CMCTeMa c HepacTBOpMMblMM (HeB38MMOAeMCTBYIOIQMMM) KOMnOHeHTaMM



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ЗНАЕТЕ ЛИ ВЫ?

CMCTeMa c HepacTBOpMMblMM (HeB38MMOAeMCTBYIOIQMMM) KOMnOHeHTaMM



 

 

IlpuMepaMH TaKHX cucTeM HBJIHIOTCH Cu-C, W-Ag, W-Cu, Mo-Cu H .n;pyrne. BJI. IluHec c<t>opMyJIHPOBaJI TepMOAHHaMHlJeCKoe

ycJIOBHe rrpHrreKaHHH .n;eyx lJaCTHU pa3HOpO,ll;HblX HeB3aHMO,LI,eHCTBYIO­ ll(HX KOMIIOHeHTOB:

(LAB< l a.A + a.B l ' (14.41)

T.e. IIOBepXHOCTHrul 3HeprnH o6pa30BaBIIIeHCH Me)l($a3HOH rpaHHUbl AB ,LI,OJI)l(Ha 6b Tb MeHbIIIe, t.1eM cyMMa rroeepxHoCTHb X 3HeprnH: qac­ THU A u B; B rrpoTHBHOM CJiyqae rropoIIIKoeoe reJio crreKaTbCH He


3 4


BO)l(,ll;aeTc» yeeJIHlJeHHeM ee o6'beMa Ha 22 % (e pacqere Ha 1 MOJib

Si3N4), H 3a ClJeT 3Toro npoHcxo.n;HT qacTHlJ:Hoe 3anoJIHeHHe rropoeo-

ro npocTpaHCTBa. IlJIOTHOCTb no-

poIIIKoeoro reJia. nocJie crreKaHIDI


6y,LI,eT.

MexaHH3M u KHHeTHKa npuneKaHH» oKa3bIBaIOTCH cymecTBeHHO pa3JIHlJHb MH ,ll,JIH ,ll,Byx B03MO)l(Hb X CJiyqaeB npH co6JIIO,LI,eHHH ycJIO­ BHH (14.41):


T, r-- .......a:

 


3aBHCHT OT HCXO,ll;HOH nopHCTOC­

TH $opMOBKH, $paKIJ,HOHHOro COCTaea nopoIIIKa KpeMHHH, TeM-

rrepaTYPHo-epeMeHHb'X ycJIOBHH


a. AB< I a.A - a.B l '

(1.AB> I(1.A - (1.B I .


(14.42)

 

(14.43)


 

1000 0 + (Mo)

 

 

v;V, %

6

 

 

PHc. 254. .[J;HarpaMMa COCTOHHIDI (a) H KOHUeHTpaUHOHHaH JaBHCHMOCTb yca,nKH

(6) nopoUIKOBhIX ren CHCTeMhI Ni-Mo IlpH 1200 'C

222


cneKaHIDI.

CeoH:cTBa MarepHaJIOB, o6pa- 30BaHHb X paccMaTpHBaeMblMH CHCTeMaMH KOMIIOHeHTOB nocJie

crreKaHHH, 3aBHCHT OT ueJioro pH,n;a $aKTopoe: IIOJIHOTblfOMO­ reHH3aIJ,HH B o6JiaCTH orpaHH­ lJeHHb X TBep,n;blX paCTBOpOB, rro­ pHCTOCTH, COBepIIIeHCTJ;Ja Me)l(­

$a3Hb X H O,ll;HO$a3Hb X KOHTaK­ TOB H .n;p. PoJib rerepo.n;H$$y3HH CBO,ll;HTCH K o6ecrrelJeHHIO Bb paB­ HHBaHIDI KOHUeHTpaIJ,HH 3JieMeH­

TOB B 06JiaCTHX orpaHHlJeHHOH paCTBOPHMOCTH, rrpHlJeM ,ll;OCTH­

)l(eHHe roMoreHHOCTH B 60Jib­ lllHHCTBe CJiyqaee )l(eJiaTeJibHO (rrpH rrpe.n;eJibHblX KOHUeHTpa­ UHHX MHOrne CBOHCTBa orpaHH-


B CJiyqae, KOr,LI,a BblIIOJIHHeTCH COOTHOIIIeHHe (14.42), 3HepreTH­

lJeCKH ueJiecoo6pa3HO IIOKpblTHe rroeepXHOCTH lJaCTHUhl eemecTBa c 6oJibllleH IIOBepXHOCTHOH 3Heprneu eemecTBOM c MeHbllleH rroeepx­ HOCTHOH 3Heprneu (pHc. 255). BHat.JaJie qacTHua TaKoro eemecrea (rrycTb

3TO 6y,LI,eT eemecTBo B) rroKpoeTCH cJioeM aroMoB BToporo eemecTBa (e HaIIIeM cJiyqae eemecTBa A) c rroMOll.lbIO MexaHH3Ma rroeepxHOCT­ HoH: AH$$y3HH HJIH rrepeHOCOM qepe3 ra30BYIO $a3y; rrpH 3TOM <t>op­

Ma HCXO,ll,Hb X t.JaCTHU coxpaHHeTCH. 3aTeM KOHTaKTHrul IIJIOll(a,ll;b Me)I(-

 

 

PHc. 255. CxeMaTw1ecKoe HJo6pa)l(eHHe 3Tanos (a - z) npHneKaHHSI 'laCTHU


.UY qacnu.1,eH: A H qacTuueH: B, noKphITOH CJIOeM BemecTBa A, yBeJIH­ quBaeTC.st, qTO conpOBO)l(,lJ,aeTC.SI yMeHbllleHHeM cyMMapHOH noBepx­ HOCTH B CHCTeMe A-B H, COOTBeTCTBeHHO, ee CB060,lJ,HOH 3HeprHH.

K1rneTHKa 3Toro 3Tana npuneKaHH.SI 6JIH3Ka K KHHeTHKe npuneKaHH.SI

,lJ,Byx 0,lJ,HOPO.ll.HhlX cct>epuqeCKHX qacTHU, XOT.SI BeIUeCTBO B o6JiaCTh npHKOHTaKTHOfO nepellleHKa 6y.n.eT nocrynaTb OT O,lJ,HOH nopolllHHKH

A, a He OT o6oux qacTHU A H B. CJIH.SIHHe cct>epuqecKHX qacTHU A u B

.UOJI)l(HO JaBeplllHThC.SI o6pa3oBaHHeM cct>epuqecKoro reJia, MPOM KO­ Toporo 6y.n.eT qacTHUa B.

Kor.n.a HH)l(ff.ff.SI rpaHHUa BeJIHqHHhIa.A8 Ja.n.aeTc.st ycJioBHeM (14.43)

(6oJiee pacnpocTpaHeHHhlH CJiyqaH: ,lJ,JI.SI npaKTHKH nopOlllKOBOH Me­

TaJIJIYPrHH), npuneKaHHe qacTHU cymecTBeHHO OTJIHqaeTC.SI OT pac­ CMOTpeHHOfO. Pacnpe.n.eJieHHe BeIUecTBa A H B B o6JiaCTH KOHTaKTHoro

nepellleH:Ka onpe.n.eJI.steTc.st rpaHuueH:, HMeiomeH: ct>opMy yqacTKa cct>e­ phIc BhITIYKJIOCThIO B CTOpoHy qacTHUhl c MeHbllleH noBepXHOCTHOH 3HeprueH:, H nopOlllHHKa BemecTBa c 60JibllleH noBepXHOCTHOH 3Hep­ rueH: KaK 6b1 B.UaBJIHBaeTC.st B nopolllHHKY BemecTBa c MeHhllleH: no­ BepxHOCTHoH: 3HeprueH:. IloJIHoe yTIJIOTHeHHe nopolllKOBoro TeJia npu 3TOM He ,lJ,OCTHraeTC.SI.

B o6meM cJiyqae npouecc ynJIOTHeHH.st nopolllKoBoro TeJia B Haqa­ Jie H30TepMuqecKoro cneKaHH.SI MO)l(eT 6hITh OTIHCaH ypaBHeHHeM

(14.40). 0.n.HaKO 3aBHCHMOCTh napaMeTpOB 3T0f0 ypaBHeHH.SI OT TeMne­

paryphl cymecTBeHHO HCKa)l(eHa H 06b1qHo He COOTBeTCTByeT TeMne­ paTypHOH 3aBHCHMOCTH .ll.Jl.SI 0,lJ,HOcPa3HhlX nopOlllKOBh X TeJI.

 

KoHmpoAbHble eonpocbl

1. KaKOBhI.UBIUHe CHJihI npu TBep.n.oct>aJHOM cneKaHHH MHO­ roKoMnoHeHTHh X nopOlllKOBh X TeJI?

2. PaccKa)l(HTe 0 TBep.n.oct>aJHOM cneKaHHH CHCTeM c TIOJIHOH B3a­

HMHOH paCTBOpHMOCTh IO KOMTIOHeHTOB.

3. KaKOBhIMexaHH3MhIct>opMHpoBaHH.SI MexqacTHqHhIX cB.st3eH: npu TBep.n.oct>aJHOM cneKaHHH CHCTeMblc HepacTBOpHMhlMH KOMilOHeHTa­ MH?

 

PeKoMeHaameAbHblii 6u6Auo2pa<jJu11ecKuii cnucoK

1. CKopoxoa B.B., CoAOHUH C.M. <l>H3HKo-MeTaJIJiypmqecKue ocHOBhI cneKaHH.st nopolllKOB. - M.: MeTaJIJiyprH.st, 1984. -159 c. (c. 76-99).

2. AHapueecKuii P.A. IlopolllKOBoe MarepHaJIOBe.n.eHue. - M.: MeTaJI­

Jiypm.st, 1991. - 205 c.(c. 94- 104).


rnaea 15. >KMAKo<t>aaHoe cneKaHMe

 

)i(}i,llKo<t>aJttoe cneKamte - cneKattHe no­ powKoooro Tena npH TeMnepazype, o6ec­ net.tHBatomeH: IlOl!BJieHHe JKH,llKOH <t>aJbl

 

 

15.1. 06U,\af1 xapaKTepMCTMKa cneKaHMH

 

CneKaHHe c yqacTHeM )l(H,lJ,KOH ct>aJhIHMeeT lllHpoKoe TeXHuqec­ Koe npHMeHeHHe npH npOH3BO,lJ,CTBe pa3JIH1IHh X THTIOB nopOlllKOBhlX KOMTI03HUHOHHhlX MarepHaJIOB. TipHMepaMH CHCTeM, cneKaHHe·KOTO­ pbIX npoucxo.n.HT c yqacTHeM )l(H,lJ,KOH ct>aJh , MOryT cJITh Cu-Sn

(227 °C), Fe-Cu (1083 °C), Fe-P (1050 °C), Cu-Pb (326 °C), Cu­

Bi (270 °C), Cu-Cd (314 °C), W-Cu (1083 °C), W-Ag (961 °C),

Mo-Cu (1083 °C), Mo-Ag (961 °C), Cr3C2-Ni (1200 °C), WC-Co

(1340 °C), TiC-Ni (1280 °C) H MHOrHe .n.pyrue (B CK06Kax yKa3aHbl

TeMnepaTypbl B03MO)l(ff0f0 TIO.SIBJieHH.SI )l(H,lJ,KOH ct>aJbl B pe3yJihTare TIJiaBJieHH.SI JiefKOTIJiaBKOH KOMTIOHeHThl HJIH CTpyICTypHOH COCTaB­

JI.SIIOIUeH, o6pa3yioIUeHC.SI cornacHO COOTBeTCTBYIOIUeH .uuarpaMMe co­ CTO.SIHH.SI).

TepMO.UHHaMuqecKHM ycJIOBHeM 3cPcPeKTHBHoro )l(H,lJ,Koct>aJHoro

cneKaHH.SI .SIBJI.SleTC.SI CTpeMJieHHe MHOfOKOMilOHeHTHOH CHCTeMbl K MHHHMYMY CB060,lJ,HOH noBepXHOCTHOH 3HeprHH H XHMHqecKoro no­

TeHUHaJia, KaK H npu TBep.n.oct>aJHOM cneKaHHH. Ho B ornuque oT TBep.n.oct>aJHOfO npH )l(H,lJ,KOcPa3HOM cneKaHHH H3-3a 60JibllleH no.n.­ BH)l(HOCTH CHCTeMbl )l(H,lJ,KOe-TBep.n.oe 6oJiee HafJI.Sl,lJ,HO npO.SIBJI.SleTC.SI

.n.eH:CTBHe OCHOBHh X .ll.B·IUHX CHJI o6beMHOfO YTIJIOTHeHH.SI nopolll­

KOBOfO reJia - CHJI KanHJIJI.SlpHoro CT.SlfHBaHH.SI. B npucyrCTBHH )l(H,lJ,­

KOH ct>aJhI npu onpe.n.eJieHHh X ycJIOBH.SIX o6JieNaeTc.st pa3BHTHe CHJI cueTIJieHH.SI Me)l(,lJ,y OT,lJ,eJibHhlMH qacTHUaMH nopOlllKa H MO)l(eT cct>op­

MHpOBaTbC.SI MaJIOnopHCTa.SI (Il « 1%) CTpyKrypa.IlpH )l(H,lJ,KOcPa3-

HOM cneKaHHH B nopolllKOBOM TeJie B03HHKaeT CBOero po.n.a KanHJI­ JI.SlpHa.SI CHCTeMa (pa3Mepbl qaCTHU nopolllKa COH3MepHMhl c none­ peqHblMH pa3MepaMH nopOBh X KaHaJIOB), COCTO.SIIUa.SI H3 TBep.n.oH:,

)l(H,lJ,KOH H ra3006pa3HOH ct>aJ. B CB.Sl3H c 3THM 60Jih11Joe 3HaqeHHe npu­

o6perneT CMaqHBaHHe TBep,lJ,b X qaCTHU )l(H,lJ,KOH ct>aJOH, Mepofl: KOTO­ poro .stBJI.steTc.st BeJiuquHa KpaeBoro yrna cMaquBaHH.SI 3 (puc. 256):


 

 


 

8 - 5582



cos S = (a - a )/a ,
T t-)1( :t:: (15.1)

r.ue aT, a)I(, aT_lK - COOTBeTCTBeHHO noBepXHOCTHbi e 3Heprn:H Ha rpa­ HHUaX pa3,UeJia TBep.uoe TeJIO- raJ, )J(fl,llKOCTb- ra3 H TBep.uoe TeJIO­

)J(fl,llKOCTb. Pa6orn a.ureJHH HJIH pa6oTa OTpbIBa )J(fl,llKoi1 KanJIH oT TBep­

.uoi1 noBepXHOCTH BblpIDKaeTCH <t>opMyJIOH


 

Coe!l11HeH11e )1(11.IIKl1M MeTaJlJl     T. °C     ATMOC<\>epa   9. rpa.a
TiCo.96 Ni BaKyyM
  Co 1 500 To )!(e
  Ni To )Ke
TiN Ni 1450- 1500 BaKyyM
  Ni 1450-1500 A30T 1 10
TiB2 Ni BaKyyM
WC Cu BaKyyM
Co AproH
Ni To )!(e

 

T a 6 JI H u a 52. 3Ha'ICHHH KpaeBOfO yrna CM3'1HB3HHH ,lUUI HCKOTOPWX CHCTCM


(15.2)

TepMO.UHHaMw-1ecKHM ycJioBHeM cMalfHBaHHH HBJIHeTCH yMeHbllleHHe CBOOO,llHOH 3HeprnH CHCTeMbl npH npeBpalll,eHHH rpaHHU pa3,lleJia TBep­

.uoe TeJio-raJ H )l(H,llKOCTb-raJ B rpaHHUY paJ,UeJia TBep.uoe TeJio­

)l(H,llKOCTb, T.e. pa6orn a.ureJHH ,llOJI)l(Ha 6bITb noJIO)l(HTeJibHa.

npH nOJIHOM CMalfHBaHHH S = 0°, npH nOJIHOM HeCMalfHBaHHH s = 180°, npH 0 < s < 90° CMalfHBaHHe ClfHTalOT xopollIHM, a npH s 90° CMalfHBaHHe nJioxoe H o6pa3oBaBlllaHCH )l(H,UKaH Q>a3a TOpMo-

3HT cneKaHHe, npenHTCTBYH ynJIOTHeHHIO nopolllKOBOro TeJia.

CMalfHBaHHe YJIYlflllaeTCH (yroJI S yMeHblllaeTCH) npH yMeHbllle­ HHH a,_)I( (HanpHMep, npH HaJIHlfHH B KOHTaKTHpYJOlll,HX Q>aJax noBepx­ HOCTHO-aKTHBHbIX Belll,eCTB HJIH npH HJMeHeHHH TeMneparypb!). 1'b­

MeHeHHe BeJIHlfHHbl aT_lK MO)l(eT TaK)l(e 6b!Tb CJie,UCTBHeM H3MeHeHHH BeJIHlfHH a H a (3KcnepuMeHTaJibHO ycTaHoBJieHo, lfTO c pocToM a

T lK T

pacTeT H aT_,., HO B 60Jiblllei1 CTeneHH, B peJyJibTaTe KpaeBOH yroJI yBeJIHlfHBaeTCH).

npH yBeJIHlfeHHH BpeMeHH KOHTaKTa )l(H,UKOe-TBep,UOe H TeMne­ parypbl KpaeBoi1 yroJI yMeHblllaeTCH H cMalfHBaHHe YJIYlfUJaeTCH. B paM­ Kax TepMO,llHHaMHlfeCKOtt TeopHH CMalfHBaHHH, OCHOBaHHOH Ha cy­ lll,eCTBOBaHHH XHMHlfeCKoro B3aHMO,lleHCTBHH Ha Me)l(Q>a3HOH rpaHH­ ue TBep,lloe TeJio-)l(H,llKOCTb, 3TO o6bHCHHeTCH ycJioBHHMH npoxo)l(­

.L I.eHHH XHMHlfeCKOH peaKUHH Ha 3TOH rpaHHUe. noBbIUJeHHe TeMnepa­ TYPbInpHBO,llHT K yMeHbllleHHIO CBo6o.uHoi1 3HeprnH CHCTeMbIH yMeHb­

UJeHHIO BeJIHlfHHbl a,_,., a BJIHHHHe BpeMeHH CBH33HO c npo,llOJI)l(H­

TeJibHOCTbIO ycTaHOBJieHHH paB­ HOBeCHH npH XHMHlfeCKOM B33H­ MO,UeHCTBHH Q>aJ.

BeJIHlfHHa KpaeBoro yrna cMa­

lfHBaHHH 33BHCHT OT OKpy:>KaIO­


 

pb!X CHCTeM.

OTMeTHM tteKOTOph1e JaKoHoMepHOCTH, xapaKTepHbi e ,ll,JIH cneKa­ HHH B npHCYTCTBHH )J(H,llKOH Q>aJbJ:

1. 06pa30BaHHe )J(fl,llKOH Q>a3bl npH cneKaHHH, KaK npaBHJIO, co­

npOBO)l(JJ,aeTCH HHTeHCHQ>HKaU Hei1 yca,UKH, lfTO B npHHUHne noJBO­ JIHeT IlOJIYlfHTb cnelfeHHblH MaTepHaJI c OlfeHb Bb COKOH nJIOTHOCTblO H MaJIOH OCTaTOlfHOH nopHCTOCTbIO npH OTHOCHTeJibHO KOpOTKOM Bpe­

MeHH npouecca; B CBH3H c 3THM cneKaHHe B npHCYTCTBHH )l(H,llKOH Q>a3bl lfaCTO npe,UCTaBJIHeT co6oi1 aJibTepHaTHBY HCnOJib30BaHHIO Bbl­ COKHX ,UaBJieHHH Q>opMoBaHHH HJIH 60JibllIHX TeMneparypblH ,ll,JIHTeJib­ HOCTH BbI,llep)l(KH npH cneKaHHH ,ll,JIH nOJIYlfeHHH MaTepHaJia Bb!COKOH nJIOTHOCTH. ).l,JIH HeKOTOpb!X nopollIKOB 01.feHb TBep,llb X MaTepHaJIOB HJIH cnJiaBOB )J(fl,llKOQ>aJHOe cneKaHHe MO)l(eT 6b!Tb e,llHHCTBeHHO B03M0)1(­ Hb!M cnoco6oM noJiyqeHHH Bb!COKOH nJIOTHOCTH KOHelfHOro npon.yKTa.

2. 3Q>Q>eKT yBeJIHlfeHHH yca,llKH JaBHCHT KaK OT Q>H3HKO-XHMH­

lfeCKHX xapaKTepHCTHK KOMnOHeHTOB, TaK H OT KOJIHlfeCTBa )l(H,llKOH Q>a3bl, pa3Mepa lfaCTHU TyronJiaBKOH COCTaBJl·HIOlll,eH H HalfaJibHOH nopHCTOCTH 6p11KeTOB. YBeJIHlfeHHe KOJIHlfeCTBa JierKonJiaBKOH cocTaB­

JIHIOlll,eH cnoco6cTByeT ycan.Ke, HO npH HaJIHlfHH HeKOTOpoi1 B33HM­


ar->K

a 6

P11c. 256. CMa'1ttBaH11e lK11!lKOCTblO

rnep!lOH no11cpXHOCTtt (a) 11 MelKKp11CTaJl­

Jll1THOro npoMCJKyrKa (6)


lll,eH 3TMocQ>epbI, CTeneHH ee OlfHCTKH, cnoco6HOCTH K o6pa- 30B3HHIO noBepXHOCTHbIX nJieHOK

H .upyrnx Q>aKTOpoB. B Ta6JI. 52 npH­ Be,lleHbI 3HalfeHHH s ,ll,JUI HeKOTO-


HOH paCTBOPHMOCTH KOMnoHeHTOB HJMeHeHHe nJIOTHOCTH npH )l(HD.­

KoQ>aJHOM cneKaHHH MO)J(eT OCJIO)l(HHTbCH npoueccaMH reTepo­ n.u<t>Q>yJHH; HCnOJib30BaHHe 6oJiee MeJIKHX Q>paKUHH ryronJiaBKOH co­ CTaBJIHIOlll,eH cnoco6cTByeT yBeJIHlfeHHIO yca,UKH. B CBHJH co JHalfH­ TeJibHbIM ynJIOTHeHHeM npH cneKaHHH pOJib BeJIHlfHHbl HCXOD.HOH nopHCTOCTH, K33aJIOCb 6bl, npen.cTaBJIHeTCH He CTOJ!b B3:>KHOH, HO 3Ha-

s• 227


llJITeJibHajf yca,n;Ka 6pMKeTOB c BbICOKOH HallaJibHOH rropMCTOCTblO JaT­ PYJlHjfeT rronyqettMe MJJleJIMH c Bb COKOH TOllHOCTbIO paJMepoB, a crre­ KattMe 6pMKeTOB c HMJKOH MCXOJlHOH rropMCTOCTblO MO)((eT rrpHBeCTM

]la)((e K MX poczy rrpM crreKaHMM, B CBjfJM c TeM 4TO BCJie]lCTBMe pacTe­ KaHMjf )((HJlKOH <f>aJbl MOryT o6paJOBbIBaTbCjf MJOJIHpOBaHHbie rropbl,

]laBJieHMe raJa B KOTopblx, KaK H B cnyqae TBepJlo<f>aJttoro crreKaHffjf, 6yJleT rrpelljfTCTBOBaTb yca,n;Ke.

3. B tteKoTopb X cnyqajfx )((HJlK <f>aJa npMCYTCTBYeT npM cneKa­

HMM JIMlllb B TelleHMe orpaHMlleHHOro BpeMeHM. IlpOTeKaHMe npouec­ COB peaKTMBHOH JlM<l><f>YJMM npMBOJlMT K o6pa30BaHMIO JlPYfMX 6onee zyroIIJiaBKHX <f>a3 HJIM K pacTBopeHMIO )((HJlKOH <f>aJbl B TBepJlOH, M cneKaHMe OCYllJeCTBJijfeTCjf B OCHOBHOM B TBepJlOH <f>aJe.

4. Tipouecc )((HJlKo<f>aJttoro cneKaHJljf qacrn npHBOJlMT K nonyqe­

HHIO MeTaJIJIHlleCKHX CTpYKTYP, o6na,n;aIOIUHX oco6eHHb MM MexaHM­ qecKMMM CBOHCTBaMH; eCJIM Ta <f>aJa, KOTopajf BO BpeMjf cneKaHMjf 6bIJia )((HJlKOH, coxpattjfeT CBOM oco6eHHOCTM B cneqeHHOM MaTepMa­ Jie, TO Otta OlleHb llaCTO npH]laeT eMy YHMKaJibHbie CBOHCTBa.

B caMoM o6IUeM cnyqae )((HJlKHe MeTaJIJibIxoporno cMallMBaIOT (Kpa­

eBoii yroJI CMallMBaHMji o6bl4HO He npeBbilllaeT 30-40° M qacTO Ha- 6JIIO]laeTCji IIOJIHoe CMallMBaHMe) llMCTb e MeTaJIJIHlleCKHe IIOBepXHOCTM M IIOBepXHOCTM Tex HeMeTaJIJIMlleCKHX HJIM MeTaJIJIOIIO]l06Hb X KOMIIO­ HeHTOB (OKCH]lOB, 6opH]lOB, Kap6H]lOB M HMTpHJlOB paJJIMllHb X Me­

TaJIJIOB, rpa<f>MTa M Jlp.), c KOTOpblMM OHM BczynaIOT B XMMMlleCKOe BJaMMOJleHCTBMe.

TiojfBJieHMe )((HJlKOH <f>aJbInpM ttarpeBe CBjfJatto c pacIIJ1aBJ1eHMeM 6onee nerKOIIJiaBKOfO KOMIIOHeHTa HJIM CTpYKTYPHOH COCTaBJijfIOIUeH

(HanpMMep, 3BTeKTMKH) cneKaeMoro MaTepMaJia, a TaK)((e c «KOHTaKT­ Hb M» IIJiaBJieHMeM, KOfJla )((HJlK <f>aJa BOJHMKaeT npM TeMnepazype 6onee HMJKOH, qeM TeMnepazypa IIJiaBJieHMjf yKaJaHHblX COCTaBJijflO­ IUHX nopollIKOBOfO Tena. IlpM 3TOM MexaHM3M cneKaHMjf c yqacTHeM

)((HJlKOH <f>aJblJaBMCMT OT xapaKTepa ]lMarpaMMblCOCTOjfHlrn COOTBeT­ CTBYJOIUeH CMCTeMblKOMIIOHeHTOB. l.JeM nyqrne CMallHBaHMe, TeM 66Jib­ llIMe KOJIMllecrna )((HJlKOH <f>aJbIMoryr YJlep)((MBaTbCjf B nopornKOBOM TeJie BO BpeMjf cneKaHMjf, He BbITeKajf M He MCKa)((ajf ero <f>opMy.

B npMcyrcTBMM )((HJlKOH <f>aJbIcymecTBeHHo yBeJIHll MBaeTCjf cKo­

pocTb caMo- M reTepOJlH<l>YJHM aTOMOB, llTO ycKopjfeT cIIJ1aB006pa­ JOBaHMe, M o6nerqaeTCjf nepeMeIUeHHe TBep]lbIX llaCTHU OTHOCMTeJib­ HO Jlpyr Jlpyra, cnoco6cTByjf JanonHeHMIO nop BemecTBoM. B CBjfJH c 3TMM npH' )((HJlKo<f>aJHOM cneKaHMM MO)((HO o6ecne4HTb IIOJiyqeHMe npaKTMlleCKH 6ecnopMCTblX nopOIIIKOBblX HJJleJIMH (MaTepHaJIOB).

PaJJIMllaIOT cneKaHMe nopornKoBoro Tena c npucyrcTBHeM )((HJl-

 

228


KOH <f>aJblJlO KOHUa M30TepMM4eCKOH Bb Jlep)((KM H c ee HClleJHOBC­ HMeM BCKOpe IIOCJie IIOjfBJieHHjf (XOTjf HarpeB npO]lOJI)((aeTCjf), a TaK­

)((e cneuM$M4eCKYIO pa3HOBHJlHOCTb nepBOfO THIIa npouecca )((MJlKO­

<f>aJHOfO cneKaHMjf, KOTopyIO HaJbIBaIOT MH$HJibTpauueM: nopOIIIKO­ BOH <f>opMOBKH.

CTaAMM cneKaHMR

B 1938 r. 3apy6e)((Hb1e MCCJie]loBaTeJIM IlpaH:c, CMMTeJic H BHJibjiMC c<f>opMyJIMpoBaJIM npeJlCTaBJieHMe 06 yIIJIOTHCHHM npM )((HJlKo<f>aJHOM CIICKaHMM KaK CJieJlCTBMe ]lByx rrOCJieJlOBaTeJibHbIX CTa,D;HH. Ilo MX MHe­ HMIO, npM IIOjfBJieHMM )((HJlKOH <f>aJblCHaqaJia (nepBajf CTa,ll;Mjf) TBep­

]lble qaCTHUbl nepeMeIUaIOTCji JlO COCTOjfHMjf IIJIOTHOH YKJia,ll;KM IIOJl BJIMjiHMeM CMJI IIOBepXHOCTHOro HaTjf)((CHMjf CMallMBaIOIUeH HX )((HJl­

KOCTM; qaCTMUbl CMeIUaIOTCjf OTHOCHTeJlbHO JlPYf Jlpyra 6JiafOJlapji BOJHMKHOBeHMIO OTpHUaTeJibHOfO KaIIMJIJijipHOfO JlaBJieHMjf B )((H]lKO­ CTHbIX «MOCTMKaX» (MaH)((eTax), COeJlMHjfJOIUMX 3TM qaCTMUbl. IlocJie JaBeprneHMjf nepHOJla cBo60JlHOro rrepeMeIUeHMjf qacTMU JlaJibHeM:rnee YIIJIOTHCHMe (BTOpajf CTa,ll;Mjf) npOHCXOJlMT 6nar0Jlapj1 HX nepeKpHC­ TaJIJIMJaUMM qepe3 )((HJlKYIO <f>aJy (06jfJaTeJibHOe ycJIOBHe KOTOpoH: - HaJIMllMe paCTBOpHMOCTM TBep]lOH <f>aJbl B )((HJlKOCTH). 0JlHaKO cpaJy

)((e BOJHMKJIM COMHeHMjf H 6bIJIM orry6JIMKOBaHbl BbICKaJbJBaHHjf He­ KOTOpblX MCCJieJlOBaTeJieH (HanpMMep, )l)KoHCOHa B 1938 r.), CBjfJaHO JIM yIIJIOTHeHMe c pocTOM qacTHU B CBjfJH c MexaHMJMOM nepeKpMc-

Til.TIJIMJaUHM.

B 1953 r. KeHHOH H JleHen yKaJaJIH eme Ha OJlHH MexaHHJM, npu-

BOMIUHH K ynnoTHeHHIO npM )((HJlKo<f>aJHOM cneKaHMH: Ha JaKJIIOllH­ TeJibHOH CTa,D;HH cneKaHHjf B npouecce JaBeprneHHjf nepeKpHCTaJIJIM­ JaUHH (npM HaJIHllHH paCTBOpMMOCTH TBepJlOH <f>aJbl B )((HJlKOCTH)

HJIM cpa3y nocJie JaBeprneHHjf nepBOH CTa,D;HH (npH OTCYTCTBHH pa­ CTBOpHMOCTH TBCPJlOH <f>aJbl B )((HJlKOCTH) pa3BHBaeTC}I npouecc cpa­ CTaHHjf qacTHU zyronJiaBKOro KOMIIOHeHTa B )((eCTKHH KapKaC («CKe­ JieT»). 0HH TaK)((e OTMeTHJIH, 4TO ynJIOTHeHHe npH nepeKpHCTaJIJIHJa­

I
UHH npoHCXOJlHT 6naroJlap}I TOMY, 4TO OJlHOBpeMeHHO c pocTOM Je­ peH npOHCXOJlHT HJMeHeHHe HX <f>opMbl, B pe3YJibTaTe KOTOpOro qac­ THUbl npuo6peTaIOT BOJMO)((HOCTb 6onee TeCHOfO npHMbIKaHH}I OJlHa

K JlpyroH.

OTMeTHM, 4TO y)l(e nollTH II}ITbJleC}IT neT TeopeTHlleCKHe pa3pa- 60TKH no )((HJlKo<f>aJHOMY cneKaHHIO 6aJHpyIOTC}I Ha YKaJaHHbIX Bbtrne npeJlCTaBJieHHjfX 0 Tpex B03MO)l(HblX MeXaHHJMaX ynJIOTHeHH}I, pa3BH­ BaIOIUHXC}I c IIO}IBJieHHeM )l(HJlKOH <f>aJbl nocJieJlOBaTeJibHO npH qac-

I 229


rn:qHOM Ha.JIO)KeHHH (pHC. 257): )l(H)J,KOe TeqeHHe (neperpynnHpOBKa), pacTBopeHHe-ocIDK,l(eHHe (nepeKpHCTa.JIJIHJau m1), cpacTaHHe qacTHl.l TYfOruiaBKOH <l>aJhI(o6paJoBaHHe )KeCTKoro KapKaca HJIH «CKeJieTa»).

KirneTHKa 3THX npoueccoe cyll.lecTBeHHo JaBHCHT OT cTeneHH OJJ.Ho­ POJJ.HOCTH CMeCH KOMilOHeHTOB, Haqa.JibHOH nopHCTOCTH nopOlllKO­ BOfO rena, KOJIHqecTBa o6pa3)'10ll.leHCH )KH)J.KOH <t>aJbl, JIHHeHHOfO paJMepa nopOlllHHOK, xapaKTepa CMaqHBaHHH TBep)J.OH <t>aJbl)l(H)J,KO­ CTblO, BJaHMHOH paCTBOpHMOCTH <t>aJ H )J.OCTaTOqHo 60JiblllOfO KOJIH­

qecTBa JJ.PYrHX <t>aKTOpOB.

PaccMOTpHM Ka)K)J.YJO HJ YKaJaHHh X CTaJJ.HH yruIOTHeHHH.

llep60Jl cmaiJUR. Ee o6blqHo HaJblBaIOT npou,eccoM nepe2pynnupo6KU (JJ.OCTaToqHo qacro B KaqecTBe CHHOHHMa fOBOPHT 0 MexaHU'leCKOU nepe2pynnupooKe). loHBHBlllaHCH )KH)J.KaH <l>aJa JanOJIHHeT JaJopbl Me)K)J.y

TBep)J.blMH qacTHl.laMH H, HrpaH pOJib )l(H)J,KOH CMaJKH, o6nerqaeT BJa­ HMHOe nepeMell.leHHe qacTHl.l, npHBOJJ.Hll.lee K yruioTHeHHIO nopolll­ Koooro TeJia. TaKoe nepeMell.leHHe qacTHl.l, conpoeo)K)J.aIOll.leecH YMeHh­ llleHHeM ceo6oJJ.HOH noeepxHocTH )l(H)J,KOCTH, npoHCXOJJ.HT noJJ. BJIHH­ HHeM )J.aBJieHHH, o6ycJioBJieHHOfO KPHBH3HOH noeepXHOCTH B03HHKa­ IOll.lei"i )l(H)J,KOCTHOH «MaH)KeTbl» (T.e. noeepXHOCTH paJ)J.eJia )l(H)J,KOCTb­ raJ), o6paJyeMoH: o6'beMOM pacruiaea, JaKJIIOqeHHoro Me)K)J.y CMe)K­ Hh MH qaCTHl.laMH (nopolllHHKaMH).

'
rp T-JK
IlpH xopollleM CMaqHBaHHH no)J. BOfttyTOH noeepXHOCTblO B 3TOM o6'beMe )l(H)J,KOCTH COJ)J.aeTCH OTpHl.laTeJibHOe KailHJIJIHpHoe )J.aBJieHHe1CTHfHBaIOll.lee TBep)J.ble qaCTHl.lhl c O)J.HOBpeMeHHb M HX noeopOTOM


80,lJ.HlllYIO K MaKCHMa.JlhHOMY JHaqeHHIO OTpHl.laTeJibHOfO KanHJIJIHp­ Horo ,lJ.aBJieHHH B )KH)J.KOCTH H CHJibl, C)KHMaIOll.leH TBep)J.ble qacTHl.lhl.

Ilpu yxy,lJ.llleHHH cMaqueaHHH KPHBHJHa eomyroii noeepXHOCTH «MaH­

)KeTh » yMeHblllaeTCH, KanHJIJIHpHbie CHJihly6bIBalOT H npH s > 65 - 85°

(B JaBHCHMOCTH OT KOJJHqecTBa )KH)J.KOCTH H reoMeTpHH KOHTaKTa

Me)K)J.y TBep)J.blMH qacTHl.laMH) noeepXHOCTb )l(H)J,KOCTHOH «MaH)KeTbl» CTaHOBHTCH BhinYKJIOH, 3HaK KanHJIJIHpttoro )J.aBJieHHH MeHHeTCH H

BMeCTO CTHrHBaHHH TBep)J.blX qaCTHl.l noHBJIHeTCH CHJia, CTpeMHll.laHCH HX pa3)J.BHHYTh (Ta6JI. 53). IlpH nJIOXOM cMaqueaHHH «Matt)KeTa» MO)KeT

He o6pa30BaThCH, a 6y)J.eT npoHCXO)J.HTb CTHrHBaHHe )KH)J.KOCTH B Kan­

JIH Ha noeepXHOCTH qaCTHl.l TBep)J.OH <t>aJbl.

ECJIH noHBJIHIOIIlaHCH )l(H)J,KaH <t>aJa pacnpeJJ.eneHa B o6'beMe nopolll­ Koeoro rena paBHOMepHO, TO B03HHKalOll.lHe KanHJIJIHpHble CHJibl no BJIHHHHIO Ha npouecc neperpynnHpOBKH 3KBHBa.JieHTHbl ,lJ.eHCTBHIO

)J.aBJieHHH eceCTOpOHHefO C)KaTHH.

,ll,Jrn o6pa30BaHHH )l(H)J,KHX npocJioeK B npHKOHTaKTHOH o6JiaCTH Me)K)J.y TBep)J.blMH qacruuaMH He06XO)J.HMO, qTo6bl 3HepreTHqecKH 6hIJIO

uenecoo6pa3HO HX pa3)J.eJieHHe noHBJIHIOll.leHCH )KH)J.KOCThlO, TaK KaK 6e3 pa3pbIBa Me)KqacTHqHb X KOHTaKTOB, B03HHKI1IHX B nopOlllKOBOM rene )J.0 nOHBJieHHH )l(H)J,KOH <t>aJhl, HeB03MO)KH0 CB060)J.HOe nepeMe­

ll.leHHe qacTHl.l, c KOTOpbIM HenocpeJJ.CTBeHHO CBH3aH npouecc HX neperpynnHpOBKH u eoJpacTaHHe ruIOTHOCTH ynaKoBKH. Cq11raeTcH, qTO c Il03Hl.lHH TepMO)J.HHaMHKH ycJIOBHeM TaKOfO pa3be)J.HHeHHH qa­

I CTHl.l noHBHBllleHCH )KH)J.KOH <t>aJOH HBJIHeTCH COOTHOllleHHe


OTHOCHTeJibHO roqKH Me)Kqa­

CTHqHoro KOHTaKTa. BMecre c


a. 2a cos ('¥/2),


(15.3)


 

PHc. 257. KHtteTWiecKfill KpHBW! yCll,ll,KH rrpH lKH,!lK<><l>aJHOM crreKaHHH: 1 - lKH,!lKoe reqe­ HHe; 2 - pacTBopeHHe H oca)l(JleHHe; 3 -

Tsep.u<><t>aJHoe crreKaHHe


noeopoTOM qaCTHl.l npOHCXO­

)J.HT nepeMell.leHHe o6beMa

)l(H)J,KOCTH, H o6JiaCTb OTpHl.la­

TeJibHOfO KanHJIJIHpHOfO )J.aB­ JieHHH pacnpOCTpaHHeTCH Ha HOBble yqaCTKH noeepXHOCTH TBepJJ.hIX qacTHU, ycKopHH HX noeopoT H BJaHMHb H C)J.BHr. IlpH IlOJIHOM CMaqHBaHHH no­ BepXHOCTb «MaH)KeTbl» HMeeT

HaH60JlblllYJO KPHBH3tty, npH- I


r)J.e a. - noeepXHOCTHaH 3HeprHH Ha Me)KqacTHqHOH rpaHHl.le; -

rp

 

 

T a 6 JI " 1..1, a 53. Jlaueiiuuyca,iuat M/ I (%) a cacTeMe W-Cu a lllBHCH­ MOCTH"OT o6i.eMa lKll)J.KOH cl»a:Jw, ttpaeaoro yrJia CMa'lllBaHJIH H Hcxo,nuoii

0JIOTHOCTb yrraKOBKH (KOOp,llHHaUHOHHOe qlfCJIO) KoJIHqeCTBO JKH.UKOH cl>aJbl, % (o6beMH.)
5,4 7,7 12,4
2,5 3,0 4,6
0,7 ±0,1 1,7 ±0,1 3,5 ±0,1
-0,9 --0,5 0,4
-1,2 ±0,1 --0,9 ±0,1 0,3 ±0,1

 

DJIOTHOCTH nopmmmaoro TeJia

 

KpaesoH yron CMaqHBaHHll, rpa.u

 

 


I KamuurnpHble CHJibl, C)((JfMaIOIUHe CMe)l(Hb e TBep,llbie qacTHUbl , coe,llHHeHHble He­

KOTOpb M OObeMOM )((Jf,llKOCTH, HMeIOT o6mee IIpOHCXO)l(JleHHe c CHJIOH, IIO,llHHMaIO­

IUeil: lKH,!lKOCTb B CTeKIDIHHOM KalIHJIJUlpe; HX BeJJHqHHa MO)l(eT .llOCTHraTb HeCKOJibKHX MerarracKaJieil:.


I 231


,ll,ByrpaHHbIH (.n.Hre,ll,pa.JibHbIH) yroJI, paBHblH = q>o +23 (% - yroJI Me)J{,lly KaCaTeJibHbIMH K noeepXHOCTH ":laCTHU B MeCTe HX conpHKOC­ HOBeHH.ff ). BbipIDKeHHe (15.3) BbinOJIH.ffeTC.ff npH JII06bIX JHa":leHH.ffX

rp T * rp T-:iK
yrna '¥ , ecnH a. > 2a. _ , HO B paeHoeecHbIX ycnoBH.ffX a. < 2a. H

cooTHoweHHe (15.3) o6bI":IHO He BhmoJIH.ffeTC.ff . B pea.JibHbIX nopow- KOBbIX Tenax, xapaKTepHJYIOIUHXC.ff ,lJ,OCTaTO":IHO Ma.JIOH eeJIH":IHHOH Me­ Ta.JIJIH":leCKHX KOHTaKTOB Me)J{,lly 1:1aCTHUaMH H Ha.JIH":IHeM Jarp.ff3HeHHH

Ha HHX, BeJIH":IHHa a.rp cymecTBeHHO BOJpacTaeT, H COJ,lJ,aIOTC.ff 6oJiee 6JiaronpH.ffTHbie yCJIOBH.ff ,ll,Jl.ff BbJnOJIHeHH.ff COOTHOWeHH.ff (15.3). npH Ha.JlfflIHH paCTBOpHMOCTH rnep.n.oii cf>aJbl B )((H,ll,KOH yCJIOBHe (15.3)


Bmopaa cmaiJuR. 0Ha onpe.n.e- i:,,;3.:.:._ ,

JI.ffeTC.ff npoTeKaHHeM npouecca nepeKpHCTa.JIJIHJaUHH qepe3 )((H,ll,- 9 KYIO cf>aJy H ee o6bl":IHO HaJbJBa-

IOT pacm6opeHue-oca:J1CiJeHue \ 7

(HHor.n.a 3TOT npouecc HaJbIBa- \

JOT XUMUiteCICOU nepezpynnup06KOU). / '\\

CymecrneHHYIO poJib 3TOT npo- 5 / / \ \

uecc MO)((eT 11rpaTh JIHWh B cHc- / // \:\

·TeMax, r.n.e TBep.n.a» cf>aJa HMeeT 3 L- ---'-.-1..--.. - - -


,ll,Jl.ff MHOfHX TeXHH":leCKH Ba)((HbJX KOMnOJHUHH BbJnOJIH.ffeTC.ff; paCTBO­

peHHe B nopOWKOBOM TeJie npeHMYIUeCTBeHHO H,lJ,eT B,lJ,OJlb Me)((JepeH­


HeKoTopyIO paCTBOpHMOCTb B 0

)((H,ll,KOH.


20 40 (j() 80

)/(uOKoR l/Ja30, % (OOoeMH.)


100


HblX rpaHHU H paCTBOp.ffIOIUa.ff )((H,lJ,KOCTb paJo6maeT TBep,ll,ble 1:1aCTHUbl. OrMeTHM, ":ITO 1:1eM HH)((e HCXO,ll,Ha.ff nJIOTHOCTb nopowKoeoro TeJia, TeM MeHbWe eepO.ffTHOCTb o6paJOBaHH.ff B HeM npO":IHOro )((eCTKOro KapKaca Ha Ha":la.JibHOH CTa,ll,HH cneKaHH.ff H TeM ner1:1e H,lJ,eT npouecc neperpynnHpOBKH ":laCTHU.

npH OTHOCHTeJibHO OOJiblUOM CO,ll,ep)((aHHH JiefKOJl.JiaBKOfO KOMnO­


nocKOJlbKY paCTBOpHMOCTb rnep.n.oro eemecTea B )((H,ll,KOCTH yeeJIHlJHBaeTC.ff c yeeJIHlfeHHeM KpHBHJHbI(c YMeHhWeHHeM paJ­ Mepa 1:1acTHU rnep.n.oft: cf>aJhI), MeJIKHe 1:1acTHUbl paCTBOp.ffIOTC.ff


Pttc. 258. KpHBbie JIHtteiittoii .yca,uKH & npeccosoK HJ nopoUIKa cnnasa cHCTeMbI W-Ag B JaBHCHMOCTH oT o6beMttoro co.aep.lKaHHR )((H,llKOH Q>a3bl npH 1300 'C: 1 - HHQ>HJ!bTP3UHR; 2 - cneKaHHe


HeHTa [10-30 % (o6beMH.)], Ma.JIOM paJMepe lJaCTHU rnep,ll,OH cf>aJblH

n.o crnTO":IHO BbICOKOH TeMnepazype cneKaHH.ff npouecc neperpyn­ nHpoeKH lJaCTHU c HX nepeMeIUeHHeM ,ll,O COCTO.ffHH.ff nJIOTHOH yna­ KOBKH COCTaBJI.ffeT OCHOBHOH MeXaHHJM YJl.JIOTHeHH .ff. nocJie ero Ja­ eepweHH.ff npOCTpaHCTBO Me)J{,lly TBep,ll,blMH lJaCTHUaMH OKaJbIBaeTC.ff nO'ITH noJIHOCTblO JanoJIHeHHblM )((H,ll,KOH cf>aJOH. OrMeTHM, 'ITO B

60JibWHHCTBe cny1:1aee neperpynnHpoeKa 1:1aCTHU He o6ecnelfHBaeT JaBepweHH.ff ynJIOTHeHH.ff H nocJie ee OKOHlJaHH.ff npocTpaHCTBO Me)((­

.ll.Y TBep,ll,bIMH 1:1aCTHUaMH JanOJIHeHo He TOJlbKO )((H,lJ,KOCTbIO, HO H

nopaMH.

B o6meM CJ1y1:1ae Ha 3TOH CTa,ll,HH YJl.JIOTHeH H.ff BeJIHlJHHa OTHOCH­

TeJibHOH o6beMHOH yca.n.KH nopowKoeoro Tena AV/ V npH6JIH)((eHHo onHcbIBaeTC.ff JaKOHOM AV/ V - •k ( k > 1). BKJia.n. npouecca MexaHHlJec­

KOH neperpynnHpOBKH B o6my10 OObeMHyIO yca.n.J<Y cneKaeMoro nopow­ Koeoro TeJia yeeJIHlJHBaeTC.ff c poCTOM KOJIHlJeCTBa )((H,ll,KOH cf>aJbl H yMeHbWeHHeM paJMepa lJaCTHU zyronnaBKOH cf>aJbl , TaK KaK npH 3TOM yMeHbWaeTC.ff eepO.ffTHOCTb JaKJIHHHBaHH.ff TBep,ll,bIX qaCTHU npH HX BJaHMonepeMeIUeHHH.

C1:1HTaIOT, 1:1To nonHoe yJl.JioTtteHHe B peJyJihTaTe TOJibKo o.n.ttoro npouecca neperpynnHpOBKH MO)((eT 6bITh nonyqeHo npH co.n.ep)((aHHH

)((H,ll,KOH cf>aJbl 35-50 % (o6beMH.) (pHC. 258). )],JI.ff CHCTeM c HeBJaH­

MO,lJ,eHCTBYIOIUHMH KOMnoHeHTaMH 3TOT npouecc ,ll,Jl.ff ynJIOTHeHH.ff nopoWKOBOfO Tena .ffBJI.ffeTC.ff OCHOBHbIM.


H HClJeJaIOT, B TO epeM.ff KaK KpynHb e paCTYT, npHHHMa.ff 6onee npa­

BHJlbHYIO cf>opMy (HanpHMep, OKpyrnyIO HJIH orpaHeHHYIO ), o6ecne­ lJHBaIOIUYIO MHHHMHJHpoBaHHe noeepxHOCTHOH 3HeprnH. TpaHcnopT MaTepHa.Jia npoHCXO,lJ,HT nyTeM 6bICTpOH .ll.H<l>cf>YJHH 1:1epe3 )((H,ll,KYJO cf>aJy. BoJMO)((HO, 1:1To 3TOT npouecc ttenocpe.n.crneHHO He npHBO.lJ.HT K yca.n.­ Ke, O,lJ,HaKO cnoco6CTByeT eii,noJBOJl.ff.ff qaCTHUaM Jief":le nepeMeIUaTbC.ff

8 npouecce B.ffJKoro Te":leHH.ff )((H,ll,KOCTH Ha nepeoii CTa,ll,HH cneKaHH.ff.

0.n.HaKo cymecTeyeT MHeHHe, 'ITO MexaHHJM pacrnopeHHe-oca)J{,lle­ HHe enp.HMYIO npHBO,ll,HT K yca.n.Ke: B peJyJibTaTe nepeoH CTa,lJ,HH cne­ KaHH.ff lJaCTHUbl zyronnaBKOH cocTaBJI.ffIOIUeH OKaJbIBaIOTC.ff OT,lJ,eJieHbl

n.p yr OT .n.pyra TOHKHMH npOCJIOHKaMH )((H,ll,KOH cf>aJblH KanHJIJl.HpHoe

.n.aeJieHHe B 3TOM cnyqae ·ypaBHOBellrnBaeTC.ff Hanp.ff)((eHH.ffMH C)((aTH.ff B JOHe KOHTaKTa. Hanp.ff)((eHHOe COCTO.ffHHe KOHTaKTOB o6ycJIOBJIHBaeT

I
.rpa.n.HeHT XHMHlJeCKOfO noTeHUHa.Jla H o6ecnelJHBaeT noBbIWeHHOe pacTeopeHHe aemecTBa B o6beMe )((H,ll,KOCTH, HaXO,lJ,.fflUHMC.ff B JOHe KOHTaKTa c TBep.n.oft: cf>aJOH, H ero nepeHOC nYTeM ,ll,Hcf>cf>YJHH B )((H,ll,­ KOH cf>aJe Ha cao6o,ll,Hbie noaepxHoCTH 1:1acTHU (nopowHHOK). TaKHM o6pa30M, 3a3op Me)J{,lly 1:1acTHUaMH yaeJIHlJHBaeTC.ff H C03,ll,aIOTC.ff B03- MO)((HOCTH ,ll,Jl.ff ,lJ,a.JlbHeHWeH yca,ll,KH (ueHTpbl 1:1acTHU c6JIH)((alOTC.ff).

npouecc nepeKpHCTa.JIJIH3aUHH BKJIIOlJaeT He Mettee TpeX 3JieMeH­ TapHblX npoueccoe: 1) pacrnopeHHe aemecrna MeJIKHX qaCTHU, T.e. nepexo.n. aTOMOB c noeepxHoCTH 3THX qacTHU B pacrnop (npouecc, qacTO HaJbJBaeMblH peaKuHeH Ha Me)((cf>a3HOH noaepXHOCTH); 2) .lJ.Hcf>-


 

<l>Y3HIO pacTBopeHHh X aTOMOB B )l(H,l(KOCTH Me)l()J.y IlOBepXHOCT51.MH

MeJIKHX H KpynHhlX qacTHU; 3) OTJIO)KeHHe pacTBopeHHOfO Bern.ecTBa Ha noBepxttoCTH KpynHh X qacrHu. PocT JepeH no 3TOMY MexaHH3MY npH )l(H,l(Ko$a3HOM cneKaHHH no;::i;qHm1eTCH TOH )Ke epeMeHHOH JaBH­

CHMOCTH, qTQ H pocT 3epHa npH co6HpareJihHOH peKpHCTaJIJIH3aU HH. B

o6rn.eM BH,Ue


HHH. J.13 Bh pa)f(eHHH (15.5) CJie,UyeT, qTO ,UJIH IlOJiyqeHHH yca,UKH 3a­

,UaHHOH eeJIHqHHhlnpH MaJIOH paCTBOpHMOCTH TBep,UOH <t>a3hlB )l(H,Zl­ KOH Tpe6yeTcH JHaqnTeJihHOe KOJIHqecTBO pacilJiaBa e nopornKoeoM TeJie, Tor.ua KaK npH 3aMeTHOH paCTBOpHMOCTH MO)f(HO orpaHHqHThCH tte60JihIIIHM co.uep)l(aHHeM JiefKOilJiaBKOH .uo6aBKH.

Tpembfl cmaiJUJl. Otta HBJIHeTCH 3aKJ110qnreJihHot:I H 06h1qtto ee tta-

3hIBaIOT mBepiJorjJa3HblM cneKaHueM. Ha 3TOH CTa,UHH cyw.ecTBeHHO B03-


d 11 - d 11 = Kt

0 '


(15.4)


pacraeT KOJIHqecTBO TBep,Uh X qacTHU, He pa3,UeJieHHh X )KH,llKOH npo­


r.ue d H d0 - TeKyID.aH H HaqaJihHaH cpe.umrn BeJiffqHHa 3eptta (qacTH­ Uh ) COOTBeTCTBeHHo; 't - BpeMH cneKaHHH; K - KOHCTaHTa.IloKa3a­

TeJlh CTeneHH 3aBHCHT OT Toro, KaKOH 3JieMeHTapHh H aKT onpe.uemieT

CKOpOCTh Bcero npouecca; HanpHMep, eCJIH 3TO nepBh H H3 YKa3aH­ Hh X BhlIIIe, TO n = 2, a eCJIH BTOpOH, TO n = 3. OrMeTHM, qTQ 3Haqe­

HHe n He Bcer;::i;a UeJIOqHCJieHHO H B HeKOTOph X CJiyqaHX OHO MO)KeT

MemlThCH BO epeMeHH.IlpH MaJIOM co.uep)KaHHH )KH,ZlKOH <t>a3hlKOH­ TaKT Me)f(,Uy qacTHUaMH TBep,UOH <t>a3hl 3HaqHTeJihHO ycJIO)f(HHeT KH­ HeTHKy HX pocra.

Ilpouecc ynJIOTHeHHH CBH3aH c nepeKpHCTaJIJIHJauHeH KOCBeHHO H B OTHOCHTeJihHO He60JihIIIOH creneHH, XOTH qacTo Ka)f(eTCH, qTo IlPHMaH H cyw.ecTBeHHaH CBH3h eCTh. 3aBHCHMOCTh yca;::i;KH Ha 3TOM

1 3
3Taile OT Ilpo,UOJDKHTeJihHOCTH H30repMffqeCKOH BhI,Uep)f(KH MO)KeT 6b1Th OilHCaHa COOTHOIIIeHHeM l:i V/ v - i; 1 (,UJIH c<t>epHqeCKHX qacTHU), a OT

V/ V - a-4/3.


CJIOHKOH, KOTOphle B3aHMHO npHneKaIOTCH (cpaCTalOTCH) H B IlOP_?IIl­ KOBOM TeJie 06pa3yeTCH )KeCTKHH «CKeJieT»; K TOMY )Ke B KaKOH-TO

MOMeHT Harpeea )l(H,l(KaH <t>aJa MO)KeT ncqeJttyTh (3aKpHCTaJIJIHJOBaThCH

BCJie,UCTBHe o6orarn.eHHH ee TYfOilJiaBKHM KOMilOHeHTOM HJIH paCTBO­ pHThCH B TYfOilJiaBKOH <t>aJe). B JII06oM H3 3THX c.rryqaeB KHHeTHKa yca;::i;KH

6y;::i;eT onpe,UeJIHThCH JaKOHOMepHOCTHMH TBep.uo<t>aJHOfO cneKaHHH,

KOTOph e paCCMOTpeHhlpattee.

OrMeTHM, qTo cpacTaHHe qacTHU (nopOIIIHHOK) MO)KeT 6bITh CJie,U- CTBHeM HeCKOJlhKHX MeXaHH3MOB nepeMern.eHHH Bern.ecTBa, HeKOTO­ phle HJ KOTOPh X npHBO,UHT K yilJIOTHeHHIO nopHCTOro nopoIIIKOBOfO TeJia, a tteK0Toph1e HeT. TaKne npouecchI, KaK .UH<t><l>YJHH qepeJ )KH,Zl­

KYIO <t>aJy (octtoettoii npouecc, o6ecne'IHBaIOW.HH pocT qacTHU) HJIH

caMO.UH<t><l>YJHH B npHilOBepXHOCTHOM CJIOe qacTHU TBep.uoii <t>aJhl, Bh13hIBaH pocT KOHTaKTa, He npHBO,ll,HT K YMeHhIIIeHHIO o6beMa nop B cneKaeMOM nopoIIIKOBOM Telle H, COOTBeTCTBeHHO, K YilJIOTHeHHIO.


pa.ueyca qacTHU l:i

MexaHH3M pacTBopeHHe-oca)l()J.eHHe npaKTHqecKH oKa3h eaeTC$1 cyrn.ecTBeHHh M, KOf,Ua KOJIHqecTBO )l(H,l(KOH <t>a3hl COCTaBJI$leT 5 % (o6'beMH.).

B CJiyqae MaJihIX KOJiffqeCTB )f(H)J;KOH <t>a3hl(no-BH,UHMOMY, <3-5 %),

KOTOpb e He MOryT Bhl3BaTh MexaHHqeCKyIO neperpynnHpOBKY' HO o6ecneqHeaIOT HaJIHqHe XHMHqecKoii neperpynnHpOBKH, yilJIOTHeHHe nopornKoeoro reJia MO)KeT HMeTh MecTo Ja cqeT YMeHhIIIeHHH o6oeMa TYroilJiaBKoH: <t>aJhl, ceslJattttoro c pacTBopettHeM HeKoToporo o6oeMa qacTHU B )f(H,UKOH <t>aJe. A.Il. CaBHUKHH ,UJIH 3Toro cJiyqasi: npe,UJIO)f(HJI aHaJIHTHqecKoe Bh pa)KeHHe ,UJIH oueHKH nopHCTOCTH cneqeHHOfO nopornKoeoro TeJia:

n= n - c ·c1 (I- n )


TaK )Ke KaK npH TBep.uo<t>aJHOM cneKamm, ynJIOTHeHHe nocJie JaBep­ rneHHH neperpynnHpOBKH qaCTHU npH )l(ff,llKO<t>aJHOM cneKaHHH MO­

)l(eT o6ecneqHTh TOJlhKO o6beMHOe Te'leHHe eew.ecTBa qaCTHU TBep,UOH Qroh .



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