Enhancing the mechanical properties of porcelain stoneware tiles

Leonelli, Cristina; Bondioli, Federica; Veronesi, Paolo; Romagnoli, Marcello; Manfredini, Tiziano; Pellacani, Gian Carlo; Cannillo, Valeria

doi:10.1016/s0955-2219(00)00266-1

Cited by 121 publications

(77 citation statements)

References 6 publications

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“…The linear shrinkage, LS (%), of the fired samples was determined by the following equation: International, 40 (2014) 1365-1377; doi: 10.1016/j.ceramint.2013.07.018 4 [1] where Ls and Lc are the length (mm) of the unfired and fired specimens, respectively. The linear shrinkage values of the ten specimens were averaged for each firing temperature.…”

Section: Methodsmentioning

confidence: 99%

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Microstructure and technological properties of porcelain stoneware tiles moulded at different pressures and thicknesses

Pérez

Romero

2014

Ceramics International

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Moulding pressure and thickness are pre-fixed variables in the porcelain stoneware tile industry. This paper examines the effect of both parameters on technological and microstructure properties of unfired and fired porcelain stoneware bodies. The moulding pressure in unfired tiles has a noticeable effect on bending strength and load borne. Common technological properties such as water absorption, porosity, bulk density and bending strength were obtained from the fired tiles. The results indicate that the variation in properties is independent of the thicknesses of the tiles. Moulding pressure affects at lower values, whereas higher moulding pressure produces tiles with similar technological properties. The microstructure exhibits a constant amount of mullite and quartz in all pieces after the firing process. Observations from scanning electron microscopy show that mullite crystals enlarge as moulding pressure increases, but the shape of the crystals are unaffected by the individual thicknesses. Furthermore, the aspect ratio of the mullite needles increases with the moulding pressure, which is invariable to the thicknesses of the tiles. Although the total porosity remains constant, the number of pores is influenced by the thickness. The moulding pressure also influences pore size. The results show a strong relationship between the number of closed pores and the thickness of the ceramic tile.

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Section: Methodsmentioning

confidence: 99%

“…Porcelain stoneware is composed of clay, flux agent and filler. The clay is typically comprised of kaolinite, which confers plasticity to green paste and is the precursor of mullite crystals [1][2][3][4]. The fluxing agent is feldspar and the filler is quartz, which most likely lead to higher strengths of the unfired tiles [5][6].…”

Section: Introductionmentioning

confidence: 99%

Microstructure and technological properties of porcelain stoneware tiles moulded at different pressures and thicknesses

Pérez

Romero

2014

Ceramics International

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“…where AD (g/cm 3 ) is the absolute density of the sample, which was previously measured according to ASTM C329-88, the test method involves crush, ground and sieve the sample to pass −80 mesh (177 μm). The measurements were carried out on 8-10 g of powder sample by using a pycnometer (50 ml capacity) consisting of a suitable bottle with a capillary tube stopper.…”

Section: Methodsmentioning

confidence: 99%

“…The compaction process used in manufacturing porcelain stoneware tile typically consist of a double-pressing technology, which involves a first pressing step at very low pressure values (30-60 bar) to produce a semi-compact body with a minimum mechanical strength, in which layers of powder decoration are applied. After the pre-compacted body has gone through the decoration processes, it is placed inside a second die for definitive pressing at the traditional porcelain stoneware tile shaping pressure (400 bar) [3] and [9]. Moreover, in the industrial process the raw material batch is spray-dried before pressing.…”

Section: Fired Bodiesmentioning

confidence: 99%

“…factor affecting bending strength of green bodies is porosity, because as less pores exist, there is less space to contribute the fracture, since it is known that the relative fracture energy is influenced by pore volume fraction [21], which is the only varying parameter in green bodies moulded at different pressure. Nevertheless, although open porosity has an effect on bending strength in fired tiles [16], there are other factors affecting, such as mullite formation and quartz particles [3], [4], [5], [15] and [22]. Fig .…”

Section: Fired Bodiesmentioning

confidence: 99%

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Effect of moulding pressure on microstructure and technological properties of porcelain stoneware

Pérez

Rincón

Romero

2012

Ceramics International

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Foaming Species and Trapping Mechanisms in Barium Silicate Glass Sealants

et al. 2021

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Glass powders are widely used in fabricating sintered glasses, sintered glassÀceramics, glass matrix composites, seals, and glass-bonded ceramics or pastes. [1][2][3] For many of these applications, glasses with low crystallization tendency are used, for example, for low-temperature cofired ceramics, [4,5] pastes, [6] or sealants [7,8] to ensure sufficient sinterability.Due to the low viscosity required for joining and gas tight sealing, gas bubble formation and subsequent swelling (foaming) often occur, even when organic aids are not used in powder processing. In contrast to the extensive and ongoing study of desired foaming phenomena utilized for foam glasses or glassÀceramic foams, [9][10][11][12][13][14][15] this nondesired foaming effect and its underlying mechanisms are rarely reported. Lucchini [16] observed bubble formation for sodium and calcium lead silicate glass-bonded barium hexaferrites and discussed glass volatilization as the underlying mechanism. Pore formation was also found in porcelain stoneware tiles [17] and lead borosilicate glass frits, [18] where effusing oxygen or water, physically or chemically adsorbed to the powder surface, was discussed as the foaming source. Lara et al. [19] reported foaming during the sintering and crystallization of Ca, Mg, and Zn alumosilicate glass powders used for solid oxide fuel cell (SOFC) sealing. The authors believed that density changes or gas evolution during crystallization are responsible for foaming. Undesired porosity was also reported to occur during sintering of BaO-B 2 O 3 -SiO 2 , [20] lead-free Bi 2 O 3 -B 2 O 3 -SiO 2 solder glass, [21] LTCC glass powders; [22] as well as during porcelain tiles production. [23] More recently, Agea-Blanco et al. [24] studied sintering and foaming of commercial barium zinc alumino boro silicate glass powders, used for SOFC sealing, with heating microscopy, differential thermal analysis (DTA), and vacuum hot extraction (VHE). It was shown that foaming intensity increases with milling duration. For moderately milled glass powders, consecutive storage in air could also promote foaming. Although powder compacts were pressed and sintered in air, foaming was affected by different milling atmospheres among which CO 2 proved to enhance foaming most strongly. Similarly, VHE studies revealed that foaming is predominantly driven by C, CO, and CO 2 , even for powders milled in Ar and N 2 . It was therefore concluded that foaming is caused by carbonaceous species adsorbed on the glass powder surface during milling and later storage.The present study is focused on the nature of these species and the mechanisms keeping them trapped during heating to the temperature of foaming. To ensure detectable amounts of foaming species, K01 glass powders were milled for several hours. Recrushed powder compacts, or those heated to different temperatures and quenched in air were studied with heating

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Enhancing the mechanical properties of porcelain stoneware tiles

Cited by 121 publications

References 6 publications

Microstructure and technological properties of porcelain stoneware tiles moulded at different pressures and thicknesses

Microstructure and technological properties of porcelain stoneware tiles moulded at different pressures and thicknesses

Effect of moulding pressure on microstructure and technological properties of porcelain stoneware

Foaming Species and Trapping Mechanisms in Barium Silicate Glass Sealants

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