Name: high temperature fabrication of nanostructured yttria-stabilized-zirconia (ysz) scaffolds by in situ carbon templating xerogels
Uploaded: 2017-04-16T15:00:00.000+00:00
Duration: 7 min 13 s
Description: Watch this Scientific Journal Video about High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia YSZ Scaffolds by In Situ Carbon Templating Xerogels at JoVE.com

Questo lavoro è stato sostenuto dalla Wake Forest Dipartimento di Chimica e il Centro Wake Forest Energia, Ambiente e sostenibilità (CEES). Ringraziamo Charles Mooney e l&#39;analitica Instrumentation Facility della North Carolina State University per l&#39;assistenza con l&#39;imaging SEM.

1. Preparazione Pellet xerogel <ol><li> Gel Sintesi <ol><li> Aggiungere da 25mm di ancoretta magnetica e 113 mL di acqua deionizzata in un bicchiere da 500 mL. Magneticamente agitare l&#39;acqua deionizzata al tasso più elevato che non forma un vortice. </li><li> Aggiungere lentamente 13,05 g (0,056 moli) di cloruro di zirconio anidro all&#39;acqua deionizzata in piccoli incrementi. Dopo tutto del cloruro di zirconio anidro è sciolto, aggiungere 53.29 g (0,296 moli) di glucosio alla soluzione. </li><li> Dopo tutto il glucosio è disciolto nella soluzione, aggiungere 3,73 g (0,01 moli) di nitrato esaidrato ittrio alla soluzione. Aumentare la velocità di agitazione magnetica a ~ 700 rpm ed attendere che tutto l&#39;esaidrato di nitrato di ittrio da sciogliere in soluzione. </li><li> Aggiungere 42 ml di ossido di propilene alla soluzione. Continua agitazione a ~ 700 rpm per l&#39;ossido di propilene per mescolare con la soluzione acquosa. Una volta che l&#39;ossido di propilene viene miscelato con la soluzione acquosa (~ 10 s), diminuire il magnetico t agitazioneO ~ 150 rpm. </li><li> Continuare a mescolare fino alla ancoretta magnetica sia fermo a causa della formazione del gel. Il gel si forma tipicamente entro 3 min. NOTE: L&#39;aggiunta di cloruro di zirconio anidro in acqua deionizzata è una reazione altamente esotermica e cloruro di zirconio anidro si pennacchio se viene aggiunto troppo rapidamente. La formulazione prevista nel paragrafo 1.1. corrisponde ad un glucosio per metalli (in zirconio + ittrio) rapporto molare di 4,5: 1. La sezione rappresentativa risultati include dati per il glucosio al totale rapporti molari di metalli 0: 1, 2,25: 1 e 4,5: 1. La quantità di glucosio nella formulazione è limitato solo dalla solubilità del glucosio nella soluzione. Per riferimento, la solubilità massima del glucosio in acqua a 20 ° C è del 47,8% in peso. 15 </li></ol></li><li> Invecchiamento e lavaggio del gel <ol><li> Strettamente coprire il becher contenente il gel con parafilm e lasciare che l&#39;età per 24 h lasciando il becher coperto a temperatura ambiente. </li><li> Rimuovere il coperchio dal bicchiere e decantare il liquido sulla superficie del gel. </li><li> Aggiungere 300 ml di etanolo assoluto al bicchiere contenente il gel, strettamente coprire il becher con parafilm e lasciare il becher coperto a temperatura ambiente per 24 h. </li><li> Ripetere il punto 1.2.3 altre due volte per un totale di tre lavaggi etanolo per un periodo totale di 72 h. </li></ol></li><li> Asciugatura del gel in un xerogel <ol><li> Rimuovere il gel dal bicchiere e metterlo in una capsula 2 L porcellanato (24 cm di diametro esterno superiore) con una spatola laboratorio. </li><li> Rompere il gel in circa 1 cm x 1 cm pezzi con una spatola e diffondere i pezzi sulla superficie della capsula. </li><li> Lasciare che i pezzi di gel asciugare in condizioni ambiente per una settimana o fino a quando il gel è asciutto. Il gel è considerato secco quando può essere macinato in una polvere fine. </li><li> Macinare tutta la xerogel in una polvere fine con un mortaio e pestello. NOTA: Una volta che il gel è asciutto, èconsiderata uno xerogel perché è stato essiccato sotto condizioni ambientali. </li></ol></li><li> Premendo il xerogel in un pellet <ol><li> Posizionare 1 g di polvere in un xerogel cilindrica pellet pressa stampo con un diametro di 13 mm. </li><li> Utilizzando una pressa idraulica, applicare 22 kN di forza per 90 s per premere il gel xerogel in un pellet. </li><li> Rilasciare lentamente la forza applicata dalla stampa. Lentamente espellere la pallina fuori dello stampo pellet e poi rimuovere con attenzione il pellet. </li></ol></li></ol> 2. sinterizzazione dei xerogel Pellet in atmosfera inerte <ol><li> Posizionare il pellet xerogel su una piastra di allumina o ossido di zirconio stabilizzato con ittrio e caricare la piastra al centro di un forno tubolare. </li><li> Flusso di argon ad una velocità di un terzo del volume del tubo di lavoro al minuto. Ciò corrisponde ad una velocità di flusso di argon di 750 mL · min -1 per il tubo di lavoro utilizzato in questo lavoro. Sfiatare l&#39;uscita del gas ad una cappa aspirante. </li><li> Flusso argon per almeno 15 min brima di iniziare il riscaldamento del forno a tubo. </li><li> Mentre scorre continuamente argon a una velocità costante, il programma di controllo della temperatura del forno tubo al seguente schema di riscaldamento: <ol><li> Mantenere a temperatura ambiente per 15 min. </li><li> Riscaldare a 850 ° C ad una velocità di rampa di 5 ° C · min -1. </li><li> Riscaldare a temperatura di sinterizzazione ad una determinata velocità di rampa di 2 ° C · min -1. </li><li> Tenere alla temperatura di sinterizzazione desiderata per 2 h. </li><li> Raffreddare a 850 ° C ad una velocità di rampa di 2 ° C · min -1. </li><li> Raffreddare a temperatura ambiente ad una velocità di rampa di 5 ° C · min -1. </li></ol></li><li> Avviare il programma e doppio controllo che il forno tubolare sta riscaldando seguire lo schema fornito nella sezione 2.3. </li><li> Rimuovere pellet dal forno tubo dopo il programma di riscaldamento è stato completato. </li></ol> 3. Determinazione Concentrazione modello Carbon <ol><li> Tagliare un pezzo mg ~ 50 fuorisinterizzata pellet xerogel con un taglierino e macinare in una polvere fine con un mortaio di agata e pestello. </li><li> Posto ~ 50 mg della polvere fine in una coppetta campione di allumina per analisi termogravimetrica. </li><li> Utilizzando un analizzatore termogravimetrica (TGA), riscaldare il campione ad una velocità di 10 ° C · min -1 dalla temperatura ambiente a 1200 ° C mentre scorre aria sopra il campione ad una velocità di 100 ml · min -1. </li><li> Calcolare la variazione percentuale di peso che si verifica tra ~ 350 ° C e ~ 700 ° C. Questo peso percento corrisponde al contenuto totale di carbonio nel campione. NOTA: Se un aumento di peso si verifica nel 350 ° C a 700 ° C gamma, una fase di carburo si è formato e il calcolo del contenuto di carbonio è più complessa. Per questo caso, fare riferimento a calcoli descritti in letteratura. 14 Carbon analisi elementare è stata utilizzata per confermare che il contenuto di carbonio può essere calcolato dalle misurazioni TGA. </li></ol> 4. Preparazione ad alta Superficie YSZ Impalcature per la rimozione del modello Carbon <ol><li> Posizionare il pellet xerogel sinterizzato in un crogiolo di allumina. </li><li> Mettere il crogiolo in una fornace di dialogo a 700 ° C per 2 ore. </li><li> Rimuovere con attenzione il crogiolo caldo dal forno scatola con pinze crogiolo in acciaio inox e lasciarlo raffreddare a temperatura ambiente per un&#39;ora prima di rimuovere il poroso, impalcatura YSZ bianco. </li></ol>

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	<li>Badwal, S. P. S., Giddey, S. S., Munnings, C., Bhatt, A. I., Hollenkamp, A. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Emerging+electrochemical+energy+conversion+and+storage+technologies.">Emerging electrochemical energy conversion and storage technologies.</a> Front. Chem. 2 (79), 1-28 (2014).</li><li>Gross, M. D., Vohs, J. M., Gorte, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+examination+of+SOFC+anode+functional+layers+based+on+ceria+in+YSZ.">An examination of SOFC anode functional layers based on ceria in YSZ.</a> J. Electrochem. Soc. 154 (7), B694-B699 (2007).</li><li>Smith, B. H., Gross, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+highly+conductive+oxide+anode+for+solid+oxide+fuel+cells.">A highly conductive oxide anode for solid oxide fuel cells.</a> Electrochem. Solid-State Lett. 14 (1), B1-B5 (2011).</li><li>Vo, N. M., Gross, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+vanadium+deficiency+on+the+stability+of+Pd+and+Pt+catalysts+in+lanthanum+strontium+vanadate+solid+oxide+fuel+cell+anodes.">The effect of vanadium deficiency on the stability of Pd and Pt catalysts in lanthanum strontium vanadate solid oxide fuel cell anodes.</a> J. Electrochem. Soc. 159 (5), B641-B646 (2012).</li><li>Sholklapper, T. Z., Jacobson, C. P., Visco, S. J., De Jonghe, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+dispersed+and+contiguous+nanoparticles+in+solid+oxide+fuel+cell+electrodes.">Synthesis of dispersed and contiguous nanoparticles in solid oxide fuel cell electrodes.</a> Fuel Cells. 8 (5), 303-312 (2008).</li><li>Jiang, Z., Xia, C., Chen, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nano-structured+composite+cathodes+for+intermediate-temperature+solid+oxide+fuel+cells+via+an+infiltration/impregnation+technique.">Nano-structured composite cathodes for intermediate-temperature solid oxide fuel cells via an infiltration/impregnation technique.</a> Electrochim. Acta. 55 (11), 3595-3605 (2010).</li><li>Zhan, Z., Bierschenk, D. M., Cronin, J. S., Barnett, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+reduced+temperature+solid+oxide+fuel+cell+with+nanostructured+anodes.">A reduced temperature solid oxide fuel cell with nanostructured anodes.</a> Energy Environ. Sci. 4, 3951-3954 (2011).</li><li>Gross, M. D., Vohs, J. M., Gorte, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+progress+in+SOFC+anodes+for+direct+utilization+of+hydrocarbons.">Recent progress in SOFC anodes for direct utilization of hydrocarbons.</a> J. Mater. Chem. 17, 3071-3077 (2007).</li><li>Gross, M. D., Carver, K. M., Deighan, M. A., Schenkel, A., Smith, B. M., Yee, A. Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Redox+stability+of+SrNbxTi1-xO3-YSZ+for+use+in+SOFC+anodes.">Redox stability of SrNbxTi1-xO3-YSZ for use in SOFC anodes.</a> J. Electrochem. Soc. 156 (4), B540-B545 (2009).</li><li>Savaniu, C. D., Irvine, J. T. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=La-doped+SrTiO3+as+anode+material+for+IT-SOFC.">La-doped SrTiO3 as anode material for IT-SOFC.</a> Solid State Ionics. 192 (1), 491-493 (2011).</li><li>Choi, S., Shin, J., Kim, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+electrochemical+and+thermodynamic+characterization+of+PrBaCo2-xFexO5+&#948;+(x=0,0.5,1)+infiltrated+into+yttria-stabilized+zirconia+scaffold+as+cathodes+for+solid+oxide+fuel+cells.">The electrochemical and thermodynamic characterization of PrBaCo2-xFexO5+&#948; (x=0,0.5,1) infiltrated into yttria-stabilized zirconia scaffold as cathodes for solid oxide fuel cells.</a> J. Power Sources. 201, 10-17 (2012).</li><li>Kungas, R., Kim, J. S., Vohs, J. M., Gorte, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Restructuring+porous+YSZ+by+treatment+in+hydrofluoric+acid+for+use+in+SOFC+cathodes.">Restructuring porous YSZ by treatment in hydrofluoric acid for use in SOFC cathodes.</a> J. Am. Ceram. Soc. 94 (7), 2220-2224 (2011).</li><li>Jung, W., Dereux, J. O., Chueh, W. C., Hao, Y., Haile, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+electrode+activity+of+nanostructured,+columnar+ceria+films+for+solid+oxide+fuel+cells.">High electrode activity of nanostructured, columnar ceria films for solid oxide fuel cells.</a> Energy Environ. Sci. 5, 8682-8689 (2012).</li><li>Cottam, M., Muhoza, S., Gross, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preserving+nanomorphology+in+YSZ+scaffolds+at+high+temperatures+via+in+situ+carbon+templating+of+hybrid+materials.">Preserving nanomorphology in YSZ scaffolds at high temperatures via in situ carbon templating of hybrid materials.</a> J. Amer. Ceram. Soc. 99 (8), 2625-2631 (2016).</li><li>Alves, L. A., Silva, J. B. A., Giulietti, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Solubility+of+D-Glucose+in+Water+and+Ethanol/Water+Mixtures.">Solubility of D-Glucose in Water and Ethanol/Water Mixtures.</a> J. Chem. Eng. Data. 52, 2166-2170 (2007).</li><li>Thommes, M., Smarsly, B., Groenewolt, M., Ravikovitch, P. I., Neimark, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adsorption+hysteresis+of+nitrogen+and+argon+in+pore+networks+and+characterization+of+novel+micro-+and+mesoporous+silicas.">Adsorption hysteresis of nitrogen and argon in pore networks and characterization of novel micro- and mesoporous silicas.</a> Langmuir. 22, 756-764 (2006).</li><li>Chervin, C. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+non-alkoxide+sol-gel+method+for+the+preparation+of+homogeneous+nanocrystalline+powders+of+La0.85Sr0.15MnO3.">A non-alkoxide sol-gel method for the preparation of homogeneous nanocrystalline powders of La0.85Sr0.15MnO3.</a> Chem. Mater. 18, 1928-1937 (2006).</li><li>Clapsaddle, B. J., Sprehn, D. W., Gash, A. E., Satcher, J. H., Simpson, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+versatile+sol-gel+synthesis+route+to+metal-silicon+mixed+oxide+nanocomposites+that+contain+metal+oxides+as+a+major+phase.">A versatile sol-gel synthesis route to metal-silicon mixed oxide nanocomposites that contain metal oxides as a major phase.</a> J. Non-Crystalline Solids. 350, 173-181 (2004).</li><li>Gash, A. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+epoxides+in+the+sol-gel+synthesis+of+porous+iron+(III)+oxide+monoliths+from+Fe(III)+salts.">Use of epoxides in the sol-gel synthesis of porous iron (III) oxide monoliths from Fe(III) salts.</a> Chem. Mater. 13, 999-1007 (2001).</li></ol>

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Con questo approccio in situ di template di carbonio, si può creare e conservare nanomorphology in misto-metallo-ossidi a temperature ceramici tradizionali scaffold sinterizzazione. Le superfici risultanti sono fino a 80 volte superiore rispetto scaffold tradizionalmente sinterizzate e fino a 4 volte superiore rispetto ponteggi fabbricati mediante tecniche di deposizione complesse. 14 Il sistema gel ossido di propilene-glucosio è molto flessibile per l&#39;ottimizzazione della concentr...

La cella a combustibile ad ossidi solidi (SOFC) molto promettente come tecnologia di conversione di energia alternativa per l&#39;efficiente generazione di energia elettrica pulita. 1 Notevoli progressi sono stati fatti nella ricerca e sviluppo di questa tecnologia; Tuttavia, il miglioramento delle prestazioni dell&#39;elettrodo sono ancora necessari per raggiungere commercializzazione affidabile. L&#39;elettrodo spesso comprende un&#39;impalcatura di ceramica porosa con particelle elettrocatalitiche decorati sulla superficie ponteggio. Una grande quantità di ricerca si è focalizzata sulla aumentando l&#39;area superficiale delle particelle elettrocatalitiche per aumentare le prestazioni, 2, 3, 4, 5, 6, 7, 8, ma è molto piccola ricerca sul aumentando la superficie ponteggio. Aumentando la superficie patiboloarea è difficile perché sono sinterizzati a temperature elevate, 1.100 ° C a 1.500 ° C. Scaffold elaborati da sinterizzazione tradizionale tipicamente hanno una superficie specifica di 0,1-1 m 2 · g -1. 8, 9, 10, 11 ci sono un paio di rapporti sul aumentando la superficie patibolo. In un caso, la superficie di un ponteggio tradizionalmente sinterizzato si arricchisce di dissoluzione e precipitazione della superficie ponteggio con acido fluoridrico, ottenendo una superficie specifica di 2 m 2 · g -1. 12 In un altro, alte temperature sono stati evitati del tutto utilizzando deposizione laser pulsato, ottenendo una superficie specifica di 20 m 2 · g -1. 13 La logica alla base dello sviluppo della nostra tecnica è stato quello di creare una fabbricazione a basso costoprocesso che fornisce superfici scaffold senza precedenti e utilizza temperature di sinterizzazione tradizionali in modo che il processo possa essere adottata facilmente. Con la tecnica riportata qui, superfici impalcatura fino a 80 m 2 · g-1 sono state dimostrate mentre viene elaborata a temperature di sinterizzazione tradizionali. 14 La nostra ricerca è motivata principalmente dal ingegneria elettrodo SOFC, ma la tecnica è più ampiamente applicabile ad altri settori e applicazioni. Generalmente, il metodo in situ di template di carbonio è un approccio flessibile che può produrre nanostrutturati, elevata area superficiale mista metallo materiali ceramici in polvere o impalcatura porosa. È flessibile dal fatto che la composizione ceramica mista metallo, area superficiale, porosità e dimensioni dei pori possono tutti essere sintonizzato sistematicamente. Le alte temperature sono spesso necessari per formare la fase desiderata nella ceramica mista metallo, e questo approccio conserva nanomorphology ceramica wentre permettendo di scegliere essenzialmente qualsiasi temperatura di lavorazione. Questo metodo comporta la sintesi di un gel a base di propilene-ossido inorganico-organico ibrido, con una stechiometria ben definire di ioni metallici e il rapporto di inorganico contenuto organico. Il gel viene essiccato in condizioni ambiente per formare uno xerogel. Xerogel viene sinterizzato in un&#39;atmosfera di argon alla temperatura desiderata. In seguito a riscaldamento, la componente organica decompone lasciando un modello di carbonio in situ, che rimane per la durata del sinterizzazione. Il modello di carbonio viene successivamente rimosso mediante ossidazione a bassa temperatura in aria, con conseguente nanostrutturati, elevata area superficiale ceramico.

<table><tbody><tr><td>Zirconium(IV) chloride, 99.5+%</td><td>Alfa Aesar</td><td>12104</td><td>Air sensitive</td></tr><tr><td>Yttium(III) nitrate hexadydrate, 99.9%</td><td>Alfa Aesar</td><td>12898</td><td>Oxidizer</td></tr><tr><td>D+ Glucose Anhydrous, &amp;ge;99.5%</td><td>US Biological Life Sciences</td><td>G3050</td><td></td></tr><tr><td>(&amp;plusmn;)-Propylene Oxide, &amp;ge;99%</td><td>Sigma Aldrich</td><td>110205</td><td>Extremely flammable</td></tr><tr><td>Ethanol 200 Proof</td><td>Decon Laboratories, Inc.</td><td>2716GEA</td><td></td></tr><tr><td>Argon, 99.997%</td><td>Airgas</td><td>AR 300</td><td>Industrial grade</td></tr></tbody></table>

high temperature fabrication of nanostructured yttria-stabilized-zirconia (ysz) scaffolds by in situ carbon templating xerogels

Abbiamo dimostrato un metodo per la fabbricazione ad alta temperatura microporosa, nanostrutturati stabilizzato con ittrio-zirconio (YSZ, 8% in moli di ossido di ittrio - 92 moli% di ossido di zirconio) scaffold con aree superficiali specifiche sintonizzabili fino a 80 m 2 · g -1. Una soluzione acquosa di un sale di zirconio, sale ittrio, e glucosio è mescolato con ossido di propilene (PO) per formare un gel. Il gel viene essiccato in condizioni ambiente per formare uno xerogel. Xerogel viene pressata in pellets e successivamente sinterizzato in un&#39;atmosfera di argon. Durante la sinterizzazione, un YSZ forme fase ceramica ed i componenti organici decompongono, lasciando dietro di carbonio amorfo. Il carbonio formato in situ funge da modello duro, mantenendo una elevata area superficiale YSZ nanomorphology alla temperatura di sinterizzazione. Il carbonio viene successivamente rimosso mediante ossidazione all&#39;aria a bassa temperatura, con un conseguente poroso nanostrutturato YSZ ponteggio. La concentrazione del template carbonio e la superficie scaffold finale può essere sistematicoly sintonizzato variando la concentrazione di glucosio nella sintesi gel. La concentrazione modello di carbonio è stata quantificata mediante analisi termogravimetrica (TGA), la distribuzione area superficiale e dimensione dei pori è stata determinata mediante misurazioni di adsorbimento fisico, e la morfologia è stata caratterizzata mediante microscopia elettronica a scansione (SEM). Fase purezza e la dimensione dei cristalliti è stato determinato utilizzando la diffrazione a raggi X (XRD). Questo approccio fabbricazione fornisce un nuovo, piattaforma flessibile per la realizzazione di superfici scaffold senza precedenti e nanomorphologies per applicazioni di conversione di energia elettrochimica a base di ceramica, ad esempio celle a combustibile ad ossidi solidi (SOFC) elettrodi.

Fase purezza è stata confermata mediante diffrazione di raggi X (XRD), come precedentemente riportato da Cottam et al. 14 YSZ scaffold superficie specifica in funzione della concentrazione di carbonio template è mostrato in Figura 1. La concentrazione è mostrato come la percentuale in volume di solidi totali in pellet xerogel sinterizzato. La concentrazione modello carbonio aumenta sistematicamente all&#39;aumentare della concentrazion...

Watch this Scientific Journal Video about High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia YSZ Scaffolds by In Situ Carbon Templating Xerogels at JoVE.com

High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia YSZ Scaffolds by In Situ Carbon Templating Xerogels

Un protocollo per fabbricare scaffold porosi, nanostrutturati stabilizzato con ittrio-zirconio (YSZ) a temperature comprese tra 1000 ° C e 1400 ° C è presentato.

Fabbricazione ad alta temperatura di Nanostrutturati di ossido di ittrio stabilizzato-Zirconia (YSZ) Ponteggi da<em&gt; In Situ</em&gt; Carbon Templating xerogel

We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) ...

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Universidad San Sebastian

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High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia (YSZ) Scaffolds by In Situ Carbon Templating Xerogels

10.5K Views.  Wake Forest University.  Un protocollo per fabbricare scaffold porosi, nanostrutturati stabilizzato con ittrio-zirconio (YSZ) a temperature comprese tra 1000 ° C e 1400 ° C è presentato. 

Video: High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia YSZ Scaffolds by In Situ Carbon Templating Xerogels

Fabrication, Densification, and Replica Molding of 3D Carbon Nanotube Microstructures

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip devices, and their applications. In particular, capabilities for cost-effective fabrication of polymer microstructures were transformed by the advent of soft lithography and other micromolding techniques 1, 2, and this led a revolution in applications of microfabrication to biomedical engineering and biology. Nevertheless, it remains challenging to fabricate microstructures with well-defined nanoscale surface textures, and to fabricate arbitrary 3D shapes at the micro-scale. Robustness of master molds and maintenance of shape integrity is especially important to achieve high fidelity replication of complex structures and preserving their nanoscale surface texture. The combination of hierarchical textures, and heterogeneous shapes, is a profound challenge to existing microfabrication methods that largely rely upon top-down etching using fixed mask templates. On the other hand, the bottom-up synthesis of nanostructures such as nanotubes and nanowires can offer new capabilities to microfabrication, in particular by taking advantage of the collective self-organization of nanostructures, and local control of their growth behavior with respect to microfabricated patterns. 
Our goal is to introduce vertically aligned carbon nanotubes (CNTs), which we refer to as CNT "forests", as a new microfabrication material. We present details of a suite of related methods recently developed by our group: fabrication of CNT forest microstructures by thermal CVD from lithographically patterned catalyst thin films; self-directed elastocapillary densification of CNT microstructures; and replica molding of polymer microstructures using CNT composite master molds. In particular, our work shows that self-directed capillary densification ("capillary forming"), which is performed by condensation of a solvent onto the substrate with CNT microstructures, significantly increases the packing density of CNTs. This process enables directed transformation of vertical CNT microstructures into straight, inclined, and twisted shapes, which have robust mechanical properties exceeding those of typical microfabrication polymers. This in turn enables formation of nanocomposite CNT master molds by capillary-driven infiltration of polymers. The replica structures exhibit the anisotropic nanoscale texture of the aligned CNTs, and can have walls with sub-micron thickness and aspect ratios exceeding 50:1. Integration of CNT microstructures in fabrication offers further opportunity to exploit the electrical and thermal properties of CNTs, and diverse capabilities for chemical and biochemical functionalization 3.

We present methods for fabrication of patterned microstructures of vertically aligned carbon nanotubes (CNTs), and their use as master molds for production of polymer microstructures with organized nanoscale surface texture. The CNT forests are densified by condensation of solvent onto the substrate, which significantly increases their packing density and enables self-directed formation of 3D shapes.

Molding Fabrication, densificazione e Replica di microstrutture 3D Nanotubi di carbonio

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip ...

Ricerca

Ingegneria

Preparation and Reactivity of Gasless Nanostructured Energetic Materials

High-Energy Ball Milling (HEBM) is a ball milling process where a powder mixture placed in the ball mill is subjected to high-energy collisions from the balls. Among other applications, it is a versatile technique that allows for effective preparation of gasless reactive nanostructured materials with high energy density per volume (Ni+Al, Ta+C, Ti+C). The structural transformations of reactive media, which take place during HEBM, define the reaction mechanism in the produced energetic&#160;composites. Varying the processing conditions permits fine tuning of the milling-induced microstructures of the fabricated composite particles. In turn, the reactivity, i.e., self-ignition temperature, ignition delay time, as well as reaction kinetics, of high energy density materials depends on its microstructure. Analysis of the milling-induced microstructures suggests that the formation of fresh oxygen-free intimate high surface area contacts between the reagents is responsible for the enhancement of their reactivity. This manifests itself in a reduction of ignition temperature and delay time, an increased rate of chemical reaction, and an overall decrease of the effective activation energy of the reaction. The protocol provides a detailed description for the preparation of reactive nanocomposites with tailored microstructure using short-term HEBM method. It also describes a high-speed thermal imaging technique to determine the ignition/combustion characteristics of the energetic materials. The protocol can be adapted to preparation and characterization of a variety of nanostructured energetic composites.

This protocol describes the preparation of gasless nanostructured energetic materials (Ni+Al, Ta+C, Ti+C) using the short-term high-energy ball milling (HEBM) technique. It also describes a high-speed thermal imaging method to study the reactivity of mechanically fabricated nanocomposites. These protocols can be extended to other reactive nanostructured energetic materials.

Preparazione e reattività di gasless Nanostrutturati materiali energetici

High-Energy Ball Milling (HEBM) is a ball milling process where a powder mixture placed in the ball mill is subjected to high-energy collisions from the ...

Formation of Thick Dense Yttrium Iron Garnet Films Using Aerosol Deposition

Aerosol deposition (AD) is a thick-film deposition process that can produce layers up to several hundred micrometers thick with densities greater than 95% of the bulk. The primary advantage of AD is that the deposition takes place entirely at ambient temperature; thereby enabling film growth in material systems with disparate melting temperatures. This report describes in detail the processing steps for preparing the powder and for performing AD using the custom-built system. Representative characterization results are presented from scanning electron microscopy, profilometry, and ferromagnetic resonance for films grown in this system. As a representative overview of the capabilities of the system, focus is given to a sample produced following the described protocol and system setup. Results indicate that this system can successfully deposit 11 &#181;m thick yttrium iron garnet films that are &#160;&#62; 90% of the bulk density during a single 5 min deposition run. A discussion of methods to afford better control of the aerosol and particle selection for improved thickness and roughness variations in the film is provided.

This report describes the use of a custom-built system to perform aerosol deposition of thick films of yttrium iron garnet onto sapphire substrates at RT. The deposited films are characterized using scanning electron microscopy, profilometry, and ferromagnetic resonance to give a representative overview of the capabilities of the technique.

La formazione di spesse Dense ittrio ferro Garnet Films Utilizzando Aerosol Deposizione

Aerosol deposition (AD) is a thick-film deposition process that can produce layers up to several hundred micrometers thick with densities greater than 95% ...

Aerosol-assisted Chemical Vapor Deposition of Metal Oxide Structures: Zinc Oxide Rods

Whilst columnar zinc oxide (ZnO) structures in the form of rods or wires have been synthesized previously by different liquid- or vapor-phase routes, their high cost production and/or incompatibility with microfabrication technologies, due to the use of pre-deposited catalyst-seeds and/or high processing temperatures exceeding 900 &#176;C, represent a drawback for a widespread use of these methods. Here, however, we report the synthesis of ZnO rods via a non-catalyzed vapor-solid mechanism enabled by using an aerosol-assisted chemical vapor deposition (CVD) method at 400 &#176;C with zinc chloride (ZnCl2) as the precursor and ethanol as the carrier solvent. This method provides both single-step formation of ZnO rods and the possibility of their direct integration with various substrate types, including silicon, silicon-based micromachined platforms, quartz, or high heat resistant polymers. This potentially facilitates the use of this method at a large-scale, due to its compatibility with state-of-the-art microfabrication processes for device manufacture. This report also describes the properties of these structures (e.g., morphology, crystalline phase, optical band gap, chemical composition, electrical resistance) and validates its gas sensing functionality towards carbon monoxide.

Columnar zinc oxide structures in the form of rods are synthesized via aerosol-assisted chemical vapor deposition without the use of pre-deposited catalyst-seed particles. This method is scalable and compatible with various substrates based on either silicon, quartz or polymers.

Aerosol-assisted Chemical Vapor Deposition di strutture in ossido di metallo: aste di ossido di zinco

Whilst columnar zinc oxide (ZnO) structures in the form of rods or wires have been synthesized previously by different liquid- or vapor-phase routes, ...

Chimica

Chemical Synthesis of Porous Barium Titanate Thin Film and Thermal Stabilization of Ferroelectric Phase by Porosity-Induced Strain

Barium titanate (BaTiO3, hereafter BT) is an established ferroelectric material first discovered in the 1940s and still widely used because of its well-balanced ferroelectricity, piezoelectricity, and dielectric constant. In addition, BT does not contain any toxic elements. Therefore, it is considered to be an eco-friendly material, which has attracted considerable interest as a replacement for lead zirconate titanate (PZT). However, bulk BT loses its ferroelectricity at approximately 130 &#176;C, thus, it cannot be used at high temperatures. Because of the growing demand for high-temperature ferroelectric materials, it is important to enhance the thermal stability of ferroelectricity in BT. In previous studies, strain originating from the lattice mismatch at hetero-interfaces has been used. However, the sample preparation in this approach requires complicated and expensive physical processes, which are undesirable for practical applications.
In this study, we propose a chemical synthesis of a porous material as an alternative means of introducing strain. We synthesized a porous BT thin film using a surfactant-assisted sol-gel method, in which self-assembled amphipathic surfactant micelles were used as an organic template. Through a series of studies, we clarified that the introduction of pores had a similar effect on distorting the BT crystal lattice, to that of a hetero-interface, leading to the enhancement and stabilization of ferroelectricity. Owing to its simplicity and cost effectiveness, this fabrication process has considerable advantages over conventional methods.

Here, we present a protocol for the synthesis of porous barium titanate (BaTiO3) thin film by a surfactant-assisted sol-gel method, in which self-assembled amphipathic surfactant micelles are used as an organic template.

Sintesi chimica di Film sottile di titanato di bario poroso e stabilizzazione termica della fase ferroelettrica dallo sforzo indotto da porosità

Barium titanate (BaTiO3, hereafter BT) is an established ferroelectric material first discovered in the 1940s and still widely used because of its ...

Multi-material Ceramic-Based Components &#8211; Additive Manufacturing of Black-and-white Zirconia Components by Thermoplastic 3D-Printing (CerAM - T3DP)

To combine the benefits of Additive Manufacturing (AM) with the benefits of Functionally Graded Materials (FGM) to ceramic-based 4D components (three dimensions for the geometry and one degree of freedom concerning the material properties at each position) the Thermoplastic 3D-Printing (CerAM -&#160;T3DP) was developed. It is a direct AM technology which allows the AM of multi-material components. To demonstrate the advantages of this technology black-and-white zirconia components were additively manufactured and co-sintered defect-free.
Two different pairs of black and white zirconia powders were used to prepare different thermoplastic suspensions. Appropriate dispensing parameters were investigated to manufacture single-material test components and adjusted for the additive manufacturing of multi-color zirconia components.

Here we describe a protocol for additively manufacturing black-and-white zirconia components by Thermoplastic 3D-Printing (CerAM -&#160;T3DP) and co-sintering defect-free.

Componenti ceramici multi-materiali – additivo produzione di componenti di Zirconia in bianco e nero di stampa 3D termoplastico (CerAM - T3DP)

To combine the benefits of Additive Manufacturing (AM) with the benefits of Functionally Graded Materials (FGM) to ceramic-based 4D components (three ...

Fused Filament Fabrication (FFF) of Metal-Ceramic Components

Technical ceramics are widely used for industrial and research applications, as well as for consumer goods. Today, the demand for complex geometries with diverse customization options and favorable production methods is increasing continuously. With fused filament fabrication (FFF), it is possible to produce large and complex components quickly with high material efficiency. In FFF, a continuous thermoplastic filament is melted in a heated nozzle and deposited below. The computer-controlled print head is moved in order to build up the desired shape layer by layer. Investigations regarding printing of metals or ceramics are increasing more and more in research and industry. This study focuses on additive manufacturing (AM) with a multi-material approach to combine a metal (stainless steel) with a technical ceramic (zirconia: ZrO2). Combining these materials offers a broad variety of applications due to their different electrical and mechanical properties. The paper shows the main issues in preparation of the material and feedstock, device development, and printing of these composites.

Fused Filament Fabrication FFF of Metal-Ceramic Components

This study shows multi-material additive manufacturing (AM) using fused filament fabrication (FFF) of stainless steel and zirconia.

Filamento fuso fabbricazione (FFF) dei componenti in metallo-ceramica

Technical ceramics are widely used for industrial and research applications, as well as for consumer goods. Today, the demand for complex geometries with ...

Additive Manufacturing of Functionally Graded Ceramic Materials by Stereolithography

An additive manufacturing technology is applied to obtain functionally graded ceramic parts. This technology, based on digital light processing/stereolithography, is developed within the scope of the CerAMfacturing European research project. A three-dimensional (3-D) hemi-maxillary bone-like structure is 3-D printed using custom aluminum oxide polymeric mixtures. The powders and mixtures are fully analyzed in terms of rheological behavior in order to ensure proper material handling during the printing process. The possibility to print functionally graded materials using the Admaflex technology is explained in this document. Field-emission scanning electron microscopy (FESEM) show that the sintered aluminum oxide ceramic part has a porosity lower than 1% and no remainder of the original layered structure is found after analysis.

This manuscript describes the processing of single multifunctional ceramic components (e.g., combinations of dense-porous structures) additively manufactured by stereolithography.

Produzione di additivi di materiali ceramici funzionalmente graduate di stereolitografia

An additive manufacturing technology is applied to obtain functionally graded ceramic parts. This technology, based on digital light ...

Fabrication of Mechanically Tunable and Bioactive Metal Scaffolds for Biomedical Applications

Biometal systems have been widely used for biomedical applications, in particular, as load-bearing materials. However, major challenges are high stiffness and low bioactivity of metals. In this study, we have developed a new method towards fabricating a new type of bioactive and mechanically reliable porous metal scaffolds-densified porous Ti scaffolds. The method consists of two fabrication processes, 1) the fabrication of porous Ti scaffolds by dynamic freeze casting, and 2) coating and densification of the porous scaffolds. The dynamic freeze casting method to fabricate porous Ti scaffolds allowed the densification of porous scaffolds by minimizing the chemical contamination and structural defects. The densification process is distinctive for three reasons. First, the densification process is simple, because it requires a control of only one parameter (degree of densification). Second, it is effective, as it achieves mechanical enhancement and sustainable release of biomolecules from porous scaffolds. Third, it has broad applications, as it is also applicable to the fabrication of functionally graded porous scaffolds by spatially varied strain during densification.

Bioactive and mechanically reliable metal scaffolds have been fabricated through a method which consists of two processes, dynamic freeze casting for the fabrication of porous Ti, and coating and densification of the Ti scaffolds. The densification process is simple, effective and applicable to the fabrication of functionally graded scaffolds.

Fabbricazione di meccanicamente Tunable e Bioactive metallo Ponteggi per applicazioni biomediche

Biometal systems have been widely used for biomedical applications, in particular, as load-bearing materials. However, major challenges are high stiffness ...

Bioingegneria

Epitaxial Nanostructured &alpha;-Quartz Films on Silicon: From the Material to New Devices

In this work, we show a detailed engineering route of the first piezoelectric nanostructured epitaxial quartz-based microcantilever. We will explain all the steps in the process starting from the material to the device fabrication. The epitaxial growth of &#945;-quartz film on SOI (100) substrate starts with the preparation of a strontium doped silica sol-gel and continues with the deposition of this gel into the SOI substrate in a thin film form using the dip-coating technique under atmospheric conditions at room temperature. Before crystallization of the gel film, nanostructuration is performed onto the film surface by nanoimprint lithography (NIL). Epitaxial film growth is reached at 1000 &#176;C, inducing a perfect crystallization of the patterned gel film. Fabrication of quartz crystal cantilever devices is a four-step process based on microfabrication techniques. The process starts with shaping the quartz surface, and then metal deposition for electrodes follows it. After removing the silicone, the cantilever is released from SOI substrate eliminating SiO2 between silicon and quartz. The device performance is analyzed by non-contact laser vibrometer (LDV) and atomic force microscopy (AFM). Among the different cantilever&#8217;s dimensions included in the fabricated chip, the nanostructured cantilever analyzed in this work exhibited a dimension of 40 &#181;m large and 100 &#181;m long and was fabricated with a 600 nm thick patterned quartz layer (nanopillar diameter and separation distance of 400 nm and 1 &#181;m, respectively) epitaxially grown on a 2 &#181;m thick Si device layer. The&#160;measured&#160;resonance frequency was&#160;267 kHz and the estimated quality factor, Q, of the whole mechanical structure was Q ~ 398 under low vacuum conditions. We observed the voltage-dependent linear displacement of cantilever with both techniques (i.e., AFM contact measurement and LDV). Therefore, proving that these devices can be activated through the indirect piezoelectric effect.

Epitaxial Nanostructured &#945;-Quartz Films on Silicon: From the Material to New Devices

This work presents a detailed protocol for the microfabrication of nanostructured &#945;-quartz cantilever on a Silicon-On-Insulator(SOI) technology substrate starting from the epitaxial growth of quartz film with the dip coating method and then nanostructuration of the thin film via nanoimprint lithography.

Pellicole α al quarzo epitassiale su silicio: dal materiale ai nuovi dispositivi

In this work, we show a detailed engineering route of the first piezoelectric nanostructured epitaxial quartz-based microcantilever. We will explain all ...

Fabbricazione ad alta temperatura di Nanostrutturati di ossido di ittrio stabilizzato-Zirconia (YSZ) Ponteggi da

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