Tenacidade à fratura e dureza de porcelana feldspática adicionada de óxido de zircônio: efeito da concentração e da temperatura de sinterização
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Data
2009-07-23
Autores
Ribeiro, João Gustavo Rabelo [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O objetivo deste estudo foi avaliar o efeito da adição de óxido de zircônio, em diferentes concentrações e temperaturas de sinterização, na tenacidade à fratura (KIC) e na dureza Vickers (HV) da porcelana feldspática Duceragold. Foram confeccionados discos cerâmicos (9,0 x 3,0mm; n=10) para os grupos: (G1) Duceragold sem adição de ZrO2, (G2) Duceragold adicionada de 1% de ZrO2, (G3) 2% de ZrO2, (G4) 3% de ZrO2, (G5) 4% de ZrO2, (G6) 5% de ZrO2, (G7) 6% de ZrO2 e (G8) 7% de ZrO2, sinterizados a: (a) 800 ºC, (b) 850 ºC, (c) 900 ºC, (d) 950 ºC e (e) 1000 ºC, totalizando 400 corpos-de-prova. Após a sinterização, em forno Alumini Press, procedeu-se sua inclusão e polimento até lixa 1500 em politriz. A HV foi mensurada em durômetro Buelher, com carga de 9,8 N, por 20 segundos; as imagens obtidas foram capturadas por meio de câmera JVC e os cálculos de KIC, executados com auxílio do software Laica. Para observação da superfície das amostras, foram realizadas fotomicrografias por MEV. Os resultados de KIC e HV foram submetidos a ANOVA e teste de Tukey (p!0,05). Observou-se que, independentemente da temperatura de sinterização, o aumento da concentração de óxido de zircônio, aumenta o KIC, todavia, a partir de 6%, a HV diminui; independentemente da concentração, o aumento da temperatura de sinterização proporciona aumento dos valores de HV, contudo, temperaturas de 950ºC e 1000ºC diminuem o KIC; com o aumento da concentração de óxido de zircônio e da temperatura de sinterização, aumentam o número de poros tanto na fase vítrea da porcelana, quanto na fase dispersa de zircônia. Considerando as propriedades estudadas e a caracterização da superfície, pode-se observar que as amostras com adição de até 4% de óxido de zircônio à porcelana feldspática Duceragold, sinterizadas em temperaturas de até 900ºC apresentam-se como as mais promissoras.
The objective of this study was to evaluate the effect of adding zirconium oxide at different concentrations and temperatures of sintering, on the fracture toughness (KIC) and Vickers hardness (HV) of feldspathic porcelain Duceragold. Ceramic discs were prepared (9.0 x 3.0 mm, n = 10) for the groups: (G1) Duceragold without the addition of ZrO2, (G2) Duceragold added 1% of ZrO2, (G3) 2% of ZrO2, (G4) 3% of ZrO2, (G5) 4% of ZrO2, (G6) 5% of ZrO2, (G7) 6% of ZrO2 and (G8) 7% of ZrO2, sintered at: (a) 800 ºC, (b) 850 ºC, (c) 900 ºC, (d) 950 °C and (e) 1000 ºC, totaling 400 specimens of the samples. After sintering at Alumini Press furnace, inclusion and polishing by sandpaper polishing (# 1500) were proceeded. The HV was measured in a Buelher durometer, with a load of 9.8 N for 20 seconds, the images were captured using a JVC camera and calculation of KIC, performed with the aid of software Laica. To observe the surface of the samples were performed by SEM photomicrographs. The results of KIC and HV were submitted to ANOVA and Tukey's test (p ! 0.05). It was observed that regardless of sintering temperature, the concentration of zirconium oxide, increases the KIC, however, from 6%, HV decreases; regardless of the concentration, the increase of sintering temperature gives increased HV values, however, temperatures of 950 °C and 1000 °C decrease the KIC; with increasing concentration of zirconium oxide and sintering temperature, increase the number of pores in the vitreous and dispersed phase of zirconia. Considering the studied properties and characterization of the surface can be observed that the samples with the addition of up to 4% zirconium oxide in Duceragold feldspathic porcelain, sintered at temperatures up to 900 º C are presented as the most promising.
The objective of this study was to evaluate the effect of adding zirconium oxide at different concentrations and temperatures of sintering, on the fracture toughness (KIC) and Vickers hardness (HV) of feldspathic porcelain Duceragold. Ceramic discs were prepared (9.0 x 3.0 mm, n = 10) for the groups: (G1) Duceragold without the addition of ZrO2, (G2) Duceragold added 1% of ZrO2, (G3) 2% of ZrO2, (G4) 3% of ZrO2, (G5) 4% of ZrO2, (G6) 5% of ZrO2, (G7) 6% of ZrO2 and (G8) 7% of ZrO2, sintered at: (a) 800 ºC, (b) 850 ºC, (c) 900 ºC, (d) 950 °C and (e) 1000 ºC, totaling 400 specimens of the samples. After sintering at Alumini Press furnace, inclusion and polishing by sandpaper polishing (# 1500) were proceeded. The HV was measured in a Buelher durometer, with a load of 9.8 N for 20 seconds, the images were captured using a JVC camera and calculation of KIC, performed with the aid of software Laica. To observe the surface of the samples were performed by SEM photomicrographs. The results of KIC and HV were submitted to ANOVA and Tukey's test (p ! 0.05). It was observed that regardless of sintering temperature, the concentration of zirconium oxide, increases the KIC, however, from 6%, HV decreases; regardless of the concentration, the increase of sintering temperature gives increased HV values, however, temperatures of 950 °C and 1000 °C decrease the KIC; with increasing concentration of zirconium oxide and sintering temperature, increase the number of pores in the vitreous and dispersed phase of zirconia. Considering the studied properties and characterization of the surface can be observed that the samples with the addition of up to 4% zirconium oxide in Duceragold feldspathic porcelain, sintered at temperatures up to 900 º C are presented as the most promising.
Descrição
Palavras-chave
Cerâmica odontológica, Materiais dentários, Prótese dentária, Dental porcelain, Dental materials, Dental prothesis
Como citar
RIBEIRO, João Gustavo Rabelo. Tenacidade à fratura e dureza de porcelana feldspática adicionada de óxido de zircônio: efeito da concentração e da temperatura de sinterização. 2009. 150 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Odontologia de Araraquara, 2009.