The mobile phone is an essential accessory for modern people, but how much do you know about it? Let’s take a look at how many things are hidden in a mobile phone.
Many kinds of common metals
Picking up the phone, the first thing you see is the boxy shell. At present, most smartphones are designed with all-metal casings, and most of their processing materials are aluminum-magnesium alloys. Even if the body is made of plastic, metal elements such as bromine and nickel will be mixed into the casing. The metal casing not only looks more high-end, but also has improved strength, which can better protect the internal structure of the phone. More importantly, the metal shell can reduce electromagnetic interference, keep the signal stable, and better realize the communication function.
Open the back cover, the most obvious is a square battery, the battery also contains many metal elements. At present, the most mainstream mobile phone battery is a lithium battery, which uses lithium cobalt oxide as the positive electrode and graphite as the negative electrode, and the electrodes are filled with electrolyte. Electrons move back and forth in the electrolyte, so that the function of repeated charging and discharging can be realized. In addition, the raw material used in the battery shell is metallic aluminum. The strength of aluminum is relatively high, which is close to or exceeds that of high-quality steel, but its plasticity is much better than that of steel. With the same strength, the aluminum shell can be made thinner. Moreover, the volume of the battery changes during charging and discharging. When charging, lithium ions flow to the positive electrode, and the volume of the positive electrode expands; during discharge, lithium ions are inserted into the negative electrode from the positive electrode, and the negative electrode expands. The aluminum shell with good plasticity can better adapt to the volume change of the battery. .
Above the battery is the motherboard, which is the most expensive part of the entire mobile phone and the part that contains the most metal elements. Tin and lead are the two most abundant metals on motherboards, and they are often used for soldering between components on integrated circuit boards. Tin-lead alloy is a high-quality and cheap soldering material. The strength, hardness and corrosion resistance of the alloy are much better than pure metal. Even if some parts of the circuit board are faulty, the tin-lead alloy at the connection is still strong. However, due to the toxicity of lead, tin-lead alloys have been gradually replaced by alloys composed of tin, silver and copper in recent years.
The main component of the motherboard is the chip, and many metals are also used in the chip. Chips are micro-integrated circuits that contain many electronic components such as resistors, capacitors, and inductors. The conductive paths between these components are made of copper. In addition to copper, other metals or compounds are deposited on the chip, such as tin-copper or tin-gold alloy. This is to surround and protect the chip and ensure that the function of its internal sensitive sensors is not affected.
The material used in the mobile phone vibrator is tungsten. Because the vibrator needs to rotate and vibrate at a high speed when the mobile phone sounds, tungsten with better hardness and wear resistance has become the first choice for vibrators. The important components of the handset of the mobile phone are made of iron, and the iron sheet vibrates under the action of a magnetic field to transmit the sound to the other end of the mobile phone. In addition, nickel is used in mobile phone microphones, zirconium is used in fingerprint buttons, etc. In many details of mobile phones, various metals are also hidden.
There are so many precious metals
In addition to common metals, those precious metals we know well, such as gold, silver, copper, and platinum, can also be seen everywhere in mobile phones.
Many components of mobile phone motherboards contain gold. Gold is a good conductor of electricity, and its stability is very good, and it almost never rusts. Gold is also very malleable. 1 gram of gold can pull out 300 meters of filaments that are thinner than hair. These characteristics make gold popular in electrical products that pursue miniaturization, such as mobile phones and computers. Motherboard circuits, chips, interfaces and sockets, processor sockets and other circuit connections are often covered with a gold layer of a few microns thick, which fully guarantees the transmission of current.
Compared with gold, the price of copper is much cheaper, and the conductivity of copper is not bad. Therefore, in some circuits with lower requirements for corrosion performance, copper is the more commonly used wire material. In addition, copper can be alloyed with many metals such as zinc, tin, nickel, and silver, and can be used in different parts of mobile phones according to their electrical conductivity, corrosion resistance, and ductility. Similarly, silver, which is cheaper than gold and has the same electrical conductivity, is often used in the energized parts of mobile phones.
Platinum has high chemical stability and a high melting point. It is often used to make corrosion-resistant electronic components. For example, in mobile phone chips, the interfaces with special requirements need to be made of platinum. In addition, the alloy formed by platinum and cobalt has strong magnetism and high magnetic stability. It can also be used in the sound transmission process of mobile phone receivers and microphones.
Enriched rare metals
Rare metals refer to metals that are not high in nature, such as indium group elements, rare earth metals, etc., but in mobile phones, the content of these elements can be quite large.
There are many rare metal elements in mobile phone screens. Our common smart phone screen is composed of multiple layers of glass and electronic components. The main component of electronic components is the indium group element, such as tin-doped indium oxide, which is a mixture of indium oxide and tin oxide. With the addition of this substance, the screen can convert the touch action of the human hand into an electric current, thereby responding to people’s requirements. In addition, rare earth metal elements, such as lanthanum, terbium, praseodymium, europium, etc., are used to develop color on mobile phone screens. These rare earth metal ions can emit colorful light when excited by energy, so they are used on mobile phone screens. There are also some rare earth elements that can block ultraviolet rays from entering the mobile phone.
In addition to screens, rare earth elements are also used in other parts of mobile phones. Neodymium iron boron magnets composed of rare earth element neodymium have strong magnetism and are used in the electro-acoustic part of mobile phones, imaging systems and parts of measurement and control devices. The mobile phone camera uses optical glass containing the rare earth element lanthanum, which has the characteristics of high refractive index and low dispersion, which can effectively expand the field of view of the lens and improve the image quality. There are also a series of rare earth elements used in various parts of mobile phones, such as praseodymium, gadolinium, and neodymium alloys for microphones and loudspeakers, and neodymium, terbium, and dysprosium for vibration units.
Rare metal tantalum is the main component material of microcapacitors. Electrolytic capacitors made of tantalum have the advantages of large capacity, small size and good reliability. They have the functions of storing electricity and charging and discharging. They are indispensable accessories for all kinds of electronic equipment. Tantalum is also a material for making parts such as electron emission tubes and high-power electron tubes, which together constitute the main board of the mobile phone.
Now, do you know more about mobile phones? A variety of metals are used in the manufacture of mobile phones, some of which have much higher content than metal ores of the same weight. They are all non-renewable resources, so mobile phones are very precious. Cherish and take good care of mobile phones, extend the useful life of mobile phones, and recycle old mobile phones, which can make the lifespan of mobile phones on the earth longer.