DSC Data Research Articles

Wax Precipitation in Crude Oil by Coutinho Model Based on Conventional Gas Chromatography Data

Wax precipitation in crude oils can produce problems in oil production and transportation operations. Prediction is the key of avoidance or remediation of the wax problem of flow assurance. Among the wax prediction thermodynamic model, Coutinho model can be run using limited laboratory data, but the result is comparably accurate. The model requires n-paraffin distribution, which commonly determined by high-temperature gas chromatography (HTGC) analysis. However, only few laboratories could perform the HTGC. Lemigas has abundant database of crude oil with conventional gas chromatography data. An extended n-paraffin distribution was calculated based on the conventional GC data by performing extrapolation and normalization to total wax content. The n-paraffin distribution was applied in Coutinho model to predict wax precipitation of a crude oil sample. The WAT obtained from the model deviated only 2°C from DSC data. The result was also valid to DSC data in term of precipitated wax amount along temperature range.

Assessment of activation energy of enthalpy relaxation in sucrose-water system: effects of DSC cycle type and sample thermal history

The purpose of this study is to critically analyze different methods of calculation of activation energy of relaxation in sucrose-water system from differential scanning calorimetry data. We consider the use of different thermal cycles for calculations together with Moynihan and Kissinger equations. We study the effect of two methods of glass transition temperature determination (half-step and inflection point) on the activation energy values. Along with experimental DSC data, we use the data simulated using Tool–Narayanaswamy–Moynihan model to validate the use of cooling and heating curves and to check the reproducibility of the activation energy calculations. The obtained results show that the thermal cycle with equal cooling and heating rates provides the most reliable data set and the glass transition temperature definition using inflection point rather than half step can be recommended for calculations. Moreover, due to technical reasons, heating rather than cooling scans provide the most reliable results of activation energy calculations. Furthermore, a simple method based on the width of the glass transition region shows reasonable results for single scan experiments. The activation energies of the glass transition in sucrose-water system with different water contents and different thermal histories were studied. Since it is impossible to apply traditional methods based on Moynihan equation for the activation energy evaluation for freeze-dried samples, we propose using another method based on the properties of the recovery peak. Combining the results obtained by different methods, we present a dependence of activation energy in sucrose-water system on water content. The results show that water decreases the activation energy of relaxation process in sucrose matrix.

A comparative kinetic study between TGA & DSC techniques using model-free and model-based analyses to assess spontaneous combustion propensity of Indian coals

Kinetic study of coal was carried out using simultaneous thermal analysis (STA) technique to assess the spontaneous combustion propensity of coal samples collected from various Indian coalfields having both fiery and non-fiery seams. The kinetic parameters were estimated by using both model-free and model-based analysis for both TGA & DSC data. The model-based method comprises four different consecutive reaction steps, viz. A→B→C→D→E for the spontaneous combustion process and the second reaction step (B→C) were used for this investigation. Chemometric analysis was applied to know the relation between the proximate analysis and activation energy of the samples using model-free and model-based techniques. The activation energy for the second reaction step of the model-based method for both TGA and DSC data showed a good relationship with the standard methods i.e., crossing point temperature (XPT) and Tgign of the samples. It indicates that the activation energy values at the oxidation stage (2nd stage) play a significant role in the spontaneous combustion propensity of coal. The study also reveals that the model-based analysis provided better results in comparison to model-free analysis to assess the spontaneous combustion propensity of coal.

Long Persistent Luminescent HDPE Composites with Strontium Aluminate and Their Phosphorescence, Thermal, Mechanical, and Rheological Characteristics.

In this work, HDPE/strontium aluminate-based auto glowing composites (SrAl2O4: Eu, Dy (AG1) and Sr4Al14O25: Eu, Dy (AG2)) were prepared, and their phosphorescence studies were conducted. In HDPE/AG1 composites, the green emission was observed at ~500 nm after the UV excitation at 320 nm. The HDPE/AG2 has a blue emission at ~490 nm and, in both cases, the intensity of emission is proportional to the AG1 and AG2 content. The DSC data show that the total crystallinity of both the composites was decreased but with a more decreasing effect with the bulky AG2 filler. The melting and crystallization temperatures were intact, which shows the absence of any chemical modification during high shear and temperature processing. This observation is further supported by the ATR-FTIR studies where no new peaks appeared or disappeared from the HDPE peaks. The tensile strength and modulus of HDPE, HDPE/AG1, and HDPE/AG2 composites were improved with the AG1 and AG2 fillers. The rheological studies show the improvement in the complex viscosity and accordingly the storage modulus of the studied phosphorescent HDPE composites. The SEM images indicate better filler dispersion and filler–matrix adhesion, which improves the mechanical characteristics of the studied HDPE composites. The ageing studies in the glowing composites show that there is a decrease in the intensity of phosphorescence emission on exposure to drastic atmospheric conditions for a longer period and the composites become more brittle.

Making progress towards promising energetic cellulosic microcrystals developed from alternative lignocellulosic biomasses

ABSTRACT This study reported the valorization of various alternative lignocellulosic feedstocks including giant reed (GR), palm fronds (PF) and esparto grass (EG) for the development of promising nitrated structurally modified cellulosic biopolymers (NNCs). The extracted nanostructured cellulose precursors and their nitrated derivatives were analyzed for their physicochemical properties, chemical structure, crystallinity and thermal stability. Experimental findings confirmed the successful formation of the desired energetic NNCs polymers with increased densities (1.698–1.711 g/cm3) and high nitrogen contents (13.10–13.26%) followed the order NNC-EG>NNC-PF>NNC-GR, which are greater than those of the commonly used nitrocellulose (1.650–1.670 g/cm3 and 12.50–12.70%). Furthermore, isoconversional integral models (TAS, it-KAS and VYA/CE) were exploited based on non-isothermal DSC data to investigate their thermal decomposition kinetics. The predicted kinetic parameters displayed that the synthesized energy-rich NNCs presented close values of Arrhenius parameters within the range of 156 ≤ Eα (kJ/mol) ≤163 and 14.7 ≤ Log(A(s−1) ≤ 15.6, and decomposed following diverse reaction mechanisms. Consequently, the explored lignocellulosic biomasses could be considered as valuable alternative non-woody resources for the production of advanced high-energy dense cellulosic biopolymers for potential application in the next generation of solid propellant formulations and composite explosives.

Characterization and controlled release of pequi oil microcapsules for yogurt application

Pequi oil is a valuable product for food industries due to its high levels of unsaturated fatty acids and carotenoids. This work used the complex coacervation technique with cashew gum/chitosan and cashew gum/gelatin matrices to encapsulate pequi oil in the production of enriched yogurt. Both wall materials achieved good results in encapsulation efficiency (>80%), yield (>50%), and loading capacity (<50%). The FTIR data demonstrated the presence of electrostatic interactions, thereby confirming encapsulation, and TGA, DSC and Rancimat data verified the microcapsule's stability. The acid release and temperature resistance results showed greater stability at pH's close to the optimum condition of the coacervation process and at temperatures below 80 °C. Finally, the potential for its application in yogurts was realized, showing that the preparation procedure of yogurt influenced the oil release rate and fatty acid profile, and that the addition of microcapsules should be optimally done during the cooling step.

Synthesis and characterization of Poly(ethylene glycol)-based segmented ionenes block copolymer with aliphatic or DABCO hard segments

A series of poly(ethylene glycol) (PEG)-based segmented block copolymers were synthesized with two structurally different hard segments, linear and heterocyclic aliphatic amines. Ionenes were synthesized via a modified Menshutkin reaction with three different weight fractions of hard domains (amine rich segment) and soft domains (PEG oligomers). TGA results show that both aliphatic and DABCO-based ionenes were thermally stable up to 250 °C. DSC and XRD data indicate that increasing the weight fraction of the soft segment from 25 wt% to 50 wt% triggered better chain packing of the PEG soft segment for both hard segments. Also, the DABCO-based ionenes displayed the highest PEG crystallite purity at 50 wt% of soft segment. The segmented ionenes exhibited high strain elongation percentages at elevated temperatures (i.e., above the PEG melting temperature). The mechanical properties of ionenes changed by varying the nature and the weight fractions of soft and hard domains. DMA analysis concluded that DABCO-based ionenes possess superior elastomeric behavior by having a wider rubbery plateau and higher rubbery plateau storage modulus compared to aliphatic analogs at all weight fractions potentially due to better microphase separation and ionic aggregation. DMA and AFM confirmed that the 25 wt% soft segment ionenes had a relatively higher degree of microphase separation among the other weight fractions.

Composite oleogels formed by cellulose particles and sorbitan acid esters

Developing a facile method to prepare edible oleogels under moderate conditions would be of great interest. In this research, oleogels were obtained directly from the mixtures of cellulose particles (average particle size ≈ 25 µm), sorbitan fatty acid esters (Span60 and Span40) and medium chain triglycerides (MCT). Results showed that 6% (w/w) cellulose particles combined with 9% (w/w) sorbitan fatty acid esters could form a strong network to trap the oil phase through ultra-sonic treating. The strength of the oleogels could be regulated by the cellulose particles content and its ratio to surfactant. XRD, DSC and SEM data revealed that there was synergetic effect between the cellulose particles and fatty acid esters during the gelation. The cellulose particles covered with Span60 could associate with each other to form a network in the oil phase, in the similar way to the Span60 micelles. These findings would be significant for the development and application of food grade oleogels. • Cellulose particles combined with surfactant could be used to prepare oleogels. • Oleogels was formed by ultra-sonic treating the mixture of gelators and oil phase. • The cellulose particles were surface modified by the surfactants in oil phase. • The surface modified cellulose particles could form a network in oil phase.

Synthesis, characterization and biological activities study of metal complexes of 5,6-dimethylbenzimidazole with Co(II), Cu(II), Cd(II) and Hg(II)

The present work aimed at the synthesis of cobalt(Ⅱ), copper(Ⅱ), cadmium(Ⅱ) and mercury(Ⅱ) complexes of 5,6-dimethylbenzimidazole by simple and straight forward methods. Several elemental, spectroscopic and thermal studies such as; solubility, melting point, elemental analysis, FTIR spectroscopy, UV–visible spectroscopy, magnetic susceptibility, conductivity test, TGA, DSC and XRD were carried out to characterize the synthesized complexes. Elemental analysis (C, H, N, M) data confirmed 1:2 metal to ligand ratio represented as [M(L)2Cl2]. UV–visible spectra and Magnetic susceptibility values suggested tetrahedral geometry of the synthesized metal complexes. The lattice types were predicted by XRD data and conductivity values indicated non-electrolytic nature of the complexes. TGA and DSC data demonstrated their thermal decomposition patterns as well as formation of corresponding metal oxides. Combining all the analytical results, the proposed empirical formulae of the complexes are [Co(C9H10N2)2Cl2], [Cu(C9H10N2)2Cl2], [Cd(C9H10N2)2Cl2] and [Hg(C9H10N2)2Cl2]. The synthesized complexes were also subjected to antimicrobial and cytotoxicity activity screening. Cd(II) and Hg(II) complexes showed activity against both gram positive and negative bacterial strains at relatively higher concentration. Most of the complexes were less or insensitive to bacterial and fungal strains at lower concentration. All of the synthesized complexes exhibited potential cytotoxic activity.

The melting properties of D-α-glucose, D-β-fructose, D-sucrose, D-α-galactose, and D-α-xylose and their solubility in water: A revision

Saccharides are still commonly isolated from biological feedstock by crystallization from aqueous solutions. Precise thermodynamic data on solubility are essential to optimize the downstream crystallization process. Solubility modeling, in turn, requires knowledge of melting properties. In the first part of this work, following our previous work on amino acids and peptides, D-α-glucose, D-β-fructose, D-sucrose, D-α-galactose, and D-α-xylose were investigated with Fast Scanning Calorimetry (FSC) in a wide scanning rate range (2000 K·s−1 to 10000 K·s−1). Using the experimental melting properties of saccharides from FSC allowed successfully modeling aqueous solubility for D-sucrose and D-α-galactose with the equation of state PC-SAFT. This provides cross-validation of the measurement methods to determine accurate experimental melting properties with FSC. Unexpectedly, the experimental FSC melting temperatures, extrapolated to zero scanning rates for thermal lag correction, were higher than results determined with DSC and available literature data. To clarify this inconsistency, FSC measurements towards low scanning rates from 10000 K·s−1 to 1 K·s−1 (D-α-glucose, D-β-fructose, D-sucrose) overlapping with the scanning rates of DSC and literature data were combined. At scanning rates below 1000 K·s−1, the melting properties followed a consistent non-linear trend, observed in both the FSC and the literature data. In order to understand the non-linear decrease of apparent melting temperatures with decreasing heating rate, the endothermic peaks were investigated in terms of isoconversional kinetics. The activation energies in the non-linear dependency region are in the range of 300<{E}_{A}< 600 {text{kJ}}bullet {text{mo}}{text{l}}^{-1}. These values are higher than the enthalpy of sublimation for D-α-glucose, indicating that the non-linear behavior does not have a physical nature but attributes to chemical processes corresponding to the decomposition of molecular compounds within the crystal lattice before melting. The melting properties reported in the literature, commonly determined with conventional methods such as DSC, lead to inaccurate results due to the decomposition of these biomolecules at low heating rates. In addition, the FSC results at lower scanning rates coincide with results from DSC and literature in the overlapping scanning rate range, further validating the accuracy of FSC measurements to determine reliable melting properties of thermally labile biomolecules. The experimental FSC melting properties determined at higher scanning rates are considered as the correct equilibrium melting properties, which are not influenced by any chemical processes. The combination of FSC and PC-SAFT opens the door to model solubility of solid compounds that commonly decompose before melting.

CYCLODEXTRIN INCLUSION COMPLEXES OF PHARMACEUTICALLY ACTIVE DERIVATIVES OF THE CYTISINE ALKALOID AND THEIR HEMORHEOLOGICAL ACTIVITY

The alkaloid cytisine is of great importance for modern pharmacological studies. This alkaloid can be used as a component of the supramolecular system with cyclic oligosaccharides, namely β-cyclodextrins, which have a truncated cone-shaped molecule with internal protons Н3 and Н5 and external ones Н2 and Н4. The aim of the work is to obtain inclusion complexes of pharmaceutically active derivatives of the alkaloid cytisine. The inclusion complexes of cytisine alkaloid derivatives with β-CD and 2-HP-β-CD were obtained by the coprecipitation method. Thermogravimetric, differential thermal, and differential scanning calorimetric analyzes were performed. It was shown that inclusion complexes of substrate with cyclodextrin cavity of receptors were formed. The greatest change in the chemical shifts of protons during the formation of supra-molecular complexes occurs with the internal protons H-3 and H-5 of the cyclodextrin cavity. All calculated values are in good agreement with experimental data. The prepa-ration of supramolecular complexes has been proven using a variety of physicochemical methods of analysis. According to DSC data, the process of complexes destruction in the temperature range of 30-610°C was studied in comparison with the data of the initial cyclodextrin. The hemorheological effects of the investigated samples were studied in vitro. Among four samples studied, two samples showed the ability to reduce blood viscosity in vitro in the blood hyperviscosity model.

Laboratory investigation of the spontaneous combustion characteristics and mechanisms of typical vegetable oils

To effectively prevent and control the autoignition of vegetable oil, the spontaneous combustion characteristics and oxidation mechanisms of three typical vegetable oils were investigated. Microcal, TG-DSC, Raman spectroscopy and GC-MS were used to analyze the self-ignition characteristics of the samples at both macro- and micro-scales. The results showed that the initial exothermic temperatures were between 65 and 90 °C, after which vigorous oxidation began to release abundant heat. DSC data showed that the entire combustion process of the samples includes 4 typical stages: low-temperature oxidation stage, thermal decomposition stage, combustion stage, and after-combustion stage. The activation energy of the low-temperature oxidation stage reached as low as 33.13 kJ/mol, indicating that the vegetable oil is extremely prone to self-oxidation even when the temperature <200 °C. And the self-ignition tendency was in the order linseed oil > perilla seed oil > safflower seed oil. Based on analysis of the organic molecular structures, it was found that the unsaturated groups in vegetable oil are responsible for its autoignition behavior. Taking linseed oil as an example, 3 peroxide intermediates, namely 10,12-Octadecadienoicacid,9-hydroperoxy-, (10E,12Z)-;9,11-Octadecadienoicacid, 13-hydroperoxy-, (9Z,11E, 13S)-, and 9-Octadecenoic acid, 13-hydroperoxy-, (Z)-(8CI, 9CI) were marked as significant indicators to trace the low temperature oxidation reaction path of the oil samples.

Determination of the Degree of Crystallinity of Poly(2-methyl-2-oxazoline).

A new method for purification of 2-methyl-2-oxazoline using citric acid was developed and living cationic ring-opening polymerization of 2-methyl-2-oxazoline was carried out. Polymerization was conducted in acetonitrile using benzyl chloride—boron trifluoride etherate initiating system. According to DSC data, the temperature range of melting of the crystalline phase of the resulting polymer was 95–180 °C. According to small-angle X-ray scattering and wide-angle X-ray diffraction data, the degree of crystallinity of the polymer was 12%. Upon cooling of the polymer melt, the polymer became amorphous. Using thermogravimetric analysis, it was found that the thermal destruction of poly(2-methyl-2-oxazoline) started above 209 °C.

Fabrication of three-dimensional-printed ofloxacin gastric floating sustained-release tablets with different structures

The objective of this study was to develop a novel ofloxacin gastric floating system with different internal structures by paste extrusion printing and to explore the relationship between tablets with different structures and the release behavior and floating time. The gastric floating sustained release tablets consisted of conventional sustained release pharmaceutical excipients without the addition of foaming agent or light materials. First, the proper alcohol/water proportion was determined for the binding agent. The desired drug release behavior was obtained through modification of the composition of the formulation. In vitro, printed tablets with different structures were evaluated based on drug release, lag time, and floating duration time. Analysis of the floating state data revealed that different internal structures have a significant effect on the floating time. Analysis of the dissolution data of these tablets reveals that the release behavior and release mechanism of tablets with different structures are very similar. DSC, XRD and FTIR data reveal that the drug still exists in crystalline form and that no obvious interaction occurs between the drug and excipients. All these results showed that 3D printing offers unique advantages for the generation of gastric floating preparations, and this method can adjust the floating time without altering the release behavior.

Thermodynamic data of belite polymorphs

One major component of Portland cement clinker is Ca2SiO4 (C2S, belite). Synthetic samples of three polymorphs, β-C2S (larnite), γ-C2S (calcio olivine), and x-C2S were investigated by high-temperature oxide melt solution calorimetry at 700 °C to obtain their enthalpies of formation. A natural sample of wollastonite (CaSiO3) was measured for comparison. Low-temperature heat capacity data of the C2S phases were recorded by relaxation calorimetry using a PPMS. Supplementary DSC data of β- and γ-C2S were obtained to verify their heat capacity evolution to 400 °C.The recommended values for β-C2S and γ-C2S are:ΔfH0298γ−C2S = −2316.0 ± 4.5 kJ mol−1, S0298γ−C2S = 119.7 ± 0.9 J mol−1 K−1,CP(γ-C2S) = (249.098 − 1949.5 T–0.5 – 1.60822 ∙ 106 T−2 + 2.77532 ∙ 108 T−3) J K−1 mol−1, [T] = K,ΔfH0298β−C2S = −2307.6 ± 4.5 kJ mol−1, S0298β−C2S = 122.2 ± 0.9 J mol−1 K−1, andCP(β-C2S) = (259.721 − 2466.09 T–0.5 + 2.62687 ∙ 106 T−2 – 4.77891 ∙ 108 T−3) J K−1 mol−1, [T] = K.

Thermogravimetric parameters of the oxidation of organic matter and asphaltenes from the rocks of the Permian deposits of heavy oil field before and after catalytic hydrothermal treatment

In this work, on the example of rock samples from Permian deposits of the heavy oil field from the depth interval 117.5–188.6 m, a comprehensive study of the composition of oil-saturated rocks, as well as thermogravimetric parameters and kinetics of oxidation of organic matter (OM) and extracted asphaltenes before and after catalytic hydrothermal treatment was carried out of the rocks. It was shown that rocks with different mineral composition, OM content, and group composition of oil extracts also have different quantitative characteristics of the thermal effect in the processes of OM oxidation. According to the DSC data in the range of 20–600 °C in air atmosphere, several exothermic effects of chemical reactions of OM at stages low-temperature (LTO) and high temperature oxidation (HTO) oxidation were fixed indicating various destructive processes. By the TG/DTG method was shown that asphaltenes, regardless of the chemical nature of OM, have a similar and almost identical set of mass loss peaks. Catalytic hydrothermal treatment of the rock samples at 300 °C in CO2 media in the presence of a catalytic composition based on transition metal carboxylates (Fe, Co and Cu) led to a significant increase in the content of saturated and aromatic hydrocarbons in produced oil extracts due to the intense destruction of resins and asphaltenes. The presence of the catalyst composition in the reaction system leads to a decrease in the initial temperature of asphaltenes oxidation by almost 10 °C, as well as to a decrease in the activation energy by more than 1.5 times as compared to asphaltenes from the original rock. The research results show that the use of thermal and catalytic methods is promising for the successful implementation of the residual oil-bearing potential of productive strata of the Permian deposits of Tatarstan.

Folding Free Energy Surfaces from Differential Scanning Calorimetry.

Protein folding/unfolding processes involve a large number of weak, non-covalent interactions and are more appropriately described in terms of the movement of a point representing protein conformation in a plot of internal free energy versus conformational degrees of freedom. While these energy landscapes have an astronomically large number of dimensions, it has been shown that many relevant aspects of protein folding can be understood in terms of their projections onto a few relevant coordinates. Remarkably, such low-dimensional free energy surfaces can be obtained from experimental DSC data using suitable analytical models. Here, we describe the experimental procedures to be used to obtain the high-quality DSC data that are required for free-energy surface analysis.

Physico-Chemical Properties of NaV3O8 Prepared by Solid-State Reaction.

Sodium–vanadium oxide NaV3O8 is synthesized via solid-state method and optimum synthesis conditions are chosen based on the data of DSC and TG analysis. The material synthesized is characterized by X-ray phase analysis, Raman spectroscopy and scanning electron microscopy. The ratio V4+/V5+ in the sample obtained is determined by X-ray photoelectron spectroscopy. Conductivity of the material synthesized was measured by impedance spectroscopy, pulse potentiometry and DC method over the range RT–570 °C. It is shown that NaV3O8 has rather high conductivity essentially electron in type (6.3 × 10−2 at room temperature). AC and DC conductivity measurements are performed and cycling of symmetricNaV3O8|Na3.85Zr1.85Nb0.15Si3O12|NaV3O8 cell in galvanostatic conditions. Thermal stability is studied across 25–570 °C temperature range. The results obtained are compared with the properties of NaV3O8 produced via aqueous solution.

Green and efficient in-situ biosynthesis of antioxidant and antibacterial bacterial cellulose using wine pomace

Biologically active bacterial cellulose (BC) was efficiently synthesized in situ using wine pomace and its hydrolysate. The structural and biomechanical properties together with the biological functions of the BC were investigated. Functional BC from wine pomace and its enzymatic hydrolysate were of high purity and had higher crystallinity indexes (90.61% and 89.88%, respectively) than that from HS medium (82.26%). FTIR results proved the in-situ bindings of polyphenols to the functionalized BC. Compared to BC from HS medium, wine pomace-based BC had more densely packed ultrafine fibrils, higher diameter range distributions of fiber ribbon, but lower thermal decomposition temperatures, as revealed by the SEM micrographs and DSC data. Meanwhile, wine pomace-based BC exhibited higher loads in tensile strength and higher hardness (4.95 ± 0.31 N and 5.13 ± 0.63 N, respectively) than BC in HS medium (3.43 ± 0.14 N). Furthermore, BC synthesized from wine pomace hydrolysate exhibited a slower release rate of phenolic compounds, and possessed more antioxidant activities and better bacteriostatic effects than BC from wine pomace. These results demonstrate that BC synthesized in situ from wine pomace (especially from enzymatic hydrolysate) is a promising biomolecule with a potential application in wound dressing, tissue engineering, and other biomedical fields.

Influence of Ca/Al ratio on physical and dielectric properties of Al2O3/CaO-B2O3-SiO2 glass-ceramics composite coatings prepared by high enthalpy atmospheric plasma spraying

The dielectric layer plays a key role in regulating electromagnetic wave broadband scattering based on meta-surface technology. Herein, the physical properties of composite powder, prepared by spray drying of CaO-B2O3-SiO2 (CBS) glass-ceramic powder and Al2O3 in different mass ratios, are systematically investigated. Meanwhile, a high enthalpy atmospheric plasma spraying equipment is utilized to prepare CBS/Al2O3 composite coatings, and the morphology, physical properties and dielectric properties of the composite coating are analyzed. The XRD and DSC data of the composite coating reveal that the crystallization behavior of β-CaSiO3 and CaB2O4 gradually disappear with the increase of Al2O3 content. Hence, only CaAl2Si2O8 phase is observed during heat treatment. The experimental results confirm that the dielectric properties of CBS/Al2O3 composite coating conform to the rule of mixture for composite materials. Also, the dielectric properties are affected by porosity and crystallization rate.