Thermal insulation and strength of autoclaved light concrete

Abstract

The primary objective of this study was to develop an autoclaved light concrete (ALC) material with ultra-thermal insulation property and to investigate the relationship between its physical characteristics and mechanical properties. Through tests of dry bulk density and compressive strength, relationship of physical characteristics and mechanical properties of samples were studied, resulting in a material with ultra-thermal insulation property. Scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX) were applied to analyze the micro-morphology and elemental composition of samples. To identify the product phases, X-ray diffraction (XRD) was engaged. The test results showed that compressive strength and thermal coefficient were reduced with the increasing of aluminum powder within the mixtures. As a result the optimal thermal coefficient and compressive strength of samples were improved to 0.061 W/(m·k) and 1.2 MPa, respectively. SEM, EDX and XRD analyses showed that calcium silicate hydrate and tobermorite crystal were main resultant phases.

Synthetic Effects of Frequency and Duty Ratio on Growth Characteristics, Energy Consumption and Corrosion Properties of Microarc Oxidized Coating Formed on Ti6Al4V

“…When the ITSPP is constant, the thickness of coating decreases gradually with diminishing DTSPP in Fig. 3b, which is in agreement with the results in the literature [30,31]. The ESPP is mainly determined by DTSPP in constant potential mode, and the ESPP affects the formation of coating during the MAO process.…”

“…On account of the above standpoints, the phenomena of the thickness of coating changing with the frequency and duty ratio can be explained. In the related reported literature [30][31][32][33][34], the thickness of coating reduces with increasing the frequency and it should be pointed out that the cumulating time of positive pulse is same and independent of altering the frequency with uniform duty ratio and processing time in the literature. The augmentation of frequency leads to the concurrent decrease in DTSPP and ITSPP.…”

“…The processing time, voltage, current, frequency, duty ratio and the number of positive and negative pulses decide the output waveform in the potentiostatic or galvanostatic regime for bipolar pulse waveform [27][28][29]. The effect of frequency or duty ratio on the characteristics of coating during the MAO process has been reported by a host of literature [30][31][32][33][34]. According to these studies, with increasing frequency or decreasing duty ratio, the roughness and thickness of coating decreased gradually and the properties of coating varied proportionally with frequency and duty ratio.…”

Microstructure and Tribological Behavior of a TiO2/hBN Composite Ceramic Coating Formed via Micro-arc Oxidation of Ti–6Al–4V Alloy

“…[15][16][17] or hard particles (Al 2 O 3 , Si 3 N 4 , SiC, etc.) [18][19][20] have been added to MAO composite coatings to significant reinforce their wear resistance. The former possess poor high-temperature resistance and durability, whilst the anti-friction property of the latter is not sufficient, Hexagonal boron nitride (hBN) particles, referred to "white graphite", in contrast, exhibit a layered structural characteristic and constitute an excellent solid lubricant.…”

Influence of Applied Frequency on Microstructural and Electrochemical Characteristics of Ceramic Coating Produced on Al-Mg Alloy by Pulsed Plasma Electrolytic Oxidation

“…Other researchers have reported the similar results with respect to relationship between the applied frequency and the thickness growth of PEO coating. They claimed that the increase of applied frequency promotes the thickness growth rate for PEO coating of AZ91D Mg alloy [12]. However, the result of this study is limited to the frequency effects with a relatively low duty cycle, and it is worth noting that different influences of frequencies can be expected at higher duty cycle.…”