Cadmium solder

Silver Brazed Joints These are similar to soldered joints except that a temperature of about 600°C (1100°F) is required. A 15 percent silver, 80 percent copper, 5 percent phosphorus solder is used for copper and copper alloys, while 45 percent silver, 15 percent copper, 16 percent zinc, 24 percent cadmium solders are used for copper, copper alloys, carbon steel, and alloy steel. Silver-brazed joints are used for temperatures up to 200°C (400°F). Cast-bronze fittings and valves with preinserted rings of 15 percent silver, 80 percent copper, 5 percent phosphorus brazing alloy are available. 

Inhalation (breathing) When cadmium is scattered in the air as dust or fume, it can be inhaled and enter the upper respiratory tract and lungs. Operations that generate cadmium dust and fumes include welding with cadmium solder, or heating cadmium-containing compounds. Use a respirator to protect from this hazard. 

Solders are alloys that have melting temperatures below 300°C, formed from elements such as tin, lead, antimony, bismuth, and cadmium. Tin—lead solders are commonly used for electronic appHcations, showing traces of other elements that can tailor the solder properties for specific appHcations. 

The presence of the so-called heavy metals, eg, lead, cadmium, and antimony, iu traditional solders has become an important environmental issue owiag to concerns for health and safety. As a result, solders containing no lead and antimony such as tin—silver are finding a growing number of apphcations (Table 2). 

Cadmium is an impoitant component in brazing and low melting alloys, used in bearings, solders, and nuclear reactor control rods, and as a hardener for... 

For soldering aluminum, combinations of cadmium and zinc are widely used, the most satisfactory being the 60% Cd—40% Zn alloy, in addition to a 95% Cd—5% Ag solder. In high speed and high temperature appHcations, which are too severe for tin or lead bearings, SAE 18, containing 1% nickel and 99% cadmium, and SAE 180, containing 0.7% silver, 0.6% copper, and 98.7% cadmium, are employed. 

Solders. Modem dental solders are made from mostly corrosion-resistant, nontoxic metals. Minimal quantities of tin and other elements are often added, some of which could produce toxic effects in the unalloyed state. Each solder is used for specific appHcations (180—188) typical compositions and properties of solders used in dentistry are presented in Table 11. Most of the ingredients of solders are resistant to corrosion, and alloying them with other ingredients renders the alloy safe for use in appHances placed in the oral environment. Silver solders corrode, but are used only for temporary appHances. Available products do not contain cadmium, although cadmium was an ingredient of some silver solders up to ca 1980. 

A low fin alloy, more correcdy 90% 2inc—tin alloy, has been proposed as an economical solderable substitute for cadmium. For this 10% fin deposit, the same type of plafing bath, but usiag 40 g/L tin, 15 g/L 2iac, 15 g/L potassium cyanide, and 45 g/L free potassium hydroxide is used. 

Silver-brazed joints are used when temperature or the combination of temperature and pressure is beyond the range of soldered joints. They are also more reliable in the event of plant fires and are more resistant to vibration. If they are used for fluids that are flammable, toxic, or damaging to human tissue, appropriate safeguarding is required by the code. There are OSHA regulations governing the use of silver brazing alloys containing cadmium and other toxic materials. 

Solders are cathodic to steel, zinc and cadmium, and anodic to Monel metal. Although tin or tin-coated metals may be used safely in contact with aluminium when they are not fused with it, a joint in aluminium made with a tin-lead solder is liable to destructive corrosion. The formation, on fusion, of the grain-boundary state, which, as already mentioned, makes aluminium so dangerous an impurity in tin, is responsible. Tin-zinc solders may be used the zinc gives a useful degree of protection. 

Heat-resisting steels have limited uses in contact with molten metals. They are not recommended for use with molten zinc, cadmium, aluminium, antimony or copper, because of excessive attack and embrittlement effects. In brazing and silver soldering, contact between the molten non-ferrous alloy and the steel occurs for only a very limited period of time. 

Cadmium also provides a sacrificial coating to steel which gives better protection than zinc in applications where strong acids and alkalis may be encountered and those involving immersion in stagnant or soft neutral waters. It should be used in applications involving bimetallic contact with aluminium and in electrical applications where ease of solderability is important. Cadmium has a low torque resistance and should be used as a coating material in cases where bolted assemblies have to be frequently... 

Cadmium is easier to solder and has a lower contact resistance than zinc, and for such reasons it may be selected for certain applications. However, account must be taken of the toxic nature of cadmium and cadmium vapour. 

Cadmium alloyed with silver forms a type of solder with a low melting point. It is used to join electrical junctions and other specialized metallic components. Precautions are required... 

Uses. The metal is used in electroplating, in solder for aluminum, as a constituent of easily fusible alloys, as a deoxidizer in nickel plating, in process engraving, in cadmium-nickel batteries, and in reactor control rods. Cadmium compounds are employed as TV phosphors, as pigments in glazes and enamels, in dyeing and printing, and in semiconductors and rectifiers. 

Cadmium (Cd) is a transition metal widely used in industry. Workers are exposed to cadmium in the manufacture of nickel cadmium batteries, pigments, low-melting-point eutectic materials, in solder, television phosphors, and in plating operations. 

Solders and brazes for jewelry gold alloys are usually gold—silver—copper alloys that can be modified to yield a desired melting range by adjusting the silver-to-copper ratio. Additions of zinc, cadmium, tin, or nickel compensate for the changes in color introduced by compositional modification (87). 

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