Issue 14

V. Di Cocco et

alii, Frattura ed

Integrità Strutt

urale, 14 (2010)

52-63; DOI: 10

.3221/IGF-ESIS.

14.06

Compact dark grey phase 302

“Like δ” phase 181

Lamellar structure 66

Light grey phase 35

Table

2 : Zn + 0.5 %

wt Ti bath. I

ntermetallic ph

ases microhar

dness values[H

V 0.1

].

Ti tim lam

strongly influ es higher if c ellar structur

ences interm ompared to e + light gre

etallic phases the coating o y phase) thick

growth kine btained with ness is up to

tics (Fig. 8): a a Zn or Zn the 95% of

fter 180 s, co + Sn baths. “ the global co

ating thickn Mixed” zone ating thickne

ess with Ti is (compact d ss (180 s).

more than th ark grey phas

ree e +

Outer layer

Coating



600

500

400

Thickness [  m] 200 300

100

0

ence on the c ms 9) show t best behavio he coated pla orresponds t ecially for lo ating chemic s) (Fig. 10, 11 . 10) and fo ). Lower dipp orresponding at  inte n compressi parameter, the investiga ge level, due oth Fig. 13a 0 400 6 Time [s

oating and inte 00 800 1 ]

000

0 20

Figure 8 atings mechan ding mome rostructure o wt Sn bath: investigated racterized by ue with the b mage analysi nsidering gra nsidering co tribution foll the  phase: pagation co logous dama responding t nsidering cra rease of the lytical relatio rmetallic ph ot a frequen

: Zn – 0.5 %w ical resistance nt – bendin n coatings m higher “YS” bending ang lowest “YS ending angle s shows an e ins shapes, d atings obtain ows the “clas these cracks uld be arrest ge morpholo o higher dipp cks density intermetallic nship betwee ases thicknes t phenomeno

t Ti bath. Dip and damage m g angle dia echanical re values are ob les. The wors ” values: furt is observed. vident influe istribution an ed using a Z sical” morph could either ed either in gy. Focusing ing times. as a quantita phases dam n dipping tim s. However, n.

ping time influ icromechanis grams (Fig. sistance: the tained and t t behaviour c hermore, esp nce of the co d dimension n bath (Fig ology (Fig. 1 be arrested c  phase or the specime tive damage age, for all e and dama considering b

rmetallic phas

es thickness e

volution.

Co Ben mic 3 % the cha val Da (co Co dis to pro ana cor Co inc ana inte is n

he influence ur correspon tes are chara o the coating wer dipping al compositi and 12). cusing the te ing times im  -  interfac rface. Highe on side, only the increase ted dipping to the strong and 13b, it i

of coating ds to the co cterized by h obtained us times, a decr on, microstru nsile specim ply radial cra e or propaga r dipping ti some therm of the bend times. It wa influence of s evident tha

chemical c atings obtain igher resistan ing a Zn + 0 ease of the b cture and ph en side, inte cks nucleatio te in  phase mes are cha al cracks we ing angle al s not possib the dipping t cracks arres

omposition ed using a Z ce values fo .5 Ti bath, th ending mom ase morpho rmetallic ph n correspond . In this case racterized by re observed o ways implies le to identify conditions to t at  -  inter

and n + r all at is ent logy ases ing the an nly an an the face

57