Biomo phic Ce amics om Wood De i ed P ecu so s
J. Ramí ez-Ricoa
*
, J. Ma ínez-Fe nandeza, M. Singhb
a Dp o. Física de la Ma e ia Condensada. Ins i u o de Ciencia de Ma e iales de Se illa (ICMS).
Uni e sidad de Se illa. Consejo Supe io de In es igaciones Cien í icas (CSIC). A da. Reina
Me cedes S/N, 41012 Se illa, Spain
2 Ohio Ae ospace Ins i u e, 22800 Ceda Poin Road, Cle eland, OH 44142, USA
Joaquín Ramí ez Rico ob ained his PhD om he Uni e si y o Se ille in 2008, whe e he
is cu en ly Assis an P o esso in he Solid S a e Physics Depa men a he Uni e si y o
Se ille. He has au ho ed mo e han 55 pape s in pee - e iewed jou nals and his cu en
in e es s a e in na u al and bioinspi ed ma e ial, no el s uc u al ce amics and ce amic-
ma ix composi es, and in-si u ma e ials cha ac e iza ion using x- ay echniques.
Julián Ma inez Fe nandez is P o esso o Solid S a e Physics and Ma e ials Science, a
he Uni e si y o Se ille, Spain, whe e he also se es as he Di ec o o Resea ch Facili ies.
He has published o e 160 pape s in pee - e iewed jou nals and has been he PI o o e
20 na ionally and in e na ionally unded esea ch g an s. His esea ch in e es s include
he s udy o biomo phic silicon ca bide, single c ys al and polyc ys alline zi conia and
alumina, alumina-based composi es, silicon ni ide, elec onic ce amics, ce amic joining,
and single c ys als ibe s.
M i yunjay Singh is Chie Scien is , Ohio Ae ospace Ins i u e, NASA Glenn Resea ch
Cen e , Cle eland, Ohio. He has edi ed/co-edi ed hi y eigh books and i e jou nal
olumes, au ho ed/co-au ho ed en book chap e s/in i ed e iews and mo e han wo
hund ed i y pape s in jou nals and edi ed olumes. He is in ol ed wi h a ious ac i i ies
in p ocessing, manu ac u ing, joining and a achmen echnologies, and cha ac e iza ion o
ad anced ce amics and composi es, ligh weigh cellula ce amics, en i onmen conscious
ce amics, and po ous ce amic oams, high conduc i i y composi es and g aphi e oams o
he mal managemen sys ems, ce amic ma ix composi es o u bomachine y and
p opulsion sys ems, and a wide a ie y o ma e ials o ul a high empe a u e and
ex eme en i onmen applica ions.
*
Co esponding au ho – Email: [email p o ec ed]s, Tel: +34 954 550 936
Biomo phic Ce amics om Wood De i ed P ecu so s
Ma e ials de elopmen is d i en by mic os uc u al complexi y, in many cases inspi ed
by biological sys ems like bones, shells, and wood. In one app oach, one selec s he main
mic os uc u al ea u es esponsible o imp o ed p ope ies a designs p ocesses o
ob ain ma e ials wi h such mic os uc u es (con inuous- ibe - ein o ced ce amics,
po ous ce amics, ib ous ce amic monoli hs, e c.). In a di e en app oach, i is possible o
use na u al ma e ials di ec ly as mic os uc u al empla es. Biomo phic ce amics a e
p oduced om na u al and enewable esou ces (wood o wood-de i ed p oduc s). A
wide a ie y o SiC based ce amics can be ab ica ed by in il a ion o silicon o silicon
alloys in o cellulose-de i ed ca bonaceous empla es, p o iding a low-cos ou e o
ad anced ce amic ma e ials wi h nea -ne shape po en ial and amenable o apid
p o o yping. These ma e ials ha e ailo able mic os uc u e and p ope ies, and beha e
like ce amic ma e ials manu ac u ed by ad anced ce amic p ocessing app oaches. This
e iew aims o be a comp ehensi e desc ip ion o he de elopmen o bioSiC ce amics:
om wood empla es and hei mic os uc u e o po en ial applica ions o bioSiC
ma e ials.
Keywo ds: biomo phic; ce amics; wood; silicon ca bide; mechanical p ope ies; high
empe a u e; po ous ma e ials
1 In oduc ion
Silicon ca bide-based ce amics a e in e es ing ma e ials o key enginee ing applica ions,
especially hose equi ing good he momechanical pe o mance and speci ic p ope ies.
Howe e , in many cases SiC ma e ials do no ind ex ensi e usage due o hei high cos , as
hey a e ob ained a e y high sin e ing empe a u es and equi e expensi e
manu ac u ing (ex usion, molding, and machining, e c) echniques o p oduce complex-
shaped componen s. Fo his eason, SiC ce amics a e o en limi ed o niche applica ions.
Mac opo ous ce amics [1] and speci ically mac opo ous silicon ca bide ma e ials [2] a e
also in e es ing candida es o a wide ange o applica ions, especially in high empe a u e
en i onmen s in ol ing co osi e gases and high mechanical loading. En isioned
applica ions could be ca alys suppo s, he mal insula ion and managemen , o il a ion
o mol en me als, liquids o gases (such as in diesel pa icula e il e s o in gasi ica ion
p ocesses). Thus, he e is echnological po en ial in any p ocess ha allows one o ob ain
SiC monoli hs wi h educed p ocessing and machining cos s, bu also ha enables he
p oduc ion o po ous SiC ce amics, ideally wi h he same low cos a ibu es as ou lined
abo e.
A way o o e come hese p oblems is o syn hesize SiC ce amics by mel in il a ion o a
po ous ca bonaceous p e o m, ypically ob ained om he py olysis o a cas polyme , o
p oduce Reac ion Fo med SiC (RFSC) [3-10], a p ocess de eloped in he ea ly 90s ha is
nea -ne shape and allows o ob ain monoli hic SiC ma e ials wi h small amoun s o
un eac ed ca bon and silicon. The mic os uc u e o hese ma e ials depend on he
cha ac e is ics o he ca bon empla e and a e, in a way, inhe i ed om i , so by ailo ing
he empla e and inc easing i s mic os uc u al complexi y, a wide a ie y o SiC ma e ials
could be ob ained.
Biomo phic silicon ca bide (bioSiC) a e bio- empla ed SiC ma e ials ha s a wi h a
po ous ca bon sca old de i ed om na u al p ecu so s such as wood, which is la e
con e ed in o a SiC ce amic by a a ie y o me hods, mos commonly by mel in il a ion.
In his case, bioSiC is simply a ype o eac ion o med silicon ca bide in which he ca bon
empla e is ob ained by py olysis o wood, wi h he ad an age o a complex, hie a chical
mic os uc u e ha is he esul o millions o yea s o e olu ion and is op imized o
p ope ies such as luid anspo o high s eng h o densi y a ios [11].
Se e al ou es ha e been de eloped o ob ain SiC ce amics s a ing om wood-de i ed
ca bon p e o ms, in a way ha e ains mos o he mic os uc u al ea u es o he
empla e. Figu e 1 summa izes he h ee mos common ones: mel -in il a ion o liquid Si,
apo in il a ion o Si ei he di ec ly o h ough decomposi ion o SiO, o in il a ion o
SiO2 sols o gel p ecu so s ha eac wi h ca bon ia ca bo he mal educ ion o o m SiC.
All h ee p ocesses s a wi h a ca bon empla e ob ained om a wood p ecu so ha is
chosen acco ding o he desi ed p ope ies o he inal ma e ial, al hough in some wo ks
wood is imp egna ed wi h a SiO2 p ecu so so ca boniza ion and ca bo he mal educ ion
is ca ied ou in a single s ep. All h ee ou es also ha e in common ha hey a e nea -ne -
shape p ocesses because a e con e sion he size and shape o he inal ma e ial is equal
o ha o he p e o m, and any olume change associa ed wi h he eac ion is bu e ed by
he p ecu so ’s po osi y. This makes he con e sion o ca bonaceous p ecu so s in o SiC a
highly cos e ec i e me hod o p oduce SiC ce amics, po ous o o he wise, as any desi ed
machining can be done o he ca bon p e o m and only inishing will need o be pe o med
in he inal componen , g ea ly dec easing p ocessing cos s when compa ed o ypical
sin e ing and ho -p essing p ocesses ha migh equi e ex ensi e machining wi h
expensi e diamond ools. As an example o he complexi y o shapes ha can be p oduced,
Figu e 2 shows some componen s manu ac u ed by mel in il a ion o MDF de i ed
bioSiC/Si, whe e all machining was pe o med in he ca bon s age.
F om a his o ical poin o iew, he i s men ions in he li e a u e o using wood as a
empla e o ad anced ma e ials p ocessing is om O a e al. [12] who syn hesized “SiC
wood” by e ae hyl-o hosilica e in il a ion and la e ca bo he mal educ ion o wood
cha s. By ne and Nagle made impo an con ibu ions o he ield by laying he
g oundwo ks o wood py olysis wi h ma e ials applica ions in iew, such as op imiza ion
o hea ing a es, densi ies and sh inkage a ios, as well as hei e ec on mechanical
p ope ies [13-15]. La e epo s on biomo phic SiC a e om G eil and cowo ke s [16-19],
as well as Singh, who coined he e m “Ecoce amics” o e e o his new class o wood-
de i ed ma e ials [20, 21]. Se e al gene al pape s exis ha deal wi h he basics o
biomo phic SiC ma e ials [19, 20, 22-24].
2 Ca bon Templa es om Na u al Wood P ecu so s
2.1 Wood S uc u e and Composi ion
Wood can be conside ed a na u al ma e ial wi h a complex mic os uc u e op imized by
e olu ion o a good s eng h- o-densi y a io and luid anspo [25]. I is a po ous
ma e ial wi h densi ies in he ange 0.3-0.8 g cm-3 depending on species. The wide a ie y
o comme cially a ailable wood om di e en species, and he possibili y o using
indus ial wood p oduc s (pape , ca dboa d, cellulose pas e, pa icle and ibe boa ds)
allows he p ocessing o bioSiC ma e ials wi h a wide ange o p ope ies depending on
he a ge ed applica ion.
The s uc u e o wood has been s udied in de ail [26-29] and is composed o a s acking o
elonga ed, ubula cells aligned in he ee’s g ow h di ec ion. Wood can be b oadly
classi ied in o wo g oups a ending on i s mic os uc u e: in so wood om gymnospe m
ees such as coni e s, wood is composed o only one ype o cell, called acheids, while in
angiospe m wood hese a e su ounded by smalle scle enchyma ic cells wi h a
dis ibu ion ha is cha ac e is ic o each species. Among hem, small sized, hick walled
cells a e esponsible o he mechanical s eng h o wood and ecei e he name o
lib i o m “ ibe s”. In angiospe ms, acheids can ha e diame e s o e one hund ed
mic ons and a e esponsible o luid anspo (sap channels). Due o his s uc u e, po e
dis ibu ion in angiospe m wood is bimodal, while in wood om gymnospe m species he
po e size dis ibu ion is monomodal wi h channels in he ange o 30-50 μm. Figu e 3
shows a schema ic o wood om bo h angiospe m and gymnospe m p ecu so s.
The s uc u e and composi ion o cell walls de e mines he p ope ies o wood and wood-
de i ed p oduc s [30] and is simila o so and ha dwoods. This can be desc ibed as a
lamella o laye ed mic os uc u e whe e each laye is composed o cellulose,
hemicellulose and lignin (lignocellulose). Celluloses a e long polyme ic chains (up o 1 µm
in leng h) agg ega ed in o mic o ilamen s no mally aligned wi h he cell’s longes
dimension. Hemicelluloses a e sho e chains in e connec ing cellulosic mic o ilamen s
while lignin occupies he spaces le by he cellulose and hemicellulose ne wo ks.
By i s e y na u e, wood has a highly aniso opic s uc u e and i s p ope ies a e
desc ibed along h ee planes and hei espec i e pe pendicula di ec ions: axial, adial
and angen ial (Figu e 3). In addi ion o he p esence o po es and cells, wood shows wo
ypes o mac os uc u es: ays and g ow h ings. Rays a e ho izon ally aligned cells used
o nu ien s o age and adia e om he axis o he h ee, while g ow h ings a e
concen ic ings ha esul om changing po e sizes due o seasonal a ia ions in ee
g ow h. Due o he absence o sap channels, so woods om gymnospe ms a e usually
e e ed o as non-po ous, while ha dwoods om angiospe ms a e classi ied acco ding o
hei g ow h ing mo phology in o ing po ous o di use po ous: in ing po ous
ha dwoods sap channels a e seg ega ed in o bands while in di use-po ous wood he e is
no such seg ega ion (Figu e 4) [28, 29].
2.2 Py olysis o Wood
Py olysis o wood o he p oduc ion o ca bon empla es o be u he con e ed in o SiC
ce amics is pe o med in ine a mosphe es ( ypically A o N2) by slowly hea ing he
wood p ecu so s up o empe a u es in excess o 800°C. Du ing py olysis he di e en
polyme ic componen s o wood decompose in a s ep-wise manne wi h hemicellulose
b eaking-down i s a 200-260 °C, ollowed by cellulose a 240-350ºC and lignin a 280-
500°C and up. Figu e 5 shows ypical he mog a ime ic and loss a e pe uni
empe a u e cu es o he mal decomposi ion o Que cus ub a ( ed oak) wood,
exhibi ing he s ep-wise p ocess desc ibed ea lie [14]. Labeled egions co espond o (1)
loss o adso bed wa e , (2) polyme decomposi ion o hemicellulose and (3) cellulose as
well as lignin, (4) o al decomposi ion o cellulose and decomposi ion o emaining lignin
abo e 400 ºC (5). These s ages mo e o less co espond o hose desc ibed by Tang and
Bacon and o he s [31], in ol ing (a) he deso p ion o adso bed wa e up o 150 ºC; (b)
he spli ing o o cellulose s uc u e wa e be ween 150 and 240 °C; (c) depolyme iza ion
and b eaking o C-O and C-C bonds wi hin ing uni s e ol ing wa e , CO and CO2; (d)
a oma iza ion o ming g aphi ic laye s abo e 400 °C. In lignocellulosic ma e ials such as
wood he ca bon- o- ola iles mass a io inc eases wi h py olysis empe a u e, yielding
~90% ca bon a 600 °C, while he es is mos ly ni ogen and oxygen, wi h small amoun
o o he elemen s. Ash con en a ies wi h species and is be ween 0.5 o 3 w . % o he
ca bon monoli hs. Ashes om wood de i ed ca bon con ain mos ly sodium, magnesium,
phospho , po assium, calcium, manganese and i on.
Since c ack- ee monoli hs a e equi ed o use as empla es in SiC ce amic syn hesis,
py olysis mus be ca e ully con olled and pe o med a e y low hea ing a es, in he
ange o 1ºC/min up o 400-500 °C, whe e mos o he he mal decomposi ion o polyme s
akes place. Such a slow a e allows o gaseous eac ion p oduc s o e acua e he ma e ial
h ough he po es wi hou building up p essu e ha could lead o c acking. A e ha slow
ini ial s age, py olysis can be accele a ed o a es o he o de o 10-20 °C/min wi hou
a ec ing he in eg i y o he inal empla e. This slow p ocess has he ad an age o
p oducing high ca bon yields, in he 25-30 w . % ange when compa ed o he ini ial wood
mass.
I has been shown ha he densi y o he ca bon sca old ob ained by py olysis is
p opo ional o ha o he wood p ecu so , as was i s obse ed by By ne and Nagle as
well as o he s [14]. Some examples o his a e shown in Figu e 6, whe e a linea i o he
o m 𝜌𝑐=𝛼𝜌𝑤𝑜𝑜𝑑 is included. Values o he pa ame e 𝛼 a y wi h py olysis condi ions,
being mos ly a ec ed by he hea ing a e, bu is oughly ~0.8 o slow py olysis condi ions
such as hose ypically used o ob ain p e o ms o Si in il a ion.
Py olysis is accompanied by a sh inkage o he wood-ca bon monoli h, he ex en o which
is de e mined by he wood employed. I has been shown ha sh inkage in he adial and
angen ial di ec ions a y g ea ly om species o species, in he ange o 25-40 % leng h
educ ion, while axial sh inkage is simila o all ypes o wood and esul s in ca. 20 %
educ ion, al hough hese alues hemsel es depend on he py olysis empe a u e,
emaining cons an o e 1000 ºC (Table 1).
3 Biomo phic ce amics by mel in il a ion o ca bon p e o ms
P ocessing o bioSiC by mel in il a ion is well documen ed in he li e a u e, and
p o ec ed by pa en s [18, 22, 24, 32-40]. Basically, i in ol es he in il a ion o liquid
silicon in o he ca bon p e o m, by hea ing silicon powde in con ac wi h i a
empe a u es in excess o he mel ing poin o silicon ( ypically > 1450°C) in acuum.
Silicon quan i ies well abo e he s oichiome ic a io o ca bon a e ypically used o
ensu e almos -comple e con e sion o he ca bon empla e o SiC. Du ing eac ion, he
ca bon walls in he empla e a e con e ed in o β-SiC and he smalle po es in he
empla e, up o a po e diame e o app oxima ely 50 µm, a e illed wi h esidual silicon.
The Si, SiC and esidual ca bon con en o he inal bioSiC/Si composi e, as well as he
emaining po es’ size and dis ibu ion, i any, depend on he p ocessing condi ions,
amoun o excess Si, and he ana omy o he wooden p e o m.
In il a ion o SiC is a nea -ne shape p ocess, as he olume expansion associa ed wi h he
con e sion o C in o SiC is abso bed by he po ous s uc u e lea ing he ou e dimensions
unchanged. Va ela-Fe ia [41] pe o med a se ies o in il a ions using ca bon empla es
shaped as pa allelepipeds wi h sides o di e en leng hs and measu ed he dimensions o
he esul ing bioSiC/Si ma e ials (Figu e 8), wi h he esul ha ex e nal sample
dimensions did no change upon mel in il a ion ega dless o ini ial dimensions and
aspec a io.
In mel in il a ion, con e sion o ca bon in o SiC akes place by wo mechanisms which
a e ac i e depending on he ca bon wall hickness and opology. As will be elabo a ed
u he below, he main mechanism is dissolu ion o ca bon in o he mel ollowed by
ep ecipi a ion o mic on-sized (ca. 10 µm) β-SiC g ains a he ca bon-silicon in e ace:
silicon pene a es h ough he ca bon p e o m by capilla y e ec s and eac s wi h he
solid C spon aneously and exo he mically, wi h an en halpy o ΔH0=-117.77 kJ/mol [42]. In
dense a eas o he ca bon empla e he ca bon densi y can exceed he c i ical limi o
abou 0.97 g cm-3 which can esul in clogging o he po es p e en ing u he SiC
o ma ion by p ecipi a ion [5-7]. In hese cases solid s a e di usion and eac ion con ol
he o ma ion o SiC now a he SiC-ca bon in e ace, esul ing in he o ma ion o a nano-
g ained SiC phase (< 100 nm) [24, 39, 40, 43, 44].
This mechanism is co obo a ed i s by mic os uc u al obse a ions. Figu e 9 shows he
main mic os uc u al ea u es in bioSiC. Th ee di e en phases can be dis inguished:
polyc ys alline SiC shows in e media e con as unde backsca e ed elec ons in he SEM
(A, B and C), while Si appea s ligh g ey and esidual ca bon appea s black. Mic on-sized
SiC g ains can be ound inside channels whe e Si is majo i y (la ge channels wi h diame e
o e 5 µm). In small channels whe e Si is usually deple ed in he eac ion, a laye o nano-
sized SiC g ains can be obse ed a he in e ace be ween un eac ed ca bon and mic on-
sized SiC g ains, which a e ypically majo i y (panel D). Nanosized SiC is ound a SiC-
ca bon in e aces, bu no a SiC-Si in e aces. Whe e hin ca bon walls su ounding he
la ge channels exis ed, la ge g ained SiC appea s o ming laye s. Occasionally hese laye s
a e discon inuous and e en some isola ed SiC g ains a e obse ed ( igu e 9B, ma ked wi h
a ows). A he SiC-ca bon in e aces nanosized g ains can be ound o ming ose es
which is ypical o di usion-con olled g ow h [45], while mic on-sized SiC g ains a e
ace ed, ypical o a p ecipi a ion mechanism. Figu e 10 shows ansmission elec on
mic oscopy images o he in e aces in he egion o na ow and la ge channels, along wi h
selec ed a ea di ac ion pa e ns, co obo a ing he p e ious obse a ions.
Mic os uc u al pa ame e s o he esul ing ma e ials a e inhe i ed om he wood
empla e and he e o e show g ea a iabili y, which means ha hey can be ailo ed by
adequa e selec ion o he p ecu so . Table 1 shows se e al pa ame e s such as densi y,
silicon olume ac ion o po osi y o mel in il a ed bioSiC om di e en p ecu so s
and in compa ison wi h he ca bon empla e.
The β-SiC o ma ion has been shown o ollow i s o de kine ics, so he concen a ion o
each phase can be modelled using:
[𝐶𝑖]=[𝐶𝑖𝑓]+([𝐶𝑖0]−[𝐶𝑖𝑓])exp𝑘𝑡
Whe e k is he eac ion cons an and Ci is he concen a ion o phase i. [𝐶𝑖𝑓] inal
concen a ion o each phase, which is no necessa ily ze o since he e is excess Si as well
as un eac ed ca bon in he inal ma e ial. [𝐶𝑖0] is he ini ial concen a ion o phase i. Figu e
11 shows he e olu ion o each phase’s concen a ion wi h ime, along wi h i s using he
p e ious equa ion, om a wo k by Va ela-Fe ia e al. [39]. In hei wo k, he eac ion
cons an was de e mined as k=1.8 · 10-2 s-1, simila o ha measu ed by Pampuch e al.,
who s udied he SiC o ma ion p ocess by eac ion o bundles o C ib es 4-6 µm in
diame e wi h liquid Si a 1422 °C and 1439 °C [46, 47], and de e mined he eac ion
cons an k using DTA analysis. The possibili y o a di usion-con olled eac ion a e is no
compa ible wi h he measu ed k alues, as using da a om Hon e al. [45, 48] and
assuming he eac ion was con olled by di usion h ough he SiC laye , a alue in he
ange o 𝑘 =1.0−3.0·10−10𝑠−1 would be expec ed.
4 Mac opo ous SiC Ce amics
4.1 Residual Si Remo al
In he p ocessing o wood-de i ed SiC ce amics ob ained by mel in il a ion Si is usually
added in excess wi h espec o amoun needed o s oichiome ic eac ion, which esul s
in he p esence o esidual Si illing some o all o o iginal channels o he wood p ecu so .
Remo al o his esidual Si esul s in a mac opo ous SiC ce amic wi h elonga ed,
aniso opic and hie a chical po osi y ha is in e es ing o a wide ange o applica ions,
some o which a e discussed in sec ion 6. Se e al echniques a e a ailable o emo al o
his seconda y phase, he one mos o en used being chemical e ching using a mix u e o
HNO3 and HF in a mola a io o 1.67 acco ding o he ollowing eac ions:
3Si + 4HNO3 → 3SiO2 + 4NO + 4H2O
SiO2 + 4HF → SiF4 + 2H2O
The eac ion has been shown o be di usion limi ed and he e ching a e 𝑅 ollows ha o
a bounda y laye p oblem:
𝑅~(𝐷𝑡)−1/2
The e olu ion o he eac ion on as a unc ion o e ching ime is shown o ans e se
sec ions in Figu e 12 while Figu e 13 [49, 50] shows he eac ion on ad ance as well as
he eac ion a e in a log scale. The di e ences in e ching a es o he di e en di ec ions
wi h espec o he g ow h axis o he wood p ecu so we e a ibu ed o an e ec i e
di usion coe icien 𝐷𝑒𝑓𝑓 which depends on he appa en po osi y in each di ec ion due o
he aniso opic pe meabili y o he po ous bioSiC.
The po osi y o bioSiC a e emo al o emaining silicon esembles ha o he o iginal
wood p ecu so , howe e due o he olume expansion associa ed wi h he 𝐶+𝑆𝑖(𝑙)→
𝑆𝑖𝐶 eac ion, po es wi h sizes smalle han ~1 𝜇𝑚 close du ing he eac i e in il a ion
s ep and a e he e o e no p esen in he po ous bioSiC sca old. Pappacena e al. used
me cu y in usion po osime y o s udy he po e diame e dis ibu ion in bo h ca bon
sca olds ob ained om di e en wood p ecu so s and esul ing po ous SiC ma e ials and
ound a o al po osi y educ ion o ~10%, depending on species, mos ly de i ed om he
closu e o po es < 1 𝜇𝑚 du ing he in il a ion s ep [51]. The la ge mac opo osi y, wi h
diame e s 10 𝜇𝑚 and la ge , emained basically unchanged (Figu e 14). Connec i i y
p ope ies and excellen he momechanical pe o mance in high empe a u e
en i onmen s. By using wood as he ini ial empla e, highly complex mic os uc u es can
be ob ained, and po ous SiC ce amics wi h hie a chical po osi y can be ob ained. Since he
p ocess is nea ne -shape, biomo phic SiC can be p ocessed in o ela i ely complex shapes
cheaply. All hese ad an ages make hem in e es ing candida es o a wide ange o
echnological applica ions including ca alys suppo s, il a ion elemen s in combus ion
en i onmen s, o biomedical de ices, o name a ew.
Acknowledgemen s
Joaquin Rami ez-Rico and Julian Ma inez-Fe nandez g a e ully acknowledge suppo
om he Minis e io de Economía, Indus ia y Compe i i idad (MINECO), unde g an s
MAT2016-76526-R and MAT2013-41233-R. We also hank F. M. Va ela-Fe ia and J. Quispe
o ui ul discussions and o hei help in p epa ing some o he igu es.
Figu e Cap ions
Figu e 1. Di e en ou es o biomo phic SiC ma e ials and composi es by in il a ion o a
po ous ca bon p ecu so .
Figu e 2. Some componen s made o mel -in il a ed bioSiCp, in his case using MDF as a
p ecu so . Cou esy o biomo phic EBT.
Figu e 3. ( op) Schema ic o wood s uc u e and de ini ion o he h ee main planes used o
desc ibe o bo h gymnospe m and angiospe m specimens. (bo om) Ac ual
mic os uc u e de e mined om op ical mic oscopy in sec ions along he h ee planes.
F om [28].
Figu e 4. Axial sec ions o wood om h ee di e en species, a non-po ous so wood
(whi e pine), a ing po ous ha dwood ( ed oak) and a di use po ous ha dwood ( ulip
ee), highligh ing he h ee di e en ypes o g ow h ings. Rays a e signaled by ed
a ows, while g ow h ings a e ma ked by whi e a ows. Adap ed om [28].
Figu e 5. Weigh loss (TGA) analysis o he py olysis o Que cus ub a ( ed oak) wood
along wi h he a e o loss wi h empe a u e. Labeled egions co espond o (1) loss o
adso bed wa e , (2) polyme decomposi ion o hemicellulose and (3) cellulose as well as
lignin, (4) o al decomposi ion o cellulose and decomposi ion o emaining lignin abo e
400 ºC (5).
Figu e 6. Final ca bon densi y as a unc ion o wood densi y be o e py olysis. A linea i o
he da a is included. Solid poin s co espond o da a by By ne and Nagle while hollow
poin s co espond o ou own unpublished da a.
Figu e 7. SEM mic og aphs o axial sec ions o ca bon ob ained h ough py olysis o
di e en wood p ecu so s, highligh ing he esemblance o he ca bon sca old
mic os uc u e o ha o he o iginal wood p ecu so .
Figu e 8. Final dimensions o mel -in il a ed beech-de i ed ca bon as a unc ion o ini ial
dimension, o pa allelepipeds o di e en sizes and aspec a ios. The s aigh line has a
slope o one, indica ing ha he dimensions o he o iginal empla es we e conse ed.
Figu e 9. SEM mic og aphs o bioSiC ob ained om beech wood: A) Low magni ica ion B)
High magni ica ion mic og aph o SiC-Si in e aces. C) High magni ica ion mic og aph o
SiC-ca bon in e aces. D) TEM mic og aph o a SiC-ca bon in e ace showing a ose e o
nano-sized g ains [39].
Figu e 10. T ansmission elec on mic oscopy images and associa ed di ac ion pa e ns o
mel in il a ed bioSiC in he icini y o na ow channels (le ) and la ge channels ( igh ),
highligh ing he di e ences s a ed in he ex . In na ow channels a SiC/ca bon in e ace is
o med wi h a laye o nanosized g ains, whe eas in la ge channels SiC/silicon in e aces
a e o med be ween la ge (mic on-sized) g ains.
Figu e 11. Time dependen phase ac ions o ca bon, silicon and SiC o silicon mel
in il a ion o wood-de i ed ca bon p e o ms [39].
Figu e 12. SEM mic og aphs o ans e se sec ions o po ous bioSiC o di e en e ching
imes, om [49]. F om le o igh and op o bo om, e ching imes a e 0.5, 1, 2, 6, 18 and
64 h.
Figu e 13. E ching a e ob ained om SEM mic og aphs o sec ions o po ous bioSiC o
di e en e ching imes, o sipo wood [49] and MDF de i ed bioSiCp [50]. The e ching a e
ollows a -1/2 law ha con i ms he di usion limi ed na u e o he eac ion.
Figu e 14. Po e size dis ibu ions and po osi ies o (a) ca bon samples py olyzed o 1000
◦C and (b) silicon ca bide samples de i ed om ca bon py olyzed o 1000 ◦C om i e
wood p ecu so s as de e mined by me cu y po osime y. Cu es a e o se by (a) 20
olume% and (b) 30 olume% o ease o iewing. F om [51].
Figu e 15. T ans e se c oss sec ion om a 3D econs uc ion ob ained by x- ay mic o-
compu ed omog aphy o po ous bioSiC. Each colo ed egion ep esen s an in e connec ed
s uc u e, om [52].
Figu e 16. Mic os uc u e o po ous bioSiC ob ained om Si apo in il a ed-pine cha .
F om [53].
Figu e 17. Young’s Modulus and bending s eng h o ca bon p e o ms and bioSiC/Si
composi es ob ained om Balsa, Pine, Maple, Oak, Beech and Ebony p ecu so s, as a
unc ion o densi y, when he load was applied in he axial o adial o ien a ions. F om
[16]
Figu e 18. High empe a u e s ess s. s ain plo s o Re el RBSiC (89% SiC), Ce as a RB
(80% SiC), Ce as a RX (74% SiC), LS-RFSiC (91% SiC) and bioSiC (63% SiC, ab ica ed
om eucalyp us wood) in he axial di ec ion. A) 1000 °C and B) 1330 °C. F om [22].
Figu e 19. Comp essi e s eng h o di e en siliconized SiC ma e ials compa ed o he
s eng h o sin e ed SiC as a unc ion o SiC ac ion in he ma e ial. BioSiC ob ained om
wood wi h a ange o densi ies om 0.48-0.97 g/cm3 was s udied in bo h he axial and
adial di ec ions in he ange o 1000-1450 ºC. F om [104, 129].
Figu e 20. Rela i e s eng h o se e al siliconized SiC ce amics including bioSiC, as a
unc ion o SiC olume ac ion, a empe a u es 1000 – 1300 ºC. The p edic ions om he
minimum solid a ea models o se e al ideal mic os uc u es a e plo ed as solid lines
[102, 103]. The expe imen al alues o se e al siliconized SiC ma e ials including bioSiC
a e om [99].
Figu e 21. C eep s ain a es o bioSiC a 1175 ºC and 1600 ºC, a 250 MPa o applied
s ess. F om [99].
Figu e 22. Po ous BioSiC candle p o o ypes used o ho -gas il e ing expe imen s a
800ºC, om [113].
Tables
Table 1. P ope ies o ca bon p e o ms and Si-in il a ed SiC ma e ials om di e en ypes
o wood [16, 18, 95]
Balsa
Pine
Oak
Maple
Beech
Ebony
Paulownia
MDF
Py olysis
weigh loss
(w .%)
73.5
73.8
70.4
74.9
74.2
64.6
70.17
71.6
Py olysis
sh inkage (%)
axial
21
23
17
20
22
14
20.06
24.75
adial
22
28
28
30
32
25
20.81
23.95
angen ial
22
31
33
40
38
30
36.55
45.77
Densi y
(g/cm3)
Py olyzed
0.06
0.31
0.50
0.51
0.55
0.87
0.17
0.72
Si-
in il a ed
2.02
2.22
2.16
2.58
2.57
-
2.26
2.94
Po osi y (%)
(open/closed)
Py olyzed
22/70
21/57
30/40
43/22
42/21
23/20
75.81
42.65
Si-
in il a ed
11/14
11/14
8/5
3/5
3/2
3/-
14
3
Mean po e
diame e (µm)*
40
20
170
35
30
-
Si-con en
(w %)
67
50
27
23
37
-
57
10
* Open po e channels ee o Si.
Table 2. Mic os uc u al ea u es o pine-de i ed biomo phic SiC ob ained by apo
in il a ion o di e en p ecu so s, om [60]
Wood
Ca bon
empla e
Silicon ca bide
SiO
Si
CH3SiCl3
Densi y (g cm-3)
Geome ical
0.47
0.35
0.6
1.0
1.2
S u s
1.4
1.4
2.5
3.1
3.1
Po osi y (%)
67
76
80
70
60
Su ace a ea (m2 g-1)
-
46
16.1
3.3
0.5
S u hickness (µm)
2
1.5
1
2
4
Biaxial s eng h (MPa)
4
13
21
Table 3. Room empe a u e mechanical p ope ies o biomo phic SiC. 𝜎𝑐 and 𝜎𝑓 ep esen
comp essi e and lexu al s eng h espec i ely.
Wood
𝝆 (g·cm-3)
P (%)
Di ec ion
𝝈𝒇 (MPa)
𝝈𝒄 (MPa)
E (MPa)
KIC (MPa·m1/2)
Re .
Bamboo
2.38-2.51
51
Axial
120-180
1.75
[130]
Beech
2.50-2.61
Axial
180-200
250-290
[16]
2.50-2.61
Radial
90-130
220-280
[16]
2.10
Axial
228
438
2
[92]
2.50
Axial
216
1080
3
[92]
Po ous
53-55
Axial
330-480
115-130
1.1-1.4
[97]
Po ous
52-55
Radial
24-24
10-27
0.5-0.7
[97]
Bi ch
2.71-2.77
9
Axial
210-320
2.4-4.3
[130]
Bubinga
Axial
186-240
2.4-2.8
[22]
Eucalyp us
2.60
Axial
226
1410
4.2
[92]
2.63
Axial
290
1400
160-180
2.6-2.8
[91]
Mahogany
Po ous
45-53
Axial
160-190
35-110
0.7-1.22
[97]
Po ous
46-50
Radial
57-75
15-21
0.46-0.6
[97]
Po ous
48-50
Tangen ial
31-35
12-20
-
[97]
Axial
144
150-195
2
[21]
Maple
2.36
Axial
286-402
240-208
2.4-2.8
[21, 22]
MDF
2.68-2.72
<1
-
125-245
2.4-3.2
[130]
Pine
2.57-2.67
2
Axial
175-225
1.8-4.1
[130]
2.25-2.30
Axial
125
180
[16]
2.25-2.30
Radial
50-65
150-200
[16]
Popla
Po ous
59-64
Axial
135-250
30-76
0.8-1.1
[97]
Po ous
64-65
Radial
12
1
0-3
[97]
Po ous
58-60
Tangen ial
16-24
6-8
-
[97]
Red Oak
Po ous
47-50
Axial
220-270
28-60
0.9-1.8
[97]
Po ous
44-46
Radial
8-18
5
[97]
Po ous
44-47
Tangen ial
5-28
8
[97]
2.05-2.10
Axial
100-120
160-210
[16]
2.05-2.10
Radial
30-60
150-200
[16]
Sapelly
Po ous
54-59
Axial
50-127
15-22
[97]
Po ous
55-59
Radial
12-15
6-14
[97]
Po ous
54-57
Tangen ial
13-18
7-10
[97]
Re e ences
[1] A.R. S uda , U.T. Gonzenbach, E. Te oo , L.J. Gauckle , P ocessing ou es o
mac opo ous ce amics: A e iew, J Am Ce am Soc 89(6) (2006) 1771-1789.
[2] J.-H. Eom, Y.-W. Kim, S. Raju, P ocessing and p ope ies o mac opo ous silicon ca bide
ce amics: a e iew, Jou nal o Asian Ce amic Socie ies 1(3) (2013) 220-242.
[3] Y.M. Chiang, R.P. Messne , C. Te willige , D.R. Beh end , Reac ion-Fo med Silicon-
Ca bide, Abs Pap Am Chem S 200 (1990) 80-Ched.
[4] Y.M. Chiang, R.P. Messne , C.D. Te willige , D.R. Beh end , Reac ion-Fo med Silicon-
Ca bide, Ma Sci Eng a-S uc 144 (1991) 63-74.
[5] M. Singh, D.R. Beh end , Mic os uc u e and Mechanical-P ope ies o Reac ion-
Fo med Silicon-Ca bide (R sc) Ce amics, Ma Sci Eng a-S uc 187(2) (1994) 183-187.
[6] M. Singh, D.R. Beh end , Reac i e Mel In il a ion o Silicon-Niobium Alloys in
Mic opo ous Ca bons, J Ma e Res 9(7) (1994) 1701-1708.
[7] M. Singh, D.R. Beh end , Reac i e Mel In il a ion o Silicon-Molybdenum Alloys in o
Mic opo ous Ca bon P e o ms, Ma Sci Eng a-S uc 194(2) (1995) 193-200.
[8] M. Singh, T.A. Leonha d , Mic os uc u al cha ac e iza ion o eac ion- o med silicon
ca bide ce amics, Ma e Cha ac 35(4) (1995) 221-228.
[9] A. Wol enden, P.J. Rynn, M. Singh, Measu emen o Elas ic and Anelas ic P ope ies o
Reac ion-Fo med Silicon Ca bide-Based Ma e ials, J Ma e Sci 30(21) (1995) 5502-5507.
[10] M. Singh, R.M. Dicke son, Cha ac e iza ion o SiC ibe (SCS-6) ein o ced- eac ion-
o med silicon ca bide ma ix composi es, J Ma e Res 11(3) (1996) 746-751.
[11] T.X. Fan, S.K. Chow, Z. Di, Biomo phic mine aliza ion: F om biology o ma e ials, P og
Ma e Sci 54(5) (2009) 542-659.
[12] T. O a, M. Takahashi, T. Hibi, M. Ozawa, S. Suzuki, Y. Hikichi, H. Suzuki, Biomime ic
p ocess o p oducing SiC ''wood'', J Am Ce am Soc 78(12) (1995) 3409-3411.
[13] C.E. By ne, D.C. Nagle, Ca bonized wood monoli hs - Cha ac e iza ion, Ca bon 35(2)
(1997) 267-273.
[14] C.E. By ne, D.C. Nagle, Ca boniza ion o wood o ad anced ma e ials applica ions,
Ca bon 35(2) (1997) 259-266.
[15] C.E. By ne, D.C. Nagle, Cellulose de i ed composi es - A new me hod o ma e ials
p ocessing, Ma e Res Inno 1(3) (1997) 137-144.
[16] P. G eil, T. Li ka, A. Kaindl, Biomo phic cellula silicon ca bide ce amics om wood: II.
Mechanical p ope ies, J Eu Ce am Soc 18(14) (1998) 1975-1983.
[17] P. G eil, T. Li ka, A. Kaindl, Biomo phic cellula silicon ca bide ce amics om wood: I.
P ocessing and mic os uc u e, J Eu Ce am Soc 18(14) (1998) 1961-1973.
[18] H. Siebe , C. Ho mann, A. Kaindl, P. G eil, Biomo phic Cellula Ce amics, Ad Eng
Ma e 2(3) (2000) 105-109.
[19] P. G eil, Biomo phous ce amics om lignocellulosics, J Eu Ce am Soc 21(2) (2001)
105-118.
[20] M. Singh, Ecoce amics: Ce amics om wood, Ad Ma e P ocess 160(3) (2002) 39-41.
[21] M. Singh, J.A. Salem, Mechanical p ope ies and mic os uc u e o biomo phic silicon
ca bide ce amics ab ica ed om wood p ecu so s, J Eu Ce am Soc 22(14-15) (2002)
2709-2717.
[22] M. Singh, J. Ma inez-Fe nandez, A.R. de A ellano-Lopez, En i onmen ally conscious
ce amics (ecoce amics) om na u al wood p ecu so s, Cu Opin Solid S M 7(3) (2003)
247-254.
[23] H. Siebe , M. Singh, Mic ocellula ce amics om wood, Cellula Ce amics: S uc u e,
Manu ac u ing, P ope ies and Applica ions (2005) 122-136.
[24] A.R. de A ellano-Lopez, J. Ma inez-Fe nandez, P. Gonzalez, C. Dominguez, V.
Fe nandez-Que o, M. Singh, Biomo phic SiC: A new enginee ing ce amic ma e ial, In J
Appl Ce am Tec 1(1) (2004) 56-67.
[25] A.P. Scniewind, Concise Encyclopedia o Wood and Wood-based Ma e ials, Pe gamon
P ess, New Yo k, 1989.
[26] A.J. Panshin, C. de Zeeuw, Tex book o Wood Technology, Mc G aw-Hill, New Yo k,
1980.
[27] L.J. Gibson, M.F. Ashby, Cellula Solids: S uc u e and P ope ies, Pe gamon
P ess1988.
[28] R.F. E e , K. Esau, K. Esau, Esau's Plan ana omy : me is ems, cells, and issues o he
plan body : hei s uc u e, unc ion, and de elopmen , 3 d ed., Wiley-In e science,
Hoboken, N.J., 2006.
[29] J.M. Dinwoodie, Ins i u e o Me als., Wood : na u e's cellula , polyme ic, ib e-
composi e, Ins i u e o Me als, London ; B ook ield, VT, USA, 1989.
[30] R.H. A alla, J.M. Hackney, S uc u al Polysaccha ides in he Molecula A chi ec u e o
Plan Cell Walls, om Algae o Ha dwoods, Ma e ials Resea ch Socie y Symposium 255
(1992) 399-405.
[31] H.P. Yang, R. Yan, H.P. Chen, D.H. Lee, C.G. Zheng, Cha ac e is ics o hemicellulose,
cellulose and lignin py olysis, Fuel 86(12-13) (2007) 1781-1788.
[32] A.R. de A ellano-Lopez, J. Ma inez Fe nandez, F.M. Va ela Fe ia, R.E. Sepul eda, M.J.
Lopez Robledo, J. Llo ca, J.Y. Pas o , M. P esas, K.T. Fabe , V.S. Kaul, K.E. Pappacena, T.E.
Wilkes, P ocessing, mic os uc u e and mechanical beha io o SiC-based ce amics VIA
na u ally de i ed sca olds, Ce amics Enginee ing and Science P oceedings 27 (2006) 635-
650.
[33] P. Gonzalez, J.P. Bo ajo, J. Se a, S. Chiussi, B. Leon, J. Ma inez Fe nandez, F.M. Va ela
Fe ia, A.R. de A ellano-Lopez, A. De Ca los, A. Munoz, M. Lopez, M. Singh, A new gene a ion
o bio-de i ed ce amic ma e ials o medical applica ions, J. Biom. Ma e . Res. A (2008).
[34] P. G eil, T. Li ka, A. Kaindl, Biomo phic Cellula Silicon Ca bide Ce amics om Wood:
I. P ocessing and Mic os uc u e, J. Eu . Ce am. Soc. 18 (1998) 1961-1973.
[35] J. Ma inez-Fe nandez, A.R. de A ellano-Lopez, F.M. Va ela-Fe ia, M. Singh,
P ocedimien o pa a la Fab icación de Ca bu o de Silicio a pa i de P ecu so es Vege ales,
Spain, 2001.
[36] J. Ma inez-Fe nandez, F.M. Va ela-Fe ia, S. Lopez-Pombe o, A.R. De A ellano-Lopez,
M. Singh, C eep esis an biomo phic silicon-ca bide based ce amics, Ce amics
Enginee ing and Science P oceedings 22 (2001) 135-143.
[37] A. Muñoz, J. Ma inez Fe nandez, M. Singh, High empe a u e comp essi e mechanical
beha io o joined biomo phic silicon ca bide ce amics, J Eu Ce am Soc 22(14-15) (2002)
2727-2733.
[38] T. O a, M. Takahashi, T. Hibi, M. Ozawa, S. Suzuki, Y. Hikichi, H. Suzuki, Biomime ic
p ocess o p oducing SiC 'wood', J. Am. Ce am. Soc. 78(12) (1995) 3409-3411.
[39] F.M. Va ela-Fe ia, J. Rami ez-Rico, A.R. de A ellano-Lopez, J. Ma inez-Fe nandez, M.
Singh, Reac ion- o ma ion mechanisms and mic os uc u e e olu ion o biomo phic SiC, J
Ma e Sci 43(3) (2008) 933-941.
[40] F.M. Va ela-Fe ia, J. Ramí ez-Rico, J. Ma ínez-Fe nández, A.R. De A ellano-López, M.
Singh, In il a ion and eac ion- o ma ion mechanism and mic os uc u al e olu ion o
biomo phic SiC ab ica ed by Si-mel in il a ion, Ce amic T ansac ions 177 (2006) 93-
101.
[41] F.M. Va ela Fe ia, P ocessing, Cha ac e iza ion and Mechanical P ope ies o
Biomo phic Silicon Ca bide, Condensed Ma e Physics, Uni e sidad de Se illa, Se illa,
2004.
[42] R.C.E. Weas , Handbook o Chemis y and Physics, 55 h ed., CRC P ess, Cle eland, OH,
1974.
[43] C. Zoll ank, H. Siebe , Mic os uc u e e olu ion and eac ion mechanism o
biomo phous SiSiC ce amics, J Am Ce am Soc 88(1) (2005) 51-58.
[44] C. Zoll ank, H. Siebe , Mic os uc u e and phase mo phology o wood de i ed
biomo phous SiSiC-ce amics, J Eu Ce am Soc 24(2) (2004) 495-506.
[45] M.H. Hon, R.F. Da is, Sel -Di usion o C-14 in Polyc ys alline Be a-SiC, J Ma e Sci
14(10) (1979) 2411-2421.
[46] R. Pampuch, J. Bialosko ski, E. Walasek, Mechanism o Reac ions in he Sii + C Sys em
and he Sel -P opaga ing High-Tempe a u e Syn hesis o Silicon-Ca bide, Ce am In 13(1)
(1987) 63-68.
[47] R. Pampuch, E. Walasek, J. Bialosko ski, Reac ion-Mechanism in Ca bon Liquid Silicon
Sys ems a Ele a ed-Tempe a u es, Ce am In 12(2) (1986) 99-106.
[48] M.H. Hon, R.F. Da is, D.E. Newbu y, Sel -Di usion o Si-30 in Polyc ys alline Be a-SiC, J
Ma e Sci 15(8) (1980) 2073-2080.
[49] C. To es-Raya, D. He nandez-Maldonado, J. Rami ez-Rico, C. Ga cia-Ganan, A.R. de
A ellano-Lopez, J. Ma inez-Fe nandez, Fab ica ion, chemical e ching, and comp essi e
s eng h o po ous biomime ic SiC o medical implan s, J Ma e Res 23(12) (2008) 3247-
3254.
[50] J. Rami ez-Rico, C. To es-Raya, D. He nandez-Maldonado, C. Ga cia-Gañan, J.
Ma inez-Fe nandez, A.R. De A ellano-López, Po ous biomo phic SiC o medical implan s
p ocessed om na u al and a i icial p ecu so s, Ce amic Enginee ing and Science
P oceedings, 2010, pp. 203-214.
[51] K.E. Pappacena, S.P. Gen y, T.E. Wilkes, M.T. Johnson, S. Xie, A. Da is, K.T. Fabe ,
E ec o py olyza ion empe a u e on wood-de i ed ca bon and silicon ca bide, J Eu
Ce am Soc 29(14) (2009) 3069-3077.
[52] T.E. Wilkes, S.R. S ock, F. De Ca lo, X. Xiao, K.T. Fabe , X- ay mic o-compu ed
omog aphy o beech wood and biomo phic C, SiC and Al/SiC composi es, Philos Mag
89(17) (2009) 1373-1389.
[53] E. Vogli, H. Siebe , P. G eil, Biomo phic SiC-ce amic p epa ed by Si- apo phase
in il a ion o wood, J Eu Ce am Soc 22(14-15) (2002) 2663-2668.
[54] E. Vogli, J. Muke ji, C. Ho man, R. Kladny, H. Siebe , P. G eil, Con e sion o oak o
cellula silicon ca bide ce amic by gas-phase eac ion wi h silicon monoxide, J Am Ce am
Soc 84(6) (2001) 1236-1240.
[55] J.M. Qian, J.P. Wang, G.Y. Hou, G.J. Qiao, Z.H. Jin, P epa a ion and cha ac e iza ion o
biomo phic SiC hollow ibe s om wood by chemical apo in il a ion, Sc ip a Ma e
53(12) (2005) 1363-1368.
[56] J.W. Kim, S.W. Myoung, H.C. Kim, J.H. Lee, Y.G. Jung, C.Y. Jo, Syn hesis o SiC mic o ubes
wi h adial mo phology using biomo phic ca bon empla e, Ma Sci Eng a-S uc 434(1-2)
(2006) 171-177.
[57] D.A. S ei wiese , N. Popo ska, H. Ge ha d, Op imiza ion o he ce amiza ion p ocess
o he p oduc ion o h ee-dimensional biomo phic po ous SiC ce amics by chemical
apo in il a ion (CVI), J Eu Ce am Soc 26(12) (2006) 2381-2387.
[58] D.A. S ei wiese , N. Popo ska, H. Ge ha d, G. Emig, Applica ion o he chemical apo
in il a ion and eac ion (M-R) echnique o he p epa a ion o highly po ous biomo phic
SiC ce amics de i ed om pape , J Eu Ce am Soc 25(6) (2005) 817-828.
[59] H. Ghanem, E. Alkha eeb, H. Ge ha d, N. Popo ska, Oxida ion beha io o silicon
ca bide based biomo phic ce amics p epa ed by chemical apo in il a ion and eac ion
echnique, Ce am In 35(7) (2009) 2767-2774.
[60] P. G eil, E. Vogli, T. Fey, A. Bezold, N. Popo ska, H. Ge ha d, H. Siebe , E ec o
mic os uc u e on he ac u e beha io o biomo phous silicon ca bide ce amics, J Eu
Ce am Soc 22(14-15) (2002) 2697-2707.
[61] H. Siebe , C. Zoll ank, N. Popo ska, D. Almeida, H. Ge ha d, Gas phase p ocessing o
po ous, biomo phous TiC-ce amics, Eu o Ce amics Viii, P s 1-3 264-268 (2004) 2227-
2230.
[62] N. Popo ska, D. Almeida-S ei wiese , C. Xu, H. Ge ha d, H. Siebe , Kine ic analysis o
he p ocessing o po ous biomo phic i anium ca bide ce amics by chemical apo
in il a ion, Chem Vapo Depos 11(3) (2005) 153-158.
FIGURE 2
FIGURE 3
FIGURE 4
FIGURE 5
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Co k
Sapelly
Beech
Whi e Eucalyp us
Oak Bamboo
Red Eucalyp us
Balsa
Redwood
Whi e Pine
Basswood
Red oak
Ha d Maple
Lignum i ae
Wood densi y (g cm-3)
FIGURE 6
FIGURE 7
FIGURE 8
FIGURE 9
01x1042x1043x1044x1045x1046x104
0
20
40
60
80 Si
C
SiC
Time [s]
FIGURE 10
FIGURE 11
0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
10-3
10-2
10-1
100
bioSiC axial
bioSiC /
RF SiC
RB SiC
/SiC
FIGURE 18
0.0 0.2 0.4 0.6 0.8 1.0
10-2
10-1
100
RBSiC bioSiC/Si ( adial)
RFSiC bioSiC/Si (axial)
FIGURE 19
0.0 0.1 0.2 0.3 0.4 0.5
10-8
10-7
10-6
1175 ºC
1600 ºC
S ain (%)
FIGURE 20
FIGURE 21
