general, to result in higher impurities. For example, in the case of nickel, low current densities produce a high impurity content, and this affects stress and other properties of the deposit. In Table 12.1 we show that for nickel sulfamate solution, the hydrogen and sulfur contents are considerably higher... 

TABLE 12.1. Influence of Current Density in Nickel Sulfamate Solution on the Impurity Content of Deposits... 

Fine nickel powder reacts with sulfamic acid in hot aqueous solution under controlled conditions, forming nickel sulfamate tetrahydrate, Ni(S03NH2)2 4H20, used in electroplating baths. 

Nickel sulfamate is used as an electrolyte in nickel electroplating systems. Preparation... 

Nickel sulfamate is prepared hy heating an aqueous solution of sulfamic acid, H2NSO3H, with fine nickel powder or black nickel oxide under controlled conditions ... 

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 ... 

Nickel sulfamate is usually not isolated from its product mixtures. The product solution is sold for commercial apphcations. 

WTI has had systems operating on the following electronic and circuit board solutions acid copper plating, chelated lead brightening, and nickel sulfamate plating. Tin-lead fluoboric and electroless copper systems are to be installed in June, 1989. The systems have been or are to be installed at Cray Research, Control Data and Vitramon (a Thomas and Betts subsidiary). 

WTI, with Ensco Environmental Services, has recently won a Farr Grant to install two ARO systems in the Bay Area for long term testing and evaluation. One is to be installed at Hewlett Packard (on acid copper and nickel sulfamate) and the other, at Domain Technologies (on electroless nickel and electroless cobalt). The project should begin in late Summer, 1989. 

Nickel Sulfamate. Vltramon, a Thomas and Betts subsidiary, installed a 1 gpm ARO system to recover rinses and recycle nickel bath used to plate electronic capacitors. Previously, Vitramon had used an ion exchange system to remove the nickel. Ion exchange regenerant was shipped to a reclaimer. Water was reused. Ion exchange cost of operation was 4,000 per month. The ARO system maintains the rinse at less than 40 ppm nickel. Savings from nickel recovery and avoided treatment cost will provide a payback of approximately 10 months. 

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