Editing Refractory metals (section)

{{Short description|Heat- and wear-resistant metals}}
{{Use dmy dates|date=March 2023}}
{| style="float:right; margin:0 0 0.5em 0.5em; border:1px solid {{Element color|table border}};"
! H|| colspan="17" |&nbsp; ||He
|-
!Li||Be|| colspan="11" |&nbsp; ||B ||C ||N ||O ||F ||Ne
|-
! |Na||Mg|| colspan="11" |&nbsp; ||Al||Si||P ||S ||Cl||Ar
|-
! |K ||Ca|| ||Sc|| style="background-color:#A6FFE1;"|[[Titanium|Ti]]||style="background-color:#A6FFE1;"|[[Vanadium|V]] ||style="background-color:#A6FFE1;"|[[Chromium|Cr]]||Mn||Fe||Co||Ni||Cu||Zn||Ga||Ge||As||Se||Br||Kr
|-
!|Rb||Sr||||Y|| style="background-color:#A6FFE1;" |[[Zirconium|Zr]]||style="background-color:#FFB866;"|[[Niobium|Nb]]||style="background-color:#FFB866;"|[[Molybdenum|Mo]]||[[Technetium|Tc]]||style="background-color:#A6FFE1;"|[[Ruthenium|Ru]]||style="background-color:#A6FFE1;"|[[Rhodium|Rh]]||Pd||Ag||Cd||In||Sn||Sb||Te||I ||Xe
|-
!Cs||Ba||*||Lu||style="background-color:#A6FFE1;"|[[Hafnium|Hf]]||style="background-color:#FFB866;"|[[Tantalum|Ta]]||style="background-color:#FFB866;"|[[Tungsten|W]] ||style="background-color:#FFB866;"|[[Rhenium|Re]]||style="background-color:#A6FFE1;"|[[Osmium|Os]]||style="background-color:#A6FFE1;"|[[Iridium|Ir]]||Pt||Au||Hg||Tl||Pb||Bi||Po||At||Rn
|-
!Fr||Ra||**||Lr||Rf||Db||Sg||Bh||Hs||Mt||Ds||Rg||Cn||Nh||Fl||Mc||Lv||Ts||Og||
|-

| colspan="19" style="line-height:110%;" | &nbsp;
|-
! colspan="2"|&nbsp; || * ||La||Ce||Pr||Nd||Pm||Sm||Eu||Gd||Tb||Dy||Ho||Er||Tm||Yb|| ||
|-
! colspan="2"|&nbsp; || **||Ac||Th||Pa||U ||Np||Pu||Am||Cm||Bk||Cf||Es||Fm||Md||No|| ||
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| colspan=19 style="text-align:left;" | {{legend|#FFB866|Refractory metals}}
|-
| colspan=19 style="text-align:left;" | {{legend|#A6FFE1|Wider definition of refractory metals<ref>{{cite web | url = http://www.elsevier.com/wps/find/journaldescription.cws_home/405934/description#description | title = International Journal of Refractory Metals and Hard Materials | publisher = Elsevier| access-date = 2010-02-07}}</ref>}}
|}

'''Refractory metals''' are a class of [[metal]]s that are extraordinarily resistant to [[heat]] and [[wear]]. The expression is mostly used in the context of [[materials science]], [[metallurgy]] and [[engineering]]. The definitions of which elements belong to this group differ. The most common definition includes five elements: two of the [[Period 5 element|fifth period]] ([[niobium]] and [[molybdenum]]) and three of the [[Period 6 element|sixth period]] ([[tantalum]], [[tungsten]], and [[rhenium]]). They all share some properties, including a melting point above 2000&nbsp;°C and high [[hardness]] at room temperature. They are chemically inert and have a relatively high density. Their high melting points make [[powder metallurgy]] the method of choice for [[fabrication (metal)|fabricating]] components from these metals. Some of their applications include tools to work metals at high temperatures, wire filaments, casting molds, and chemical reaction vessels in corrosive environments. Partly due to their high melting points, refractory metals are stable against [[creep (deformation)|creep deformation]] to very high temperatures.