Getter Materials http://vacaero.com/information-resources/the-heat-t... HOME COMPANY VACUUM FURNACES THERMAL PROCESSING COATINGS SERVICE & SUPPORT RESOURCES VAC AERO News, Education & Getter Materials Training Vacuum Tec$no%ogy with The Heat By Dan Herring Treat 'octor Experience has shown us that sensitive materials in the presence of minute q Biog!a)$y - 'an He!ring contaminates can destroy the integrity and shorten the life expectance of componen Vacuum B!azi g with 'an Kay what can be done to further protect the work in a vacuum environment after the reducing the chamber pressure to as low as is economically feasible in a producti Meta%lography with George Vande! on getter materials. Voort What is a etter? Practica% Vacuum Pu#) Practice A "ette! is sim)%& a reactive mate!ial that is deliberately placed inside a vacuu# syste# with Dan Herrin" e2ficie cy o2 t$at 0acuum 1& scave "in" unwanted contaminates. Essentia%%y, when "as # Vacuum Pump Practice wit$ the& co#1ine with it chemica%%& o! 1& adsorptio so as to 1e !emoved fro# t$e e vir Howard Tring eliminates eve #inute amou ts of unwanted "ases f!om the evacuated space3 Q's and A's Getter materials 2a%% into three 1road categories: bu%5 "etters, coatin" "ette!s a d flash fro# simple foils, wraps and sta#)ed forms to #achined turni "s )laced in and arou /$at's Hot Newslette! a))lied to the surface i the fo!# of coatings o! placed in t$e gas st!eam in the for# of pe% Glossa!y Metallurgical Terms furnaces whethe! "!ap$ite o! meta%%ic (e3"3 mo%&1denu# and/o! stainless stee% shield especial%& important when )!ocessin" !eactive metals such as titaniu# o! tantalu# and i tubes, cathode !ay tubes and the %ike3 The sophistication of t$e getter is in direct relation to etter "roperties The action o2 a getter material depends o 4 Adso!)tion (i.e3 accumulation of "as molecules at t$e surface89 Abso!)tion (i.e3 di2fusion of "as molecules in the solid89 Chemical binding (i3e3 reaction with t$e surface atoms). A "ette! materia% is desi" ed to react with t$e gas species )!esent, thus creati " a chemical reactio 3 Typica% "ases )resent in vacuu# systems are carbo #onoxide (CO), carbo dioxide (CO;8, itroge 6N $ydrogen (H;8, and wate! vapo! (H;O83 Most metal surfaces have a )rotective oxide o them, which under vacuum and at hig$ te#)erature must dissolve and diffuse into t$e getter materia% 1efore it can be e2fective3 Thus a "etter #ateria% must also $ave the ability to allow diffusion of co taminati " "ases once t$ey have 1een abso!1ed3 1 of 4 05/10/2016 05:26 PM Getter Materials http://vacaero.com/information-resources/the-heat-t... Getters bind "ases on their surfaces. Thus, the "!eater t$e surface /pecialists in 0acuum Furnace Technology 1 Manufacturers of Quality 0acuum Furnaces #$%"&'( )*+NACE THERMAL PROCESS-' #$&,-' / VAC AERO Products & %&'*)&#,*+-' Heat Treatin" Quebec - Coati gs Divisio Services Horizontal Furnace Specs Ontario - Plant No.< Po%and - Plant 1 G? Years at a Glance Ve!tica% Furnace Specs Ontario - Plant No.; Po%and - Plant 2 Certificates & Approvals Hot Jones Quebec - Thermal Processi " HVOF Spray System Va%ues & Commitment Control Syste#s Division Specific Coati g A))!ovals Corpo!ate Sponsorship Custo# Vacuum Furnaces Po%and - Plant 1 Meta%lu!"ica% Services Mat!ix Corpo!ate B!ochu!e Fluoride Ion Cleani " Po%and - Plant 2 Terms & Conditions of Use Quality Cont!o% Privacy Policy Se!vice and Su))ort Furnace Request fo! Quote (RFQ) Form Al% content is copyright © 2016 by VACAERO International Inc. A%% ri"hts reserved3 Table 1 [1] Getter Capacity of Common Materials <?<@ particles (i3e3 6.7 x 10<@ hydrogen molecules or 1.34 x 1?<E hydrogen atoms)3 These <?<E titanium ato#s so that each titanium atom in the getter corresponds to 6ap)roximatel& The chemical !eactions 6in si#)li2ied for#8 are as follow 6here GM re)!esents t$e getter m 6<8 2GM F O; → 2GMO 6;8 2GM F N; → 2GMN 6C8 2GM F CO → GMC + GMO 6D8 2GM F CO; → CO + 2GMO;GMO → GMC F+ GMO 6G8 GM F H;O → H + GMO → GMO + H (bu%58 6A8 GM F H; → GMH + H 6bu%5861ulk) 6B8 GM F C:H& → GMC F+ H (bul586bu%58 6@8 GM F Inert Gas (He, Ne, Ar, ,r, Xe) → No reaction!eaction Getter capacity is a22ected by temperature since di2fusion rates of the su!2ace-bound gas a material increase wit$ te#)erature3 This he%)s keep the getter sur2ace active continuously "ases that 1ind only to t$e surface due to chemical reactions. Adsorption also continues fo saturation83 Titanium can be used as an effective getter material when !unni " titanium )arts in vacuum surfaces clean (i3e. to avoid oxidatio and discoloration) du!ing annealing at a te#)erature <D??IF) ra "e, tita ium scrap (o2ten in the fo!# of clean, dry machine tu! ings) is co##o 2 of 4 05/10/2016 05:26 PM Getter Materials http://vacaero.com/information-resources/the-heat-t... Non-Evaporative etters No *eva)orable "etters $ave 1eco#e an integ!al part of many ult!ahigh vacuum environ# surface )rope!ties which are conducive to achieving extremely hi"$ vacuum conditions (i or lower). Binary, te! ary and multico#)onent alloys 2!om G!oup IV and G!oup V 6vanadiu are #ost often used3 These "enerally consist o2 a film of a special alloy, often zirconium ba alloy #aterials must form a )assivation layer at room te#)erature which disappears whe $ave ames of t$e form St (Stabil) followed by a umbe!4 St 7?B * a 70M zirconium, 243AM vanadium balance iro allo&9 St 7@B * a 803@M zirconium, 1D3;M cobalt 1alance mischmetal a%%oy; St 1?< * a 84M zirconium and <AM aluminu# In tubes used in elect!onics, t$e getter material coats plates wit$in the tube which are heat "etters are used within more general vacuum systems, such as in se#iconductor #anufac separate )ieces o2 equi)#ent in t$e vacuum cha#1er, and tu! ed on when needed3 Final Thoughts For heat t!eaters, getters are o2ten conside!ed a %ast resort to he%) keep )arts N1ri"$t and c important !ole in successful vacuum )rocessi " of #any $ig$%y so)$isticated products and do a better job o2 understanding t$eir role; $ow and where t$ey can $e%)3 “The Heat Treat Doctor” 5 6786 The HE++-' +$*" 9 : Inc. dherring (at) heat-treat-doctor.com Dan He!!ing is preside t of THE HERRING GROUP Inc., which specializes in consulti " s metallur"&8 and technical services 6industrial education/t!aini " and process/equipment as associate professor at t$e Illinois Institute o2 Technology/Thermal Processin" Technology References <3 Jouste , Ka!l, Ha dbook o2 Vacuum Technology, Wile&*VCH, 2??@3 ;3 Kohl, /alter Heinrich, Handbook of Materials and Techniques for Vacuum 'evices, <EAB C3 Danielson, Phil, A Journal of Practical and Useful Vacuum Technology, The Vacuum La1 D3 Wikipedia 6www3wikipedia.co#8 Share this post 3 of 4 05/10/2016 05:26 PM Getter Materials http://vacaero.com/information-resources/the-heat-t... 4 of 4 05/10/2016 05:26 PM.