Comparison of the beryllium films prepared by thermionic vacuum arc and thermal evaporation methods

Comparison of the beryllium films prepared by thermionic vacuum arc and thermal evaporation methods
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   Comparison of the beryllium films prepared by thermionic vacuum arc and thermal evaporation methods C. P. Lungu 1 , I. Mustata 1 , V. Zaroschi 1 , A. M. Lungu 1 , P. Chiru 1 , A. Anghel 1 , C. Porosnicu 1 , I. Jepu 1 ,V. Bailescu 2 , G. Burcea 2 , G. Dinuta 2 , . Din 2 , !. Balan 2 , G. "er#an 2 1  National Institute for Lasers, Plasma and Radiation Physics, Bucharest, Romania 2  Nuclear Fuel Plant, Pitesti, Romania 1.Introduction $he I$%&'li(e )all Pro*ect, part o+ the J%$ progra--e in support o+ I$%& 1'1/0, to #e i-ple-ente on J%$ in'clues &D acti3ities to e3elop a -etho o+ epositing Be la4ers on inconel an an interla4er plus a Be o3erla4 onto Be tiles an characteri5ation o+ the Be coating purit4  #4 sur+ace an structure anal4sis techni6ues as 7ell.$her-ionic 3acuu- arc 8$VA9 eposition process has  #een chosen in orer to o#tain high ensit4 o+ the +il-s :'110 +or the prouction o+ the ;-ar(er< tiles. $he ;-ar(er< is a Be tile 7ith a stripe o+ 2'= >- in thic(ness o+ an easil4 etecte hea34 -etal 8e.g. ), &e, !i9 eposit'e on it as an interla4er, an 7ith a +e7 -icrons 8? @': >-9 la4er o+ #ul('li(e Be on top o+ that. I+ the outer la4er is eroe at the sa-e rate as the #ul(, then the erosion rate can #e eter-ine #4 etecting the thic(ness o+ the la4er +ro- the +inal sur+ace, +or erosion o+ less than the +il- thic(ness. $o ena#le -easure-ent o+ erosion greater than :, >- there 7ill #e notches 81/ an 2/ >- eep9 on the tiles. $he -a*or e++ort in &D is to prouce high'purit4 la4ers 7ith opti-ise co-position, an to select the #est inter'la4er -aterial to ensure goo ahesion an ther-o'-e'chanical co-pati#ilit4. $he opti-isation o+ the -anu+ac'turing process 8la4er thic(ness, structure an purit49 has  #een carrie out on 3arious su#strates glass, silicon, -et'als. $he opti-ise -ar(er la4ers +or +urther testing 8in'cluing per+or-ance uner high'heat loas9 7ere eposit'e on = c- thic( Be #loc(s o+ J%$ an I$%& rele3ant 6ualit4 8" grae +ro- Brush )ell-an9. 2.Preparation methods $7o -ethos o+ Be eposition ha3e #een use to prouce test sa-ples stanar ther-al e3aporation in 3acuu- an $her-ionic Vacuu- Arc 8$VA9 techni6ue 1'20. $he lat'ter one has #een selecte to prepare @ >- thic( +il-s on the ;s-art<-ar(er tiles an the +or-er one to prouce Be +il-s on inconel tiles. ig.1 "et'up +or #er4lliu- eposition using ther-ionic 3acuu- arc -etho.  $VA is #ase on the electron #ea-'inuce e3aporation, as sho7n in the sche-atic ig.1. A tungsten hot athoe +ila-ent surroune #4 a )ehnelt c4liner is heate #4 an eEternal lo7 3oltage'high current ac suppl4. $her-o'elec'trons e-itte +ro- the tungsten +ila-ent are accelerate to7ars the anoe. Figh e3aporation rate o+ the anoe -aterial leas to high 3apor ensit4 in +ront o+ the anoe. $he space ensit4 o+ these particles is high enough to lo7er the ioni5ation -ean +ree path -a(ing it s-aller than the cathoe  anoe istance. As a result, plas-a is ignite in that region 7hile the surrouning space is e3ac'uate to #elo7 1/ '= Pa. Hner these conitions high purit4 +il-s o+ the anoe -aterial can #e reprouce 7ithout re'uction or -oi+ication.$he coatings o+ inconel tiles 7ere per+or-e using the 3acuu- ther-al e3aporation e6uip-ent o+ the !uclear ig.2 "et'up +or #er4lliu- eposition using ther-al e3apo'ration -etho in 3acuu-. uel Plant 8!P9 in Pitesti. $he sur+ace o+ the sa-ples 7as prepare #e+ore eposition #4 the stanar san  #lasting proceure use #4 the !P. $he sche-atic ar'range-ent use +or #er4lliu- eposition #4 3acuu- ther'-al e3aporation -etho is sche-aticall4 sho7n in ig. 2. $he e3aporation cruci#le 7as #er4lliu- oEie an the heating co-ponent 7as a -ol4#enu- 7ire o+ = -- i'a-eter 7oune aroun the e3aporating cruci#le. 3.Film structure I-ages in ig. = an ig.  sho7 the structure o+ #er4lli'u- la4ers eposite #4 t7o techni6ues $VA an ther-al e3aporation, respecto3ell4. %3aporate +il-s 7ere pre' pare using the +acilities at the !uclear uel actor4 in Pitesti, &o-ania. It is notice that +il-s o#taine #4 $VA are -uch s-oother than e3aporate la4ers. 'ra4 i++rac'tion stuies ha3e also pro3en highl4 orere cr4stalline structure o+ $VA'prouce +il-s. ig.= "%M i-age o+ Be +il- prepare #4 $VA -ethoig.  "%M i-age o+ Be +il- prepare #4 ther-al e3aporation -etho  During epositions, a 6uart5 cr4stal -onitor 7as use to -easure ;in situ< the thic(ness o+ the eposite la4er #4 $VA -etho. In orer to -easure thic(nesses larger than 1 K - 8the upper li-it o+ the 6uart5 sensor9 a coole hol'er 7as esigne an #uilt ha3ing in the +ront o+ the sensor 7ino7 a isc 7ith a 1/ -- ia-eter hole. An electrical -otor 7or(ing in 3acuu- ro3e the isc 7ith 1// rp-, ensuring a +actor o+ =/ #et7een the real thic(ness eposit'e on sa-ples an the thic(ness -easure #4 the thic('ness -onitor. A+ter eposition, the thic(ness o+ the la4ers 7as -easure on the 7itness sa-ples using a st4lus pro'+iler. "teps 7ere prouce #4 -as(s on the 7itness sur'+ace or #4 che-icall4 etching a ri# in the centre o+ the sa-ple. Be +il-s thic(nesses 7ere in the range o+ . K /. K -.Ato-ic orce Microscop4 8AM9 -easure-ents, in tap'ing -oe, ha3e pro3e the s-oothness o+ the eposite +il-s 7ith pea( to 3alle4 roughness in the range o+ =// ±  / n- +or Be coatings 8ig. 9. ig.  AM i-age o+ a t4pical Be coating on stainless steel. $he cr4stalline structure o+ the eposite +il-s 7as con'+ir-e #4 'ra4 Di++raction 8&D9 anal4sis. ig.  sho7s the &D pattern o+ the Be coatings on silicon 7a+er 7ith high intensit4 an sharpness o+ the Be pea(s. $he sur+ace +il- co-position anal45e using an PFI'Per(in %l-er -oel =/1 Auger spectro-eter 8inetic energ4 rangeN /'=2// eV, resolutionN /.O9 sho7e less than 12 O oE4'gen an car#on inclusion into the thin outer-ost la4er. A t4pical Auger spectrogra- is sho7n in ig.  gi3ing the , C an Be concentration. $he +eature aroun 21 eV correspons to the Ar i-plante #4 the ion gun use +or sur+ace etching prior to the Auger -easure-ent.ig.  &D pattern o+ the #e +il- coate on "i 81119ig  Auger -easure-ents o+ Be +il-.$he Be coating sa-ples 7ere eEpose to step7ise'in'crease ther-al loas +ro- . MJ-2 to 2/ MJ- 2  8/. M)- 2  to 2. M)- 2 9. $he tests 7ere one at the start'ing te-perature t4picall4 #elo7 1// QC. $he -aEi-u- sur+ace te-perature rose up to aroun // ? @// QC. $he 20 40 60 80 10020406080100    B  e   (   1   0   1   )   B  e   (   0   0   2   )   B  e   (   1   0   0   )   S   i   (   1   1   1   )     X   R   D    I  n   t  e  n  s   i   t  y ,  c  o  u  n   t  s 2 θ  te-perature istri#ution 7as +airl4 ho-ogeneous at the loae area an no local o3erheating 7as o#ser3e #4 the I&'ca-era. $he oEiation o+ the coating sur+ace 7as o#'ser3e as nano'scale sur+ace roughening o+ the platelets, sho7ing the potential +unction o+ Be la4er as an oE4gen getter. 4. Conclusions It has #een pro3e that the $VA an ther-al e3aporation -ethos are applica#le +or Be eposition #ecause the4 are clean -ethos o+ eposition in high 3acuu- conitions. $he -ean eposition rates 7ere  R /. n-s +or Be epo'sition using $VA -etho an a#out 1 R /. n-s +or Be eposition #4 ther-al e3aporation in 3acuu-.$he results o#taine +ro- the -easure-ents -ae on the Be +il-s pro3e that the structures present'"-ooth sur+aces'Figh ensit4'Figh purit4 o+ the +il-s 'Goo ahesion o+ the +il-s to the su#strate.'Goo resistance to ther-al tests. References 10 $. Firai, . %5ato, P. Ma*erus, Materials $ransactions,  82//9 12'2.20 F. Maier, Materials "cience oru- ': 82//9 1='1=@2.=0 F. Maier, &. !eu, F. Greuner, Ch. Fop+, G. . Mat'the7s, G. Pia55a, $. Firai, G. Counsell, . Courtois, &. Mitteau, %. Gauthier, J. Lin(onen, G. Maaluno, V. Phil'ipps, B. &iccari, C. &uset, %DA'J%$ $ea-, ;$ungsten coatings +or the J%$ I$%&'li(e )all Pro*ect<, presente at 1th P"I con+erence, Fe+ei China, Ma4 2//.0 F. Greuner, F. Bolt, B. BSs7irth, $. ran(e, P. Mc!eel4, ". #er-a4er, !. &ust, &. "TU, usion %ng. Des. ': 82//9 ==/. 0 F. Maier, J. Luthin, M. Baen, J.Lin(e, .och, F. Bolt, "ur+ace an Coatings $echnolog4 P. Ma*erus, $. Firai, J. Lin(e, ). Thnlein, M. &Sig, &. Du7e, usion Design an %ng. ': 82//9 ='=:.0 M. &u#el, J.P. Coa, . "tenstrS-, P. )ienhol, J. Li(onen, G.. Matthe7s,V. Philipps, 3er3ie7 o+ tracer techni6ues in stuies o+ -aterial erosion, re'eposition an +uel in3entor4 in to(a-a(s, J. !ucl. Mater.=2:'=== 82//9 :'::.0 J.P. Coa, J. Li(onen, M. &u#el, %. Vainone'Ahlgren, D.%. Fole, $. "a*a3aara, $. &en3all, G.. Matthe7s, 3er'3ie7 o+ -aterial re'eposition an +uel retention stuies at J%$ 7ith the Gas BoE i3ertor, !ucl. usion  82//9 =/'=.@0 . "ch-i, M.J. Bal7in, &.P. Doerner, In+luence o+  #er4lliu- plas-a seeing on the erosion o+ car#on, J.  !ucl. Mater. =='==: 82//9 @2'@. :0  C. P. Lungu, I. Mustata, G. Musa, A. M. Lungu, V. Zaroschi, . I7asa(i, &. $ana(a, . Matsu-ura, I. I7ana'ga, F. $ana(a, $. i, . u*ita "ur+. an Coat. $echn., 200  82//9 =::. 1/0  C. P. Lungu, I. Mustata, V. Zaroschi, A. M. Lungu, P. Chiru, A. Anghel, G. Burcea, V. Bailescu, G. Dinuta, . Din, JAM,   82//9 @@.110 C P Lungu, I Mustata, V Zaroschi, A M Lungu, A Anghel, P Chiru, M. &u#el, P. Coa, G  Matthe7s an J%$'%DA contri#utors,  P   HYS  . S  R . 2// !12"  1
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