Antimony ore

Element source: it exists in most zirconium mines

Element use: It is useful because it is easy to emit electrons (such as filaments used as incandescent lamps). The cathode ray tube as an X, hafnium and tungsten or molybdenum alloy as an electrode high pressure discharge tube. It can be used as a getter for many aeration systems. The getter removes unwanted gases such as oxygen, nitrogen, etc. present in the system.铪 is also used in nuclear reactor control rods.

Discovered by: D.Coster, G.Von Hevesy, Discovered: 1923

Discovery process:

It was discovered by X-ray spectroscopy in 1923 by Danish scientist D.Coster and Hungarian scientist G.Von Hevesy.

Element description:

There are two kinds of crystal structures: hexagonal close-packed (α-form) when it is below 1300 °C; body-centered cubic (β-form) when it is above 1300 °C. A plastic metal that is hard and brittle when impurities are present. It is stable in the air and only darkens on the surface when burning. The filaments can be ignited by the flame of a match. The nature is like zirconium Does not interact with water, dilute acid or strong alkali, but is easily dissolved in aqua regia and hydrofluoric acid. It is mainly +4 valence in the compound. Tantalum alloy (Ta4HfC5) is the material with the highest melting point (about 4215 ° C).

Element source:

The content in the earth's crust is small. Often coexisting with zirconium, no separate ore. It can be obtained by reduction of hafnium tetrachloride (HfCl 4 ) and sodium by heat.

Element use:

Often used as a cathode and tungsten wire manufacturing industry for X-rays. Because of its good absorption capacity for neutrons, it is often used as a control rod for nuclear reactors to slow down the rate of nuclear chain reactions while suppressing the "flame" of atomic reactions.

Used in the latest intel45 nano processor.

Elemental auxiliary materials:

After Mosley's X-ray study of the elements, it was determined that there should be 16 elements between the é’¡ and é’½. At this time, in addition to the elements No. 61 and No. 72, the other 14 elements have been discovered, and they belong to the lanthanide system that belongs to today, which is the rare earth element at that time.

Then element 72 should belong to rare earth elements? Or is it the same family as titanium and zirconium? Most chemists at the time advocated belonging to the former. After 1911, French chemist Urban isolated from ytterbium, lutetium oxide, and isolated a new element. In 1914, Urban went to England to send samples of this element to Mosley for X-ray spectroscopy. The conclusion was no, and no line equivalent to element 72 was found. Urban is convinced of the existence of new elements and believes that the result is that the newly developed machine is not sensitive enough to detect the presence of trace new elements in the sample. After returning to Paris, he used the X-ray spectrometer improved after the First World War with the spectrum scientist Davillier. In May 1922, they announced the detection of two X-ray lines, and concluded that new elements were present. In 1913, the Danish physicist Bohr proposed the quantum theory of atomic structure. Then, between 1921-1922, the theory of electron distribution outside the atom was proposed. Bohr believes that according to his theory, element 72 is not a rare earth element, but is a homogenous element like zirconium. That is to say, element 72 does not appear from rare earth minerals, but should be found in ores containing zirconium and titanium.

According to Bohr's inference, in 1922, the Hungarian chemist Hevisi and the Danish physicist Koster performed X-ray spectroscopy on various zirconium-containing ores, and this element was discovered. In order to commemorate the discovery of the element, the capital of Denmark, Copenhagen, named it hafnium, the element symbol is Hf. Later, Hevisi made a few milligrams of pure sputum samples.

Double Head Chamfering Machine

  1. Designed both inside and outside of the tube and rod end, chamfering and face milling can be done once a uniform, rapid and accurate.
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