Hafnium Powder, Hf 

　　　　

Hafnium for silver gray metal, metallic luster; There are two variants of the hafnium 

metal: hafnium is a hexagonal dense packing variant (1750℃) with a higher transition 

temperature than zirconium. Hafnium metal has allotropic variants at high temperature. 

Hafnium metal has a high neutron absorption cross section and can be used as a 

control material for reactors.
The crystal structure can be divided into two types: hexagonal dense packing (-) when 

the temperature is below 1300℃; Above 1300℃, is the body center cubic (- formula). 

A plastic metal that becomes hard and brittle in the presence of impurities. Stable in 

the air, darkens only on the surface when burned. A filament can be ignited by the 

flame of a match. Zirconium like in nature. Not water, dilute acid or strong alkali action, 

but easy to dissolve in aqua aqua and hydrofluoric acid. It has a +4 valence in the 

compound. Hafnium alloy (Ta4HfC5) is known to have the highest melting point 

(about 4215℃).
Crystal structure: The cell is hexagonal

CAS no.	7440-58-6
Melting point	2 227℃
The boiling point	4602℃
The density of	13.31g/cm3(20℃)
Content in the Crust (PPM)	5.3
Elements in the sun :(parts per million)	0.001
Element content in seawater :(PPM)	0.000007
Mohs hardness	5.5
The rate at which sound travels (m/S)	3010
Quality of proton	1.20456E-25
Proton relative mass	72.504

Chemical properties
Hafnium is very similar to zirconium in chemical properties. It has good 

corrosion resistance and is not easy to be attacked by common acid base 

aqueous solution. It is easily soluble in hydrofluoric acid and forms a 

fluorinated complex. At high temperature, hafnium can also combine 

directly with gases such as oxygen and nitrogen to form oxides and nitrides.
USES:
Hafnium is useful because it emits electrons easily (eg as a filament for an 

incandescent lamp). Alloys of hafnium and tungsten or molybdenum are 

used as electrodes for high voltage discharge tubes. Commonly used in 

X-ray cathode and tungsten manufacturing industries. Pure hafnium has 

plasticity, easy to process, high temperature resistance and corrosion 

resistance, is an important material in atomic energy industry. Hafnium 

thermal neutron capture cross section is an ideal neutron absorber, which 

can be used as control rod and protection device in atomic reactor. 

Hafnium powder ACTS as a booster for rockets. Cathodes of X-ray tubes 

can be manufactured in the electrical industry. Hafnium alloys can be 

used as front guards for rocket nozzles and glider re-entry vehicles, 

and HF-TA alloys can be used to make tool steel and resistance materials. 

Hafnium is used as an additive element in heat resistant alloys, such as 

tungsten, molybdenum, and tantalum. HfC can be used as carbide additive 

due to its high hardness and melting point. The melting point of 4TaCHfC 

is about 4215℃, which is the highest known chemical compound. Hafnium 

is used as an getter in many aeration systems. Hafnium getter removes 

oxygen, nitrogen, etc. from the system without gases. Hafnium is often 

used as an additive in hydraulic oil to prevent the volatilization of hydraulic 

oil in high-risk operations, with a strong anti-volatilization, this characteristic, 

so generally used in industrial hydraulic oil. Medical hydraulic oil. Hafnium 

is also used in the latest intel45 nanometer processors.