Sunday, March 15, 2015

glazed tiles: the difference of microstructure and topography comparing to unglazed tiles

Porcelain stoneware is a synergy of the manufacturing technology and mechanical properties has been excellent between developed special effect products. Despite its excellent technical characteristics, slip resistance can be significantly different, depending on the tile surface finish: structured or smooth, glazed or polished. Aimed at reducing the risk of slipping on ceramic tiles have been installed, some of the surface treatment has been introduced into the market. Most of these treatments include acid-based applications (hydrofluoric acid or ammonium bifluoride), which can produce chemically etched ceramic surface.
In the literature, many works microstructure glazed tile treated in an acidic or alkaline environment modification. Issue a means using a chemical etching process slip minority works considered relevant in terms of security, no further study the characteristics of ceramic surfaces. Deep knowledge of the tile surface microstructure, morphology and structure parameters in assessing if the acid treatment will result in a non-slip surface, without causing damage to the key role of ceramic products.
In particular, the surface topography is an important feature of the tile surface. In order to measure parameters of the surface, there are many different types of instruments . Typically, the measurement techniques can be divided into two categories: (a) the type of contact and (b) non-contact type. Touch probe contour is the most popular, however, recently, non-contact profile, such as confocal and interferometric microscope , has been developed and is widely used. Today, the availability of a new generation of measuring instruments to promote qualitative and quantitative characterization of surface texture, not only for advanced ceramics, but also for the traditional ceramics. Typically the surface of ceramic tiles using the stylus of 2D analyzer for analysis, however, very often, 2D measurement is not enough to give an accurate description of the surface.
In the present work, both before and after commercial glazed porcelain stoneware tiles non-slip surface treatment were studied and analyzed. Our goal is to find out whether there own slip resistance (slip resistance) and their microscopic structure and three-dimensional surface topography, as well as the correlation between the surface texture parameters.

Experimental

Two glazed porcelain tiles with different surface treatments like chemical and mineral composition were studied: A picture is characterized by heterogeneous, textured surfaces and tiled B band uniform, smooth surface. Commercially available non-slip surface treatment comprises applying to the ceramic surface, according to the manufacturer's instructions (manual), and allowed to stand tiles A and 30 seconds 1 minute B. tile surface characterization of a hydrofluoric acid-based solution has been In two tiles A ("untreated" or "treated") and W B ("B untreated" or "B TREATED") of untreated and surface treated samples performed.
Ceramic surface impact caused by micro-scale treatment in the study has been carried out following analysis:
  • Mineralogy and microstructure analysis:
    • X- ray diffraction (XRD PW 3830; Philips, The Netherlands);
    • Scanning electron microscopy (SEM, Zeiss EVO 40, D) and X- ray energy dispersive spectroscopy elemental analysis (EDS, Inca, Oxford Instruments, UK) operating at 25 kV accelerating voltage of typical electronic (EHT);
And
  • The surface morphology characterization and mapping:
    • Three-dimensional optical microscopy / contour machine (Leica DCM 3D) using confocal mode.
As the purpose of this study was to evaluate the effect of brick (slip resistance) of the surface treatment of non-slip performance, tests have been carried out in accordance with the following standards: DIN 51130 and DIN 51097. These standards describe the test known as ramps, one of them wearing shoes feet (shoes), or walking barefoot in the method of inclined surfaces. Inclined surface to be coated with a lubricant, such as oil, soap, water and the like. Based on these criteria, the test person walking back and forth on a flat surface covered with tiles to be investigated, and it is gradually tilted. The surface may be cleaned or coated with a lubricant. Tilt angle which people start to slip in, and then OK.

The results

Table 1 shows, the untreated sample tiles for rich, mineralogy determined stage "A unprocessed" and "B untreated" surface. XRD patterns of the two samples also showed a large amount of an amorphous (non-crystalline) phase, in the presence of typical compositions were ceramic tiles.
Label 1: untreated mineral composition of the sample tiles A and B
Sample
Mineralogical stage
"Untreated"
Quartz, plagioclase, zircon (trace)
"B untreated"
Quartz, plagioclase, zircon, corundum (traces)
Figure 1 shows a SEM-EDS elemental microanalysis performed from the sample "A untreated" and "B untreated" surface analysis results. The same elements on the surface of the sample analysis process performed not reported here, since the elements no significant change with respect to the untreated sample has been detected.
Figure 1: Tile EDS spectra obtained on the surface of A and B of untreated samples: "A untreated" [span = 251 words] (a) and "B untreated" [span = 686 count] (b).
A typical SEM micrograph shown in Figure 2-5 and the untreated and treated samples A and B of the brick by comparing these micrographs (untreated and treated sample), it can be inferred, in the non-etched surface treatment crystal phase, and lead to the mineralogy (crystal) phase of the surface current is highlighted in micrograph.
Figure 2: SEM photograph of a ceramic tile in typical low magnification photographing untreated and the treated surface of the sample: "A untreated" (one) and "treated" (two).
Figure 3: untreated and treated samples A brick SEM micrographs of the surface at high magnification: "An untreated" (one) and "treated" (two).
Figure 4: SEM micrograph of a typical acetic tiles at lower magnification photographing surface untreated and treated samples: "B untreated" (a) and "B TREATED" (b) in Fig.
Figure 5: micrograph of untreated and treated samples B SEM image at higher magnification photographing surface: "B untreated" (a) and "B TREATED" (b) in Fig.
Both samples using a 10 × objective lens tiles A ("A untreated" and "treated") surface area (each 2.93 × 2.2 MM) has been imaged by confocal microscopy. 6 images taken samples map "untreated", the Z range of surface morphology and Levels of representation in microns (μm) of the calibration of "treated" show 3D.
By contrast images, no tiles between the two samples A significant morphological differences are seen. Contour map (see Fig. 7) forming in the same Figure 6 shows two regions of different levels of the curve points representing the same height with the micron-scale level on the surface. After the observation chart, you can see the differences in the level curves have a similar shape for the two samples. In addition, there is no substantial difference in the height values ​​have been determined for each of the analysis region (see Table 2) of the roughness parameters obtained.
Figure 6: a three-dimensional confocal microscope image (10 × objective lens), z range of the region on the surface of the untreated and treated samples of the color scale of tiles A,: "An unhandled" 5.8 mm × 4.4 mm × 130.8 m] (a) and "treated" 毫米 5.8 mm x 141.6 x 4.4 micron] (b).
Figure 7: Outline drawing, with the color scale of the z range, the untreated and treated samples on the tile surface area A in FIG. 6a and 6b: "A untreated" (one) and "treated The "(two).
Tag 2: List A height of about tile shown in Figure 6 in the area of the surface roughness parameters of untreated or partially treated samples (Gaussian cut-off filter: 0.25 mm).
ISO 25178 High parameters
"Untreated"
"Treated"
p (m)
Peak height
62.52
82.14
v (m)
Deepest pit
74.41
65.34
Ž (micron)
And S p + S v
136.93
147.49
a (m)
The arithmetic mean of the absolute values ​​of the height
12.06
11.05
At higher magnification (using a 20 × objective lens) imaging the surface area of ​​2.92 × 1.71 mm.Three-dimensional image (refer to FIG. 8) surface is analyzed, and the surface roughness parameters (see Table 3), reflecting the similar texture tile A (treated and untreated) of two samples.
Figure 8: a three-dimensional confocal microscope image (20 × objective lens), is used to scale the surface of untreated tiles with color A and the treated sample area within the range Z,: "An unhandled" [2.9 mm × 1.7 mm × 62.9 m] (a) and "treated" [2.9 mm × 1.7 × 68.6 micron 毫米] (b).
Tag 3: lists on a height of a surface roughness parameter area of the portion A of the untreated tile shown in FIG. 8 or the treated sample (Gaussian cut-off filter: 0.25 mm).
ISO 25178 High parameters
"Untreated"
"Treated"
p (m)
Peak height
36.71
39.83
v (m)
Deepest pit
26.16
28.78
Ž (micron)
And S p + S v
62.87
68.61
a (m)
The arithmetic mean of the absolute values ​​of the height
7.82
7.94
Operating confocal microscope largest multiple possible (150 × objective lens), can be observed on the surface of the sample tiles morphological differences A (treated and untreated) between the two.On the surface of the sample "treated" (see FIG. 9B), there is a region in which the crystals are present, in agreement with the SEM observations (see Fig. 3B). These "A untreated" on the surface of the crystal sample (see FIG. 9a) is not visible, because they are embedded in the amorphous phase.
Figure 9: a three-dimensional confocal microscope images (150x objective), z range region on the surface of untreated tiles with color scale A and the treated sample pairs,: "An unhandled" [84.9 x 61.6 × 4 m] (a) and "treated" [84.9 x 61.6 x 8.1 m] (b).
For sample B of tile, "B untreated" and "B TREATED", the area (2.93 × 2.2 mm) of using a 10x objective has been imaged by confocal microscopy. Two images shown in Figure 10 is a sample "B untreated" (see FIG. 10a) and "B TREATED" (with reference to FIG. 10b) in. Z range of surface morphology and color scale that they appear in a three-dimensional representation of each region micron alignment. According to the comparison between the image seen, no significant differences in the morphology of both samples, although it can be observed that the treated surface shows a peak slightly smooth, in other words, the peak is smaller than those of untreated whole projection surface.
Figure 10: Three-dimensional confocal microscope image (10 × objective lens), the z range region on the surface of the untreated and treated samples of the color scale of the tile B, "B untreated" [2.9 mm × 2.1 mm × 56.3 [mu] m [(a) and "B TREATED" [2.9 毫米 毫米 × 26.6 × 2.2 m] (b) in Fig.
Comparison of the profile view, FIG. 10 for the two regions, but it can be noted, is suitably separated and provided in a very high level for the sample "B untreated" boundary detected peaks (see Fig. 11A) ( about 33 microns), while for sample "B treated" (see Fig. 11b), the presence of very small uneven wide spread area exists.
Figure 11: Outline drawing, with the color scale of the z range, the surface area of ​​the untreated and treated samples on tile B in Figures 10a and 10b as shown in "B untreated" (a) and " B TREATED "(two). 
Comparison of the surface roughness parameter value of two samples (see Table 4) of the display area is consistent with the conclusions of the 3D image data: all surface roughness parameters, in terms of height, showed a slight decrease of treatment relative to untreated sample sampling.
Tag 4: (0.25 mm Gaussian filter cutoff) value of the surface roughness parameter is about the height of the untreated tile A in Fig. 10 or the treated sample area of the part.
ISO 25178 High parameters
"B untreated"
"B TREATED"
p (m)
Peak height
29.06
18.53
v (m)
Deepest pit
27.08
19.75
Ž (micron)
And S p + S v
56.14
38.28
a (m)
The arithmetic mean of the absolute values ​​of the height
1.85
1.69
Images obtained again confocal microscope (objective 150 times) of the maximum magnification, morphological differences could be observed between the two sample surface for tile B, treated and untreated, because this is the case for the tile A on the sample surface of the sample "B TREATED" (with reference to FIG. 12B), there is a region with a crystal exists. On the crystal surface is not visible sample "B untreated" (see FIG. 12A), because they are embedded in the amorphous phase.
Figure 12: Three-dimensional confocal microscope images (150x objective), untreated and treated samples of the color scale of the surface area of ​​the tile B for z- series, "B untreated" [84.9 x 61.6 X 6.3 micron] (a) and "B TREATED" [84.9 x 61.6 X 3.3μm] (b) of Fig.
Can be assumed to tile B, characterized in that it has a smooth, uniform texture on the surface, the non-slip treatment caused significant changes in the surface roughness parameters, i.e., reduce the average parameter values ​​after treatment).
Tile A, which is characterized by a more fragment B surface more structured and heterogeneous texture, surface morphology can be seen that the effect of the acid treatment, at high magnification, but still on the surface roughness parameter value is not significantly changed.
Slip resistance (slip resistance), the results (see Table 5) is determined, the test method specified in the standard DIN 51130 [7] did not improve tiles A (heterogeneity, textured surface) through non-slip handle, because it remains classified R9, even slip angle increases 1 °. The results for both samples B Watts (uniform, smooth surface) shows that it is not appropriate to have a high risk of sliding, even after non-slip handle studio. People walking barefoot on wet surfaces, in the pool area or in the shower or tub conditions, the experimental study made according to the method specified in the standard DIN 51097 [8] showed that for tile treatment to achieve the best classification , A + B + C, while the untreated sample can not be classified (UC). However, these data seem to indicate that, in the non-slip performance is more dependent on the tile lubricant used and tiles, rather than the surface roughness of the surface chemical composition.
Label 5: slip resistance (slip resistance) from compliance with DIN 51130 and DIN 51097 test results on the handling of tiles A and B and untreated samples.
Sample
Test Methods
The average slip angle (°)
Slip resistance group
"Untreated"
DIN 51130

6
R9
"Treated"
7
R9
"B untreated"
0
UC
"B TREATED"
0
UC
"Untreated"
DIN 51097

8
UC
"Treated"
33
A + B + C
"B untreated"
11.7
UC
"B TREATED"
35
A + B + C
Legend:
UC = non-confidential
Group DIN 51130 (based on the slip angle): R9⇒6 ° -10 °; R10⇒10 ° -19 °; R11⇒19 ° -27 °; R12⇒27 ° -35 °; R13⇒> 35 °
Group DIN 51097 (based on slip angle): A⇒12 ° -17.9 °; B ⇒18 ° -23.9 °; Ç⇒> 24 °

In conclusion

Two types of tiles were investigated in this report: Tile A, with heterogeneous and textured surfaces and tiled B band uniform, smooth surface. Both types of glazed tiles have similar chemical and mineral composition. Slip handle acid used to modify the surface, it seems suitable for this glazed tile. The effect is particularly remarkable wet (water) surface, wherein the sample is treated under the tiles A and B exhibit anti-skid (skid resistance) significantly increases. In addition, non-slip handle tile cleanliness is not compromised. The data suggest that the surface chemistry of the lubricant composition on the tile and slip resistance than the surface roughness of more significant effect, but further research must To better understand this phenomenon to achieve.
Tile surface topography analysis showed that treatment with anti-skid, change the surface structure can be detected at the microscopic scale. Microscopic surface roughness changes only tile B (smooth and homogeneous texture), the surface morphology of the etched glazed tile wherein the amorphous phase due to the overall smoothing significantly.
For this type of tile, from microscopic structural point of view, the application of the treatment will result in an amorphous (non-crystalline) phase of the etching, and the crystalline phase (quartz, feldspar, zircon and corundum) does not change.