Síntese, sinterização e caracterização de ferrita de níquel

Paulo Roberto Cunha dos Santos

Síntese, Sinterização e Caracterização da Ferrita de Níquel

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Dissertação de Mestrado

Natal/RN, maio de 2014

INSTITUTO DE QUÍMICA

Síntese, Sinterização e Caracterização da Ferrita de Níquel

Natal / RN 2014

Dissertação apresentada ao programa de Pós- Graduação em Química da Universidade Federal do Rio Grande do Norte, em cumprimento as exigências para obtenção do título de Mestre em Química.

Catalogação da Publicação na Fonte

Santos, Paulo Roberto Cunha dos.

Síntese, sinterização e caracterização de ferrita de níquel. - Natal, RN, 2014.

99 f. : il.

Orientador: Prof. Dr. Ademir Oliveira da Silva.

Dissertação (Mestrado em Química) – Universidade Federal do Rio Grande do Norte. Centro de Ciências Exatas e da Terra. Instituto de Química. Programa de Pós-Graduação em Química.

1. Ferrita – Níquel. 2. Ferrita – Método de Combustão - Sinterização. I. Silva, Ademir Oliveira da. II. Título.

❆ ❉❡✉s✱ ♣♦r ❡st❛r ♣r❡s❡♥t❡ ❡♠ t♦❞♦s ♦s ♠♦♠❡♥t♦s ❞❛ ♠✐♥❤❛ ✈✐❞❛✳

❆♦s ♣r♦❢❡ss♦r❡s ❆❞❡♠✐r ❖❧✐✈❡✐r❛ ❞❛ ❙✐❧✈❛ ❡ ❏♦ã♦ ❇♦s❝♦ ▲✉❝❡♥❛ ❞❡ ❖❧✐✈❡✐r❛✱ ♣❡❧♦ ♦ ❛♣♦✐♦ ❡ ❛ ❛t❡♥çã♦ ❞✉r❛♥t❡ ♦ ♣❡rí♦❞♦ ❞❛ ❡①❡❝✉çã♦ ❞❡st❡ tr❛❜❛❧❤♦✳

❆♦s ♠❡✉s ❛♠✐❣♦s q✉❡ ❝♦♥tr✐❜✉ír❛♠ ❞✐r❡t❛ ❡ ✐♥❞✐r❡t❛♠❡♥t❡✱ ❡♠ ❡s♣❡❝✐❛❧ ❛♦s ❛♠✐✲ ❣♦s ❆❧❞r✐♥ ❘✉✜♥♦✱ ❙❛✉❧♦ ●r❡❣ór✐♦✱ ❏❛r❧❡②✱ ❆rt❤✉r ❋❡❧✐♣❡✱ ●✉st❛✈♦ ❈❛✈❛❧❝❛♥t❡✱ ◆✐♥❛ ❙♦✉③❛✱ ❆❧❜❡rt♦ ❡ ❱❛❧❞✐❝✱ q✉❡ ♠❡ ❛❥✉❞❛r❛♠ ♠✉✐t♦ ♥❡ss❛ ❝❛♠✐♥❤❛❞❛✳

❆♦s ♠❡✉s ❛♠✐❣♦s ❞♦ ■❋❘◆ q✉❡ ❞❡s❞❡ ❞♦ ♣r✐♠❡✐r♦ ♠♦♠❡♥t♦ ♠❡ ✐♥❝❡♥t✐✈❛r❛♠✳ ❆ t♦❞♦s q✉❡ ❢❛③❡♠ ♣❛rt❡ ❞♦ Pr♦❣r❛♠❛ ❞❡ Pós✲●r❛❞✉❛çã♦ ❞❡ ◗✉í♠✐❝❛✱ ♣❡❧♦ ♦ ❛❝♦❧❤✐✲ ♠❡♥t♦ ❡ ♣❡❧♦s s❡r✈✐ç♦s ♣r❡st❛❞♦s✳

❊♠ ❡s♣❡❝✐❛❧ à ♠✐♥❤❛ ❢❛♠í❧✐❛✿ ♠ã❡✱ ❡s♣♦s❛✱ ✜❧❤♦s✱ ✐r♠ã♦ ❡ s♦❜r✐♥❤♦s ♣❡❧♦ ❝❛r✐♥❤♦✱ ❝♦♠♣r❡❡♥sã♦✱ ♣❛❝✐ê♥❝✐❛ ❡ ✐♥❝❡♥t✐✈♦✳

❉❡❞✐❝♦ ❡st❡ tr❛❜❛❧❤♦✿

❊st❡ tr❛❜❛❧❤♦ ❞❡s❝r❡✈❡ ❛ ♦❜t❡♥çã♦ ❞❡ ❢❡rr✐t❛ ❞❡ ♥íq✉❡❧ ♣❡❧♦ ♠ét♦❞♦ ❞❡ sí♥t❡s❡ ❞❡ ❝♦♠❜✉stã♦✱ s❡❣✉✐❞❛ ♣❡❧❛ s✐♥t❡r✐③❛çã♦ ❡♠ ❢♦r♥♦✱ às t❡♠♣❡r❛t✉r❛ ❞❡750o

C✱ 950o

C

❡ 1250o

C✳ ❖s ♣r❡❝✉rs♦r❡s ♦①✐❞❛♥t❡s ✉t✐❧✐③❛❞♦s ❢♦r❛♠✿ ♥✐tr❛t♦s ❞❡ ♥íq✉❡❧ ❡ ❢❡rr♦ ■■■

❝♦♠♦ r❡❞✉t♦r✱ ❢♦✐ ✉s❛❞❛ ❛ ✉ré✐❛ ✭❝♦♠❜✉stí✈❡❧✮✳ ❉❡♣♦✐s ❞❛ ♦❜t❡♥çã♦ ❞♦ ♣ós✲♠✐st✉r❛s✱ ♦ ♣r♦❞✉t♦ ❢♦✐ ❞❡s❛❣❧♦♠❡r❛❞♦ ❡ ♣❛ss❛❞♦ ❡♠ ✉♠❛ ♣❡♥❡✐r❛ ❞❡ ♠❡s❝❤270✳ ❆ ❡str✉t✉r❛✱ ❛

♠♦r❢♦❧♦❣✐❛✱ ♦ t❛♠❛♥❤♦ ❞❛s ♣❛rtí❝✉❧❛s ❡ ❛s ♣r♦♣r✐❡❞❛❞❡s ♠❛❣♥ét✐❝❛s ❡ ❡❧étr✐❝❛s ❞❛s ♥❛✲ ♥♦♣❛rtí❝✉❧❛s ♦❜t✐❞❛s ❞❛s ❛♠♦str❛s ♣ós s✐♥t❡r✐③❛❞❛s ❢♦r❛♠ ❝❛r❛❝t❡r✐③❛❞❛s ♣♦r ❞✐❢r❛çã♦ ❞❡ r❛✐♦s✲❳ (DRX)✱ ❡s♣❡❝tr♦s❝♦♣✐❛ ❞❡ ✢✉♦r❡s❝ê♥❝✐❛ ❞❡ r❛✐♦s✲❳(F RX)✱ ♠✐❝r♦s❝♦♣✐❛

❡❧❡trô♥✐❝❛ ❞❡ ✈❛rr❡❞✉r❛ (M EV)✱ ❡s♣❡❝tr♦s❝♦♣✐❛ ❞❡ ❡♥❡r❣✐❛ ❞✐s♣❡rs✐✈❛ (EDS)✱ ♠❛❣✲

♥❡tô♠❡tr♦ ❞❡ ❛♠♦str❛ ✈✐❜r❛♥t❡ (M AV) ❡ ❛♥á❧✐s❡ ❡❧étr✐❝❛✳ ❖s r❡s✉❧t❛❞♦s ✐♥❞✐❝❛r❛♠

❛ ❢❛s❡ ♠❛❥♦r✐tár✐❛ ❞♦ ❡s♣✐♥é❧✐♦ ✐♥✈❡rs♦ ❢❡rr✐t❛ ❞❡ ♥íq✉❡❧ ❡ ❛ ❢❛s❡ s❡❝✉♥❞ár✐❛ ❞❡ ❤❡✲ ♠❛t✐t❛ ❡ ó①✐❞♦ ❞❡ ♥íq✉❡❧✳ ❆tr❛✈és ❞❛ ✐♥t❡♥s✐❞❛❞❡ ❞♦s ♣✐❝♦s ❞❡ ❞✐❢r❛çã♦ ❞❡ r❛✐♦s✲❳ ❡ ❞❛ ❧❛r❣✉r❛ ❞❡ ♠❡✐❛ ❛❧t✉r❛ ♥♦ ❡s♣❡❝tr♦✱ ❢♦✐ ❝❛❧❝✉❧❛❞♦ ♦ t❛♠❛♥❤♦ ♠é❞✐♦ ❞♦ ❝r✐st❛❧✐t♦ ♣❡❧❛ ❡q✉❛çã♦ ❙❝❤❡rr❡r✱ ♦❜s❡r✈❛♥❞♦✲s❡ ♦s ♣✐❝♦s ❞❡ t♦❞❛s ❛s r❡✢❡①õ❡s✱ ✈❡r✐✜❝❛♥❞♦ ❛ ❝r✐st❛❧✐♥✐❞❛❞❡ ❞❛s ❛♠♦str❛s✱ ❡ ❝♦♠ ❢♦r♠❛çã♦ ❞❡ ♥❛♥♦♣❛rtí❝✉❧❛s✳ ▼♦r❢♦❧♦❣✐❝❛♠❡♥t❡✱ ♣❛r❛ ❛s ♥❛♥♦❢❡rr✐t❛s ❞❡ ♥íq✉❡❧ s✐♥t❡r✐③❛❞❛s✱ ♦❜s❡r✈♦✉✲s❡ ❛ ❢♦r♠❛çã♦ ❞❡ ❛❣❧♦♠❡r❛❞♦s ♠♦❧❡s ♥♦s três s✐st❡♠❛s ❝♦♠ ♣❛rtí❝✉❧❛s ❞❡ t❛♠❛♥❤♦ ✐♥❢❡r✐♦r ❛ 100nm✳ ❖ t❛♠❛♥❤♦

♠é❞✐♦ ❞♦s ❣rã♦s ❡stá ❡♠ ❡s❝❛❧❛ ♠✐❝r♦♠étr✐❝❛✳ ❖s ❡s♣❡❝tr♦s ❞❡ F RX ❡ EDS ♠♦s✲

tr❛r❛♠ q✉❛❧✐t❛t✐✈❛♠❡♥t❡ ❛ ♣r❡s❡♥ç❛ ❞♦s ❡❧❡♠❡♥t♦s ❢❡rr♦✱ ♥íq✉❡❧ ❡ ♦①✐❣ê♥✐♦✳ ❆tr❛✈és ❞♦s ❞❛❞♦s q✉❛♥t✐t❛t✐✈♦s✱ ♣♦❞❡✲s❡ ♦❜s❡r✈❛r ❛ ♣r❡s❡♥ç❛ ❞❛ ❢❛s❡ s❡❝✉♥❞ár✐❛✳ ❆s ♣r♦♣r✐✲ ❡❞❛❞❡s ♠❛❣♥ét✐❝❛s✱ ❝♦♠♦ ❛ ♠❛❣♥❡t✐③❛çã♦ ❞❡ s❛t✉r❛çã♦ ❡ ♦ ❝❛♠♣♦ ❝♦❡r❝✐t✐✈♦✱ ❡stã♦ ❞❡ ❛❝♦r❞♦ ❝♦♠ ❛ ❢❡rr✐t❛ ❞❡ ♥íq✉❡❧✱ ❡♠ q✉❡ ❛ ❝✉r✈❛ ❞❡ ❤✐st❡r❡s❡ t❡♠ ❛s♣❡❝t♦s ❞❡ ✉♠ ♠❛t❡r✐❛❧ ♠♦❧❡✳ ❖s ✈❛❧♦r❡s ❞❡ ❝♦♥st❛♥t❡ ❞✐❡❧étr✐❝❛ ❡stã♦ ❛❜❛✐①♦ ❞❡10❡ ❜❛✐①❛ t❛♥❣❡♥t❡

❞❡ ♣❡r❞❛s✳

■♥ t❤✐s ✇♦r❦ ✇❡ ♦❜t❛✐♥ ♥✐❝❦❡❧ ❢❡rr✐t❡ ❜② t❤❡ ❝♦♠❜✉st✐♦♥ s②♥t❤❡s✐s ♠❡t❤♦❞ ✇❤✲ ❝✐❤ ✐♥✈♦❧✈❡s s②♥t❤❡s✐s✐♥❣ ✐♥ ❛♥ ♦✈❡♥ ❛t t❡♠♣❡r❛t✉r❡s ♦❢ 750o

C✱ 950o

C ❛♥❞ 125o

C✳

❚❤❡ ♣r❡❝✉rs♦rs ♦①✐❞✐③✐♥❣ ✉s❡❞ ✇❡r❡ ♥✐❝❦❡❧ ♥✐tr❛t❡✱ ❢❡rr✐❝ ❛s ❛♥ ♦①✐❞✐③✐♥❣ ❛♥❞ r❡✲ ❞✉❝✐♥❣ ✉r❡❛ ✭❢✉❡❧✮✳ ❆❢t❡r ♦❜t❛✐♥✐♥❣ t❤❡ ♠✐①t✉r❡✱ t❤❡ ♣r♦❞✉❝t ✇❛s ❞❡❛❣❣❧♦♠❡r❛t❡❞ ❛♥❞ ♣❛st t❤r♦✉❣❤ ❛ 270 ♠❡s❤ s✐❡✈❡✳ ❚♦ ❛ss❡ss t❤❡ str✉❝t✉r❡✱ ♠♦r♣❤♦❧♦❣②✱ ♣❛rt✐❝❧❡

s✐③❡✱ ♠❛❣♥❡t✐❝ ❛♥❞ ❡❧❡❝tr✐❝❛❧ ♣r♦♣❡rt✐❡s ♦❢ ♥❛♥♦♣❛rt✐❝❧❡s ♦❜t❛✐♥❡❞ t❤❡ s❛♠♣❧❡s ✇❡r❡ s✐♥t❡r❡❞ ❛♥❞ ❝❤❛r❛❝t❡r✐③❡❞ ❜② ①✲r❛② ❞✐✛r❛❝t✐♦♥ (XRD)✱ ①✲r❛② ✢✉♦r❡s❝❡♥❝❡ s♣❡❝tr♦s✲

❝♦♣② (F RX)❀ s❝❛♥♥✐♥❣ ❡❧❡❝tr♦♥ ♠✐❝r♦s❝♦♣②(SEM)✱ ❡♥❡r❣② ❞✐s♣❡rs✐✈❡ s♣❡❝tr♦s❝♦♣② (EDS)✱ ✈✐❜r❛t✐♥❣ s❛♠♣❧❡ ♠❛❣♥❡t♦♠❡t❡r(M AV)❛♥❞ ❡❧❡❝tr✐❝❛❧ ♣❡r♠✐tt✐✈✐t②✳ ❚❤❡ r❡✲

s✉❧ts ✐♥❞✐❝❛t❡❞ t❤❡ ♠❛❥♦r✐t② ♦❢ ♣❤❛s❡ ✐♥✈❡rs❡ s♣✐♥❡❧ ❢❡rr✐t❡ ❛♥❞ ❍❡♠❛t✐t❡ s❡❝♦♥❞❛r② ♣❤❛s❡ ♥✐❝❦❡❧ ❛♥❞ ♥✐❝❦❡❧ ♦①✐❞❡✳ ❚❤r♦✉❣❤ t❤❡ ✐♥t❡♥s✐t② ♦❢ t❤❡ ❞✐✛r❛❝t✐♦♥✱ t❤❡ ❛✈❡r❛❣❡ s✐③❡ ♦❢ t❤❡ ❝r②st❛❧❧✐③❛t✐♦♥ ♣❡❛❦s ✇❡r❡ ❤❛❧❢✲❤❡✐❣❤t ✇✐❞t❤ ✇❤✐❝❤ ✇❛s ❝❛❧❝✉❧❛t❡❞ ✉s✐♥❣ t❤❡ ❙❝❤❡rr❡r ❡q✉❛t✐♦♥✳ ❋r♦♠ ♦❜s❡r✈✐♥❣ t❤❡ ♣❡❛❦s ♦❢ ❛❧❧ t❤❡ r❡✢❡❝t✐♦♥s✱ ✐t ❛♣♣❡❛rs t❤❛t s❛♠♣❧❡s ❛r❡ ❝r②st❛❧ ❝❧❡❛r ✇✐t❤ t❤❡ ❢♦r♠❛t✐♦♥ ♦❢ ♥❛♥♦♣❛rt✐❝❧❡s✳ ▼♦r♣❤♦❧♦❣✐❝❛❧❧②✱ t❤❡ ♥❛♥♦❢❡rr✐t❛s s✐♥t❡r❡❞ ♥✐❝❦❡❧ ♣❡❧❧❡t ❢♦r♠❛t✐♦♥ ✇❛s ♦❜s❡r✈❡❞ ✇✐t❤ t❤r❡❡ s②st❡♠s ♦❢ ♣❛rt✐❝❧❡ s✐③❡ ❜❡❧♦✇ 100mn✱ ✇❤✐❝❤ ❢❛✈♦r❡❞ t❤❡ ❢♦r♠❛t✐♦♥ ♦❢ s♦❢t ♣❡❧❧❡ts✳ ❚❤❡ ❛✈❡r❛❣❡

s✐③❡ ♦❢ t❤❡ ❣r❛✐♥s ✐♥ t❤❡✐r ♠✐❝r♦♠❡tr✐❝ s❝❛❧❡✳ F RX ❛♥❞ EDS s❤♦✇❡❞ q✉❛❧✐t❛t✐✈❡❧②

t❤❡ ♣r❡s❡♥❝❡ ♦❢ ✐r♦♥ ❡❧❡♠❡♥ts ♥✐❝❦❡❧ ❛♥❞ ♦①②❣❡♥✱ ✇❤❡r❡ t❤r♦✉❣❤ q✉❛♥t✐t❛t✐✈❡ ❞❛t❛ ✇❡ ❝❛♥ ♦❜s❡r✈❡ t❤❡ ♣r❡s❡♥❝❡ ♦❢ t❤❡ s❡❝♦♥❞❛r② ♣❤❛s❡✳ ❚❤❡ ♠❛❣♥❡t✐❝ ♣r♦♣❡rt✐❡s ❛♥❞ t❤❡ s❛t✉r❛t✐♦♥ ♠❛❣♥❡t✐③❛t✐♦♥ ❛♥❞ t❤❡ ❝♦❡r❝✐✈❡ ✜❡❧❞ ❛r❡ ✐♥ ❛❝❝♦r❞❛♥❝❡ ✇✐t❤ t❤❡ ♥✐❝✲ ❦❡❧✱ ❢❡rr✐t❡ ✇❤❡r❡ t❤❡ ❝✉r✈❡ ♦❢ ❤②st❡r❡s✐s ❤❛s ❛s♣❡❝ts ♦❢ ❛ s♦❢t ♠❛t❡r✐❛❧✳ ❉✐❡❧❡❝tr✐❝ ❝♦♥st❛♥t ✈❛❧✉❡s ❛r❡ ❜❡❧♦✇ 10 ❛♥❞ ❧♦✇ t❛♥❣❡♥t ❧♦ss✳

❆ ❈át✐♦♥s ❞✐✈❛❧❡♥t❡ ❡♠ sít✐♦s t❡tr❛é❞r✐❝♦s ❇ ❈át✐♦♥s tr✐✈❛❧❡♥t❡s ❡♠ sít✐♦s ♦❝t❛é❞r✐❝♦s ❆ ❙ít✐♦s t❡tr❛é❞r✐❝♦s

❇ ❙ít✐♦s ♦❝t❛é❞r✐❝♦s ▼ ❮♦♥ ♠❡t❛❧ ❞✐✈❛❧❡♥t❡ ❘❉ ❘❡ss♦❛❞♦r❡s ❞✐❡❧étr✐❝♦s

ε′

P❡r♠✐ss✐✈✐❞❛❞❡ ❡❧étr✐❝❛ r❡❧❛t✐✈❛

ε0 P❡r♠✐ss✐✈✐❞❛❞❡ ❡❧étr✐❝❛ r❡❧❛t✐✈❛ ❞♦ ✈á❝✉♦

ε P❡r♠✐ss✐✈✐❞❛❞❡ ❡❧étr✐❝❛ εar P❡r♠✐ss✐✈✐❞❛❞❡ ❞♦ ❛r

❉❘❳ ❉✐❢r❛t♦♠❡tr✐❛ ❞❡ ❘❛✐♦s✲❳

▼❊❱ ▼✐❝r♦s❝♦♣✐❛ ❊❧❡trô♥✐❝❛ ❞❡ ❱❛rr❡❞✉r❛ ❊❉❙ ❊s♣❡❝tr♦♣✐❛ ❞❡ ❊♥❡r❣✐❛ ❉✐s♣❡rs✐✈❛ ❋❘❳ ❋❧✉♦r❡s❝ê♥❝✐❛ ❞❡ ❘❛✐♦s✲❳

▼❆❱ ▼❛❣♥❡t♦♠❡tr✐❛ ❞❡ ❆♠♦str❛ ❱✐❜r❛♥t❡ ❆❈ ❈♦rr❡♥t❡ ❛❧t❡r♥❛❞❛

❛ P❛râ♠❡tr♦s ❞❡ r❡❞❡

µ P❡r♠❡❛❜✐❧✐❞❛❞❡ ♠❛❣♥ét✐❝❛

µo P❡r♠❡❛❜✐❧✐❞❛❞❡ ♠❛❣♥ét✐❝❛ ♥♦ ✈á❝✉♦

❊✈ ❊❧❡tr♦✈♦❧ts

❚❛♥δ ❚❛♥❣❡♥t❡ ❞❡ ♣❡r❞❛s

χ ❙✉s❝❡♣t✐❜✐❧✐❞❛❞❡ ❡❧étr✐❝❛ ❞♦ ♠❛t❡r✐❛❧

o

❱ ▼♦♠❡♥t♦ ♠❛❣♥ét✐❝♦ ❛tó♠✐❝♦ ✉♥✐❞❛❞❡ ❞❡ ✈♦❧✉♠❡

− →

B ■♥❞✉çã♦ ♠❛❣♥ét✐❝❛ ♦✉ ❞❡♥s✐❞❛❞❡ ❞♦ ✢✉①♦ ♠❛❣♥ét✐❝♦

❚ ❚❡s❧❛

▼ ▼❛❣♥❡t✐③❛çã♦

− →

H ❱❡t♦r ❈❛♠♣♦ ▼❛❣♥ét✐❝♦ ❊①t❡r♥♦

▼▼ ▼❛ss❛ ▼♦❧❡❝✉❧❛r

▼s ▼❛❣♥❡t✐③❛çã♦ ❞❡ ❙❛t✉r❛çã♦ ▼r ▼❛❣♥❡t✐③❛çã♦ ❞❡ ❘❡♠❛♥❡s❝❡♥t❡ ❡♠✉✴❣ ❆❜r❡✈✐❛t✉r❛ ❞❡ ✉♥✐❞❛❞❡ ♠❛❣♥ét✐❝❛

◆ ◆ú♠❡r♦ ❞❡ ❆✈♦❣❛❞r♦ ❣ ❋❛t♦r ▲❛♥❞é

❏ ❏♦✉❧❡

❑ ❈♦♥st❛♥t❡ ❞❛ ❡q✉❛çã♦ ❞❡ ❙❝❤❡rr❡r ✬❉✬ ❉✐â♠❡tr♦ ♦✉ t❛♠❛♥❤♦ ❞❡ ❝r✐st❛❧✐t♦ ✬❞✬ ❉✐stâ♥❝✐❛

β ▲❛r❣✉r❛ ❞♦ ♣✐❝♦ ❞❡ ♠❡✐❛ ❛❧t✉r❛ εJ ▼♦♠❡♥t♦ ❛♥❣✉❧❛r

❍❝ ❈❛♠♣♦ ❝♦❡r❝✐✈♦ ♠ ▼❛ss❛

❣ ●r❛♠❛ ➴ ➶♥❣str♦♥

❋❞✲✸♠ ●r✉♣♦ ❡s♣❛❝✐❛❧ ❞♦ ❡s♣✐♥é❧✐♦ ❈♦s ❈♦ss❡♥♦

❙❡♥ ❙❡♥♦

❍❦❧ ❮♥❞✐❝❡s ❞❡ ▼✉❧❧❡r

Σ ❙♦♠❛tór✐♦

❉ ❆❧❛r❣❛♠❡♥t♦ ❞❛ ❜❛♥❞❛ ❞♦ ❞✐❢r❛t♦❣r❛♠❛ ♣✐❝♦ ❜❛s❡ ▼❡s❤ ❆❜❡rt✉r❛ ❞❛ ♣❡♥❡✐r❛

♠♠ ▼✐❧í♠❡tr♦ ♣♦r ♠✐❧í♠❡tr♦ ♥♠ ◆❛♥ô♠❡tr♦ ✶✵−9

µB ▼❛❣♥ét♦♥ ❞❡ ❇♦❤r −

→

µi ❉✐♣♦❧♦ ♠❛❣♥ét✐❝♦

❙■ ❙✐st❡♠❛ ✐♥t❡r♥❛❝✐♦♥❛❧ ❞❡ ✉♥✐❞❛❞❡s ❤ ❈♦♥st❛♥t❡ ❞❡ P❧❛♥❝❦

❡ ❈❛r❣❛ ❞♦ ❡❧étr♦♥ ❈ ❈❛♣❛❝✐tâ♥❝✐❛ ❆o ➪r❡❛

❋✐❣✉r❛ ✸✳✶ ❈é❧✉❧❛ ❯♥✐tár✐❛ ❡ ❊str✉t✉r❛ ❞♦ ❊s♣✐♥é❧✐♦ ✷✶

❋✐❣✉r❛ ✸✳✷ ❊s♣✐♥é❧✐♦ ◆♦r♠❛❧ ✷✷

❋✐❣✉r❛ ✸✳✸ ❊s♣✐♥é❧✐♦ ■♥✈❡rs♦ ✷✷

❋✐❣✉r❛ ✸✳✹ ❊str✉t✉r❛ ❈r✐st❛❧✐♥❛ ❞❛ ❋❡rr✐t❛ ❞❡ ◆íq✉❡❧ ✷✹

❋✐❣✉r❛ ✸✳✺ ❆♠♦str❛ ❞❡ ❯r❡✐❛ ✷✻

❋✐❣✉r❛ ✸✳✻ ❊str✉t✉r❛ ❞♦ ❮♦♥ ❞❡ ◆✐tr❛t♦ ✷✼

❋✐❣✉r❛ ✸✳✼ ◆✐tr❛t♦ ❞❡ ◆íq✉❡❧ ❤❡①❛❤✐❞r❛t❛❞♦ ✷✽ ❋✐❣✉r❛ ✸✳✽ ◆✐tr❛t♦ ❞❡ ❋❡rr♦ ◆♦♥♦❤✐❞r❛t❛❞♦ ✷✽ ❋✐❣✉r❛ ✸✳✾ ■❧✉str❛çã♦ ❞❛s ❊t❛♣❛s ❞❡ ❙✐♥t❡r✐③❛çã♦ ✷✾ ❋✐❣✉r❛ ✸✳✶✵ ❘❡❣✐õ❡s ❞❡ ❉♦♠í♥✐♦s ▼❛❣♥ét✐❝♦s ✸✸

❋✐❣✉r❛ ✸✳✶✶ ❈✉r✈❛ ❞❡ ❍✐st❡r❡s❡ ✸✺

❋✐❣✉r❛ ✸✳✶✷ ❈✉r✈❛ ❞❡ ❍✐st❡r❡s❡ ❞❡ ▼❛t❡r✐❛❧ ❉✉r♦ ❡ ▼♦❧❡ ✸✻ ❋✐❣✉r❛ ✸✳✶✸ ❊t❛♣❛ ❞❛s ❘❡❛çõs ♥♦ ▼ét♦❞♦ P❡❝❤✐♥✐ ♥❛ ❋♦r♠❛çã♦ ❞♦ ◗✉❡❧❛t♦ ✹✸ ❋✐❣✉r❛ ✸✳✶✹ ❊t❛♣❛ ❞❛s ❘❡❛çõs ♥♦ ▼ét♦❞♦ P❡❝❤✐♥✐ ♥❛ r❡❛çã♦ ❞❡ ♣♦❧✐❡st❡r✐✲

✜❝❛çã♦

✹✸

❋✐❣✉r❛ ✹✳✶ ❊sq✉❡♠❛ ❇✐❞✐♠❡♥s✐♦♥❛❧ ❞❛ ❉✐❢r❛çã♦ ❞♦s ❘❛✐♦s✲❳ ❡♠ P❧❛♥♦s P❛r❛❧❡❧♦s

✺✵

❋✐❣✉r❛ ✹✳✷ ❘❡♣r❡s❡♥t❛çã♦ ❞♦ ❘❛✐♦✲❳ ✺✹

❋✐❣✉r❛ ✹✳✸ ▼❛❣♥❡tô♠❡tr♦ ❞❡ ❆♠♦str❛ ❱✐❜r❛♥t❡s ✺✺ ❋✐❣✉r❛ ✹✳✹ ❇♦❜✐♥❛ ❞❡ ❉❡t❡❝çã♦ ♥♦ ▼❛❣♥❡ô♠❡tr♦ ❞❡ ❆♠♦str❛ ❱✐❜r❛♥t❡s ✺✻ ❋✐❣✉r❛ ✹✳✺ ❘❡♣r❡s❡♥t❛çã♦ ❞❡ ❘❉ ❡♠ P❧❛❝❛s P❛r❛❧❡❧❛s ✺✼ ❋✐❣✉r❛ ✺✳✶ ❋❧✉①♦❣r❛♠❛ ❞❛ ▼❡t♦❞♦❧♦❣✐❛ ❊♠♣r❡❣❛❞❛ ♥❛ ❖❜t❡♥çã♦ ❞❛ ❋❡r✲

r✐t❛ ❞❡ ◆íq✉❡❧

❋✐❣✉r❛ ✻✳✶ ✭❜✮ ❉✐❢r❛t♦❣r❛♠❛s ❞❛s ❋❡rr✐t❛s ❞❡ ◆íq✉❡❧ ❙✐♥t❡r✐③❛❞❛s ❡♠ ❉✐❢❡✲ r❡♥t❡s ❚❡♠♣❡r❛t✉r❛s

✻✹

❋✐❣✉r❛ ✻✳✶ ✭❝✮ ❉✐❢r❛t♦❣r❛♠❛s ❞❛s ❋❡rr✐t❛s ❞❡ ◆íq✉❡❧ ❙✐♥t❡r✐③❛❞❛s ❡♠ ❉✐❢❡✲ r❡♥t❡s ❚❡♠♣❡r❛t✉r❛s

✻✺

❋✐❣✉r❛ ✻✳✷ ❙✉♣❡r♣♦s✐çõ❡s ❞♦s ❉✐❢r❛t♦❣r❛♠❛s ❡♠ ❚❡♠♣❡r❛t✉r❛s ❉✐❢❡r❡♥t❡s ✻✺ ❋✐❣✉r❛ ✻✳✸ ❆♣❛r❡❧❤♦ ❞❛ ▼✐❝r♦s❝♦♣✐❛ ❊❧❡trô♥✐❝❛ ❞❡ ❱❛rr❡❞✉r❛ ✼✶ ❋✐❣✉r❛ ✻✳✹ ✭❛✮ ▼✐❝r♦❣r❛✜❛ ❞♦ ◆❛♥♦♣ós ❞❡ ❋❡rr✐t❛ Pr❡♣❛r❛❞❛ ♣♦r ❘❡❛çã♦ ❞❡

❈♦♠❜✉stã♦

✼✷

❋✐❣✉r❛ ✻✳✹ ✭❜✮ ▼✐❝r♦❣r❛✜❛ ❞♦ ◆❛♥♦♣ós ❞❡ ❋❡rr✐t❛ Pr❡♣❛r❛❞❛ ♣♦r ❘❡❛çã♦ ❞❡ ❈♦♠❜✉stã♦

✼✷

❋✐❣✉r❛ ✻✳✹ ✭❝✮ ▼✐❝r♦❣r❛✜❛ ❞♦ ◆❛♥♦♣ós ❞❡ ❋❡rr✐t❛ Pr❡♣❛r❛❞❛ ♣♦r ❘❡❛çã♦ ❞❡ ❈♦♠❜✉stã♦

✼✸

❋✐❣✉r❛ ✻✳✺ ■♠❛❣❡♠ ❞♦ ❊❉❙ ❞❛ ❆♠♦str❛ ❛ ✼✺✵◦ ✼✹

❋✐❣✉r❛ ✻✳✻ ■♠❛❣❡♠ ❞♦ ❊❉❙ ❞❛ ❆♠♦str❛ ❛ ✾✺✵◦ ✼✺

❋✐❣✉r❛ ✻✳✼ ■♠❛❣❡♠ ❞♦ ❊❉❙ ❞❛ ❆♠♦str❛ ❛ ✶✳✷✺✵◦ ✼✻

❚❛❜❡❧❛ ✸✳✶ ❊st❛❞♦s ❞❡ ❖①✐❞❛çã♦ ❞❡ ❛❧❣✉♥s ❊s♣✐♥é❧✐♦s ✷✸ ❚❛❜❡❧❛ ✸✳✷ ❱❛♥t❛❣❡♥s ❡ ❉❡s✈❛♥t❛❣❡♥s ❞♦ ▼ét♦❞♦ ❙♦❧✲●❡❧ ✹✷ ❚❛❜❡❧❛ ✸✳✸ ❱❛♥t❛❣❡♥s ❡ ❉❡s✈❛♥t❛❣❡♥s ❞♦ ▼ét♦❞♦ P❡❝❤✐♥✐ ✹✹ ❚❛❜❡❧❛ ✸✳✹ ❱❛♥t❛❣❡♥s ❡ ❉❡s✈❛♥t❛❣❡♥s ❞♦ ▼ét♦❞♦ ❞❡ ❈♦✲♣r❡❝✐♣✐t❛çã♦ ✹✺ ❚❛❜❡❧❛ ✸✳✺ ❱❛♥t❛❣❡♥s ❡ ❉❡s✈❛♥t❛❣❡♥s ❞♦ ▼ét♦❞♦ ❍✐❞r♦tér♠✐❝♦ ✹✻ ❚❛❜❡❧❛ ✸✳✻ ❱❛♥t❛❣❡♥s ❡ ❉❡s✈❛♥t❛❣❡♥s ❞♦ ▼ét♦❞♦ ❞❡ ❈♦♠❜✉stã♦ ✹✽ ❚❛❜❡❧❛ ✹✳✶ ❈♦♥st❛♥t❡ ❉✐❡❧étr✐❝❛ ❡♠ ❘❡❧❛çã♦ ❛♦ ▼❡✐♦ ✺✼ ❚❛❜❡❧❛ ✺✳✶ ■♥❢♦r♠❛çõ❡s ❞♦s ❘❡❛❣❡♥t❡s ❯t✐❧✐③❛❞♦s ♥❛ ❙í♥t❡s❡ ❞❡ ❈♦♠❜✉s✲

tã♦ ❞❡ ❋❡rr✐t❛ ❞❡ ◆íq✉❡❧

✺✾

❚❛❜❡❧❛ ✻✳✶ ❆rq✉✐✈♦s ❞♦ Pr♦❣r❛♠❛ ♠❛t❝❤ ✻✻

❚❛❜❡❧❛ ✻✳✷ ❆rq✉✐✈♦s ❞♦ Pr♦❣r❛♠❛ ♠❛✉❞ ✻✻

❚❛❜❡❧❛ ✻✳✸ P❧❛♥♦s ❞❡ ❘❡✢❡①ã♦ ❇❛s❛✐s ❤❧❦✱ ✐♥t❡♥s✐❞❛❞❡ ❡ t❛♠❛♥❤♦ ❞♦ ❝r✐s✲ t❛❧✐t♦ ❛ ✼✺✵◦

✻✼

❚❛❜❡❧❛ ✻✳✹ P❧❛♥♦s ❞❡ ❘❡✢❡①ã♦ ❇❛s❛✐s ❤❧❦✱ ✐♥t❡♥s✐❞❛❞❡ ❡ t❛♠❛♥❤♦ ❞♦ ❝r✐s✲ t❛❧✐t♦ ❛ ✾✺✵◦

✻✼

❚❛❜❡❧❛ ✻✳✺ P❧❛♥♦s ❞❡ ❘❡✢❡①ã♦ ❇❛s❛✐s ❤❧❦✱ ✐♥t❡♥s✐❞❛❞❡ ❡ t❛♠❛♥❤♦ ❞♦ ❝r✐s✲ t❛❧✐t♦ ❛ ✶✳✷✺✵◦

✻✽

❚❛❜❡❧❛ ✻✳✻ ❚❛♠❛♥❤♦ ▼é❞✐♦ ❞♦ ❈r✐st❛❧✐t♦ ❡♠ ❆♠♦str❛s ❉✐❢❡r❡♥t❡s ✻✽ ❚❛❜❡❧❛ ✻✳✼ P❛râ♠❡tr♦ ❞❡ ❘❡❞❡ ❞❛s ❆♠♦str❛s ❞❡ ❋❡rr✐t❛ ❞❡ ◆íq✉❡❧ ✻✾ ❚❛❜❡❧❛ ✻✳✽ ❚❛♠❛♥❤♦ ▼é❞✐♦ ❞♦ ❈r✐st❛❧✐t♦ ❡ P❛râ♠❡tr♦ ❞❡ ❘❡❞❡ ❞❛s ❆♠♦s✲

tr❛s ❞❛s ❋❡rr✐t❛s ❞❡ ◆íq✉❡❧

✼✵

❚❛❜❡❧❛ ✻✳✾ ❘❡s✉❧t❛❞♦ ◗✉❛♥t✐t❛t✐✈♦ ❞♦ ❊❉❙ ♣❛r❛ ❆♠♦str❛ ❙✐♥t❡r✐③❛❞❛ ❛ ✼✺✵◦

✼✸

❚❛❜❡❧❛ ✻✳✶✵ ❘❡s✉❧t❛❞♦ ◗✉❛♥t✐t❛t✐✈♦ ❞♦ ❊❉❙ ♣❛r❛ ❆♠♦str❛ ❙✐♥t❡r✐③❛❞❛ ❛ ✾✺✵◦

❚❛❜❡❧❛ ✻✳✶✷ ❘❡s✉❧t❛❞♦s ❞❡ ❋❧✉♦r❡s❝ê♥❝✐❛ ❞❡ ❘❛✐♦s✲❳ ♣❛r❛ ▼❛t❡r✐❛✐s ❙✐♥✲ t❡t✐③❛❞♦s

✼✼

❚❛❜❡❧❛ ✻✳✶✸ ▼❛ss❛ ▼♦❧❛r❡s ❞❛s ❙✉❜stâ♥❝✐❛s ❊♥✈♦❧✈✐❞❛s ♥❛ ❖❜t❡♥çã♦ ❞❛ ❋❡rr✐t❛ ❞❡ ◆íq✉❡❧

✼✼

❚❛❜❡❧❛ ✻✳✶✹ ❉❛❞♦s ❞♦s ❋❘❳✴❊❉❙ ✽✶

❚❛❜❡❧❛ ✻✳✶✺ ❉✐❢❡r❡♥ç❛ ❞❡ P❡r❝❡♥t✉❛❧ ❚❡ór✐❝♦ ❆tr❛✈és ❞♦s ❘❡s✉❧t❛❞♦s ❞♦ ❋❘❳

✽✶

❚❛❜❡❧❛ ✻✳✶✻ ❆♥á❧✐s❡ ❞♦ ❊①❝❡ss♦ ❞❡ ❘❡❛❣❡♥t❡s ❆tr❛✈és ❞♦ ❊❉❙ ✽✷

✶ ■♥tr♦❞✉çã♦ ✶✻ ✶✳✶ ■♥tr♦❞✉çã♦ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✶✻

✷ ❖❜❥❡t✐✈♦s ✶✾

✷✳✶ ❖❜❥❡t✐✈♦s ●❡r❛✐s ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✶✾ ✷✳✷ ❖❜❥❡t✐✈♦s ❊s♣❡❝í✜❝♦s ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✶✾

✸ ❘❡✈✐sã♦ ❇✐❜❧✐♦❣rá✜❝❛ ✷✵

✹✳✷ ▼✐❝r♦s❝ó♣✐♦s ❊❧❡trô♥✐❝❛ ❞❡ ❱❛rr❡❞✉r❛ ✭▼❊❱✮ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✺✶ ✹✳✸ ❊s♣❡❝tr♦s❝♦♣✐❛s ❞❡ ❊♥❡r❣✐❛ ❉✐s♣❡rs✐✈❛ ✭❊❉❙✮ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✺✷ ✹✳✹ ❋❧✉♦r❡s❝ê♥❝✐❛ ❞❡ ❘❛✐♦✲❳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✺✸ ✹✳✺ ▼❛❣♥❡tô♠❡tr♦ ❞❡ ❆♠♦str❛ ❱✐❜r❛♥t❡ ✭❱❙▼✮ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✺✹ ✹✳✻ P❡r♠✐ss✐✈✐❞❛❞❡ ❊❧étr✐❝❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✺✻ ✹✳✻✳✶ ❉❡t❡r♠✐♥❛çã♦ ❞❛ ❈♦♥st❛♥t❡ ❉✐❡❧étr✐❝❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✺✼

✺ ❘❡❛❣❡♥t❡s ❡ ▼ét♦❞♦ ✺✾

✺✳✶ ❘❡❛❣❡♥t❡s ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✺✾ ✺✳✷ ▼ét♦❞♦ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✻✵

✻ ❘❡s✉❧t❛❞♦s ❡ ❉✐s❝✉ssã♦ ✻✸

✻✳✶ ❆♥á❧✐s❡ ❞❡ ❉✐❢r❛çã♦ ❞❡ ❘❛✐♦s ❳ ✲ ❉❘❳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✻✸ ✻✳✷ ▼✐❝r♦s❝♦♣✐❛ ❊❧❡trô♥✐❝❛ ❞❡ ❱❛rr❡❞✉r❛ ✭▼❊❱✮ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✼✵ ✻✳✸ ❆♥á❧✐s❡ ❞♦ ❊❉❙ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✼✸ ✻✳✹ ❋❧✉♦r❡s❝ê♥❝✐❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✼✻ ✻✳✹✳✶ ❆♥á❧✐s❡ ◗✉❛♥t✐t❛t✐✈❛ ♣❛r❛ ♦ ❋❘❳ ❡ ♦ ❊❉❙ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✼✼ ✻✳✺ ❆♥á❧✐s❡ ❞❡ ▼❛❣♥❡t✐③❛çã♦ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✽✸ ✻✳✻ ❆♥á❧✐s❡ ❊❧étr✐❝❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✽✻

✼ ❈♦♥❝❧✉sã♦ ✾✵

❘❡❢❡rê♥❝✐❛s ❇✐❜❧✐♦❣rá✜❝❛s ✾✶

■♥tr♦❞✉çã♦

✶✳✶ ■♥tr♦❞✉çã♦

❆s ❢❡rr✐t❛s sã♦ ♠❛t❡r✐❛✐s ❝❡râ♠✐❝♦s ♦♥❞❡ ♥❛s ú❧t✐♠❛s ❞é❝❛❞❛s tê♠✲s❡ r❡❛❧✐③❛❞♦ ♠✉✐t❛s ♣❡sq✉✐s❛s ❡ ❡st✉❞♦s s♦❜r❡ ❡❧❛s✱ q✉❡ ❛♣r❡s❡♥t❛♠ ♣r♦♣r✐❡❞❛❞❡s ❡❧étr✐❝❛s ❡ ♠❛❣✲ ♥ét✐❝❛s✳ ❆ ♦❜t❡♥çã♦ ❞❛s ❢❡rr✐t❛s ♦❝♦rr❡ ❛ ♣❛rt✐r ❞❛ ♠✐st✉r❛ ❞❡ ó①✐❞♦s ❢❡rr✐♠❛❣♥ét✐❝♦s ❡ t❡♠ ❛ s❡❣✉✐♥t❡ ❝♦♠♣♦s✐çã♦ q✉í♠✐❝❛ M OF e2O3✱ ❡♠ q✉❡ M é ✉♠ í♦♥ ♠❡tá❧✐❝♦ ❞✐✲

✈❛❧❡♥t❡ (M n;Zn;Cu;N i;Co;F e)✳ ❉❡✈✐❞♦ ❛ ✈❛st❛ ❣❛♠❛ ❞❡ ❛♣❧✐❝❛çã♦✱ t❛✐s ❝♦♠♦

❡♠ tr❛♥s❢♦r♠❛❞♦r❡s ❞❡ ❛❧t❛ ❢r❡q✉ê♥❝✐❛ ✉t✐❧✐③❛❞♦s ❡♠ ❡q✉✐♣❛♠❡♥t♦s ❡❧❡trô♥✐❝♦s✱ ❞✐s✲ ♣♦s✐t✐✈♦s ❞❡ ♠✐❝r♦♦♥❞❛s✱ ❛♣❛r❡❧❤♦s ❞❡ t❡❧❡❝♦♠✉♥✐❝❛çã♦✱ ❝✐r❝✉✐t♦s ❞❡ ❝♦♠♣✉t❛❞♦r❡s✱ ❣❡r❛❞♦r❡s✱ ❢♦♥t❡s ❞❡ ♣♦tê♥❝✐❛✱ ✜❧tr♦s ❞❡ ❢r❡q✉ê♥❝✐❛ ✈❛r✐á✈❡❧✱ s✉♣r❡ss♦r❡s ❞❡ r✉í❞♦✱ ❣r❛✈❛çã♦ ♠❛❣♥ét✐❝❛ ❡ ❡♠ ❛❜s♦r✈❡❞♦r❡s ❞❡ r❛❞✐❛çã♦ ❡❧❡tr♦♠❛❣♥ét✐❝❛ ❬✶❪✳

❙ã♦ ♠❛t❡r✐❛✐s q✉❡ ❛♣r❡s❡♥t❛♠ ❡st❛❜✐❧✐❞❛❞❡ tér♠✐❝❛ ❡ q✉í♠✐❝❛✱ tê♠ ❜❛✐①♦ ❝✉st♦✱ sã♦ ❞❡ ❢á❝✐❧ ♣r♦❝❡ss❛♠❡♥t♦✱ ❡ t❛♠❜é♠ ❛♣r❡s❡♥t❛♠ ❜♦❛s ♣r♦♣r✐❡❞❛❞❡s ♠❛❣♥ét✐❝❛s✱ ❜❛✐①❛ ♣❡r❞❛ ❞✐❡❧étr✐❝❛ ❡ ❡❧❡✈❛❞❛ r❡s✐st✐✈✐❞❛❞❡ ❡❧étr✐❝❛✳ ❆♣r❡s❡♥t❛♠ ✈❛❧♦r❡s ❞❡ ♠❛❣✲ ♥❡t✐③❛çã♦ ✐♥❢❡r✐♦r❡s à ♠❡t❛❞❡ ❞♦s ✈❛❧♦r❡s ❞❛s ❧✐❣❛s ❢❡rr♦♠❛❣♥ét✐❝❛s✱ ♣♦r ✐ss♦ ❛♣r❡✲ s❡♥t❛♠ ❛❧❣✉♠❛s ✈❛♥t❛❣❡♥s t❛✐s ❝♦♠♦✿ ❛ rá♣✐❞❛ r❡s♣♦st❛ ❞❡ ♠❛❣♥❡t✐③❛çã♦ ❬✷❪✳

◗✉❛♥t♦ à s✉❛ ♦❜t❡♥çã♦✱ ❛s ❢❡rr✐t❛s ♣♦❞❡♠ s❡r ♣r♦❞✉③✐❞❛s ♣❡❧♦ ♠ét♦❞♦ ❝❡râ♠✐❝♦ ❝♦♥✈❡♥❝✐♦♥❛❧✱ q✉❡ ❝♦♥s✐st❡ ♥❛ ♠✐st✉r❛ ❞♦s ó①✐❞♦s ♠❡❞✐❛♥t❡ ♠♦❛❣❡♠✱ s❡♥❞♦ ❡st❡ ✉♠ ♠ét♦❞♦ ❢ís✐❝♦ ✭♠❡❝â♥✐❝♦✮ q✉❡ ❝♦♥s♦♠❡ ❛❧t❛ ❡♥❡r❣✐❛ ❡ ❝✉❥♦ ♣r♦❞✉t♦ ✜♥❛❧ ♣♦❞❡ ❛♣r❡s❡♥t❛r ❜❛✐①❛ ♣r♦❞✉t✐✈✐❞❛❞❡✱ ♣♦✉❝❛ ❤♦♠♦❣❡♥❡✐❞❛❞❡ ❡ ❛ ♣r❡s❡♥ç❛ ❞❡ ❢❛s❡s ♥ã♦ ❞❡s❡❥❛❞❛s ❬✸❪✳

❊①✐st❡♠ t❛♠❜é♠ ♦s ♠ét♦❞♦s ♥ã♦ ❝♦♥✈❡♥❝✐♦♥❛✐s ❞❡ ♦❜t❡♥çã♦ ❞❛s ❢❡rr✐t❛s✱ ❞♦s

q✉❛✐s ♣♦❞❡✲s❡ ❝✐t❛r✿ s♦❧✲❣❡❧✱ ❝✐tr❛t♦s ♣r❡❝✉rs♦r❡s✱ ❝♦✲♣r❡❝✐♣✐t❛çã♦✱ ♣♦r r❡❛çã♦ ❞❡ ❝♦♠✲ ❜✉stã♦✱ P❡❝❤✐♥✐ ♦✉ ❞♦s ♣r❡❝✉rs♦r❡s ♣♦❧✐♠ér✐❝♦s ❡ ♦ ♠ét♦❞♦ ❤✐❞r♦tér♠✐❝♦✳ ◆❛ ❡s❝♦❧❤❛ ❞❡ ✉♠ ❞❡ss❡s ♣r♦❝❡ss♦s ❞❡✈❡♠ s❡r ❧❡✈❛❞♦s ❡♠ ❝♦♥s✐❞❡r❛çã♦ ✈ár✐♦s ❛s♣❡❝t♦s ❡ss❡♥❝✐✲ ❛✐s ♣❛r❛ ❛ ♣r♦❞✉çã♦ ❞❛s ❢❡rr✐t❛s✱ ❝♦♠♦ ♦ ❝♦♥tr♦❧❡ ❞❛ ♠✐❝r♦❡str✉t✉r❛ ❞❛s ♣❛rtí❝✉❧❛s ❡ ❞❛s ♣r♦♣r✐❡❞❛❞❡s ❡❧❡tr♦♠❛❣♥ét✐❝❛s✱ ♦ ❝♦♥tr♦❧❡ ❞❛s ❝❛r❛❝t❡ríst✐❝❛s ❞♦s ♣ós ✭♣✉r❡③❛✱ ❤♦♠♦❣❡♥❡✐❞❛❞❡ q✉í♠✐❝❛✱ ♠♦r❢♦❧♦❣✐❛ ❡ t❛♠❛♥❤♦ ♠é❞✐♦ ❞❛s ♣❛rtí❝✉❧❛s✮ ❬✹❪✳

❆s ❢❡rr✐t❛s ❛♣r❡s❡♥t❛♠ ❡str✉t✉r❛ ❝r✐st❛❧✐♥❛ ❞♦ t✐♣♦ ❡s♣✐♥é❧✐♦✱ ❝✉❥♦ ♥♦♠❡ é ♣r♦✈❡✲ ♥✐❡♥t❡ ❞♦ ♠✐♥❡r❛❧ ❡s♣✐♥é❧✐♦✱ M gAl2O4✳ ❆ ❡str✉t✉r❛ ❞❡ss❡ ❡s♣✐♥é❧✐♦ é ❝✉❜✐❝❛ ❞❡ ❢❛❝❡

❝❡♥tr❛❞❛✱ ❡♠ q✉❡ ♦s ❝át✐♦♥s ❞✐✈❛❧❡♥t❡M g2+ _{❡stã♦ ❞✐str✐❜✉í❞♦s ♥♦s sít✐♦s t❡tr❛é❞r✐❝♦s}

❡ ♦s ❝át✐♦♥s tr✐✈❛❧❡♥t❡sAl3+ _{❡stã♦ ❞✐str✐❜✉í❞♦s ♥♦s sít✐♦s ♦❝t❛é❞r✐❝♦s✳ ❆ ❞✐str✐❜✉✐çã♦}

♥❛ ❡str✉t✉r❛ ❝r✐st❛❧✐♥❛ ❛♣r❡s❡♥t❛ 8 ♣♦s✐çõ❡s ❝♦♠ s✐♠❡tr✐❛ t❡tr❛é❞r✐❝❛ ❡ 16 ♣♦s✐çõ❡s

❝♦♠ s✐♠❡tr✐❛ ♦❝t❛é❞r✐❝❛✱ ✐st♦ é✱ ♦s í♦♥s ❞❡ ♦①✐❣ê♥✐♦ ❝✐r❝✉♥❞❛♠ ♦s í♦♥s ♠❡tá❧✐❝♦s ❢♦r♠❛♥❞♦ sít✐♦s t❡tr❛é❞r✐❝♦s ❡ ♦❝t❛é❞r✐❝♦s✳ ❉❡✈✐❞♦ à ♣r❡s❡♥ç❛ ❞♦s í♦♥s F e✱ N i✱ Co✱ M n ♦✉ t❡rr❛s r❛r❛s✱ ♥♦ ❧✉❣❛r ❞♦ M g ♦✉ ❞♦ Al✱ ❛s ❢❡rr✐t❛s ❛♣r❡s❡♥t❛♠ ♣r♦♣r✐❡❞❛❞❡s

♠❛❣♥ét✐❝❛s✳

◗✉❛♥t♦ ❛ ❞✐str✐❜✉✐çã♦ ❞♦s í♦♥s ♥♦s sít✐♦s✱ ❛s ❢❡rr✐t❛s ♣♦❞❡♠ s❡r ❝❧❛ss✐✜❝❛❞❛s ❝♦♠♦✿

❊s♣✐♥é❧✐♦ ♥♦r♠❛❧✿ s❡ ♦s í♦♥s ❞✐✈❛❧❡♥t❡s ❡st✐✈❡r❡♠ ♥♦ s✐t✐♦ t❡tr❛é❞r✐❝♦ ❡ ♦s tr✐✈❛❧❡♥t❡s ♥♦ sít✐♦ ♦❝t❛é❞r✐❝♦✿

❊s♣✐♥é❧✐♦ ✐♥✈❡rs♦✿ s❡ ♦s í♦♥s ❞✐✈❛❧❡♥t❡s ❡st✐✈❡r❡♠ ♥♦ sít✐♦ ♦❝t❛é❞r✐❝♦ ❡ ♦s tr✐✲ ✈❛❧❡♥t❡s ♥♦ sít✐♦ t❡tr❛é❞r✐❝♦ ❡ ♦❝t❛é❞r✐❝♦✳

❆ ❢❡rr✐t❛ ❞❡ ♥íq✉❡❧ é ✉♠ ❡①❡♠♣❧♦ ❞❡ ✉♠ ❡s♣✐♥é❧✐♦ ✐♥✈❡rs♦✱ ♣♦✐s ♥❛ s✉❛ ❡str✉t✉r❛ ♣♦❞❡✲s❡ ♦❜s❡r✈❛r q✉❡ ♦s ❝át✐♦♥s ❞✐✈❛❧❡♥t❡ ❞❡ ♥íq✉❡❧(N i2+

)♦❝✉♣❛♠ ♣r❡❢❡r❡♥❝✐❛❧♠❡♥t❡

♦s sít✐♦s ♦❝t❛é❞r✐❝♦s ❞❡✈✐❞♦ à ❞✐str✐❜✉✐çã♦ ❞❡ ❝❛r❣❛ ❞❡ss❡ í♦♥ ♥♦ ❝❛♠♣♦ ❝r✐st❛❧✐♥♦✳ ◗✉❛♥t♦ ❛♦s ❝át✐♦♥s tr✐✈❛❧❡♥t❡s ❞❡ ❢❡rr♦ (F e3+

)✱ ♠❡t❛❞❡ ♦❝✉♣❛ ♦s sít✐♦s t❡tr❛é❞r✐❝♦s

❡ ❛ ♦✉tr❛ ❡stá ♥♦s sít✐♦s ♦❝t❛é❞r✐❝♦s ❬✺❪✳ ❊ss❛ ❞✐str✐❜✉✐çã♦ ❞♦s í♦♥s ❡♥tr❡ ♦s sít✐♦s ♦❝✲ t❛é❞r✐❝♦s ❡ t❡tr❛é❞r✐❝♦s é ❞❡t❡r♠✐♥❛❞❛ ♣♦r ✉♠ ❜❛❧❛♥ç♦ ❞❡ ❡♥❡r❣✐❛ ♥❛ r❡❞❡ ❝r✐st❛❧✐♥❛✳ ❆❧❣✉♠❛s ♣r♦♣r✐❡❞❛❞❡s ❞❛s ❢❡rr✐t❛s t❛♠❜é♠ ❡stã♦ r❡❧❛❝✐♦♥❛❞❛s ❝♦♠ ❛ ❞✐str✐❜✉✐çã♦ ❞❡ss❡s í♦♥s ♥❡ss❡s sít✐♦s t❡tr❛é❞r✐❝♦s ❡ ♦❝t❛é❞r✐❝♦s✳ P♦ré♠✱ ❡①✐st❡♠ ♦✉tr♦s ❢❛t♦r❡s q✉❡ ✐♥✢✉❡♥❝✐❛♠ ❛s ♣r♦♣r✐❡❞❛❞❡s ❞❛s ❢❡rr✐t❛ ❝♦♠♦ ♣♦r ❡①❡♠♣❧♦s ♦ t❛♠❛♥❤♦✱ ❛ ❢♦r♠❛ ❞♦s ❣rã♦s ❡ ♦ ❤✐stór✐❝♦ tér♠✐❝♦ ❞❛s ❛♠♦str❛s✱ ❛❧é♠ ❞♦ ♠ét♦❞♦ ❞❡ ♦❜t❡♥çã♦ ❬✻❪✳

❆ ❡s❝♦❧❤❛ ❞♦ ♠ét♦❞♦ ❞❛ ♣r❡♣❛r❛çã♦ ❞❛s ❢❡rr✐t❛s é ♠✉✐t♦ ✐♠♣♦rt❛♥t❡✱ ♣♦r ❡①❡♠✲ ♣❧♦✱ ♦ ❞❡ sí♥t❡s❡ ♣♦r r❡❛çã♦ ❞❡ ❝♦♠❜✉stã♦ ♣♦ss✉✐ ♠❡❧❤♦r ✈✐❛❜✐❧✐❞❛❞❡ ❡ é ♠✉✐t♦ ❡✜❝❛③✳ ❊ss❡ ♠ét♦❞♦ ❛♣r❡s❡♥t❛ ✈ár✐❛s ✈❛♥t❛❣❡♥s✱ ❝♦♠♦ s❡r s✐♠♣❧❡s ❡ ♣r❡❝✐s❛r ❞❡ ♣♦✉❝♦ t❡♠♣♦

♣❛r❛ s✉❛ ❡①❡❝✉çã♦ ❡ ♦❜t❡♥çã♦ ❞♦ ♣r♦❞✉t♦ ✜♥❛❧✳ ■ss♦ ♣♦rq✉❡ ♥ã♦ ♥❡❝❡ss✐t❛ ❞❡ ❡t❛✲ ♣❛s ✐♥t❡r♠❡❞✐ár✐❛s ❡ ♦ ♣ós✲♠✐st✉r❛ ❛♣r❡s❡♥t❛ ❛❧t♦ ❣r❛✉ ❞❡ ♣✉r❡③❛ ❡ ❤♦♠♦❣❡♥❡✐❞❛❞❡ q✉í♠✐❝❛✱ ❣❡r❛♥❞♦✱ ♥♦r♠❛❧♠❡♥t❡✱ ♣r♦❞✉t♦s ❝♦♠ ❡str✉t✉r❛s ❡ ❝♦♠♣♦s✐çõ❡s ❞❡s❡❥❛❞❛s✳ ◆❡ss❡ ♠ét♦❞♦✱ ❞✉r❛♥t❡ ♦ ❡①♣❡r✐♠❡♥t♦✱ ❛ ♠✐st✉r❛ é ❛q✉❡❝✐❞❛ ❡✱ q✉❛♥❞♦ ❛t✐♥❣❡ ❝❡rt❛ t❡♠♣❡r❛t✉r❛✱ ❡♥tr❛ ❡♠ ✐❣♥✐çã♦ ❛tr❛✈és ❞❡ r❡❛çã♦ ❞❡ ❝♦♠❜✉stã♦ ❛✉t♦ss✉st❡♥t❛❞❛ ❡ rá✲ ♣✐❞❛✱ r❡s✉❧t❛♥❞♦ ❡♠ ✉♠ ♣ó s❡❝♦✱ ❣❡r❛❧♠❡♥t❡ ❝r✐st❛❧✐♥♦ ❡ ✜♥♦✱ s❡♥❞♦ q✉❡ ❛s ♣❛rtí❝✉❧❛s ♦❜t✐❞❛s ♣♦ss✉❡♠ t❛♠❛♥❤♦ ✐♥❢❡r✐♦r❡s ❛ ✶✵✵ ♥♠ ❬✼❪ ❬✽❪✳

◆❡st❡ tr❛❜❛❧❤♦✱ r❡❛❧✐③♦✉✲s❡ ❛ ♣r❡♣❛r❛çã♦✱ à s✐♥t❡r✐③❛çã♦ ❡ ❛ ❝❛r❛❝t❡r✐③❛çã♦ ❞❡ ❢❡rr✐t❛s ❞❡ ♥íq✉❡❧✱ ❝♦♠♦ t❛♠❜é♠ ❛✈❛❧✐♦✉✲s❡ s✉❛ ♣♦ssí✈❡❧ ❛♣❧✐❝❛çã♦ ❡♠ ❛♥t❡♥❛s✳ P❛r❛ ✐ss♦ ♣r♦❝❡❞❡✉✲s❡ ❛♦ ❡st✉❞♦ ❡ à ♣❡sq✉✐s❛ ❞❛ ✐♥✢✉ê♥❝✐❛ ❞❛ t❡♠♣❡r❛t✉r❛ ❞❡ s✐♥t❡r✐③❛✲ çã♦ ❞♦s ♣ós✲♠✐st✉r❛s ♦❜t✐❞♦s✳ ❆❧❣✉♠❛s ♣r♦♣r✐❡❞❛❞❡s ❢♦r❛♠ ❞❡t❡r♠✐♥❛❞❛s✱ ❝♦♠♦ ♦ t❛♠❛♥❤♦ ❞❛s ♣❛rtí❝✉❧❛s✱ ❛ ♠♦r❢♦❧♦❣✐❛✱ ❡ ❛❧❣✉♠❛s ♣r♦♣r✐❡❞❛❞❡s ❡❧❡tr♦♠❛❣♥ét✐❝❛s✱ ❛ ♠❛❣♥❡t✐③❛çã♦ ❡ ❛ ♣❡r♠✐ss✐✈✐❞❛❞❡ ❡❧étr✐❝❛✳ P♦rt❛♥t♦✱ ❡st❡ tr❛❜❛❧❤♦ ❛✈❛❧✐♦✉ ♦ ❝♦♠✲ ♣♦rt❛♠❡♥t♦ ♣ós✲s✐♥t❡r✐③❛çã♦ ❞❡ ❢❡rr✐t❛s ❞❡ ♥íq✉❡❧ ♦❜t✐❞❛s ❡♠ t❡♠♣❡r❛t✉r❛s ❞❡ 750✱ 950 ❡ 1200o

C✱ ❛tr❛✈és ❞❛ sí♥t❡s❡ ♣♦r r❡❛çã♦ ❞❡ ❝♦♠❜✉stã♦✱ ✉s❛♥❞♦ ❛ ✉r❡✐❛ ❝♦♠♦

❝♦♠❜✉stí✈❡❧✳ ❖s ♣r♦❞✉t♦s ❞♦ ♣ós✲s✐♥t❡r✐③❛❞♦s ❢♦r❛♠ ❝❛r❛❝t❡r✐③❛❞♦s ♣♦r ❉✐❢r❛çã♦ ❞❡ ❘❛✐♦s✲❳ (DRX)✱ ❋❧✉♦r❡s❝ê♥❝✐❛ ❞❡ ❘❛✐♦s✲❳ (F RX)✱ ▼✐❝r♦s❝♦♣✐❛ ❊❧❡trô♥✐❝❛ ❞❡ ❱❛r✲

r❡❞✉r❛ (M EV) ❝♦♠ EDS✱ ▼❛❣♥❡tô♠❡tr♦ ❞❡ ❆♠♦str❛ ❱✐❜r❛♥t❡ (M AV) ❡ ❆♥á❧✐s❡

❊❧étr✐❝❛✳

❖❜❥❡t✐✈♦s

✷✳✶ ❖❜❥❡t✐✈♦s ●❡r❛✐s

❙✐♥t❡t✐③❛r✱ s✐♥t❡r✐③❛r✱ ❝❛r❛❝t❡r✐③❛r ❢❡rr✐t❛s ❞❡ ♥íq✉❡❧✳

✷✳✷ ❖❜❥❡t✐✈♦s ❊s♣❡❝í✜❝♦s

Pr♦♠♦✈❡r ❛ sí♥t❡s❡ ❞❡ ❢❡rr✐t❛s ❞❡ ♥íq✉❡❧✱ ❛tr❛✈és ❞♦ ♠ét♦❞♦ ❞❡ ❝♦♠❜✉stã♦✱ ✉s❛♥❞♦ ❝♦♠♦ ♦①✐❞❛♥t❡ ♦s ♥✐tr❛t♦s ❞❡ ♥íq✉❡❧ ❡ ❞❡ ❢❡rr♦ ❡ ❝♦♠♦ r❡❞✉t♦r✱ ❛ ✉r❡✐❛✳

❙✐♥t❡r✐③❛r ♦ ♣ós✲♠✐st✉r❛ ❞❡ ❢❡rr✐t❛ ❞❡ ♥íq✉❡❧ ❡♠ três t❡♠♣❡r❛t✉r❛s ❞✐❢❡r❡♥t❡s750✱ 950✱ ❡1250♦C✳

■♥✈❡st✐❣❛r ❛ ♠✐❝r♦❡str✉t✉r❛ ❞♦s ♣ós✲♠✐st✉r❛s s✐♥t❡r✐③❛❞♦s ♣♦rDRX✱F RX✱M EV

❡ EDS✳

■♥✈❡st✐❣❛r ❛s ♣r♦♣r✐❡❞❛❞❡s ❡❧étr✐❝❛s ❡ ♠❛❣♥ét✐❝❛s ❞♦s ♣ós✲s✐♥t❡r✐③❛❞♦s ♣♦rM AV

❡ ♣♦r ♣❡r♠✐ss✐✈✐❞❛❞❡ ❡❧étr✐❝❛✳

■♥✈❡st✐❣❛r ❛ ❛♣❧✐❝❛çã♦ ❞♦s ♠❛t❡r✐❛✐s ❡♠ ❛♥t❡♥❛s ♥❛ ❢❛✐①❛ ❞❡ ♠✐❝r♦✲♦♥❞❛s✳

❘❡✈✐sã♦ ❇✐❜❧✐♦❣rá✜❝❛

✸✳✶ ❋❡rr✐t❛

❋❡rr✐t❛s sã♦ ❝♦♠♣♦st♦s ❢♦r♠❛❞♦s ❛ ♣❛rt✐r ❞♦s ó①✐❞♦s ❢❡rr✐♠❛❣♥ét✐❝♦s ❞❡ ❝♦♠✲ ♣♦s✐çã♦ M OF e2O3✱ s❡♥❞♦ M ✉♠ í♦♥ ♠❡tá❧✐❝♦ ❞✐✈❛❧❡♥t❡ (M n;Zn;Cu;N i;Co;F e)✳

◗✉❛♥t♦ à s✉❛ ❝♦♠♣♦s✐çã♦ q✉í♠✐❝❛ ❡ à ❞✐str✐❜✉✐çã♦ ❝r✐st❛❧♦❣rá✜❝❛✱ sã♦ ❝❧❛ss✐✜❝❛❞❛s ❡♠ três t✐♣♦s ❣❛r♥❡t❡s✱ ❤❡①❛❣♦♥❛✐s✱ ❡s♣✐♥é❧✐♦ ❡ ♣❡r♦✈s❦✐t❛✳ ❉❛s q✉❛tr♦ ❡str✉t✉r❛s ❝✐t❛❞❛s✱ ❛s ❞♦ t✐♣♦ ❡s♣✐♥é❧✐♦ sã♦ ❛s q✉❡ ♠❛✐s ❡♥❝♦♥tr❛♠ ❛♣❧✐❝❛çõ❡s ♥♦ ❝♦t✐❞✐❛♥♦ ❬✾❪✳ ◆❛ ❡str✉t✉r❛ ❞❛s ❢❡rr✐t❛s✱ ❛ ♣r❡s❡♥ç❛ ❡ ❛ ❞✐str✐❜✉✐çã♦ ❞♦s ❝át✐♦♥s ♥❛ r❡❞❡ ❞❡✲ ♣❡♥❞❡♠ ❞♦ ♠ét♦❞♦ ❡♠♣r❡❣❛❞♦ ♥❛ sí♥t❡s❡ ❞❡ss❡s ♠❛t❡r✐❛✐s✱ q✉❡ sã♦ ❛❧t❛♠❡♥t❡ s❡♥✲ sí✈❡✐s ❛♦ tr❛t❛♠❡♥t♦ tér♠✐❝♦✳ ❖ ❡s♣✐♥é❧✐♦ ♦r✐❣✐♥❛❧ ❛♣r❡s❡♥t❛ s❡♠❡❧❤❛♥ç❛ ❛♦ ♠✐♥❡r❛❧

M gAl2O4 ❬✶✵❪ ❡ ♣♦ss✉✐ ❢ór♠✉❧❛ ♠í♥✐♠❛ AB2O4✱ ❡♠ q✉❡ A r❡♣r❡s❡♥t❛ ♦s ❝át✐♦♥s

❞✐✈❛❧❡♥t❡s ❡ B r❡♣r❡s❡♥t❛ ♦s ❝át✐♦♥s tr✐✈❛❧❡♥t❡s✳ ❊ss❡ ❡s♣✐♥é❧✐♦ ❛♣r❡s❡♥t❛ ❡str✉t✉r❛

❝ú❜✐❝❛ ❞❡ ❢❛❝❡ ❝❡♥tr❛❞❛✱ ❡♠ q✉❡ ♦s ❝át✐♦♥s ❞✐✈❛❧❡♥t❡s M g2+ _{❡stã♦ ❞✐str✐❜✉í❞♦s ❡♠}

sít✐♦s t❡tr❛é❞r✐❝♦s✱ ❡♥q✉❛♥t♦ ♦s ❝át✐♦♥s tr✐✈❛❧❡♥t❡s Al3+ _{❡stã♦ ❞✐str✐❜✉í❞♦s ♥❛s ♣♦s✐✲}

çõ❡s ♦❝t❛é❞r✐❝❛s✳ ❚❛❧ ❞✐str✐❜✉✐çã♦ é ❞❡♥♦♠✐♥❛❞❛ ❝♦♠♦ ❡s♣✐♥é❧✐♦ ♥♦r♠❛❧ ❡ ♥ã♦ ♦❝♦rr❡ ♥❡❝❡ss❛r✐❛♠❡♥t❡ s❡❣✉✐❞❛ ♣♦r ♦✉tr♦s s✐st❡♠❛s q✉❡ s❡ ❢♦r♠❛♠ ❛ ♣❛rt✐r ❞❡st❛✳ ❚r❛❞✐❝✐♦✲ ♥❛❧♠❡♥t❡✱ ❝❤❛♠❛✲s❡ t❛♠❜é♠ ❞❡A❡B❛s ♣♦s✐çõ❡s q✉❡ r❡♣r❡s❡♥t❛♠✱ r❡s♣❡❝t✐✈❛♠❡♥t❡✱

♦s sít✐♦s t❡tr❛é❞r✐❝♦s ❡ ♦❝t❛é❞r✐❝♦s✱ ♦s q✉❛✐s s❡ ❡♥❝♦♥tr❛♠ r♦❞❡❛❞♦s ❞❡ â♥✐♦♥s O2_−✱

s❡♥❞♦ q✉❛tr♦ â♥✐♦♥s ♦①✐❣ê♥✐♦ ❛♦ r❡❞♦r ❞♦ í♦♥ q✉❡ ♦❝✉♣❛ ♦ ✐♥t❡rstí❝✐♦ t❡tr❛é❞r✐❝♦ ❡ s❡✐s â♥✐♦♥s ♦①✐❣ê♥✐♦✱ ❝❡r❝❛♥❞♦ ❛ ♣♦s✐çã♦ ♦❝t❛é❞r✐❝❛✳ ❆ ❝❡❧❛ ✉♥✐tár✐❛ ❞♦ ❡s♣✐♥é❧✐♦ é ❝♦♥st✐t✉í❞❛ ❞❡ ♦✐t♦ ❢ór♠✉❧❛s ♠í♥✐♠❛s✱ ❞❡ ♠♦❞♦ q✉❡ ❝❛❞❛ ❝❡❧❛ ♣♦ss✉✐ 32 â♥✐♦♥s

♦①✐❣ê♥✐♦✱ 8 ❝át✐♦♥s ❞✐✈❛❧❡♥t❡s ❡ 16 ❝át✐♦♥s tr✐✈❛❧❡♥t❡s✳ ❆♦ t♦❞♦ sã♦ 96 ✐♥t❡rstí❝✐♦s

♥✉♠❛ ❝❡❧❛ ✉♥✐tár✐❛✱ s❡♥❞♦64♣♦s✐çõ❡s t❡tr❛é❞r✐❝❛s ❡ 32♣♦s✐çõ❡s ♦❝t❛é❞r✐❝❛s❀ ♣♦ré♠✱

❛♣❡♥❛s 8❞❛s 64♣♦s✐çõ❡s t❡tr❛é❞r✐❝❛s ❡16❞❛s 32♣♦s✐çõ❡s ♦❝t❛é❞r✐❝❛s sã♦ ♦❝✉♣❛❞❛s

♣♦r ❝át✐♦♥s✱ s❡♥❞♦ ♦ r❡st❛♥t❡ ♣♦s✐çõ❡s ✜①❛s ❞♦ â♥✐♦♥ ♦①✐❣ê♥✐♦ ❬✶✶❪✳

❆ ❋✐❣✉r❛ 3.1❛♣r❡s❡♥t❛ ❛ r❡♣r❡s❡♥t❛çã♦ ❡sq✉❡♠át✐❝❛ ♣❛r❛ ❛ ❡str✉t✉r❛ ❡s♣✐♥é❧✐♦✳

❋✐❣✉r❛ ✸✳✶✿ ✭❛✮ sít✐♦ t❡tr❛é❞r✐❝♦ ✭❜✮ sít✐♦ ♦❝t❛é❞r✐❝♦ ✭❝✮ ❝é❧✉❧❛ ✉♥✐tár✐❛ ❡ ❡str✉✲ t✉r❛ ❞♦s ❝✉❜♦s ✐♥❢❡r✐♦r❡s

❋♦♥t❡✿ ❈❆❘❱❆▲❍❖✱ ❉❛♥✐❡❧❡ ●♦♠❡s✳

❘❡❧❛❝✐♦♥❛♥❞♦ ❛s ♣♦s✐çõ❡sA ❡ B ❝♦♠ ♦s sít✐♦s t❡tr❛é❞r✐❝♦s ❡ ♦❝t❛é❞r✐❝♦✱ ♦s q✉❛✐s

s❡ ❡♥❝♦♥tr❛♠ r♦❞❡❛❞♦s ❞❡ â♥✐♦♥s O2₋✱ ♦s ❡s♣✐♥é❧✐♦s ♣♦❞❡♠ s❡r ❝❧❛ss✐✜❝❛❞♦s ❝♦♠♦✿

❊s♣✐♥é❧✐♦ ♥♦r♠❛❧✿ é ❛q✉❡❧❡ q✉❡ ❝♦♥té♠A♥♦s sít✐♦s t❡tr❛é❞r✐❝♦s ❡ B ♥♦s sít✐♦s

♦❝t❛é❞r✐❝♦s✳ P♦❞❡ s❡r r❡♣r❡s❡♥t❛❞♦ ♣♦r A[B2]O4✱ ♠♦str❛❞❛ ♥❛ ❋✐❣✉r❛3.2✳

❋✐❣✉r❛ ✸✳✷✿ ❊s♣✐♥é❧✐♦ ♥♦r♠❛❧

❋♦♥t❡✿ ▼❊▲▲❖✱ ❘✳ ❘✳

❊s♣✐♥é❧✐♦ ✐♥✈❡rs♦✿ ❝♦♥t❡♥❞♦ A ❡B ♦❝✉♣❛♥❞♦ ✐❣✉❛❧♠❡♥t❡ ♦s sít✐♦s ♦❝t❛é❞r✐❝♦s

❡B✱ ♦s sít✐♦s t❡tr❛é❞r✐❝♦s✳ P♦❞❡ s❡r r❡♣r❡s❡♥t❛❞♦ ♣♦rB[AB]O4✱ ♠♦str❛❞❛ ♥❛ ❋✐❣✉r❛

3.3✳

❋✐❣✉r❛ ✸✳✸✿ ❊s♣✐♥é❧✐♦ ✐♥✈❡rs♦

❋♦♥t❡✿ ▼❊▲▲❖✱ ❘✳ ❘✳

❊s♣✐♥é❧✐♦ ♣❛r❝✐❛❧♠❡♥t❡ ✐♥✈❡rs♦ ♦✉ ✐♥t❡r♠❡❞✐ár✐♦✿ ❛ q✉❛♥t✐❞❛❞❡ ❞❡ A q✉❡

♦❝✉♣❛ ♦s sít✐♦s ♦❝t❛é❞r✐❝♦s ❢♦r♥❡❝❡ ♦ ❣r❛✉ ❞❡ ✐♥✈❡rsã♦✱ ♣♦❞❡♥❞♦ s❡r r❡♣r❡s❡♥t❛❞♦ ♣❡❧❛ ❡str✉t✉r❛ B1₋xAx[A1₋xB1+x]O4 ❬✶✷❪✳

❊♠ r❡❧❛çã♦ às ♣r♦♣r✐❡❞❛❞❡s ♠❛❣♥ét✐❝❛s✱ ♦s ❡s♣✐♥é❧✐♦s sã♦ ♠✉✐t♦ ✐♠♣♦rt❛♥t❡s✱ ♣r✐♥❝✐♣❛❧♠❡♥t❡✱ ♦s ó①✐❞♦s q✉❡ ❛♣r❡s❡♥t❛♠ ❝át✐♦♥s q✉❡ ♣♦ss✉❡♠ ❡st❛❞♦ ❞❡ ♦①✐❞❛çã♦

2 ❡ 3❝♦♠♦ ❛ ❢❡rr✐t❛ ❞❡ ♥íq✉❡❧ ❬✶✸❪✳

◆❛ ❚❛❜❡❧❛3.1sã♦ ❛♣r❡s❡♥t❛❞♦s ❛❧❣✉♥s ❡st❛❞♦s ❞❡ ♦①✐❞❛çã♦ ❞❡ ❛❧❣✉♥s ❡s♣✐♥é❧✐♦s✳

❚❛❜❡❧❛ ✸✳✶✿ ❊st❛❞♦s ❞❡ ♦①✐❞❛çã♦ ❞❡ ❛❧❣✉♥s ❝♦♠♣♦st♦s q✉❡ t❡♠ ❡str✉t✉r❛ ❡s♣✐✲ ♥é❧✐♦✳

❋♦♥t❡✿ ❆✉t♦r✳

✸✳✷ ❋❡rr✐t❛ ❞❡ ◆íq✉❡❧

❆ ❢❡rr✐t❛ ❞❡ ♥íq✉❡❧(N iF e2O4)é ✉♠ ♠❛t❡r✐❛❧ ❝❡râ♠✐❝♦ ❢❡rr✐♠❛❣♥ét✐❝♦ q✉❡ ❝r✐st❛✲

❧✐③❛ ♥✉♠❛ ❡str✉t✉r❛ ❞❡ ❡s♣✐♥é❧✐♦ ✐♥✈❡rs♦ ❞♦ t✐♣♦A2+

B3+

2 O4✳ ❊ss❡ ❡s♣✐♥é❧✐♦ ❛♣r❡s❡♥t❛

✉♠❛ ❡str✉t✉r❛ ✉♥✐tár✐❛ ♦❝✉♣❛❞❛ ❝♦♠ 32 â♥✐♦♥s ❞❡ ♦①✐❣ê♥✐♦s O2_{−✱ ❝♦♠}

8 ❝át✐♦♥s ❞✐✲

✈❛❧❡♥t❡s ❡8❝át✐♦♥s tr✐✈❛❧❡♥t❡s ♥♦s sít✐♦s ♦❝t❛é❞r✐❝♦s ✭❆✮✱ ❡ ❝♦♠8❝át✐♦♥s tr✐✈❛❧❡♥t❡s

♥♦s sít✐♦s t❡tr❛é❞r✐❝♦s ✭❇✮✳ ➱ ✉♠ ❡s♣✐♥é❧✐♦ ✐♥✈❡rs♦ ❢❡rr✐♠❛❣♥ét✐❝♦✱ q✉❡ é ♦r✐❣✐♥❛❞♦ ❞♦ ♠♦♠❡♥t♦ ♠❛❣♥ét✐❝♦ ❞❡ ❣✐r♦s ❛♥t✐✲♣❛r❛❧❡❧♦s ❡♥tr❡ í♦♥s F e3+ _{❡♠ ♣♦s✐çã♦ t❡tr❛é✲}

❞r✐❝❛ ❡ í♦♥s ❞❡ N i2+ _{❡♠ ♣♦s✐çã♦ ♦❝t❛é❞r✐❝❛✳ ❙ã♦ ❡♠♣r❡❣❛❞❛s ♥❛ ❝♦♥str✉çã♦ ❞❡}

❡q✉✐♣❛♠❡♥t♦s ❡❧étr✐❝♦s✱ ❝♦♠♦ ❛♥t❡♥❛s ❡ tr❛♥s❢♦r♠❛❞♦r❡s✳

◆❛ ❋✐❣✉r❛ 3.4 é ❛♣r❡s❡♥t❛❞♦ ❛ ❡str✉t✉r❛ ❝r✐st❛❧✐♥❛ ❞❛ ❢❡rr✐t❛ ❞❡ ♥íq✉❡❧✳

❋✐❣✉r❛ ✸✳✹✿ ❊str✉t✉r❛ ❝r✐st❛❧✐♥❛ ❞❛ ❋❡rr✐t❛ ❞❡ ♥íq✉❡❧

❋♦♥t❡✿ ❈❆❘❱❆▲❍❖✱ ❉❛♥✐❡❧❡ ●♦♠❡s✳

✸✳✸ Pr❡❝✉rs♦r❡s

◗✉❛♥t♦s ❛♦s ♣r❡❝✉rs♦r❡s ✉s❛❞♦s ♥❛ sí♥t❡s❡ ♣♦r ❝♦♠❜✉stã♦ é ✐♠♣♦rt❛♥t❡ s❛❜❡r ♦ t✐♣♦ ❡ ❛ q✉❛♥t✐❞❛❞❡ ❞♦s ❝♦♠♣♦st♦s ✉t✐❧✐③❛❞♦s✱ ❞❡ ❛❝♦r❞♦ ❝♦♠ às ❝❛r❛❝t❡ríst✐❝❛s ❞❡s❡❥❛❞❛s ❞♦s ♣ós✲♠✐st✉r❛s✳ ❆ss✐♠✱ ❛❧❣✉♥s ❛s♣❡❝t♦s ❞❡✈❡♠ s❡r ❝♦♥s✐❞❡r❛❞♦s ❝♦♠♦✱ ♣♦r ❡①❡♠♣❧♦✱ ❛ q✉❛❧✐❞❛❞❡ ❞♦ ❝♦♠❜✉stí✈❡❧ ❡ ❞♦s ♦①✐❞❛♥t❡s ❡ ❛ s♦❧✉❜✐❧✐❞❛❞❡ ❡♠ á❣✉❛ q✉❡ sã♦ ❢✉♥❞❛♠❡♥t❛✐s ♥❡ss❡ ♣r♦❝❡ss♦✳

◆♦ ♣r♦❝❡ss♦ ❞❡ sí♥t❡s❡ ♣♦r ❝♦♠❜✉stã♦✱ ♦s s❛✐s ❞❡ ♥✐tr❛t♦s sã♦ ❜❛st❛♥t❡ s♦❧ú✈❡✐s ❡♠ á❣✉❛ ❡ s❡ ❞❡❝♦♠♣õ❡ r❛♣✐❞❛♠❡♥t❡ ❥✉♥t♦ ❝♦♠ ♦ ❝♦♠❜✉stí✈❡❧✳

❆ r❡❧❛çã♦ ❞♦ ♦①✐❞❛♥t❡ ❝♦♠ ♦ ❝♦♠❜✉stí✈❡❧ ❞❡✈❡ s❡r ❛❞❡q✉❛❞❛ ❞❡✈✐❞♦ ❛♦ ❛❧t♦ ❝❛❧♦r ❣❡r❛❞♦ ♣❛r❛ ❛t✐♥❣✐r ❛ t❡♠♣❡r❛t✉r❛ ❞❡ ✐❣♥✐çã♦✳ ❆❧❣✉♠❛s ♣r♦♣r✐❡❞❛❞❡s ❞♦ ♣r♦❞✉t♦ ♣ós✲ ♠✐st✉r❛ ❡stã♦ r❡❧❛❝✐♦♥❛❞❛s ❝♦♠ ❛ r❛③ã♦ ❡♥tr❡ ❛ ❝♦♠♣♦s✐çã♦ ❝♦♠❜✉stí✈❡❧✴♦①✐❞❛♥t❡✱ t❛✐s ❝♦♠♦ ♦ t❛♠❛♥❤♦ ❞♦ ❝r✐st❛❧✐t♦✱ ❛ ár❡❛ s✉♣❡r✜❝✐❛❧ ❡ ❛ ♠♦r❢♦❧♦❣✐❛✳ ❊ss❛ r❛③ã♦ ❡♥tr❡ ♦s ♣r❡❝✉rs♦r❡s ❡ ♦ ❝♦♠❜✉stí✈❡❧ t❛♠❜é♠ ✐♥✢✉❡♥❝✐❛ ❛ ❧✐❜❡r❛çã♦ ❞♦s ❣❛s❡s ❞✉r❛♥t❡ ❛ ❝♦♠❜✉stã♦✳ P♦r ❡①❡♠♣❧♦✱ s❛❜❡✲s❡ q✉❡ q✉❛♥t♦ ♠❛✐♦r ❛ q✉❛♥t✐❞❛❞❡ ❞❡ ❝♦♠❜✉stí✈❡❧✱ ♠❛✐♦r é ♦ t❛♠❛♥❤♦ ❞♦s ♣♦r♦s ❞❛s ♣❛rtí❝✉❧❛s✳

✸✳✸✳✶ ❘❡❞✉t♦r❡s

❖s r❡❞✉t♦r❡s tê♠ ✉♠ ♣❛♣❡❧ ✐♠♣♦rt❛♥t❡ ♥❛ sí♥t❡s❡ ♣♦r ❝♦♠❜✉stã♦✳ ❊❧❡s ✐♥✢✉❡♥✲ ❝✐❛♠ ❛s ❝❛r❛❝t❡ríst✐❝❛s ❞♦ ♣r♦❞✉t♦ ✜♥❛❧✳ ❉❡♥tr❡ ♦s r❡❞✉t♦r❡s ♠❛✐s ✉t✐❧✐③❛❞♦s ❡stã♦ ✉r❡✐❛✱ ❣❧✐❝✐♥❛ ❝❛r❜♦❤✐❞r❛③✐♥❛✳ ❚♦❞♦s ♦s r❡❞✉t♦r❡s ❝✐t❛❞♦s ❛t✉❛♠ ❝♦♠♦ ❝♦♠❜✉stí✈❡❧ ❡ t❡♠ ♣r♦♣r✐❡❞❛❞❡s ❞✐❢❡r❡♥t❡s✱ ❝♦♠♦ ♦ ❝❛❧♦r ❞❡ ❝♦♠❜✉stã♦ ❡ ♦ ❝❛❧♦r ❞❡ ❢♦r♠❛çã♦✳

✸✳✸✳✶✳✶ ●❧✐❝✐♥❛

➱ ✉♠ ❝♦♠♣♦st♦ ♦r❣â♥✐❝♦ ❞❛ ❝❧❛ss❡ ❞♦s ❛♠✐♥♦á❝✐❞♦s ♣r❡s❡♥t❡ ♥❛s ♣r♦t❡í♥❛s ❞♦s s❡r❡s ✈✐✈♦s✳ ❆♣r❡s❡♥t❛✲s❡ ♥❛ ♥❛t✉r❡③❛ ❡♠ ❢♦r♠❛ ❞❡ ✉♠ ❝r✐st❛❧ ❜r❛♥❝♦ ♦✉ ♣ó ❝r✐st❛❧✐♥♦✱ s❡♠ ♦❞♦r ❡ ❞❡ s❛❜♦r ❛❞♦❝✐❝❛❞♦✳ ➱ ❜❛st❛♥t❡ s♦❧ú✈❡❧ ❡♠ á❣✉❛ ❡ ❡♠ á❝✐❞♦ ❢ór♠✐❝♦ ❡✱ ♣r❛t✐❝❛♠❡♥t❡✱ ✐♥s♦❧ú✈❡❧ ❡♠ ❡t❛♥♦❧✳ ❆ ❣❧✐❝✐♥❛ é s✐♥t❡t✐③❛❞❛ ❛ ♣❛rt✐r ❞❡ ❢♦r♠❛❧❞❡í❞♦✱ ♦✉ á❝✐❞❛ ♠♦♥♦❝❧♦r♦❛❝ét✐❝♦✱ ❡ ❛♠♦♥í❛❝♦✳

❊ss❡ ❝♦♠❜✉stí✈❡❧ ❛t✉❛ ♥❛ sí♥t❡s❡ ♣♦r ❝♦♠❜✉stã♦ ❛♦ s❡r ♦①✐❞❛❞♦ ♣❡❧♦s í♦♥s ♥✐tr❛✲ t♦s✳ ➱ ✉♠ ❛♠✐♥♦á❝✐❞♦ ❞❡ ❜❛✐①♦ ❝✉st♦ ❡ ❝♦♠♣❧❡①❛♥t❡✳ ◆❛ s✉❛ ❡str✉t✉r❛✱ t❡♠ ✉♠ ❣r✉♣♦ ❝❛r❜♦①í❧✐❝♦ ❡ ✉♠ ❣r✉♣♦ ❛♠✐♥♦ q✉❡ ♣❛rt✐❝✐♣❛♠ ♥❛ ❝♦♠♣❧❡①❛çã♦ ❞♦s í♦♥s ♠❡tá✲ ❧✐❝♦s✳ ❈❛❞❛ ✉♠ ❞❡ss❡s ❣r✉♣♦s r❡❛❣❡ ❝♦♠ ♦s ❝át✐♦♥s ♣♦r ❝♦♠♣❧❡①❛çã♦✳ ❖s ❝át✐♦♥s ❞♦s ♠❡t❛✐s ❛❧❝❛❧✐♥♦s sã♦ ❝♦♠♣❧❡①❛❞♦s ♣❡❧♦ ❣r✉♣♦ ❝❛r❜♦①í❧✐❝♦✱ ❡♥q✉❛♥t♦ ♦ ❣r✉♣♦ ❛♠✐♥♦ ❝♦♠♣❧❡①❛ ♦s ❝át✐♦♥s ❞❡ ♠❡t❛✐s ❞❡ tr❛♥s✐çã♦✳

✸✳✸✳✶✳✷ ❯r❡✐❛

➱ ✉♠ ❝♦♠♣♦st♦ ♦r❣â♥✐❝♦ ❝r✐st❛❧✐♥♦✱ ✐♥❝♦❧♦r✱ ❞❡ ❢ór♠✉❧❛ (N H2)2CO✱ ❝♦♠ ✉♠

♣♦♥t♦ ❞❡ ❢✉sã♦ ❞❡ 132,7o

C✳ ➱ ✉♠ ❝♦♠❜✉stí✈❡❧ ✉t✐❧✐③❛❞♦ ♣❛r❛ ♦r✐❣✐♥❛r ❛ ❢♦r♠❛çã♦

❞❡ ♣ós ❝♦♠ t❛♠❛♥❤♦ ❞❡ ❝r✐st❛❧✐t♦s ♥❛♥♦♠étr✐❝♦s ❡ ❛t✉❛ ❝♦♠♦ ❛❣❡♥t❡ ❝♦♠♣❧❡①❛♥t❡ ♣❛r❛ í♦♥s ♠❡tá❧✐❝♦s ❞❡✈✐❞♦s ❛ s❡✉s ❣r✉♣♦s ❛♠✐♥♦s ❧♦❝❛❧✐③❛❞♦s ♥❛s ❡①tr❡♠✐❞❛❞❡s✳

◆❛ ♣r❡s❡♥ç❛ ❞❡ ♥✐tr❛t♦ ❞❡ ❢❡rr♦✱ ♣r♦♣♦r❝✐♦♥❛ ✉♠❛ ❝♦♠❜✉stã♦ ♠❛✐s ❡✜❝❛③✱ ❞❡✈✐❞♦ à ♣r❡s❡♥ç❛ ❞♦ ❧✐❣❛♥t❡ N H2✳

❆ ✉r❡✐❛ é ✉♠ ❜♦♠ ❝♦♠❜✉stí✈❡❧ ♥❛ sí♥t❡s❡ ♣♦r ❝♦♠❜✉stã♦✱ ♣♦rq✉❡✱ ❞✉r❛♥t❡ ♦ ♣r♦❝❡ss♦✱ ❢♦r♠❛✲s❡ ✉♠❛ ❣r❛♥❞❡ q✉❛♥t✐❞❛❞❡ ❞❡ ❣❛s❡s✱ ♦ q✉❡ ❢❛✈♦r❡❝❡ ❛ ❝r✐st❛❧✐♥✐❞❛❞❡✱ ❛ ❤♦♠♦❣❡♥❡✐❞❛❞❡ ❞❛ ♣ós ❡♠ ❡s❝❛❧❛ ♥❛♥♦♠étr✐❝❛✱ ❝♦♠ q✉❛♥t✐❞❛❞❡s ♠❡♥♦r❡s ❞❡ ❛❣❧♦✲ ♠❡r❛❞♦s✱ ❝♦♠♣❛r❛♥❞♦✲s❡ ❛ ✉r❡✐❛ ❝♦♠ ♦✉tr♦s ❝♦♠❜✉stí✈❡✐s✱ ❝♦♠♦✱ ♣♦r ❡①❡♠♣❧♦✱ ❛ ❣❧✐❝✐♥❛✳ ❆ ✉r❡✐❛ ♣♦r t❡r ♠❡♥♦r s♦♠❛tór✐♦ ❞❡ ✈❛❧ê♥❝✐❛ ❞♦ q✉❡ ❛ ❣❧✐❝✐♥❛✱ ❛♣r❡s❡♥t❛ t❡♠♣❡r❛t✉r❛ ❞❡ r❡❛çã♦ ♠❛✐s ❜❛✐①❛✳ ❙❡♥❞♦ ❛ss✐♠✱ é ♠❛✐s ❛♣r♦♣r✐❛❞❛ ♣❛r❛ ♣r❡♣❛r❛çã♦ ❞❡ ❝❡râ♠✐❝❛s✳

❊❝♦♥♦♠✐❝❛♠❡♥t❡✱ ❛ ✉r❡✐❛ é ✉♠ r❡❛❣❡♥t❡ ❞❡ ❢á❝✐❧ ❛q✉✐s✐çã♦ ❡ ❜❛✐①♦ ❝✉st♦ ❡♠ r❡❧❛çã♦ ❛♦s ❞❡♠❛✐s✱ ♣♦✐s ❛❧❣✉♥s ❞♦s ❝♦♠❜✉stí✈❡✐s ♣r❡❝✐s❛♠ s❡r ❛♥t❡s s✐♥t❡t✐③❛❞♦s✳

❆ ❋✐❣✉r❛ 3.5❛♣r❡s❡♥t❛ ❛ ✉r❡✐❛ ♥♦ ❡st❛❞♦ só❧✐❞♦ ❣r❛♥✉❧❛❞❛✳

❋✐❣✉r❛ ✸✳✺✿ ❆♠♦str❛ ❞❡ ✉r❡✐❛

❋♦♥t❡✿ ✇✇✇✳✐♥❢r✉t❛❧✳❝♦♠✳❜r✳

✸✳✸✳✷ ❖①✐❞❛♥t❡s

❉❡♥tr❡ ♦s s❛✐s ✉t✐❧✐③❛❞♦s ♥❛ sí♥t❡s❡ ♣♦r ❝♦♠❜✉stã♦ ♣❛r❛ ❛ ♦❜t❡♥çã♦ ❞❡ ♣ós✲ ♠✐st✉r❛s✱ ♦s ♥✐tr❛t♦s sã♦ ❣❡r❛❧♠❡♥t❡ ❡s❝♦❧❤✐❞♦s ♣♦r s❡r❡♠ ♠❛✐s s♦❧ú✈❡✐s ❡♠ á❣✉❛✱ ♣❡r♠✐t✐♥❞♦ ✉♠❛ ♠❛✐♦r ❤♦♠♦❣❡♥❡✐③❛çã♦✱ ❛❧é♠ ❞❡ ❢♦r♥❡❝❡r✱ ❡✈✐❞❡♥t❡♠❡♥t❡✱ ♦s í♦♥s ♠❡tá❧✐❝♦s✳ ❖✉tr♦s ♦①✐❞❛♥t❡s q✉❡ ♣♦❞❡♠ s❡r ✉t✐❧✐③❛❞♦s sã♦ ♦s s✉❧❢❛t♦s ❡ ♦s ❝❛r❜♦♥❛✲ t♦s✳ ❈♦♠♦ ♦s ♥✐tr❛t♦s ❞❡ ❢❡rr♦ ❡ ❞❡ ♥íq✉❡❧ ♣r❡❝✐s❛♠ ❞❡ ❜❛✐①❛ t❡♠♣❡r❛t✉r❛ ❡ sã♦ ❞❡ ❢á❝✐❧ ❛q✉✐s✐çã♦✱ ❞❛í ❛ ❡s❝♦❧❤❛ ♣♦r ❡ss❡s r❡❛❣❡♥t❡s ♣❛r❛ ❛s r❡❛çõ❡s q✉í♠✐❝❛s ✉t✐❧✐③❛❞❛s ♥❡st❡ tr❛❜❛❧❤♦✳

✸✳✸✳✷✳✶ ◆✐tr❛t♦s ▼❡tá❧✐❝♦s

❖s ♥✐tr❛t♦s sã♦ s✉❜stâ♥❝✐❛s q✉í♠✐❝❛s ❢♦r♠❛❞❛s ❛ ♣❛rt✐r ❞❛ ❝♦♠❜✐♥❛çã♦ ❞❛ ❧✐❣❛✲ çã♦ q✉í♠✐❝❛ ❡♥tr❡ ♦s át♦♠♦s ❞❡ ♥✐tr♦❣ê♥✐♦ ❡ ♦①✐❣ê♥✐♦✱ ❡ss❛ ❧✐❣❛çã♦ ♦❝♦rr❡ ❡♠ ✉♠❛ ♣r♦♣♦rçã♦ ❞❡ ✉♠ át♦♠♦ ❞❡ ♥✐tr♦❣ê♥✐♦ ♣❛r❛ três ❞❡ ♦①✐❣ê♥✐♦s✳ ❖ ♥✐tr❛t♦ é ✉♠ í♦♥ ♥❡❣❛t✐✈♦ ♠♦♥♦✈❛❧❡♥t❡ ❝♦♠♣♦st♦✱ ❝♦♠ ❝❛r❣❛ ❞❡−1✭♠❡♥♦s ✉♠✮✱ s✉❛ ❢ór♠✉❧❛(N O−

3)✱

❡ s✉❛ ❡str✉t✉r❛ é r❡♣r❡s❡♥t❛❞❛ ❝♦♥❢♦r♠❡ ❛ ❋✐❣✉r❛ 3.6✳

❋✐❣✉r❛ ✸✳✻✿ ❊str✉t✉r❛ ❞♦ ❮♦♥ ♥✐tr❛t♦

❋♦♥t❡✿ ❆✉t♦r✳

❉❡♥tr❡ ❛s ❢✉♥çõ❡s ✐♥♦r❣â♥✐❝❛s q✉❡ sã♦ ❝♦♥s✐❞❡r❛❞❛s s❛✐s✱ ♣♦❞❡✲s❡ ❞❡st❛❝❛r ♦s ❞❡ ♠❡t❛✐s ❛❧❝❛❧✐♥♦s✱ ❝♦♠♦ ♦ ♥✐tr❛t♦ ❞❡ só❞✐♦ (N aN O3)✱ ♦ ♥✐tr❛t♦ ❞❡ ♣♦táss✐♦ (KN O3)

❡ ♦ ♥✐tr❛t♦ ❞❡ ❧ít✐♦ (LiN O3)✱ ❡ ♦s ❞❡ ♠❡t❛✐s ❛❧❝❛❧✐♥♦s t❡rr♦s♦s✱ ❝♦♠♦ ♦ ♥✐tr❛t♦ ❞❡

❝á❧❝✐♦ ❡ ♦ ♥✐tr❛t♦ ❞❡ ♠❛❣♥és✐♦✱ ❞❡ ❢ór♠✉❧❛s ♠♦❧❡❝✉❧❛r❡s✱ r❡s♣❡❝t✐✈❛♠❡♥t❡✱Ca(N O3)2

❡ M g(N O3)2✳

◆✐tr❛t♦ ❞❡ ◆íq✉❡❧✿ ➱ ✉♠ s❛❧ ❞❡ ❢ór♠✉❧❛ N i(N O3)2.6H2O ✭❤❡①❛❤✐❞r❛t❛❞♦✮✱

❛❧t❛♠❡♥t❡ ❤✐❣r♦s❝ó♣✐❝♦ ❡✱ ♣♦r ✐ss♦✱ ❛♣r❡s❡♥t❛✲s❡ ♥❛ ♥❛t✉r❡③❛ ❞❡ ❢♦r♠❛ ❤✐❞r❛t❛❞♦✳ ➱ ✉♠ só❧✐❞♦ ❢♦r♠❛❞♦ ♣♦r ❝r✐st❛✐s ❞❡ ❝♦r ✈❡r❞❡✱ ❜❛st❛♥t❡ s♦❧ú✈❡❧ ❡♠ á❣✉❛✳ ❆ s♦❧✉çã♦ ❝♦♥❝❡♥tr❛❞❛ ❞❡ ♥✐tr❛t♦ ❞❡ ♥íq✉❡❧ é ✉s❛❞❛ ♣❛r❛ ❛ ♣r❡♣❛r❛çã♦ ❞♦s ❝❛t❛❧✐s❛❞♦r❡s ❞❡ ♥íq✉❡❧ ✉t✐❧✐③❛❞♦s ♣❛r❛ ❛ ❤✐❞r♦❣❡♥❛çã♦ ❞❡ ❞❡r✐✈❛❞♦s ♦r❣â♥✐❝♦s✳

❆ ❋✐❣✉r❛ 3.7❛♣r❡s❡♥t❛ ❝r✐st❛✐s ❞❡ ♥✐tr❛t♦ ❞❡ ♥íq✉❡❧ ❤❡①❛❤✐❞r❛t❛❞♦✳

❋✐❣✉r❛ ✸✳✼✿ ◆✐tr❛t♦ ❞❡ ◆íq✉❡❧ ❤❡①❛❤✐❞r❛t❛❞♦

❋♦♥t❡✿ ❤tt♣✴✴✇✇✇✳❜r❛s✐❧❛❣r✐❝♦❧❛✳❝♦♠✴✷✵✶✶✴✵✾

◆✐tr❛t♦ ❢érr✐❝♦✿ ➱ ✉♠ s❛❧ ❞❡ ❢ór♠✉❧❛ F e(N O3)3.9H2O ✭♥♦♥♦❤✐❞r❛t❛❞♦✮✱ t❛♠✲

❜é♠ ❤✐❣r♦s❝ó♣✐❝♦✳ ➱ ✉♠ só❧✐❞♦ ❝♦♠ ❝r✐st❛✐s q✉❡ ✈❛r✐❛♠ ❞❡ ✐♥❝♦❧♦r ❛ ✈✐♦❧❡t❛✲♣á❧✐❞♦✳ ➱ ✉t✐❧✐③❛❞♦ ❝♦♠♦ ❝❛t❛❧✐s❛❞♦r ♣❛r❛ ❛ sí♥t❡s❡ ❞❡ ❛♠✐❞❛ ❞❡ só❞✐♦ ❛ ♣❛rt✐r ❞❡ ✉♠❛ s♦❧✉✲ çã♦ ❞❡ só❞✐♦ ❡♠ ❛♠ô♥✐❛✳ ❚❛♠❜é♠ é ✉s❛❞♦ ❡♠ ❝❡rt❛s ❛r❣✐❧❛s t❡♥❞♦ s❡ ♠♦str❛❞♦ út✐❧ ❝♦♠♦ ♦①✐❞❛♥t❡ ❡♠ sí♥t❡s❡ ♦r❣â♥✐❝❛✳ ➱ ✉♠ s❛❧ ❜❛st❛♥t❡ s♦❧ú✈❡❧ ❡♠ á❣✉❛✳

❆ ❋✐❣✉r❛ 3.8❛♣r❡s❡♥t❛ ❝r✐st❛✐s ❞❡ ♥✐tr❛t♦ ❢érr✐❝♦ ♥♦♥♦❤✐❞r❛t❛❞♦✳

❋✐❣✉r❛ ✸✳✽✿ ◆✐tr❛t♦ ❋érr✐❝♦ ◆♦♥♦❤✐❞r❛t❛❞♦

❋♦♥t❡✿ ❤tt♣✴✴✇✇✇✳❜r❛s✐❧❛❣r✐❝♦❧❛✳❝♦♠✴✷✵✶✶✴✵✾

✸✳✹ ❙✐♥t❡r✐③❛çã♦

❆ s✐♥t❡r✐③❛çã♦ é ♦ ♣r♦❝❡ss♦ ❡♠ q✉❡ ♣ós ❝♦♠♣❛❝t❛❞♦s sã♦ tr❛♥s❢♦r♠❛❞♦s ❡♠ ✉♠ só❧✐❞♦ rí❣✐❞♦✳ ❖❝♦rr❡ ❛tr❛✈és ❞❡ ✉♠ ♣r♦❝❡ss♦ ♥❛t✉r❛❧✱ ❡♠ q✉❡ ❛s ♣❛rtí❝✉❧❛s ❡♥tr❛♠ ❡♠ ❝♦♥t❛t♦ s♦❜ ❛çã♦ ❞♦ ❝❛❧♦r✱ tr❛♥s❢♦r♠❛♥❞♦✲s❡ ❡♠ ✉♠ ♠❛t❡r✐❛❧ ❝♦♠ ❛❧t❛ r❡s✐stê♥✲ ❝✐❛ ♠❡❝â♥✐❝❛✱ ♣♦❞❡♥❞♦ ❛té s❡ t♦r♥❛r ❞❡♥s♦ ❬✶✹❪✳ ❆❧❣✉♠❛s ✈❛r✐á✈❡✐s ❞♦ ♣r♦❝❡ss♦ sã♦ ✐♠♣♦rt❛♥t❡s✱ ❝♦♠♦ ❛ ❝♦♠♣♦s✐çã♦ q✉í♠✐❝❛✱ ♦ t❛♠❛♥❤♦ ❞❛s ♣❛rtí❝✉❧❛s ❞♦ ♣ó ❛ ❞✐str✐✲ ❜✉✐çã♦ ❣r❛♥✉❧♦♠étr✐❝❛ ❞♦ ♠❛t❡r✐❛❧ ❞❡ ♣❛rt✐❞❛✱ ❛ ❛t♠♦s❢❡r❛ ❞❡ s✐♥t❡r✐③❛çã♦✱ ♦ t❡♠♣♦ ❞❡ ❛q✉❡❝✐♠❡♥t♦✱ ❛ t❡♠♣❡r❛t✉r❛ ❡ ❛ t❛①❛ ❞❡ ❛q✉❡❝✐♠❡♥t♦✳ ❆ s✐♥t❡r✐③❛çã♦ ♥♦ ❡st❛❞♦ só❧✐❞♦ ♦❝♦rr❡ ❡♠ três ❡t❛♣❛s✿ ✐♥✐❝✐❛❧✱ ✐♥t❡r♠❡❞✐ár✐❛ ❡ ✜♥❛❧✱ ❝♦♥❢♦r♠❡ ❋✐❣✉r❛ 3.9✳

❋✐❣✉r❛ ✸✳✾✿ ■❧✉str❛çã♦ ❞❛s ❡t❛♣❛s ❞❡ s✐♥t❡r✐③❛çã♦

❋♦♥t❡✿ ❆✉t♦r

❉✉r❛♥t❡ ♦ ❡stá❣✐♦ ✐♥✐❝✐❛❧✱ s✉r❣❡♠ ❛s ❧✐❣❛çõ❡s ❡♥tr❡ ❛s ♣❛rtí❝✉❧❛s ♥❛s r❡❣✐õ❡s ❞❡ ❝♦♥t❛t♦✱ ❛✉♠❡♥t❛♥❞♦ ♦ ❛❣❧♦♠❡r❛❞♦ ❛té q✉❡ r❡❛❥❛♠ ❡♥tr❡ s✐✳ ◆♦ ❡stá❣✐♦ ✐♥t❡r♠❡❞✐á✲ r✐♦✱ ❛ ❡str✉t✉r❛ ❞♦s ♣♦r♦s é s✉❛✈✐③❛❞❛ ❢♦r♠❛♥❞♦ ✉♠❛ ❡str✉t✉r❛ ❝✐❧í♥❞r✐❝❛ ✐♥t❡r❝♦✲ ♥❡❝t❛❞❛✳ ❆s ♣r♦♣r✐❡❞❛❞❡s ❞♦ s✐♥t❡r✐③❛❞♦ ❞❡s❡♥✈♦❧✈❡♠✲s❡ ♣r❡❞♦♠✐♥❛♥t❡♠❡♥t❡ ♥❡ss❡ ❡stá❣✐♦✱ ♣♦❞❡♥❞♦ ♦❝♦rr❡r ❝♦♥s✐❞❡rá✈❡❧ ❝r❡s❝✐♠❡♥t♦ ❞♦s ❣rã♦s ♥♦s ú❧t✐♠♦s ♠♦♠❡♥t♦s✱ ♦ q✉❡ ❛❝❛rr❡t❛ ♣♦r♦s✐❞❛❞❡ ❡♠ ❧♦❝❛✐s ✐s♦❧❛❞♦s ❞❛ ❡str✉t✉r❛✳ ❖ ❡st✉❞♦ ❞❡ss❛ ❡t❛♣❛ ❝♦♥✲ s✐st❡ ❡♠ r❡❧❛❝✐♦♥❛r ♦ ❛s♣❡❝t♦ ❡str✉t✉r❛❧ ❞❛ ❛♠♦str❛ s✐♥t❡r✐③❛❞❛ ✭♣♦r♦s✐❞❛❞❡ r❡s✐❞✉❛❧✱ ❢❛s❡s ♣r❡s❡♥t❡s✱ t❛♠❛♥❤♦ ♠é❞✐♦ ❞❡ ❣rã♦ ❡ ❞✐str✐❜✉✐çã♦ ❞❡ t❛♠❛♥❤♦ ❞❡ ❣rã♦✱ ❤♦♠♦✲ ❣❡♥❡✐❞❛❞❡ ❡str✉t✉r❛❧✱ ❡t❝✮ às ❝❛r❛❝t❡ríst✐❝❛s ❞♦s ♣ós✲s✐♥t❡r✐③❛❞♦s ✭t❛♠❛♥❤♦ ♠é❞✐♦ ❡ ❞✐str✐❜✉✐çã♦ ❞❡ t❛♠❛♥❤♦ ❞❡ ♣❛rtí❝✉❧❛s✮✳ ❖✉tr❛s ♦❜s❡r✈❛çõ❡s q✉❡ ❞❡✈❡♠ s❡r ❢❡✐t❛s ❡♠ r❡❧❛çã♦ ❛s ❝♦♥❞✐çõ❡s ❞❡ s✐♥t❡r✐③❛çã♦ sã♦ ♠❛❣♥ít✉❞❡ ❞❛ t❡♠♣❡r❛t✉r❛✱ t❡♠♣♦ ❞❡

❞✉r❛çã♦ ❡ t✐♣♦ ❛t♠♦s❢❡r❛ ❞❡ s✐♥t❡r✐③❛çã♦ ❬✶✹❪✳ ◆♦ ú❧t✐♠♦ ❡stá❣✐♦✱ ♦s ♣♦r♦s t♦r♥❛♠✲s❡ ❡s❢ér✐❝♦s ❡ ✐s♦❧❛❞♦s✳ ❆ ❡❧✐♠✐♥❛çã♦ ❞❡ss❡s ♣♦r♦s é ❡①tr❡♠❛♠❡♥t❡ ❞✐❢í❝✐❧ ♥❡ss❛ ❡t❛♣❛✳ ❆♦ r❡❛❧✐③❛r ✉♠❛ s✐♥t❡r✐③❛çã♦✱ é ♣r❡❝✐s♦ ♦❜s❡r✈❛r ♣❛râ♠❡tr♦s ❝♦♠♦ t❡♠♣❡r❛t✉r❛ ❡ t❡♠♣♦✱ ❡ss❡s ❞♦✐s ♣❛râ♠❡tr♦s ❞❡✈❡♠ s❡r ❡st❛❜❡❧❡❝✐❞♦s ❞❡ ❢♦r♠❛ ✐♥✈❡rs❛♠❡♥t❡ ♣r♦✲ ♣♦r❝✐♦♥❛❧✱ s❡♥❞♦ r❡❝♦♠❡♥❞❛❞♦ ❢❛✈♦r❡❝❡r ♦ ♣❛râ♠❡tr♦ t❡♠♣♦ ❡♠ ❞❡tr✐♠❡♥t♦ ❞❛ t❡♠✲ ♣❡r❛t✉r❛✳ ❚❡♠♣❡r❛t✉r❛s ♠✉✐t♦ ❛❧t❛s ♣♦❞❡♠ ❝❛✉s❛r ❛ ❞❡❝♦♠♣♦s✐çã♦ ❞❛ ❡str✉t✉r❛ ❡s♣✐♥é❧✐♦✱ ❝r✐❛♥❞♦ ❣r❛❞✐❡♥t❡s ❞❡ ❝♦♠♣♦s✐çã♦ ♥❛ ❢❡rr✐t❛ ❡ ❛✉♠❡♥t❛♥❞♦ ❛ ♣♦r♦s✐❞❛❞❡ ❬✶✺❪✳ ❖ t❡♠♣♦ ❞❡✈❡rá s❡r ❞❡t❡r♠✐♥❛❞♦ ❞❡ ❢♦r♠❛ q✉❡✱ ♥❛ t❡♠♣❡r❛t✉r❛ ❞❡✜♥✐❞❛ ♣❛r❛ ❛ s✐♥t❡r✐③❛çã♦✱ ♣♦ss❛♠ ♦❝♦rr❡r t♦❞❛s ❛s r❡❛çõ❡s ♥♦ ❡st❛❞♦ só❧✐❞♦ ♣❛r❛ ❛ ❢♦r♠❛çã♦ ❞❛ ❡str✉t✉r❛ ❡s♣✐♥é❧✐♦ s❡♠✱ ♥♦ ❡♥t❛♥t♦✱ ♦❝❛s✐♦♥❛r ❝r❡s❝✐♠❡♥t♦ ❞❡s❝♦♥tí♥✉♦ ❞❡ ❣rã♦✳

✸✳✺ ▼❛t❡r✐❛✐s ▼❛❣♥ét✐❝♦s

❍á ❝❡r❝❛ ❞❡ 3000 ❛♥♦s ❛trás ♦s ♠❛t❡r✐❛✐s ♠❛❣♥ét✐❝♦s ❥á ❡r❛♠ ❝♦♥❤❡❝✐❞♦s ♣❡❧♦

❤♦♠❡♠✳ ❖s ♣r✐♠❡✐r♦s r❡❧❛t♦s s♦❜r❡ s✉❛s ♣r♦♣r✐❡❞❛❞❡s ❞❡ ❛tr❛çã♦ ❡ r❡♣✉❧sã♦ sã♦ ♦r✐✉♥❞♦s ❞❛ r❡❣✐ã♦ ❞❛ ▼❛❣♥és✐❛✱ ➪s✐❛ ▼❡♥♦r ❬✶✻❪✳ ❆ ♣r✐♠❡✐r❛ ✉t✐❧✐③❛çã♦ ❞❡ ♠❛t❡r✐❛✐s ♠❛❣♥ét✐❝♦s ❝♦♠❡ç♦✉ ❝♦♠ ♦s ❛♥t✐❣♦s ❝❤✐♥❡s❡s✱ ❢♦r❛♠ ❡❧❡s ♦s ♣r✐♠❡✐r♦s ❛ ✉t✐❧✐③á✲❧♦s✱ ❝♦♥str✉✐♥❞♦ ❜úss♦❧❛s ❤á ♠❛✐s ❞❡ ❞♦✐s ♠✐❧ê♥✐♦s ❬✶✼❪✳ ❆ ♣❛rt✐r ❞❛í✱ ♣ô❞❡✲s❡ ✈❡r✐✜❝❛r ❛ ✉t✐❧✐③❛çã♦ ❞❡ ♠❛t❡r✐❛✐s ♠❛❣♥ét✐❝♦s✳ ◆♦ ✐♥í❝✐♦ ❞♦ sé❝✉❧♦ XIX✱ ❡♠ 1820✱ ❛ r❡❧❛çã♦

❡♥tr❡ ❛ ❡❧❡tr✐❝✐❞❛❞❡ ❡ ♦ ♠❛❣♥❡t✐s♠♦ ❢♦✐ ❞❡s❝♦❜❡rt❛ ♣♦r ❖❡rst❡❞✳ ■ss♦ ♦❝♦rr❡✉ q✉❛♥❞♦ ♦ ♠❡s♠♦ ✈❡r✐✜❝♦✉ q✉❡ ✉♠❛ ❝♦rr❡♥t❡ ❡❧étr✐❝❛ ♥✉♠ ✜♦ ❢❛③✐❛ ❝♦♠ q✉❡ ❛ ♦r✐❡♥t❛çã♦ ❞❛ ❛❣✉❧❤❛ ❞❡ ✉♠❛ ❜úss♦❧❛ ♠✉❞❛ss❡ s✉❛ ❞✐r❡çã♦✳ ❖❡rst❡❞ ♦❜s❡r✈♦✉ q✉❡ ❛ ❝♦rr❡♥t❡ ❣❡r❛✈❛ ✉♠ ❝❛♠♣♦ ♠❛❣♥ét✐❝♦✳ ❊♠ r❡❧❛çã♦ ❛♦ ❢❛t♦ ❤✐stór✐❝♦ ❡ ❝r♦♥♦❧ó❣✐❝♦ s♦❜r❡ ♦ ✉s♦ ❞♦s ♠❛t❡r✐❛✐s ♠❛❣♥ét✐❝♦s✱ ♣♦❞❡✲s❡ ❛♣r❡s❡♥t❛r ♦s s❡❣✉✐♥t❡s ❛❝♦♥t❡❝✐♠❡♥t♦s✿

X❊♠ ₁₈₂₀✱ ❆♥❞ré✲▼❛r✐❡ ❆♠♣èr❡ ❛♣r❡s❡♥t♦✉ à ❆❝❛❞❡♠✐❛ ❞❡ ❈✐ê♥❝✐❛s ❞❡ P❛r✐s

s✉❛s ♣r✐♠❡✐r❛s ♦❜s❡r✈❛çõ❡s s♦❜r❡ ❛s ♣r♦♣r✐❡❞❛❞❡s ♠❛❣♥ét✐❝❛s ❞❛ ❝♦rr❡♥t❡ ❡❧étr✐❝❛✳ ❊❧❡ ♠♦str♦✉ q✉❡ ❞♦✐s ✜♦s q✉❛♥❞♦ ❛tr❛✈❡ss❛❞♦s ♣♦r ✉♠❛ ❝♦rr❡♥t❡ ❡❧étr✐❝❛ ❡①❡r❝❡♠ ❛çõ❡s ❡♥tr❡ s✐✱ ❡ q✉❡✱ q✉❛♥❞♦ ❞♦✐s ✜♦s ❝♦♥❞✉t♦r❡s r❡t♦s ❡♠ ♣❛r❛❧❡❧♦s ❡ ♣ró①✐♠♦s ✉♠ ❞♦ ♦✉tr♦✱ ♣❛ss❛✈❛♠ ❝♦rr❡♥t❡s ❡❧étr✐❝❛s ♥♦ ♠❡s♠♦ s❡♥t✐❞♦✱ ❡❧❡s s❡ ❛tr❛í❛♠ ♠✉t✉❛♠❡♥t❡ ❡ q✉❡ q✉❛♥❞♦ ♣❛ss❛✈❛♠ ♣❡❧♦s ❞♦✐s ✜♦s ❝♦rr❡♥t❡s ❡❧étr✐❝❛s ❞❡ s❡♥t✐❞♦s ❝♦♥trár✐♦s✱ ❡❧❡s s❡ r❡♣❡❧✐❛♠ ♠✉t✉❛♠❡♥t❡ ❬✶✽❪✳

X❊♠₁₈₃₁✱ ❋❛r❛❞❛② ❞❡s❝♦❜r✐✉ ❛ ✐♥❞✉çã♦ ❡❧❡tr♦♠❛❣♥ét✐❝❛✳ ❈♦♠ ❡ss❛ ✐❞❡✐❛ s♦❜r❡

♦s ❝❛♠♣♦s ❡❧étr✐❝♦ ❡ ♠❛❣♥ét✐❝♦❀ ❝✉❥❛ ♥❛t✉r❡③❛ ❢♦✐ ✉t✐❧✐③❛❞❛ ♣♦r ♦✉tr♦s tr❛❜❛❧❤♦s ❝♦♠♦ ❛s ❡q✉❛çõ❡s ❞❡ ▼❛①✇❡❧❧✳