Bright Sword starts with the grenade flat.

Chapter 508: The Metal Bond Missing from Nanorobots
The materials that nanorobots are made of are different from ordinary materials. After the nanorobots form the iron armor, although they look like a whole, in fact, you don’t need a microscope to see them. You only need a magnifying glass to see the tiny nanorobots.

After all, although nanorobots are called nanorobots, this does not mean that every nanorobot has reached one nanometer.

Rather, it means that it has broken through one micron and reached more than 900 nanometers.

Of course, whether it is one micron or more than 900 nanometers, it cannot change the fact that the connection between nanorobots is far less strong than the metal bonds that directly connect the metals.

After all, the connection between the nanorobots is based on the movable hooks and latches on the nanorobots. When needed, they will hook together with the surrounding robots. When not needed, the hooks and latches of the nanorobots will be released. Because of this, the atomic binding force of the hooks and latches of the nanorobots is not as strong as that of metal bonds.

You should know that metallic bond is a type of chemical bond, which mainly exists in metals. Although metals and alloys are mainly combined in the form of metallic bonds, there may also be situations where metallic bonds are mixed with covalent bonds or ionic bonds.

It is composed of the electrostatic attraction between free electrons and metal ions arranged in a lattice. Metallic bonds have many characteristics of metals. For example, the melting point and boiling point of general metals increase with the strength of the metal bond. Its strength is usually inversely correlated with the radius of the metal ion and positively correlated with the free electron density inside the metal.

Of course, metallic bonds naturally have many advantages. For example, metal crystals are full of free electrons, and the movement of free electrons has no definite direction. However, under the condition of an external electric field, the free electrons will move in a directed manner, thus forming an electric current, so metals are easy to conduct electricity.

However, in addition to good conductivity, metal bonds also have the following characteristics: when the metal is subjected to external force, the atomic layers in the crystal will slide relative to each other, but the original arrangement will not change. The electron gas diffused between the metal atoms can play a role similar to that of a lubricant between the ball bearings.

Therefore, after relative sliding occurs between the atomic layers, this interaction can still be maintained, so even under the action of external force, it is not easy to break even if deformation occurs. Therefore, metals have good ductility.

Of course, the band theory of metallic bonds uses the viewpoint of quantum mechanics to explain the formation of metallic bonds. Therefore, the band theory is also called the quantum mechanics model of metallic bonds, which has five basic viewpoints:

First, in order for the minority valence electrons of metal atoms to meet the needs of high coordination numbers, the valence electrons must be "delocalized" during bonding, that is, they no longer belong to any specific atom, and all valence electrons should be shared by the atoms of the entire metal lattice.

The second point is that the atoms in the metal lattice are very dense and can form many molecular orbitals, and the energy difference between adjacent molecular orbitals is very small. It can be considered that the energy changes between energy levels are basically continuous.

The energy band formed by the third-point molecular orbital can also be regarded as the overlap of the electronic energy levels of tightly packed metal atoms. This energy band belongs to the entire metal crystal. For example, the 1S energy levels of lithium atoms in metallic lithium overlap to form the 1S energy band in the metal lattice, and so on. Each energy band can include many similar energy levels, so each energy band will include a fairly large energy range, sometimes up to 418 kJ/mol.

Fourthly, according to the different atomic orbital energy levels, metal crystals can have different energy bands. The low-energy energy band formed by the atomic orbital energy levels that are full of electrons is called the "full band"; the high-energy energy band formed by the atomic orbital energy levels that are not full of electrons is called the "conduction band".

Fifth, adjacent energy bands in metals can also overlap with each other. For example, the 2s orbit of beryllium is already full of electrons, so the 2s energy band should be a full band, and it seems that beryllium should be a non-conductor. However, because the energy of the 2s energy band of beryllium and the empty 2p energy band are very close and can overlap, the electrons in the 2s energy band can be upgraded to move in the 2p energy band, so beryllium is still a metal with good conductivity and has the general properties of metals. Therefore, according to the viewpoint of energy band theory, the energy difference between metal energy bands and the state of electron filling in the energy bands determine whether the substance is a conductor, non-conductor or semiconductor, which is actually called metal, non-metal or metalloid.

Therefore, if all the energy bands of a substance are full or the highest energy band is completely empty, and the energy gap between the energy bands is large, the substance will be a non-conductor; if the energy bands of a substance are partially filled with electrons, or there are empty energy bands and the energy gap is very small, and can overlap with adjacent energy bands with electrons, it is a conductor.

The energy band structure of a semiconductor is that the full band is filled with electrons, the conduction band is empty, and the width of the band gap is very narrow. Under normal circumstances, since the electrons in the full band cannot enter the conduction band, the crystal is not conductive.

Because the band gap is very narrow, under certain conditions, the electrons in the full band can easily jump to the conduction band, filling the originally empty conduction band with some electrons, while leaving vacancies in the full band. Therefore, neither the conduction band nor the original full band is filled with electrons, so it can conduct electricity.

The band theory can also well explain the common physical properties of metals. When an external electric field is applied to a metal, the electrons in the conduction band will jump to a higher energy level within the band and move through the lattice along the direction of the external electric field, which explains the conductivity of the metal.

Electrons in the energy band can absorb light energy and emit the absorbed energy again, which explains the luster of metals and the fact that metals are excellent reflectors of radiation energy. Electrons can also transmit heat energy, indicating that metals have thermal conductivity.

When stress is applied to metal crystals, since the electrons in the metal are delocalized, the metal bond in one place is destroyed and a metal bond can be formed in another place. Therefore, mechanical processing will not destroy the metal structure, but can only change the metal's appearance. This is why metals have common mechanical processing properties such as ductility, malleability, and plasticity. The more unpaired valence electrons metal atoms provide to form energy bands, the stronger the metal bond, and the higher the melting point and boiling point in physical properties, and the greater the density and hardness.

Of course, because of this, the materials composed of nanorobots that are not connected by metal bonds and only rely on simple movable mechanical connections naturally cannot meet the hardness and strength standards. Not only that, but a large part of the original metal's strength will be lost.

However, it can be seen from Iron Man's later series of armors that compared to the solid armor shell, Tony still prefers nano armor that can adapt to a variety of environments.

After all, after Tony's energy shield was created, the strength requirements for the armor material were not that high.

However, after Liu Xiu acquired the vest armor, his need for the nano armor was not so urgent.

What Liu Xiu didn't expect was that after Millie saw Kane flying in a vest-style armor, she actually wanted a set of such armor in her heart. Unfortunately, Liu Xiu ran away without giving Millie a chance to speak.

(End of this chapter)