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7/26/2019 Alloys for Corrosive Environments Nickel
1/6
NICKEL
Alloys for
Corrosive
Environments
Awide range
of
nickel-base alloys
Copper,
molybdenum, and tungstenall increase
the
inherent
corrosionresistance ofnickel. In addi-
tion, mo y enum and tungsten are significant
in highly aggressive environments, strengthening agents, dueto their largeatomic sizes.
The
compositions of a fewnickel alloys are given
____________________________________________ in
Table
1.
These
are all wrought alloys, available
Rcnil B
Rebak*
in the formof plates, sheets, bars,pipes,tubes, forg-
P 1
~ ings, and
wires.
u~ roo ~
The
role of chromium is the
same
as that in the
Haynes
International Inc. stainless steels:
it
enhances the formation of pas-
Kokomo,Indiana sive surface films, in the
presence
of oxygen. These
passive
films impede
the
corrosion process.
Iron,
if added to the
nickel alloys,
also
affects
passiva
-
ickel-base
alloys provide outstanding tion. Silicon is
beneficial
at
high
corrosionpoten-
resistance
to specific chemicals, and tials,
where chromium-rich
passivefilms cannot be
some
are extremelyversatile and
able maintained.
It offers
extended protection through
-
to handle complex
process
andwaste the
formation
of protective (silicon-rich)oxides.
streams. In particular, the versatile
alloys
are much
less subject than stainless
s~.eels
ostresscorrosion Nickel
alloy metallurgy
cracking
pitting, andcrevice attack inhot chloride-
Most
of the corrosion-resistant nickel alloyshave
b e a r i n g s o l u t i o n s . A l s o , nickelalloys are among the a single-phaseatomic structure. In
common
with
fewmaterials able towithstand
hot
hydrofluoric the austenitic stainlesssteels, this is face-centered
acid, a chemical
that
is
very
corrosive to the reac- cubic. To optimize performance, designers of the
tive
metals titanium, zirconium,
niobium,
and nickel alloys
have
taken advantageof the fact
that
tantalum).
greater quantities
of elements such as chromium
The aim of this article is to describe the general and molybdenumare soluble in this face-centered
characteristicsof nickel-base alloysand to examine cubicstructure at temperatures in excess of 1000C
the effects of different
aggressive
environmentson (1830F) than at lower temperatures. Furthermore,
the corrosion behaviorof these alloys, added elements can
be
retainedwithin this phase
if thematerialsare water-quenched from the high
temperatures.
Therefore,
such alloys are
solution
a n n e a l e d todissolve anyunwantedsecond phases,
and water quenched to freeze-in thehigh-tem-
perature structure.
Second
phases arepossible, if they are subjected
to elevated
temperature
excursions, for example
during
welding. The
kinetics of second-phasefor-
Table
1
Nominal
compositions
of
nickel alloys
Nickel
alloy
t y p e s
The nickel alloys
canbe
categorized
according
to the
main alloying
elements, as follows:
Nickel: primarily forcaustic solutions.
Nickel-copper: primarily for
mild,
reducing
solutions,
especially
hydrofluoric a c i d .
Nickel molybdenum: primarily for strong,
reducingmedia.
Nickel-iron-chromium:
primarily for oxidizing
solutions.
Nickel-chromium-silicon:
primarily
for
super-
oxidizing
media.
Nickel-chromium-molybdenum:versatile
alloys
for all
environments.
The
terms reducing and
oxidizing
refer to
the nature of the reaction at cathodic sites
during
corrosion. Reducing solutions such as hydrochloric
acid
generally
induce
hydrogen evolutionat
ca
-
thodic
sites. Oxidizing
solutions such as nitric acid
induce
cathodic reactions
with higher
potentials.
*Merliber
ofASMInternational
Group
Alloy
Ni
Cu
Mo
Fe
Cr
Others
Ni
200 99.5
Ni-Cu
400 67
31.5
1 .2
Ni-Mo B -3
68.5
28.5
1.5 1.5
Ni-Fe-Cr 82 5
43 2 .2 3 30 2 1 .5 0.9 Ti
N i - F e - C r G-30 44 2
5 1 5 3 0
2 . 5 W ,
4Co
Ni-Cr-Si D-205
65
2 2 .5 6
20
5
S i
Ni-Cr-Mo
C-2 7 6 57 16 5 16
4W
Ni-Cr-Mo C- 4 68 16 16
Ni-Cr-Mo
C-22 56
13
3 2 2
3W
Ni-Cr-Mo
C-2000 60 1 .6 16 23
H2l 1 6
Reprinted from the February 2000 issue ofAdvanced Materials & Processes
7/26/2019 Alloys for Corrosive Environments Nickel
2/6
mation
depend critically on the amount of over-
alloying
and the contentof minor elements, such
as carbon
and
s i l i c o n
Carbon iskeptas low aspos-
sible
in
th ewrought alloysby
special
melting
tech-
niques. Silicon is also held at
low levels
in
most
of
the
wrought
alloys,
since
it is a
strong promoter
of
second
phases. Indeed, this iswhy the
Ni-Cr-Si
ma-
terials are not
more
highly
alloyed.
In
cast
nickel
alloys, a small quantity of silicon is necessary for
fluidity during pouring. However, it heightens the
importance of the solution annealing and
quenching
processes
with
c a s t i n g s .
Nickel
alloyperformance
Although
the
numberof environmentsencoun-
tered
within
the chemical
processindustries
is
vast,
the
performance
of m e t a l l i c materials is
most often
based on
their resistance
to a few
aggressive
inor-
ganic chemicals.
These are predominantly hy-
drochloric acid, sulfuric acid, and hydrofluoric acid.
Also
very important
are the effects of residuals such
as ferric ions.
Caustic solutions:
The
most common caustic
so
-
lutions
are sodium hydroxide or
caustic soda
NaOH) andpotassium hydroxide
or
causticpotash
KOH).
Whencontamination
with
ironor
stress
corrosion
cracking is
not
a
problem,
these
sub
-
stances are sometimes handled
in
carbon
s t e e l ;
how-
Fig.
T he
higher the
content
of
nickel,
the lowerthe
cor
-
rosion rate in caustic solutions.
Fig.
Corrosion rateof three nickel alloys
in 30 NaOH
as afunction of the temperature.
ever, nickel and nickel alloys are the
metals
that
offer the
highest
resistance to corrosion in caustic
solutions.
F i g u r e
shows the corrosion rateof
sev
-
eral alloys in
boiling
50
NaOH solution.
The
higher thenickel content in the a l l o y , the lower
th e
corrosion rate.
The
corrosionresistanceofnickel is
a
consequence of the
formation
of
insoluble
metal
hydroxides
and salts,which slow down the
disso
-
lution rateof the alloy.
Figure 2 shows the corrosionrateof
three
alloys
in 30
NaOHas a function ofthe temperature.Ni-
200
o f f e r s
the
best resistance to corrosion,especially
at the
higher
temperatures.
Sodium h y p o c h l o r i t e
b l e a c h
can be
considered
a
m i l d l y
oxidizing
alkaline salt
that
canalso be
suc
-
c e s s f u l l y handledby
a nickel
a l l o y ,
e s p e c i a l l y
of
th e
Ni-Cr-Mo
group
(C-276
or C 2000 alloys).
Hydrochloric
acid:
Hydrochloric acid
HC1) is
very corrosive, and its
aggressiveness
can change
drastically depending on the
acid
concentration,
temperature, and
contamination
of the
acid e.g.
ferric ions). In general, steels, stainlesssteels, and
copper alloys
cannot
tolerate HCI .
O f
the
reactive
metals,
titanium does
notresist HC1
well
zirco-
nium is s a t i s f a c t o r y forpure acid, and
tantalum
of
-
fers
excellent
performance.
F i g u r e
3
shows
the
cor
-
Chemical
processes
most
often
involve
a few
aggressive
chemicals.
_I~ss
~oing ~15oc~
100- ~O/~OH
10- C-22
4
8250 06
Ni20060 0 0l0~
276 0 --2 0
1-
- 0
0.01
V
20 40 60 80 10 0
Nickel Content
Weight )
1
E+ 6
~ -T ~ 1
E+ 4
E Boiling Solutions
1E 5 316SS ~ 1E 3~
1E 4-~ lE 2~
lE 3-~-
18+2~
1E+0~
2
15 1 ~ IE-1
15 0
r I
~__~ ~702 0 -
15 .2
:c1~
Thnlalom.,
1E-1 T
~~
~1~
8
12 16 20
4 -
Hydrochloric
Acid
)
Fig. 3 Thisgraph
shows
the corrosion of
commercial
alloys
of stainless steel titanium nickel and zirconium
in boiling HCI solution.
5zi, UCI
s C-2000
~
3l6t~S
9 ~33
C276
4 400
023
1563 ~ 30 ~F 3 I
~ 54-200
1 E O 1
,5- 625
15 2 ~ / /
1E*0~
.5
1 1 5
~
15*1
~
isle
o
6~
0
3 1E*0
E-2
0
1E-1 ~ i 3
100 150 20 0 250 30 0
Temperature C)
1E+4
1E+3 ~
0~
S
5 15*2
Ct
0
15*1
50
15*0
15+2
a
5
1E*l
I
15-1 Ct
0
IE- 2
12 0
IC-I
0 40 80
Temperature
CC )
Fig. 4
Effect
oft/ic
temperature
on t he co rros ion rate of
nickel-basealloys and
316L
stainless s teel i n 5 HC1.
7/26/2019 Alloys for Corrosive Environments Nickel
3/6
Temperature
0 to5
HC1
5 to 10
HC1
10
to
20 HC1
79C
to
B.P.
(175F toB.P.)
Ni-Mo
(B-3) Ni-Mo
(B-3) Ni-Mo (B-3)
52C to 79C
(125F to 175F)
Ni-Mo (B-3)
Ni-Cr-Mo
(C-2000)
Ni-Cu
(400)
Ni-Mo
(B-3) Ni-Mo (B-3)
RT to52C
(RT
to
125F)
Ni-Mo (B-3)
Ni-Cr-Mo
(C-2000)
Ni-Fe-Cr (G-30)
Ni-Cu (400)
Ni-Mo
(B-3)
Ni-Cr-Mo
(C-2000)
Ni-Mo (B-3)
Ni-Cr-Mo
(C-2000)
For
each
alloy group,
on e example
isgiven.
BP.
boiling
point, RT
=
room temperature.
Oxidizing
impurities
rosion behavior ofseveral alloys in boiling solu- Table
2
Nickel alloy selection forpure HC1*
tions of pure hydrochloric acid. At intermediate
acid concentrations, the corrosion rateof 316SS can ________________________________________________________
bemore than four ordersofmagnitude higher than
the corrosionrate of zirconiumor
B -3
alloy. ___________________________________________________________
Figure 4 shows the effect of
temperature
on the
corrosion
rate
of several nickel-base
a l l o y s and 316L
SS.
Formostof the alloys, the
corrosion
rate
grad
-
ually
increases as the temperature increases.
For C-2000 alloy, a threshold temperature is
reached,
below which the corrosion rate
isnegli
-
gible
due to passivation
of
the
alloy;
above the
threshold temperature, the corrosionrate increases
rapidly
as the temperature increases.
However, forthe
B -3 alloy,
the corrosion ratedoes
not
depend
strongly on temperature. The fact that
the corrosion
rate
ofthe
B -3
alloy at the boiling
tem
-
p e r a t u r e is
lower than the corrosion rateat temper- centrations
and
temperatures, whereas
316L
stain
-
atures below the
boiling
point, could
be related to less steel is
generally unsuitable forhydrochloric
the
amount
of dissolved
oxygen
at
each tempera- acid
service.
Alloys 4 00
and
82 5 may
be
adequate
ture
(which decreasesas the
temperature
increases). at
room
temperature.
The
nickel alloys
that
should be
considered for TitaniumGrade2, as well as the stainless steels
service in pure hydrochloric
acid
are
shown
in containing 6 molybdenum (such as
254SM0) ,
are such as
Table 2, a nine-segment chart organized by
con- resistant
to
low
concentrations ofHCI.
Theresis-
ftrric ions
centration and temperature. The selections are tance of ,irconium r-702 alloy) to
pure
hy- are
based
on
evidence that alloys from the chosen
drochioric
add
is
exceptional;however, in
the
pres
-
groups exhibit
rates
of 0.5
mm/y
(2 0 mpy)
or
less ence of ferric ions Zr-702
would be
subjected to
detrimental
over significant concentration
and temperature
pitting corrosion. Tantalum also
exhibitsexcellent to
Ni Mo
ranges,
within
those
segments.
Table 2 covers
only resistance
to
pure
HO solutions
up
to175C (350F),
concentrations up
to2 0
wt ,
the
maximum that
but it is
unacceptable
if
the HC1
solution is
conta-
an i U
can
be
sustained in aboiling solution. It indicates minatedwith fluorides.Fluoride ion impuritiesare allot~s.
that, of the nickel alloys, only those from the nickel- also damaging to titanium and zirconium alloys.
molybdenum
group are suitable at
high
concen-
Su~fitric
acid:
Sulfuric acid is the
mostwidely
trations
and
temperatures. used
acid
in
all
branches
of
industry. Sulfuric
acid is
In fact,molybdenum is
the
mostimportant al less
corrosive thanhydrochloric
acid, and its ag-
loying
element forgood
performance
of nickel-base
gressiveness
is highly
dependent
on acid concen-
alloys
in pure
hydrochloric
acid
educing condi-
tration, temperature, and the
presence
of impuri-
tions). The
corrosion
ratein boilingHO decreases ties. Figure 6 shows the corrosion rate of several
asthe content of
molybdenum i n
the alloy increases, alloys inboiling pure
sulfuric
acid. Sulfuric
acid
Oxidizing impurities
in
hydrochloric
acid,
such
aqueous
solutions up to
96
wt are
stable
at
the
as
ferric ions
(F ), are
detrimental
to
the
perfor- boiling
point.
mance of the nickel-molybdenum and nickel- However, theseboilingpoints increase
dramati
-
copper alloys.Under suchconditions, the nickel- cally at themedium and high concentrations. For
chromium-molybdenum
alloys constitute the
best
example, at 20 sulfuric acid, the boiling point is
choice,
because they
aretolerant of residuals, al- 104C (220F), at 50 is
123C
(253F), and at
80
is
though
they
are temperature-limited at the higher 202C
(395F).
TitaniumGrade 2 and 316L stain-
acid
concentrations. less steel are notadequate forsulfuric
acid
service.
Figure 5 shows the corrosion rateof several
al
-
loys inboiling 2.5 HC1 solution as a function of
theconcentration
of ferric
ions in the solution. The
corrosion rates of 316L SS and alloy
82 5
are
high,
and are not affected significantly by the presence
of
f e r r i c
ions.
Thecorrosion
rate
of
the
B -3
alloy
in
the pure boiling
acid
is
low,
but
it
gradually in-
creases as the
content
of ferric
ions
in the solution
increases. Thecorrosionrate of C-2000 in pureacid
is higher
than that
ofthe B -3 alloy;however,a con-
tent
ofonly 3 ppm Fe
3~
produces a decline in its
corrosion
rateby almost
two
orders of
magnitude.
The oxidizing ferric ions
promote the
passivation
of C-2000 by the formation of a chromium-rich
oxide film that reduces the uniform
dissolution
rate.
Figures
3, 4,
and
5 show
t h a t
the
nickel
chromium-molybdenum alloys suchas
C-2000
are
resistant to
HO in
a
moderately broadrange
of
con-
Fig. 5 Corrosion rate ofcommercial alloys in a solution of
I I C l contaminatedwithferric
ions.
7/26/2019 Alloys for Corrosive Environments Nickel
4/6
Figure
6
shows that
theB -3 alloy has the
lowest
corrosionrate ofthe nickel alloys inboilingsulfuric
acid. Only at the highest acid concentration (>70 )
does
the
corrosion
rateof B -3
start
to increase.
The
strongconcentration effecton the
corrosion
rateof
zirconium alloy 7 02
is
also revealed.
Figure 7 shows the effectof
temperature
at a
con
-
stant
acid
concentration.As in the case of HC1
so
-
lutions
(Fig. 4 ) , the
temperature
has a
strong
influ-
ence on the
corrosion rate of Ni-Cr-Mo and
Ni-Cr-Mo-Fe
alloyssuch
as
C-2000
and G-30; how-
ever,
the
corrosion
rate
of a
Ni-Mo
alloy
(B-3)
is
al
-
mostunaffected by the temperature
low
activa-
tion
energy).
Table 3 shows the types of nickel
alloy
that
should be considered for service in pure
sulfuric
acid, depending on the acid concentration and
tem
-
perature.
The
selections are basedon evidence
that
alloys from the chosen groups exhibit
rates
of 0.5
mm/y
(2 0 mpy) or less over significantconcentra-
tion and temperature
ranges, within
those
seg
-
ments. The
important
revelationsof this
chart
are
the excellent
corrosion
resistance of the
nickel-
molybdenum
a l l o y s in
pure
sulfuric
acid,
thegood
resistance of
thenickel-chromium-molybdenum
materials,
and
the usefulness
of
several
groups
at
lower
concentrations
and temperatures.
Fig. 7
Th is g raph
shozos the effect of tens
perature
on the
corrosion
rate
of
several
nickel
base alloys.
The
presence of contaminants in
sulfuric
acid
could change the corrosionrate ofthe a lloys . F igure
8 shows the corrosion rateof alloysB -3 and C-2000
inpure sulfuric
acid
and in
sulfuric acid
contami-
nated with 2 00 ppm
chloride
ions s NaCl). The
corrosion rate of
both
alloys increases if the
solu
-
tion
is contaminated;
however, the effect seems
more pronounced for
the
Ni-Cr-Mo
alloy.
Hydro,fluoric
acid: Hydrofluoric
acid
is extremely
corrosive and unique in its corrosion behavior.
Many industriesuse it as anaqueous solution, as
a
fluorinating
agent,
for
metal pickling,
and in
the
manufacturing
of semiconductors.
Nickelalloysare the
only
alloys that arewidely
chosen forhandling aqueous solutions ofhydro-
fluoricacid,
because
stainless steels, titanium, zir-
conium,and tantalum are
not
adequate for this ap-
plication.
The
most
common alloy for handling
aqueous
hydrofluoric
acid iswroughtMonel 400.
This alloy has excellent corrosion resistance in the
absence ofair or
otheroxidizing
species; however,
if
oxygen is present, itis subject toaccelerated inter-
granular attack,
especially
in thevapor phase.
Figure
9
shows
the
corrosionrate
of three nickel
alloys in the liquidphase immersed conditions),
and in
the
vapor phasewherevapor condenses
on
the
coupons
(forthese tests, the ingress of air to the
testingkettles
was
not restricted).
Alloy 400 corrodes athigh rates in the vapor
phase,
because
of intergranular attack.
The
corro-
sionrate of alloy 4 00
is
higher at
thehigher
tem-
perature,
both
for the liquid andvaporphases.
Thecorrosion
rate
of theB -3 alloy
is
lowerin the
vapor phase
than
in the liquid phase. Moreover, at
thehigher temperature, its
corrosion rate
inboth
phases
is
lower. In general, thecorrosion rateof B -
3 is
not
highlyinfluenced by the temperature;
there
-
fore, the lowercorrosionrate at the
higher
temper-
ature
can
be
the result of
a
lower
availability
of
oxygen
both
in the liquid and vapor phases. The
B -3 alloy is subject to
pitting
corrosion inHFenvi-
ronments,bothin
the liquid
and vapor
phases.
The C-2000
alloy
showed
the lowest corrosion
rate in all the
tested
conditions.
Laboratory
testing
hasalso shown
that
the
corrosion
rate of C-2000 in
Fig. 8
This
graph
shows the
effect
ofcontamination by
chlorides
in sulfuric acid on a llo ys B -3 and C-2000..
Hydrofluoric
acid is
extemely
corrosive.
20 40 60
Sulfuric
Acid
Concentration C /
Fig. 6
Corrosion
rate in boiling sulfuric acid.
1E*3 ~
Immersion
r sts
Boiling Solutions
Full
Syrnbols~
Mded
200
ppm C1
s
is-I
v C
2000
1E+3 ~--- --------- - i
60
i-i
2
so
4
lE+l
~ C2000
1E+2 ~
~g
:H-u B-I
5
4 1 0
L
1El
Ct
0
I- -
1E+0 -
I
B. P
I
IE-1 ~ ~ ~- C~
0 40 80 120 180
Femperature
C)
t
a
15+0
I
1E-l ~
0
St
0
to
15*1
-C
1 E C 2
1E-l
3
C
It
1E*0
I
1E-l ~
if
0
C
N
-rr
l
1F-2
IE-l--
1
I 3 ~
0
20
40
H
2
S0
4
Concentration ~
60
7/26/2019 Alloys for Corrosive Environments Nickel
5/6
Table3 Nickel alloys forpure
sulfuric
acid*
thevaporphase
is
time
dependent;
that
is,
the rate
decreases
as the
test
duration in-
creases.
Thisisprobably dueto the
gradual
development of a protective
film
on the
surface.
The
corrosion rates of alloys 4 00
and C-2000 in the liquidphase do
not
depend on
the testing time.
Nickel-base alloysare
susceptible
tostress
corro
-
sioncracking in
the
presence
of
aqueous solutions
ofhydrofluoric acid.
Not
all
nickel alloysare equally
susceptible toSCC
under
thesame conditions; that
is,
cracking isstronglydependenton several variables,
such as alloy composition, temperature, presence
of
o x y g e n , and
liquid vs.vaporphase.
Mixtures
of
hydrofluoricandnitricacid
are typ-
ical in
themetal industryforpickling
processes. In
a solution of 20
HNO
3
containing different
amounts of h y d r o f l u o r i c acid, the lowestcorrosion
rate corresponds to G-30 , a Ni-Cr-Fe
alloy
con-
taining30 chromium,
The
high
chromium
con-
tentpromotes
the
formation
of a
passive
film in the
oxidant nitric acid, and
does
notseem tobe readily
attacked
by thehydrofluoricacid.
Other acids:
Phosphoric acid (H
3
PO
4
)
is
not
highly
corrosive
to
nickel
alloys.
Two distincttypes
of
phosphoric acid
are
encountered
in
the industry.
The
pure
reagent
grade) acid ismade from ele-
mental phosphorus, derived fromphosphate rock.
This is oxidized, then
reactedwith water.
Onthe
otherhand, the preferred
type
ofphosphoric acid in
the
agrichemical
industriesis madeby reacting
phos
-
phate rock
with sulfuric acid.
This
containsseveral
impurities, notably sulfuricacid, s i lica, and chloride
and fluoride ions,
which
markedlyaffect the corro-
sionbehavior
of the acid. The
levels
of these impu-
rities
vary
dependingon the source of the rock, and
differentbatchesof this so-called wetprocessacid
can
vary
considerably in their corrosivity.
The
G-30
alloy is
generallypreferred to handle
the wetprocess phosphoric acid. Forpure phos-
phoric acid, Ni-Mo (B-3), Ni-Cr-Mo (C -276 , C -2000)
and Ni-Fe-Cr (G-30) alloys can function in up to
85 acidup to theboiling point.
The
corrosion
behavior of hydrobromic acid
HBr)
is
similar
to
that
of
hydrochloric
acid;
how
-
ever,HBr is less
aggressive. Therefore,
when
pure
and hot,HBr isbest
handled by
a Ni-Mo alloy
such
as the B -3 alloy. -A
Ni-Cr-Mo
alloy
such
as C-2000
isversatileand is s u i t a b l e for
most
applications
con
-
taining HBr, especiallyin solutions contaminated
Temperature
0 to 30 H
2
S0
4
30 to 70 H
2
S0
4
70
to96 H
2
S0
4
79C toB .
P.
175F to B.P.)
Ni-Mo (B-3)
Ni-Cr-Mo C - 2 0 0 0
Ni-Fe-Cr
G - 3 0
Ni-Cr-Si (D-205)
Ni-Cu
(400)
Ni-Mo (B-3) Ni-Mo (B-3)
52C to 79C
(125F to
175F)
-
Ni-Mo (B-3)
Ni-Cr-Mo (C-2000)
Ni-Fe-Cr (G-30)
Ni-Cr-Si
(D-205)
Ni-Cu (400)
Ni-Mo (B-3)
Ni-Cr-Mo
(C-2000)
Ni-Fe-Cr (G-30)
Ni-Cr-Si
(D-205)
Ni-Cu (400)
Ni-Mo (B-3)
Ni-Cr-Mo (C-2000)
RT
to
52C
(RT to 125F)
Ni-Mo (B-3)
Ni-Cr-Mo (C-2000)
Ni-Fe-Cr
(G-30)
Ni-Cr-Si
(D-205)
Ni-Cu
(400)
Ni-Mo (B-3)
Ni-Cr-Mo C - 2 0 0 0
Ni-Fe-Cr (G-30)
Ni-Cr-Si (D-205)
Ni-Cu
(400)
Ni-Mo (B-3)
Ni-Cr-Mo
(C-2000)
Ni-Fe-Cr
(G-30)
Ni-Cr-Si (D-205)
For each al loy
group,
on e example is given.
withoxidizing species.
Organic acids
such
as formicand acetic
acids
are
nothighly corrosive for
nickel
alloys.
At
tempera-
tures
higher than 100C (212F) , the B -3 alloy
Ni-
Mo) would offer the lowestcorrosion
rate.
N i t r i c
acid
is a
strong oxidizing
acid
which be
sides zirconium and titanium alloys, can
behan
-
dled
with
stainlesssteelsornickel alloys
containing
at least 15 chromium othernickel alloyssuch as
B-3, Ni-200, andMonel 4 00 cannot
be
used in nitric
acid). For
mostpurposes,
anickel alloy
isnot
re-
q u i r e d
to
handle
nitric acid;however,nickel alloys
resist corrosionbetter
than
s t a i n l e s s steels in cases
where the
nitric
acid
is
contaminated
with
chlorides. R
Fo r
more
information: D r. Rail
B .
R e b a k
(765/456-6262) ,
is a
Corrosion
Engineer;Paul Crook ( 7 6 5 / 4 5 6 - 6 2 4 1 )is
Manager, Technical Services,
at
Haynes
Intemational,
1020
W.
Park
Ave., Kokomo, IN 46904 ; e-mail:
[email protected]; [email protected];
Web
site:
www.haynesintl.com.
References
1. Corrosion Engineering, by MG.
Fontana:
McGraw-Hill ,
Inc.,
New
York , N .Y . ,
1986.
2.
Process
Industries Corrosion Theory
and
Practice, by
J .K.
N e l s o n :
NACE
Intemational, Hou ston,
Texas,
1986.
3.
Corrosion
Control
in the Chemica l Process
Industries,
by
C.P.
Dillon:
NA CE International , Houston, Texas, 1994.
Corrosion
Resistance
Tabie,~,by P.A. Schweitzer, (New
York,
NY ; Marcel D ekker ,
Inc.,
1995.
5
T a p e r
382, by
JR .
Crum
G.D. Smith,M.J.
McNallan,
and
S H i r n y j : C o r r o s i o n / 9 9 ,
N E International,
Houston, Texas, 1999.
Phosphoric
acid is
not
highly
corrosive
to nickel
alloys.
12
U
400
Nickel-base
alloy
Fig. 9
Corrosion
ofnickel alloys in hydrofluoric
acid
liquid
an d vapor.
7/26/2019 Alloys for Corrosive Environments Nickel
6/6
A n a h e i m
C a l i f o r n i a
9 2 8 0 6
S t a d i u m
P l a z a
1 5 2 0
South
Sinclair Street
T e l : 714-978-1775
8 0 0 - 5 3 1 - 0 2 8 5
F A X : 714-978-1743
Houston, Texas 77041
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T e l : 713-937-7597
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F A X : 713-937-4596
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Tel:
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ter,Ml 2ER FAX: 39-2 2 82 82 73
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