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In nature, the most important nickel ore is red nickel ore (nickel arsenide) and alum-nickel ore (nickel sulfur arsenide).
Nickel is used extensively to make alloys. Adding nickel to steel can increase the mechanical strength. If the nickel content in the steel increases from 2.94% to 7.04%, the tensile strength increases from 52.2 kg/mm2 to 72.8 kg/mm3. Nickel steel is used to make parts that are subjected to high pressures, shocks, and reciprocating loads, such as turbine blades, crankshafts, and connecting rods. Nickel steel containing 36% nickel and 0.3-0.5% carbon, its expansion coefficient is very small, almost no thermal expansion and contraction, used to make a variety of precision machinery, precision gauges and so on. The high-nickel steel containing 46% nickel and 0.15% carbon is called “platinum-like†because its expansion coefficient is similar to that of platinum and glass. This high-nickel steel can be welded into glass. It is very important in the production of light bulbs and can be used as a substitute for platinum wire. Some precision lens frames are also made of this type of platinum steel, and the lens does not fall out of the box due to thermal expansion and contraction. An alloy composed of 67.5% nickel, 16% iron, 15% chromium, and 1.5% manganese has a large electrical resistance and is used to make various varistors and electric heaters.
Nickel is used extensively to make alloys. Adding nickel to steel can increase the mechanical strength. Very fine nickel powder, often used as a catalyst in the chemical industry.
Titanium-nickel alloys have the ability to "remember" and have a strong memory. After a long time, it is accurate to repeat tens of millions of times. Its "memory" ability is to remember its original shape, so people call it "shape memory alloy." It turns out that this kind of alloy has a characteristic transformation temperature. Above the transformation temperature, it has an organizational structure. Under the transition temperature, it has another organizational structure. Different structures, performance will be different. For example: a titanium-nickel memory alloy, when it is above the transition temperature, it is very hard, strong, and below this temperature, it is very soft, easy cold processing. In this way, when we need it to remember what shape it is made into that shape, this is its "permanent memory" shape. Below the transition temperature, because it is so soft, we can make it to a great extent. Its arbitrary deformation. When you need it to return to its original shape, simply heat it above the transition temperature.
Nickel is magnetic and can be attracted by magnets. The alloy made of aluminum, cobalt and nickel is more magnetic. When this alloy is attracted by an electromagnet, it will not only be sucked by itself, but also hangs something 60 times heavier than it will not fall off. In this way, it can be used to make electromagnetic cranes.
The nickel salts are mostly green. Nickel hydroxide is brownish black, and nickel oxide is grayish black. Nickel oxide is often used to make iron-nickel alkaline batteries.
Divalent nickel ions are usually identified by dimethyl oxime. In the ammonia solution, nickel ions (Ni2+) and dimethylglyoxime produce a bright red precipitate (Ni(dmgH)2).
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