![]() ![]() When produced in wire form they are known as Nichrome ® wire. ![]() Heating elements such as in toasters and other electrical resistance heaters make use of nickel-chromium alloys. For example, the alloy NiCr 70/30, also designated as Ni70Cr30, Nikrothal 70, Resistohm 70, and X30H70 has a melting point of 1380 oC and an electrical resistivity of 1.18 μΩ-m. Nickel-chromium alloys are prized for their high corrosion resistance, high-temperature strength, and high electrical resistance. Applications include pumps and valves, gaskets, pressure vessels, heat exchangers, and piping products. ![]() The chemical makeup for an alloy of this type, such as Alloy B-2 ®, has a concentration of molybdenum of 29-30% and a nickel concentration of between 66-74%. Nickel-molybdenum alloys offer high chemical resistance to strong acids and other reducers such as hydrochloric acid, hydrogen chloride, sulfuric acid, and phosphoric acid. This alloy as a minimum concentration of 63% nickel and 28-34% copper. As an example, Monel 400 ®, also sold under the trade names Nickelvac ® 400 or Nicorros ® 400, can find application in marine piping systems, pump shafts, and seawater valves. Nickel-copper alloys are very resistant to corrosion by salt water or seawater and thus find application in marine applications. Other nickel-iron alloys with even greater concentrations of nickel are used in applications where soft magnetic properties are important, such as transformers, inductors, or memory storage devices. This high degree of dimensional stability renders nickel-iron alloys useful in applications such as precision measurement equipment or thermostat rods. Invar 36 ®, also sold with trade names of Nilo 6 ® or Pernifer 6 ®, exhibits a coefficient of thermal expansion that is about 1/10 that of carbon steel. Nickel-iron alloys function in applications where the desired property is a low rate of thermal expansion. The sections below present information about each of these types of nickel alloys. The addition of nickel to other metals alters the properties of the resulting alloy and can be used to produce desired characteristics such as improved corrosion or oxidation resistance, increased high-temperature performance, or lower coefficients of thermal expansion, for example. Nickel will alloy easily with most metals such as copper, chromium, iron, and molybdenum. Table 1 – Characteristics and Properties of Nickel (Ni) Table 1 below summarizes some of the other key physical properties and characteristics of nickel. It is magnetic at room temperature and has a Curie temperature of 253 oC (487 oF). ![]() Nickel, whose chemical symbol is Ni, has a silvery-white appearance and is a primordial element, with a face-centered cubic crystalline structure. has the highest concentration of all the metals in the alloy). The alloy definition in the case of nickel alloys is one in which nickel is the primary element (i.e. This article will focus on reviewing the different types of nickel alloys that are commonly available. For example, grades of stainless steel can be created by the addition of nickel to produce alloys that offer corrosion resistance and high-temperature endurance, making them ideal for uses in chemical plants where exposure to caustic substances may be expected. For one, nickel is highly ductile and is valuable as an alloying element to alter the properties of other metals. First discovered and isolated by Axel Fredrik Cronstedt, a Swedish chemist and mineralogist, nickel exhibits several desirable properties that render it useful in industrial applications. Nickel is a versatile metal that is found in abundance in the earth’s crust and core. ![]()
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