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The pristine attapulgite (Atta) was pretreated by thermal and acid activation process in order to improve the loading capacity of phase change material (PCM). A series of pretreated Atta-based composite PCM was prepared combined with different kind of fatty acids. The XRD, FT-IR and XRF results shown that the pretreated process increased the purity of Atta as well as the SEM micrographs and BET results indicated that the porosity of Atta slightly increased after pretreating. What`s more, XRD and FT-IR results of the composites PCMs shown good chemical compatibility. DSC results indicated that the composite PCMs of AH-Atta/Lauric acid (LA), AH-Atta/Palmitic acid (SA) and AH-Atta/Docosanoic acid (DA) melted at 42.8 °C, 1.4 °C and 75.2 °C with the latent heat of 94.6 J g−1, 107.5 J g−1 and 84.6 J g−1 at the maximum loading of 51.0%, 50.8% and 51.3%, respectively. In addition, TGA results and 200 thermal cycles test results proved the good thermal stability and reliability of the samples. Based all above results, the prepared composite PCMs have good potential application in energy conservation buildings at different function temperature.

In this study, form-stable tetradecanol (TD)/expanded perlite (EP) composites by adding Cu powder (CuP) and carbon fiber (CF) to enhance thermal conductivities have been prepared via vacuum impregnation method. The thermal conductivity enhancer (TCE) is introduced by two methods of mixing TCE with phase change materials (PCMs) and implanting TCE into matrix materials. The result demonstrates the former is better than the latter in aspects of thermal property, thermal conductivity and controllability, moreover, adding ratio of TCEs gather in more appropriate interval from 2.5% to 3% suitable for the former. For CPCMs, FT-IR results indicate it is no chemical interaction among raw materials but physical combination via two methods. CPCMs prepared by the method of mixing TCE with PCMs have better phase change latent heat and thermal stability by DSC and TGA, while thermal cycling measurements show that form-stable composite PCMs have adequate stability even after being subjected to 200 melting/freezing cycles. Therefore, the method of mixing TCE with PCMs has better thermal property and controllability than that of implanting TCE into matrix materials and the prepared CPCM has great application prospect in solar energy utilization, building material, indoor cooling instrument and so on for thermal energy storage.

Phase change materials (PCMs) require an excellent matrix support material such as porous carbon materials. Orange peel, a discarded, readily available raw material, could potentially be used to pr...

In this study, tetradecanol–palmitic acid/expanded perlite composites containing carbon fiber (TD-PA/EP-CF CPCMs) were prepared by a vacuum impregnation method. Binary eutectic mixtures of PA and TD were utilized as thermal energy storage material in the composites, where EP behaved as supporting material. X-ray diffraction demonstrated that crystal structures of PA, TD, EP, and CF remained unchanged, confirming no chemical interactions among raw materials besides physical combinations. The microstructures indicated that TD-PA was sufficiently absorbed into EP porous structure, forming no leakage even in molten state. Differential scanning calorimetry estimated the melting temperature of TD-PA/EP-CF CPCM to 33.6 °C, with high phase change latent heat (PCLH) of 138.3 kJ kg−1. Also, the freezing temperature was estimated at 29.7 °C, with PCLH of 137.5 kJ kg−1. The thermal cycling measurements showed that PCM composite had adequate stability even after 200 melting/freezing cycles. Moreover, the thermal conductivity enhanced from 0.48 to 1.081 W m−1 K−1 in the presence of CF. Overall, the proposed CPCMs look promising materials for future applications due to their appropriate phase change temperature, elevated PCLH, and better thermal stability.

Phase change materials can be incorporated with building materials to make kinds of composite material, which can be applied in building systems due to their excellent thermal energy storage properties. In this study, a novel form-stable composite PCM CA-LA/Diatomite was prepared using vacuum impregnation method by combining a eutectic mixture of capric-lauric acid (CA-LA) as phase change material (PCM) and diatomite as supporting material. The composite products were characterized by using XRD, FT-IR and SEM analyzing methods. The thermal properties of the composite were measured by Differential Scanning Calorimetry (DSC). The results showed that the composite material melted at 23.61 °C with a latent heat of 87.33 J/g and solidified at 22.50 °C with the latent heat of 86.93 J/g. TGA investigation revealed that the composite had excellent thermal durability above their working temperature ranges. The thermal cycling test showed the composite has a good thermal reliability after 200 thermal cycles. What's more, the expanded graphite was added into the composite in order to increase the heat transfer performance. The results showed that the thermal conductivity of the composite increased gradually by 39.7%, 61.6%, 77.6% and 114.2% for the EG fractions of 3%, 5%, 7%, and 10%, respectively. As a result, the CA-LA/Diatomite/EG composite material of has a potential to be applied in modern buildings and solar energy systems due to its excellent thermal properties, good chemical and thermal reliability and high thermal conductivity.

In this study, beeswax-tetradecanol/expanded perlite composited with carbon fiber (BW-TD-CF/EP) composite phase change materials (CPCMs) have been prepared via vacuum impregnation method for solar energy utilization. The chemical compatibility, microstructure and thermal properties of CPCMs are characterized and measured, which proves that it is no chemical interaction among the raw materials but physical combination and BW-TD-CF is sufficiently absorbed into the EP porous structure with no leakage even in the molten state. According to differential scanning calorimeter (DSC) results, BW-TD-CF/EP composite melts at 34 °C with high enthalpy value of 178.7 kJ/kg, while thermal cycling measurements show that the form-stable composite PCM has adequate stability after being subjected to 200 melting/freezing cycles. Morever, thermal conductivity of BW-TD/EP composite is enhanced from 0.443 Wm−1 K−1 to 1.245 Wm−1 K−1 by adding CF. In result, the form-stable composite PCMs have more appropriate thermal properties and better thermal stability in building for solar energy utilization.

In this research, a novel form-stable composite Phase change material (PCM) of Stearic Acid (SA)/Carbonized sunflower straw (CSS) was prepared by vacuum impregnation method. Fourier Transform Infrared Spectroscopy (FT-IR) was used to measure the chemical compatibility of SA/CSS. The thermal properties and thermal stability were investigated by differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA) techniques. The results show that the SA/CSS melted at 66.4 °C with the latent heat of 186.1 J/g and freezed at 65.9 °C with the latent heat of 186.7 J/g and the composite PCM have a good thermal reliability above its working temperature. Moreover, the thermal conductivity of SA/CSS was 0.33 W/m/K which was 106.3% higher than that of SA. All results indicated that SA/CSS have suitable thermal properties used as thermal energy storage applications such as solar heat energy storage system and energy conservation buildings.

Bone char (BC) is a promising porous material that can be used for preparing a form-stable composite phase change material (PCM). In this paper, form-stable polyethylene glycol (PEG 6000)/BC composite PCMs were prepared by impregnation method. The PEG was used as the phase change material, and two different particle sizes of BC (0.8–1 mm: BC-1; 0.25–0.8 mm: BC-2) were acted as the supporting materials. The phase composition and chemical structure of the composite PCMs (PEG/BC-1 and PEG/BC-2) were characterized using X-ray diffraction and Fourier transformation infrared. The results indicated that the PEG can be well impregnated into BC pores with good compatibility. Thermal properties and thermal stability of the composite PCMs were determined by differential scanning calorimeter (DSC) and thermogravimetry analysis (TGA). DSC results showed that the maximum impregnation percentage for PEG into BC-1 and BC-2 was 38.77 and 43.91%, respectively, without melted PCM seepage from the composites. The TGA analysis revealed that the composite PCMs had good thermal stability above their working temperature range. The thermal cycle test of 100 melting–freezing cycles showed that the composite PCMs have good thermal reliability and chemical stability. The form-stable composite PCMs can be used as thermal energy storage material for waste heat storage and solar heating system.

In this study, a composite of form-stable phase change materials (FSPCMs) were prepared by the incorporation of a eutectic mixture of capric–palmitic–stearic acid (CA–PA–SA) into expanded vermiculite (EV) via vacuum impregnation. In the composites, CA–PA–SA was utilized as a thermal energy storage material, and EV served as the supporting material. X-ray diffraction and Fourier transform infrared spectroscopy results demonstrated that CA–PA–SA and EV in the composites only undergo physical combination, not a chemical reaction. Scanning electron microscopy images indicated that CA–PA–SA is sufficiently absorbed in the expanded vermiculite porous network. According to differential scanning calorimetry results, the 70 wt% CA–PA–SA/EV sample melts at 19.3 °C with a latent heat of 117.6 J/g and solidifies at 17.1 °C with a latent heat of 118.3 J/g. Thermal cycling measurements indicated that FSPCMs exhibit adequate stability even after being subjected to 200 melting–freezing cycles. Furthermore, the thermal conductivity of the composites increased by approximately 49.58% with the addition of 5 wt% of Cu powder. Hence, CA–PA–SA/EV FSPCMs are effective latent heat thermal energy storage building materials.

Phase change materials (PCMs) is an excellent performance candidate for thermal energy storage and utilization. However, low thermal conductivity and low light-to-thermal conversion efficiency of PCMs are the serious limitation factors for highly efficient energy storage and photothermal conversion. In this paper, we reported a novel composite PCM based on lauric acid (LA) as the PCM supported by Ag nanoparticles modified expanded graphite (Ag-EG). The composite PCM of Ag-EG/LA possessed good energy thermal storage properties, which melted at 47.2 °C with the latent heat of 129.5 J/g at the LA maximum loading of 70.2%. Meanwhile, based on the high thermal conductivity and local surface plasma resonance effect of Ag, the composite (Ag-EG/LA) exhibits improved thermal conductivities (2.85 W/(m•K)) and high light-to-thermal energy conversion efficiency (η=81.2%). Moreover, the TGA and thermal cycles test results shown that Ag-EG/LA have good thermal stability and reliability. Hence, this novel composite of Ag-EG/LA could be potentially applicated in solar energy harvesting system and electric devices for thermal energy management.

Stearic acid (SA) and modified expanded vermiculite (EV) shape-stabilized composite phase change materials (ss-CPCMs) with enhanced thermal conductivity were prepared. EV was impregnated with a starch solution, and then a composite of EV and carbon (EVC) was obtained by carbonizing starch in-situ in the EV layers. 63.12 wt % of SA was retained in the SA/EVC ss-CPCMs without leakage. Scanning electron microscopy (SEM) images showed that the EVC with highly porous micro-pores acted as a good support matrix for absorbing molten SA. The thermal conductivity of the SA/EVC ss-CPCMs was 0.52 W/(m K), and this was an increase of 52.9% compared with that of the SA/EV ss-CPCMs. The results from Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), and thermal cycling tests indicated that the prepared SA/EVC ss-CPCMs are a promising material for energy efficient buildings because of their optimum phase-change temperature, a high enthalpy of phase change, ideal thermal conductivity, and good chemical and thermal stability.

In this study, the effect of the introduction of carbon nanotubes (CNTs) as a filler for enhancing the thermal conductivity of paraffin-carbon nanotubes/expanded perlite form-stable composite phase change materials (PA-CNTs/EP FS-CPCMs) was experimentally investigated. Four samples of PA-CNTs/EP FS-CPCMs with different CNT mass fractions were prepared by vacuum impregnation. Scanning electron microscopy was employed to investigate the morphology and microstructure of CNTs, EP, and PA-CNTs/EP FS-CPCMs. Differential scanning calorimetry was employed to examine the thermal properties of PA-CNTs/EP FS-CPCMs, and results indicated that the latent heat and phase-change temperatures of the PA-CNTs/EP FS-CPCMs slightly change with the CNTs mass fractions. The thermal conductivity of PA-CNTs/EP FS-CPCMs5.27 (0.516 W m −1 K −1 ) was 4.82 times that of PA-CNTs/EP FS-CPCMs0. The thermal storage and release properties of PA-CNTs/EP FS-CPCMs were significantly improved as compared with those of PA-CNTs/EP FS-CPCMs0. Results obtained from Fourier transform infrared spectroscopy, thermogravimetric analysis, and thermal cycling tests showed that PA-CNTs/EP FS-CPCMs exhibit good chemical and thermal stabilities. The as-prepared PA-CNTs/EP FS-CPCMs demonstrate considerable potential as thermal energy storage materials.

Lightweight wall material (LWM) composited with EG/paraffin composite was prepared by experimental procedures of foaming, slip casting and constant temperature curing. The EG/paraffin composites were synthesized via vacuum impregnation method. The scanning electron microscope (SEM) analysis indicated that paraffin was sufficiently absorbed into the EG porous network and depicted no leakage even in the molten state. The X-ray diffractometer (XRD) and Fourier transformation infrared spectroscope (FT-IR) results revealed that paraffin and EG in the composite didn’t undergo chemical reactions but only physical combination. The compressive strength value of the sample reached 2.853 MPa, while bulk density reduced to 0.445 kg/m 3 . The differential scanning calorimeter (DSC) results revealed that the sample melts at 47.78 °C with a latent heat of 16.26 J/g and solidifies at 43.81 °C with a latent heat of 15.98 J/g. The sample with 15% EG/paraffin composites had adequate stability by contrasting mechanical property and DSC profiles before and after 200 times thermal cycles. Furthermore, the thermal conductivity of the LWM increased to 0.76 W (m K) when 20% EG/paraffin was added into the composite. This indicates that the prepared sample has a good thermal property. Hence, the LWM containing EG/paraffin composite would be useful as thermal energy storage material.

In this study, the fatty acid eutectics (capric acid (CA) and lauric acid (LA) eutectics) were impregnated into the expanded perlite (EP) and expanded vermiculite (EVM) to form the two kinds of composite phase change material (PCM). The chemical structure, crystalloid phase were determined by the Fourier transformation infrared spectroscope, X-ray diffractometer. The results show that the eutectics with the EP and EVM do not undergo a chemical reaction and only undergo a physical combination. The SEM results proved that eutectics are well adsorbed in the porous structure of the EP and EVM. The thermal properties were determined by the differential scanning calorimeter (DSC). The DSC result shows that the melting temperatures and latent heat values of the PCMs are in the range of about 21–23 °C and 81–117 J/g. The maximum impregnation ratio of fatty acid eutectics into EP and EVM were 82.93% and 57.48%. The thermal cycling test proves that the composites have good thermal reliability. TG analysis revealed that the composite PCMs had high thermal durability property above their working temperature ranges. Besides, thermal conductivity of the CA-LA/EP and CA-LA/EVM was increased approximately as 89.14% and 87.41% by adding 5 wt.% expanded graphite (EG). It is envisioned that the prepared shape-stabilized PCMs have considerable potential for developing their roles in thermal energy storage system.

The application of organic phase change material (PCM) using in thermal energy storage system was limited by low thermal conductivity and leakage problem. In this paper, we reported a low-cost supporting material with good thermal conductivity by carboning the biomass of maize straw. The composite PCM of stearic acid (SA)/carbonized maize straw (CMS) was prepared via vacuum impregnation process and characterized by XRD, FT-IR, SEM. The results show that SA/CMS has good chemical compatibility. DSC, TGA as well as thermal conductivity and thermal history method were used to evaluate the thermal properties of SA/CMS. The DSC result reveals that the composite SA/CMS melted at 67.62°C with the latent heat of 160.74 J/g and freezed at 65.28°C with the latent heat of 160.47 J/g. The maximum loading capacity of SA in composite of SA/CMS reached 77.22%. TGA and DTG results show SA/CMS have good thermal stability. Thermal conductivity of SA/CMS reached 0.30 W/(m•K), which was 87.5% higher than that of the pure SA. Compared with SA, the melting time of SA/CMS reduced 50% and the freezing time reduced 73%. 200 thermal cycling test shows the SA/CMS exhibits excellent thermal reliability. Based on all results, it can be expected that the form-stable composite PCM of SA/CMS has good potential application in solar heat energy storage system and energy-efficient buildings.

In this study, a series of Ag 3 PO 4 photocatalysts with different contents of rhombic dodecahedral particles were prepared in one pot by a facile, novel hydrothermal method using ethylene glycol (EG), which served as both a morphology modifier and reducing agent. The effects of EG content on the morphologies of Ag 3 PO 4 photocatalysts were discussed. The photocatalytic activity of the Ag 3 PO 4 photocatalysts was evaluated by the degradation of methylene blue trihydrate under visible-light irradiation. With the use of 0.8% EG in the reaction solvent, the sample exhibited excellent photocatalytic activity, attributed to the high amount of rhombic dodecahedral Ag 3 PO 4 particles with a high exposure of the {110} facets and high surface energy. The surface energy of the {110} facets was 1.31 J/m 2 , greater than that of the {100} facet (1.12 J/m 2 ). However, with 1% EG in the reaction solvent, although the Ag 3 PO 4 photocatalysts were composed of a majority of rhombic dodecahedral Ag 3 PO 4 particles, tiny Ag particles formed from Ag + under the action of EG attached on the surface of the sample decreased the absorption of visible light, resulting in low photocatalytic activity.

In this study, novel polyethylene glycol @ Si3N4 nanowires as phase-change materials (PCMs) were developed by using ultrasonic cell disruptor. The results obtained herein indicate that these nanowires can be a potential carrier for preparing PCMs. The results show that PEG is composited in a fluffy nano-network structure of Si3N4 nanowires, which could not be easily leaked from this structure for the solid–liquid phase transition. X-ray diffraction and Fourier transform infrared spectroscopy were employed for investigating the structures of PCMs; the results show that a chemical reaction does not occur between PEG and Si3N4 nanowires. Differential scanning calorimetry analysis results indicated that PCMs exhibit appropriate phase-change temperature and excellent high-phase change enthalpy. From the TGA results, PCMs exhibit perfect thermal stability. The PCMs could perfectly maintain their phase transition after 100 melting–freezing cycles. The thermal conductivity of PCMs-1 was 0.362 W/(mK), which was enhanced by 88.54% in comparison with that to pure PEG. The heat storage or release rate of PCMs is significantly more rapid than that of pure PEG for practical applications.

In this study, polyethylene glycol/expanded perlite composite with carbon layer phase-change materials were prepared. EP was impregnated with a sucrose solution, followed by carbonation in situ by the carbon-bed method, for obtaining EPC composite, thus providing an important method for enhancing the thermal conductivity of composite PCMs. Scanning electron microscopy images showed that the EPC composite with a highly porous structure composed of rough micro-pores could act as a good supporting material for absorbing molten PEG. The results obtained from differential scanning calorimeter analysis indicated that the values for the latent heat and temperature of PEPC composite during melting were 134.93 J/g and 55.19 °C, respectively, while, these values were 129.27 J/g and 46.71 °C during freezing, respectively. The thermal conductivity of PEPC composite was 0.479 W/(mK), which was 2.975 times that of PEP composite. The results obtained from Fourier transform infrared spectroscopy and thermo-gravimetric analysis showed that PEPC composite exhibited good chemical stability and thermal stability, respectively. Furthermore, thermal cycling tests indicated that PEPC composite exhibited good thermal reliability after 200 melting/freezing cycles. In conclusion, PEPC composite with excellent thermal properties, ideal thermal conductivity, good thermal reliability and chemical stability could act as the promising building filler materials for the sustainable development of energy-efficient buildings.

In this study, novel polyethylene glycol (PEG)/White Carbon Black (WCB) form-stable composite phase changes materials (FS-CPCMs) were prepared by super- ultrasound-assisted, which obviously decreases the reaction time. Test results showed that PEG does not easily leak from the fluffy network structure of WCB during solid-liquid phase transition. Results obtained from XRD and FTIR demonstrated that no new chemical bond is formed between PEG4000 and WCB. Results obtained from DSC and TGA analyses showed that FS-CPCMs exhibit excellent thermal stability and good form-stable performance. The phase change enthalpy of FS-CPCMs reached up to 101.1J/g, and the melting and solidifying times of FS-CPCMs were 34.43% and 30.51% less than that of pure PEG, respectively. The thermal conductivity data showed that WCB acted as the support material is very effective for enhancing the thermal conductivity of the FS-CPCMs. The FS-CPCMs thus prepared were safe, environmentally friendly, and cost-effective; hence, they can be used as potential building materials for the applications of thermal energy storage.

In this work, the mechanical properties and solid particle erosion wear behavior of LaMgAl11O19–Al2O3 ceramics toughened and reinforced with LaMgAl11O19 platelets were investigated. The effects of LaMgAl11O19 additions, impingement angles (30°, 45°, 60°, 75°, and 90°), and erosion temperatures varying from room temperature to 1400°C on the erosion rates and material removal mechanisms of LaMgAl11O19–Al2O3 composites were systematically studied. The results indicated that LaMgAl11O19–Al2O3 ceramics exhibited superior erosive wear resistance compared to monolithic Al2O3 ceramics at room and elevated temperatures due to their enhanced mechanical properties and improved microstructure resulting from the introduction of an appropriate amount of LaMgAl11O19 platelets. Examination of the eroded surfaces of LaMgAl11O19–Al2O3 composites revealed that erosion temperatures and impingement angles play important roles in determining the erosion behavior and mechanisms of the tested materials. For the case of elevated temperature and oblique erosion, plowing and subsurface intergranular fracture are the predominant mechanisms resulting in material removal, whereas at room temperature and normal impact, the erosion process of the targets is primarily dominated by grain ejection and lateral crack intersection.

Lauric acid(LA)/expanded vermiculite (EVM) form-stable phase change materials were synthesized via vacuum impregnation method. In the composites, lauric acid was utilized as a thermal energy storage material and the expanded vermiculite behaved as the supporting material. XRD and FT-IR results demonstrate that lauric acid and expanded vermiculite in the composite do not undergo a chemical reaction and only undergo a physical combination. Microstructural analysis indicates that lauric acid is sufficiently absorbed in the expanded vermiculite porous network, while displaying negligible leakage even under the molten state. According to DSC results, the 70 wt.% LA/EVM sample melts at 41.88 °C with a latent heat of 126.8 J/g and solidifies at 39.89 °C with a latent heat of 125.6 J/g. Thermal cycling measurements show that the form-stable composite PCM has adequate stability even after being subjected to 200 melting/freezing cycles. Furthermore, the thermal conductivity of the composite PCM increased by approximately 78% with the addition of 10 wt.% expanded graphite (EG). Thus, the form-stable composite PCM is a suitable option for thermal energy storage for building and solar heating system applications.

Novel form-stable composite phase change materials (FS-CPCMs) of polyethylene glycol (PEG)/Cu/SiO2 were prepared by adding Cu powder to PEG and SiO2 via the ultrasound-assisted sol–gel method. This method ensured the uniform distribution of Cu powder in the FS-CPCMs, thus providing an important method to develop composite phase change materials (CPCMs) with a high thermal conductivity. The FS-CPCMs were characterized by various techniques. The results showed that the FS-CPCMs remained in the solid state without leakage above the melting point of PEG. The XRD and FTIR results indicated that no new chemical bond was formed between the constituents of FS-CPCMs: Cu, PEG, and SiO2. The DSC and TGA analyses showed that the FS-CPCMs had an optimum phase-change temperature, a high enthalpy of phase change, an excellent thermal stability, and a good form-stable performance. The thermal conductivity was 0.431 W m−1 K−1 for 3.45 wt% Cu powder in the FS-CPCMs, an increase of 49.13% compared to pure PEG.

Carbon foam/expanded graphite composite (CEC) was prepared from a sucrose-expandable graphite resin using a thermal foaming method. This CEC was impregnated through its pores with paraffin to obtain a paraffin/carbon foam/expanded graphite composite (PCEC). In the case of CECs, when the amount of added expandable graphite reached 10 wt% to 15 wt%, the microstructure of the CEC was damaged because of the expansion in volume of the expandable graphite. Fourier transform infra-red spectroscopy and X-ray diffraction analysis of PCECs showed that there was no chemical interaction between the paraffin and CECs. With an increase in the amount of expandable graphite in CECs, the adsorption capacity of paraffin and the latent heat first showed an increase and then decreased. The heat transfer capability of the paraffin was truly improved by the CECs. The processes for the preparation of the CECs and PCECs were environmentally friendly, convenient, and inexpensive. The PCECs, with good thermal properties and chemical stabilities, are suitable for low temperature (40–50 °C) thermal energy storage applications.

Sialon–ZrN powders were synthesized from low-grade bauxite using a zirconite additive by carbothermal reduction nitridation (CRN). The as-synthesized Sialon–ZrN powders were subsequently used as SiC-based free-fired refractories. Their phase compositions and microstructures of the powders were determined using X-ray diffraction and scanning electron microscopy. The physical properties and blast furnace (BF) slag resistance of the SiC–Sialon–ZrN free-fired refractories were also studied. The results show that the low-grade bauxite and zirconite powders were transformed to β-Sialon and ZrN by the CRN process at 1600 °C. The phenolic resin provided a strongly bonded interface between the Sialon–ZrN matrix and SiC particles and thus enhanced their combined strength after drying at 150 °C. The strength increased as the temperature was elevated from 1000 °C to 1500 °C. As the ZrN content increased, the slag erosion rate of the SiC–Sialon–ZrN free-fired refractories initially decreased and then increased after being heated at 1500 °C. The presence of ZrO 2 in the slag (oxidized from ZrN) revealed that the ZrO 2 did not react with other oxides in the BF slag to form low melting point phases. This may play a crucial role in its BF slag erosion resistance. The corrosion mechanism of the BF slag towards the as-prepared SiC–Sialon–ZrN free-fired refractories was determined to be oxidation-erosion-dissolution-penetration.

Nanostructure reinforced nitride ceramics play an important role in the family of structural ceramics. In this study, large scale of one-dimensional (1D) β-sialon nanostructures and β-sialon-β-Si3N4 composite powders were synthesized simultaneously via a reduction nitridation process by using powders of silicon, aluminum, and silica as raw materials. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM/HRTEM), Fourier-transform infrared spectroscopy (FT-IR) and energy dispersive x-ray spectroscopy (EDS) were used to characterize the phase composition, morphology, and microstructure of the as-obtained products. As a result, large scale of 1D β-sialon nanostructures can be prepared at 1600 °C. The diameter of the as-prepared nanowires in the range of 80 to 170 nm can be tailored by the addition of aluminum. The growth of 1D β-sialon nanostructures is achieved by a vapor-solid (VS) mechanism. Photoluminescence (PL) of the 1D β-sialon nanostructures was characterized which exhibit violet/blue emission peaks, making it have the potential to be applied in optoelectronic nanodevices. Besides, nitride ceramic composite powders including β-Si3N4 and β-sialon with in situ formed β-sialon nanowires were also achieved. The phase transformation behavior and the thermodynamical analysis of the ceramic composite powders were also studied by characterizing the phase composition of the products synthesized at different temperature. The as-grown β-sialon nanowires and the composite powders have great potential to be applied in nanostructure reinforced structural ceramics.

Radial mesoporous silica (RMS) sphere was tailor-made for further applications in producing shape-stabilized composite phase change materials (ss-CPCMs) through a facile self-assembly process using CTAB as the main template and TEOS as SiO2 precursor. Novel ss-CPCMs composed of polyethylene glycol (PEG) and RMS were prepared through vacuum impregnating method. Various techniques were employed to characterize the structural and thermal properties of the ss-CPCMs. The DSC results indicated that the PEG/RMS ss-CPCM was a promising candidate for building thermal energy storage applications due to its large latent heat, suitable phase change temperature, good thermal reliability, as well as the excellent chemical compatibility and thermal stability. Importantly, the possible formation mechanisms of both RMS sphere and PEG/RMS composite have also been proposed. The results also indicated that the properties of the PEG/RMS ss-CPCMs are influenced by the adsorption limitation of the PEG molecule from RMS sphere with mesoporous structure and the effect of RMS, as the impurities, on the perfect crystallization of PEG.