Fused Quartz Ceramic Materials Research Articles

Study on the Thermal Distribution Characteristics of a Molten Quartz Ceramic Surface under Quartz Lamp Radiation.

More and more researchers are studying the heat transfer performance of aeronautical materials at high temperatures. In this paper, we use a quartz lamp to irradiate fused quartz ceramic materials, and the sample surface temperature and heat flux distribution were obtained at a heating power of 45~150 kW. Furthermore, the heat transfer properties of the material were analyzed using a finite element method and the effect of surface heat flow on the internal temperature field was investigated. The results show that the fiber skeleton structure has a significant effect on the thermal insulation performance of fiber-reinforced fused quartz ceramics and the longitudinal heat transfer along the rod fiber skeleton is slower. As time passes, the surface temperature distribution tends to stability and reaches an equilibrium state. The surface temperature of fused quartz ceramic increases with the increase in the radiant heat flux of the quartz lamp array. When the input power is 5 kW, the maximum surface temperature of the sample can reach 1153 °C. However, the non-uniformity of the sample surface temperature also increases, reaching a maximum uncertainty of 12.28%. The research in this paper provides important theoretical guidance for the heat insulation design of ultra-high acoustic velocity aircraft.

Effect of B<sub>4</sub>C-Si<sub>3</sub>N<sub>4</sub> on Crystallization and Sintering of Fused Quartz Ceramic Material

Fused quartz granules (d50=19 μm) were used as raw material, and B4C-Si3N4 (1:1, in mass) was used as additive with dosages of 1% (in mass, similarly hereinafter), 2% and 3%. Fused quartz ceramic materials were fabricated in reduction atmosphere at 1250 °C, 1300 °C, 1350 °C and 1400 °C for 1 h. The apparent porosity, bending strength and thermal expansion ratios of the samples were examined and they were analysed by means of XRD. The results showed that the sample sintered at each temperature with 1% B4C-Si3N4 had the lowest apparent porosity, the highest bending strength. This indicated that 1% B4C-Si3N4 was conducive to sintering of fused quartz ceramic materials. The results of XRD analysis and thermal expansion ratio analysis showed that 1% B4C-Si3N4 compound additive had obvious effect on inhibiting crystallization of the samples sintered at various temperatures. It can be deduced that the 1% B4C-Si3N4 compound additive plays the excellent role in inhibiting crystallization and facilitating sintering of fused quartz ceramic materials.

Influence of Nano-Yb<sub>2</sub>O<sub>3</sub>, Nano-Nd<sub>2</sub>O<sub>3</sub> and Nano-Dy<sub>2</sub>O<sub>3</sub> on Sintering and Crystallization of Fused Quartz Ceramic Materials

Fused quartz powder (d50=19μm) was used as raw material, nano-Yb2O3, nano-Nd2O3 and nano-Dy2O3 were dividedly used as additive with dosages of 3% each. Fused quartz ceramic materials were sintered in reduction atmosphere at 1300°C, 1350°C and 1400°C for 1h. The influence of rare earth nanooxides on sintering and crystallization of the fused quartz ceramic were researched by measurements of apparent porosity, bending strength and thermal expansion ratios, and analyses of XRD and SEM. The results showed that samples added nano-Yb2O3 and nano-Nd2O3 have lower apparent porosity, higher bending strength and lower thermal expansion rate. It can be deduced that additives nano-Yb2O3 and nano-Nd2O3 have obvious effect on facilitating sintering and inhibiting crystallization of fused quartz materials at experimental temperatures.

Effect of Nano-Yb<sub>2</sub>O<sub>3</sub> addition on crystallization and sintering properties of fused quartz ceramic materials

Effect of Nano-Yb<sub>2</sub>O<sub>3</sub> addition on crystallization and sintering properties of fused quartz ceramic materials

Study on Sintering Properties and Crystallization of Fused Quartz Ceramic Materials Containing BN-B<sub>4</sub>C

Different dosages of BN-B4C compound additive have been introduced for preparing specimen with fused quartz granule (d50=10μm). Fused quartz ceramic materials were fabricated in reduction atmosphere at various temperatures for 1h. The characterizations were carried out by thermal expansion ratio, apparent porosity, cold modulus of rupture (CMOR) and SEM as well as by X-ray diffraction (XRD). The effect of BN-B4C on the sintering, crystallization and properties of fused quartz was investigated. The result reveals that with increase of the temperature, the apparent porosity and CMOR of specimens decrease. The specimen C sintered at 1300°C possessed a maximum CMOR (22.31 MPa). The specimen C sintered at 1350°C has more compact microstructure. The lowest thermal expansion ratio of the specimens sintered at various temperatures was obtained when the dosages of compound additive is 3%. With increasing BN-B4C content, the role on inhibiting crystallization was improved. The specimens containing 3 wt% BN-B4C had obvious effect on inhibiting crystallization of the specimens sintered at various temperatures.

The Influence of Al<sub>2</sub>O<sub>3</sub>-AlN Compound Additive on the Crystallization Characteristics and Properties of Fused Quartz Ceramic Materials

Fused quartz granule (d50=10μm) was used as raw material, and Al2O3-AlN (1:1, in mass) was used as additive with dosages of 1 wt%, 2 wt% and 3 wt%. The crystallization characteristics of fused quartz ceramic fabricated in reduction atmosphere at 1300°C, 1350°C and 1400°C for 1h has been investigated by thermal expansion ratio and XRD. The results showed that the crystallization characteristics were markedly improved by 1 wt% AI2O3-AIN compound additive. 1 wt% Al2O3-AIN had obvious effect on inhibiting crystallization of the samples sintered at various temperatures. The apparent porosity, bending strength and SEM of the samples were also examined. The results showed that the samples with 1 wt% AI2O3-AIN had the lowest apparent porosity among the samples containing Al2O3-AlN, the highest bending strength, and the sample AA1 sintered at 1350°C had more compact microstructure, which indicated that 1 wt% Al2O3-AlN was conducive to sintering of fused quartz ceramic materials. It can be deduced that the 1 wt% Al2O3-AIN compound additive plays the excellent role on inhibiting crystallization and promoting sintering of fused quartz ceramic materials.

Influence of CeO<sub>2</sub> Nanopowder on Crystallization Behavior and Sintering Performance of Fused Quartz Ceramic Materials

Fused quartz granule was used as raw material, and CeO2 nanopowder was used as additive with dosages of 1wt %, 2 wt % and 3 wt %. Fused quartz ceramic materials were fabricated in reduction atmosphere at 1300 °C, 1350 °C and 1400 °C for 1 h, respectively. The properties of samples including apparent porosity, bending strength and thermal expansion ratio were measured. The results show that the sample with 1 wt % CeO2 nanopowder has the lowest apparent porosity, the highest bending strength and the lowest thermal expansion ratio. The XRD and SEM results show that through the CeO2 nanopowder adding, the diffraction peak intensity of quartz phase in the fused quartz ceramics decrease, and the microstructure of the samples become more compact. It can be deduced that CeO2 nanopowder plays the excellent role as the crystallization inhibitor and sintering assistant to fused quartz materials sintered at various temperatures.

Influence of La<sub>2</sub>O<sub>3</sub> Nanopowder on Crystallization Behavior and Sintering Performance of Fused Quartz Ceramic Materials

Fused quartz granule was used as raw material, and La2O3 nanopowder was used as additive with dosages of 1wt %, 2 wt % and 3 wt %. Fused quartz ceramic materials were fabricated in reduction atmosphere at 1300 °C, 1350 °C and 1400 °C for 1 h, respectively. The properties of samples including apparent porosity, bending strength and thermal expansion ratio were measured. The results show that the sample with 2 wt % La2O3 nanopowder has the lowest apparent porosity and the highest bending strength, and sample added 1% nano-La2O3 has the best inhibiting effect on crystallization of fused quartz. The samples with La2O3 nanopowder adding have lower thermal expansion ratio than blank sample. The XRD and SEM results show that the diffraction peak intensity of quartz phase decrease and the microstructure of the samples become more compact, after the La2O3 nanopowder was added into fused quartz ceramics. It indicated that La2O3 nanopowder has excellent inhibiting effect on crystallization of fused quartz and facilitating effect on sintering of fused quartz ceramics.

Influence of Nano-ZnO on Crystallization Behavior and Sintering Performance of Fused Quartz Ceramic Materials

Fused quartz granule (d50=0.019 mm) was used as raw material, nano-ZnO (size<0.08 μm) was used as additive with dosages of 1% (in mass, similarly hereinafter), 2% and 3%. Fused quartz ceramic materials were fabricated in reduction atmosphere at 1300 °C, 1350 °C and 1400 °C for 1 h. Properties of samples were researched by measurements of apparent porosity, bending strength and thermal expansion rate, and analyzed by XRD and SEM. The results showed that additive nano-ZnO had excellent inhibiting effect on crystallization of fused quartz sintered at 1300 °C and 1350 °C. As dosages of nano-ZnO increased, thermal expansion rate, diffraction peak intensity and bending strength were improved, and microstructure of the samples became more compact. It can be deduced that for fused quartz ceramic materials, with add dosage of nano-ZnO increasing, the inhibiting effect on crystallization decline, but the facilitating effect on sintering enhance.

Effect of Si<sub>3</sub>N<sub>4</sub>-Y<sub>2</sub>O<sub>3</sub> Compound Additive on Crystallization and Sintering of Fused Quartz Ceramic Materials

Fused quartz granules (d50=19 μm) were used as raw material, and Si3N4-Y2O3 (1:1, in mass) was used as additive with dosages of 1%, 2% and 3% (in mass). Fused quartz ceramic materials were fabricated in reduction atmosphere at 1300 °C, 1350 °C and 1400 °C for 1 h. The effect of Si3N4-Y2O3 on crystallization and sintering of the fused quartz ceramic materials were researched by measurements of apparent porosity, bending strength and thermal expansion rate (RT~1200 °C), and by the analyses of XRD and SEM. The results showed that the samples sintered at each temperature with 3% Si3N4-Y2O3 had the lowest apparent porosity, the highest bending strength and more compact microstructure. This indicated that 3% Si3N4-Y2O3 was conducive to sintering of fused quartz ceramic materials. The results of XRD and thermal expansion rate showed that addition of 3% Si3N4-Y2O3 compound had obvious effect on inhibiting crystallization of the samples sintered at various temperatures. It can be deduced that the Si3N4-Y2O3 compound plays the best role in inhibiting crystallization and facilitating sintering of fused quartz ceramic materials.

Effect of Gd<sub>2</sub>O<sub>3</sub>-Nd<sub>2</sub>O<sub>3</sub> Compound Additive on Crystallization and Sintering of Fused Quartz Ceramic Materials

Fused quartz granules (d50=19 μm) were used as raw material, and Gd2O3-Nd2O3 (1:1, in mass) was used as additive with dosages of 1% (in mass, similarly hereinafter), 2% and 3%. Fused quartz ceramic materials were fabricated in reduction atmosphere at 1300 °C, 1350 °C and 1400 °C for 1 h. The apparent porosity, bending strength and thermal expansion ratios of the samples were examined and the samples were further analysed by means of XRD and SEM. The results showed that the sample sintered at each temperature with 3% Gd2O3-Nd2O3 had the lowest apparent porosity, the highest bending strength and more compact microstructure. This indicated that 3% Gd2O3-Nd2O3 was helpful to sintering of fused quartz ceramic materials. The results of XRD and thermal expansion ratio analysis showed that 3% Gd2O3-Nd2O3 compound additive had better effect on inhibiting crystallization of the samples sintered at 1300 °C and 1350 °C, but had a little effect on inhibiting crystallization of the sample sintered at 1400 °C.

Effect of Si<sub>3</sub>N<sub>4</sub>-Nd<sub>2</sub>O<sub>3</sub> Compound Additive on Crystallization and Sintering of Fused Quartz Ceramic Materials

Fused quartz granules (d50=19 μm) were used as raw material, and Si3N4-Nd2O3 (1:1, in mass) was used as additive with dosages of 1% (in mass, similarly hereinafter), 2% and 3%. Fused quartz ceramic materials were fabricated in reduction atmosphere at 1300 °C, 1350 °C and 1400 °C for 1 h. The apparent porosity, bending strength and thermal expansion ratios of the samples were studied and the samples were further analysed by means of XRD and SEM. The results showed that the sample sintered at each temperature with 3% Si3N4-Nd2O3 had the lowest apparent porosity, the highest bending strength and more compact microstructure. This indicated that 3% Si3N4-Nd2O3 was useful to the sintering of fused quartz ceramic materials. The results of XRD and thermal expansion ratio analysis showed that 3% Si3N4-Nd2O3 compound additive had better effect on inhibiting crystallization of the samples sintered at 1300 °C, 1350 °C and 1400 °C.

Influence of Nano-Y<sub>2</sub>O<sub>3</sub> on Crystallization Behavior and Sintering Performance of Fused Quartz Ceramic Materials

Fused quartz granule (d50=0.019 mm) was used as raw material, nano-Y2O3 (size<0.08 μm) was used as additive with dosages of 1% (in mass, similarly hereinafter), 2% and 3%. Fused quartz ceramic materials were fabricated in reduction atmosphere at 1300 °C, 1350 °C and 1400 °C for 1 h. Properties of samples were researched by measurements of apparent porosity, bending strength and thermal expansion rate, and analyzed by XRD and SEM. The results showed that additive nano-Y2O3 had good inhibiting effect on crystallization of fused quartz sintered at various temperatures, sample added 2% nano-Y2O3 had least thermal expansion rate, diffraction peak intensity and apparent porosity, and it had higher bending strength and more compact microstructure, especially sample sintered at 1350 °C. It can be deduced that 2% nano-Y2O3 plays the excellent role as the crystallization inhibitor and sintering assistant to fused quartz materials sintered at various temperatures.

Effect of Rare Earth Nano-Oxides on Sintering and Crystallization of Fused Quartz Ceramic Materials

Fused quartz powder (size<0.04mm) was used as raw material, nano-Y2O3, nano-CeO2and nano-La2O3(size<0.08μm) were dividedly used as additives with dosage of 2% each. Fused quartz ceramic materials were sintered in reduction atmosphere at 1300°C, 1350°C and 1400°C for 1h. The effect of rare earth nano-oxides on sintering and crystallization of the fused quartz ceramic were researched by measurements of apparent porosity, bending strength and thermal expansion rate, and analyses of XRD and SEM. The results showed that additives nano-Y2O3, nano-CeO2and nano-La2O3had obvious effect of inhibiting crystallization of fused quartz, and the samples added nano-Y2O3and nano-La2O3were better. Sample added nano-Y2O3had least thermal expansion rate. Sample added nano-La2O3had higher bending strength, and it showed that nano-La2O3had better effect on sintering of fused quartz ceramic. It can be deduced that nano-La2O3plays the excellent role as the crystallization inhibitor of fused quartz materials.

Effect of B<sub>4</sub>C-Yb<sub>2</sub>O<sub>3</sub> Compound Additive on Crystallization and Sintering of Fused Quartz Ceramic Materials

Fused quartz granules (d50=19 μm) were used as raw material, and B4C-Yb2O3 (1:1, in mass) was used as additive with dosages of 1% (in mass, similarly hereinafter), 2% and 3%. Fused quartz ceramic materials were fabricated in reduction atmosphere at 1250 °C, 1300 °C, 1350 °C and 1400 °C for 1 h. The apparent porosity, bending strength and thermal expansion ratios of the samples were examined and they were analysed by means of XRD and SEM. The results showed that the sample sintered at each temperature with 3% B4C-Yb2O3 had the lowest apparent porosity, the highest bending strength and more compact microstructure. This indicated that 3% B4C-Yb2O3 was conducive to sintering of fused quartz ceramic materials. The results of XRD analysis and thermal expansion ratio analysis showed that 3% B4C-Yb2O3 compound additive had obvious effect on inhibiting crystallization of the samples sintered at various temperatures. It can be deduced that the 3% B4C-Yb2O3 compound additive plays the excellent role in inhibiting crystallization and facilitating sintering of fused quartz ceramic materials.

Influence of Rare Earth Oxides on Crystallization Behavior and Sintering Performance of Fused Quartz Ceramic Materials

Fused quartz granule (d50=0.033mm) was used as raw material, Pr6O11, Sm2O3, Gd2O3, Dy2O3 and Ho2O3 were used as additives with dosage of 2% each. Fused quartz ceramic materials were fabricated in reduction atmosphere at 1300°C, 1400°C and 1500°C for 1h. Samples were examined apparent porosity, bending strength, thermal expansion rate (RT~1200°C), and analyzed by XRD and SEM. The results indicated that additives Pr6O11, Sm2O3 and Dy2O3 had a bit inhibiting effect on crystallization of fused quartz sintered at 1300°C and 1400°C, Ho2O3 and Gd2O3 had more inhibiting effect on crystallization in samples sintered at various temperatures, sample containing Ho2O3 had least thermal expansion rate. Pr6O11, Sm2O3 and Dy2O3 had few facilitating effect on sintering, Gd2O3 and Ho2O3 had more facilitating effect on sintering of fused quartz ceramic materials, samples with Gd2O3 and Ho2O3 had lower apparent porosity and higher bending strength and more compact microstructure. It can be deduced that Gd2O3 and Ho2O3 play the excellent role as the crystallization inhibitor to fused quartz materials.

Effect of Nano-Oxides on Sintering and Crystallization of Fused Quartz Ceramic Materials

Fused quartz ceramic was prepared in air atmosphere at 1300°C, 1350°C and 1400°C for 1h with fused quartz powder as raw materials (size<0.06mm) and with nano-Cu2O or nano-ZrO2 as additives (size<0.1μm). The effect of nano-Cu2O and nano-ZrO2 (size<0.1μm) on crystallization and sintering of the fused quartz ceramic materials were researched by measurements of apparent porosity, bending strength and thermal expansion rate, and analyses of XRD and SEM. The results showed that nano-Cu2O had detrimental effect on sintering and promoted crystallization of fused quartz, and nano-ZrO2 had better facilitating effect on sintering and better effect of inhibiting crystallization of fused quartz. So, samples with nano-ZrO2 had lower apparent porosity and higher bending strength and more compact microstructure and least thermal expansion rate.

Effect of Rare Earth Oxide on Sintering and Crystallization of Fused Quartz Ceramic Materials

Fused quartz ceramic was prepared in reducing atmosphere at 1300°C, 1400°C and 1500°C for 1h with fused quartz powder as raw materials (size<0.2mm). The effect of La2O3, Nd2O3, Er2O3 and Yb2O3 on crystallization and sintering of the materials were researched by measurements of apparent porosity, bending strength and thermal expansion rate (RT~1200°C), and analyses of XRD and SEM. The results showed that La2O3 and Nd2O3 have a few facilitating effect on sintering, Er2O3 and Yb2O3 have better facilitating effect on sintering of fused quartz ceramic samples, samples ER and YB have lower apparent porosity and higher bending strength and more compact microstructure. So additives La2O3, Nd2O3 and Er2O3 have a few effect of inhibiting on crystallization, Yb2O3 has better effect of inhibiting on crystallization of fused quartz. Sample YB has least thermal expansion rate.