Common Low Melting Alloys and Their Characteristics from as852128's blog

There is a wide range of low melting alloys available. Yet some are restricted in their use based on their brittleness, toxicity, and reactive qualities. Some of these elements are bismuth, gallium, tin, indium, zinc, cadmium, tellurium, antimony, thallium, mercury, and lead. Many of these minerals may also be additives placed during the formation of the low melting alloys. ;

Density Characteristics

One of the main reasons for using low melting alloys is due to how it changes when it melts and then solidify. Some alloys are eutectic and will become pure liquid instantly, while others are Non-Eutectic and will transition through a semi-liquid state that has a type of slushy texture before becoming liquids. Low melting alloys will also change in density when solidifying. Alloys such as bismuth and gallium will expand greatly when in their liquid state and then become dense when changing back into a solid.

Knowing the density of the alloy is important as the manufacturer needs to know how much it will shrink or expand. If the metal shrinks too much, it may not create the proper bond with other materials, or have the required strength it needs to withstand stresses. If it expands too much, it can become brittle when changing back into a solid as the alloy might fail during the operation of the product or equipment.

The varying densities of the alloys can also be important to manufacturers based on how they plan to use the alloy. For delicate jewelry, you may not want a material to expand too much as it could end up damaging the surrounding metal that needs to remain intact. You also need to pay attention to the elongation, strength, tensile modulus, and yield strength of the alloy during the manufacturing process.

Bismuth-based: Bismuth alloys will have a composition that is less of a ductile characteristic than tin, as it can become brittle. Manufacturers use bismuth due to its expansion qualities when it melts and then solidifies as it can expand to up to 3.3%. The more bismuth is in an alloy, the more it expands. It is less expensive than other alloys that are featured and the least toxic as it can be used in applications where there is drinking water present. ;

Bismuth compounds account for about half the production of bismuth. They are used in cosmetics; pigments; and a few pharmaceuticals, notably bismuth subsalicylate, used to treat diarrhea. Bismuth's unusual propensity to expand as it solidifies is responsible for some of its uses, such as in the casting of printing type. Bismuth has unusually low toxicity for heavy metals. As the toxicity of lead has become more apparent in recent years, there is increasing use of bismuth alloys (presently about a third of bismuth production) as a replacement for lead.

A Brief Introduction To The Indium Alloy

Indium alloy is generally divided into binary alloys, ternary alloys, and multi-component alloys.

Generally, the melting temperature of indium alloy mainly composed of indium is relatively low, which is mainly used as some low melting point alloys or solders.

While some alloys have very little indium content, indium mainly plays a role in modification, such as improving the strength of non-ferrous metal alloys, improving their ductility, abrasion resistance, corrosion resistance, and changing the color of precious metals.

Classification Of The Indium Alloy

Generally, the indium alloy can be divided into 5 categories, which are bearing alloys, ferromagnetic alloys, memory alloys, decorative alloys, and dental and gemstone alloys. The following is a brief introduction to the 5 types of indium alloy:

1. Bearing Alloy

Bearing alloys are widely used in the aviation and automotive industries. The bearing alloys mainly used in the manufacture of high-speed engine bearings include silver-lead-indium alloy, lead-cadmium-indium alloy, cadmium silver-copper-indium, silver-thallium-indium alloy, lead-tin-indium alloy, copper-tin Indium alloy, lead tin antimony arsenic indium alloy.

2. Ferromagnetic Alloy

Ferromagnetic alloys are also called Heusler alloys. The most widely used ferromagnetic alloy is copper manganese indium alloy (Cu / Mn / In).

3. Memory Alloy

Indium thallium alloy (In / Tl) and indium cadmium alloy (In / Cd) are memory alloys, which belong to the new generation of alloys.

4. Decorative Alloy

The addition of indium to the gold-silver-palladium-copper alloy used for ornaments can improve the hardness and durability of the ornaments and increase their color of the ornaments. The commonly used Au75 / Ag20 / In5 alloy is commonly known as “green gold”.

5. Dental And Gemstone Alloy

Indium alloy is also used in dentistry and gemstones. Its composition is usually: gold 5 to 65% / palladium 2 to 30% / silver 10 to 15% / copper 10 to 15% / indium 0.5 to 5%.