Oxidation resistance of β-Sialon/TiN composites: an ion beam analysis (IBA) study

The oxidation resistance of β-Sialon processed with Y₂O₃ sintering additive and β-Sialon/TiN composites containing 1–10 wt% TiN was studied using ion beam analysis (IBA) techniques, augmented by XRD and SEM measurements. Rutherford backscattering spectrometry was used to monitor the diffusion of Y and Ti in the oxidised samples, and the diffusion of oxygen and nitrogen was observed by particle-induced gamma emission and nuclear reaction analysis. These techniques showed that in the Sialon control sample without TiN, oxygen was the first element to migrate at 1000 °C, followed by Y and N at 1100 °C. At 1200 °C, a N-poor, Y- and O-rich oxidised layer was formed, containing crystalline Y₂Si₂O₇. In the TiN-containing samples, Si, Al, Y and Ti were very mobile even at 1000 °C and the surface nitrogen was depleted by 1250 °C. The combined presence of yttrium aluminium garnet (YAG) and TiN protects the β-Sialon phase by forming an oxygen-rich crystalline barrier layer. The oxidation products of TiN in these composites are TiO₂ and Y₂Ti₂O_7. The details of the oxidation mechanism of the β-Sialon/TiN composites provided by these IBA studies (movement of yttrium and titanium, replacement of nitrogen by oxygen in the glassy yttrium phase and major crystalline and chemical changes in an outer oxidised layer) could not readily have been obtained by any other techniques, and illustrate the value of IBA for oxidation studies of non-oxide ceramics.     

Investigating the effect of SiO2–TiO2–CaO–Na2O–ZnO bioactive glass doped hydroxyapatite: characterisation and structural evaluation

The effects of increasing bioactive glass additions, SiO₂–TiO₂–CaO–Na₂O–ZnO up to 25 wt% in increments of 5 wt%, on the physical and mechanical properties of hydroxyapatite (HA) sintered at 900, 1000, 1100 and 1200 °C for 2 h was investigated. Increasing both the glass content and the temperature resulted in increased HA decomposition. This resulted in the formation of a number of bioactive phases. However the presence of the liquidus glass phase did not result in increased densification levels. At 1000 and 1100 °C the additions of 5 wt% glass resulted in a decrease in density which never recovered with increasing glass content. At 1200 °C a cyclic pattern resulted from increasing glass content. There was no direct relationship between strength and density with all samples experiencing no change or a decrease in strength with increasing glass content. Weibull statistics displayed no pattern with increasing glass content.     

Preparation and characterization of precursor powders for yttria-doped tetragonal zirconia polycrystals (Y-TZP) and Y-TZP-Al2O3 composites

Precursor powders for the preparation of tetragonal 2.5 mol% Y₂O₃-ZrO₂ containing 0 to 30 wt% Al₂O₃ were made by coprecipitation. The behaviour of this powder during calcination from room temperature to 1200° C was studied using differential thermal analysis. X-ray diffraction and transmission electron microscopy methods, and measurements of surface area. The uncalcined powder was essentially amorphous. On heating alumina-free powder, zirconia crystallized at 485° C: for increasing alumina content, zirconia crystallized from an amorphous aluminous matrix at increasing temperatures (850° C for 20 wt% Al₂O₃), while the crystallite size decreased and the surface area of the powder increased. The zirconia first crystallized as cubic, but transformed to the tetragonal form near 1100° C. The alumina crystallized as corundum at 1200° C. No monoclinic zirconia could be detected when calcined aluminous material was cooled to room temperature. The sintering behaviour of the calcined powder is discussed.     

Hot-pressed hydroxylapatite/monoclinic zirconia composites with improved mechanical properties

Composites of hydroxylapatite (HA) and monoclinic zirconia were hot-pressed at 1100 °C and 1200 °C under vacuum to study the phase transformations and the mechanical properties. X-ray diffraction results showed a higher phase transformation from monoclinic-ZrO₂ to tetragonal-ZrO₂ when the sintering temperature increased from 1100 °C to 1200 °C. HA decomposed faster when the amount of ZrO₂ in the composites increased. Moreover, small amount of α-TCP and CaZrO₃ was observed in the composites hot-pressed at 1200 °C. Hot-pressing at 1100 °C resulted in better mechanical properties than the hot-pressing at 1200 °C because of less reaction between HA and zirconia at 1100 °C. 40 wt% monoclinic zirconia and HA composite hot-pressed at 1100 °C resulted in promising mechanical properties which are 6.5 GPa of Vickers μ-hardness, 2.23 MPa√m of fracture toughness, and 66 MPa of diametral strength.     

Creep and creep-fatigue behaviour of continuous fibre reinforced glass-ceramic matrix Composites

The flexural creep and creep strain recovery behaviour during creep-fatigue tests of a cross-ply SiC fibre reinforced Barium Magnesium Aluminosilicate glass-ceramic matrix composite was investigated at 1100°C in air. Only heat-treated samples (1 h at 1100°C) were tested. Stress levels of 90, 105 and 120 MPa were examined to produce low strains (?0.4”?). A continuously decreasing creep strain rate with values between 1.6 × 10^?6 s^?1 to 4.7 × 10^?8s^?i at 120 MPa was observed with no steady-state regime. Extensive viscous strain recovery was found upon the unloading period during the short-duration cyclic creep (creep-fatigue) experiments. The creep strain recovery was quantified using strain recovery ratios. These ratios showed a slight dependence on the stress and cyclic loading frequencies investigated. The crept composites retained their ?graceful”? fracture behaviour after testing indicating that no (or limited) damage in the matrix was induced during creep and creep-fatigue loading.     

Copper effects in mechanical,thermal and electrical properties of rapidly solidified eutectic Sn–Ag alloy

The Sn–3.5 wt%Ag alloy considered as a good alternative to Pb–Sn alloys. This study aims to investigate the effects of Cu or Sb additions by 3 or 5 wt% to melt-spun Sn–3.5%Ag alloy. Ternary melt-spun Sn–Ag–Cu and Sn–Ag–Sb alloys investigated using X-ray diffractions (XRD), Scanning electron microscope (SEM), Dynamic resonance technique (DRT), Instron machine, Vickers hardness tester and Differential scanning calorimetry (DSC). The results revealed that the microstructures of the β-Sn phase, Ag₃Sn and Cu₃Sn intermetallic compounds (IMCs) in the solder matrices were refined due to the effect of Cu additions and melt-spun process. Moreover, increasing Cu content promotes Ag₃Sn intermetallic compound (IMC) formation. Consequently, the addition of “3 wt%” of Cu reduced the creep rate ? from (3.79?×?10^?3) to (1.65?×?10^?3) and delayed the fracture point. The tensile results showed an improvement in Young’s modulus by 47% (30.3 GPa), ultimate tensile strength (UST) by 11.6% (23.9 MPa), and in toughness by 20.5% (952.32 J/m³) compared to the eutectic Sn–Ag alloy. Vickers hardness has improved by 3.3% (136.71 MPa) and thermal activation energy by 54% (90.40 KJ/mol) when compared with that of eutectic Sn–Ag alloy. Those improvements are related to the lack of lattice strain from 7.56?×?10^?4 without “3 wt%” of Cu to 5.26?×?10^?4 with “3 wt%” of Cu. Its melting temperature (T_m) increased by 3 °C due to Ag₃Sn IMC increased and Cu₃Sn formation, but the pasty rang (mushy zone) decreased by 4 °C with “3 wt%” of Cu. The small lattice strains resulted with “3 wt%” of Cu made the electrical resistivity of this alloy more stable at elevated temperatures. The mechanical, thermal and electrical improvements of Sn_93.5–Ag_3.5–Cu₃ alloy provide good physical performance for soldering process and electronic assembly.     

Reactive sintering and particle morphology control of β″-alumina-based water purification filters

This paper reports on the preparation of porous membranes consisting of plate-like β″-alumina grains and the evaluation for microfiltration properties. Porous β″-alumina-based ceramics were prepared by the solid-state reactive sintering of Na₂CO₃ and α-Al₂O₃ at 1100–1300 °C. To study the effect of impurities in the starting powder mixtures, LiF-doped membranes were also prepared. As for the water filtration test, the turbidity before and after the vacuum filtration was measured using sintered porous membranes. To simulate bacteria-contaminated water, a suspension of a commercial boehmite powder (D ₅₀ = 0.7 μm) in distilled water was used. The non-doped samples sintered at 1200 °C were composed of β″-alumina (84 wt%) and β-alumina (16 wt%) grains and showed a good microfiltration performance; the turbidities before and after filtration were 894.4 NTU and 1.46 NTU, respectively.     

Microstructure of sol–gel synthesized Al2O3–ZrO2(Y2O3) nano-composites studied by transmission electron microscopy

The Al₂O₃–ZrO₂(Y₂O₃) composite powder was synthesized through a sol–gel process using aluminum sec-butoxide and zirconium butoxide as precursors. The as-received powders in an amorphous phase were crystallized with c-ZrO₂ at around 980 °C. As the calcination temperature increased, the c-ZrO₂ crystalline phase was transformed to t-ZrO₂ at about 1200 °C. However, the Al₂O₃ phase in the Al₂O₃–ZrO₂(Y₂O₃) composite powders still existed in an amorphous phase up to 1050 °C. In the sintered body using the calcined powders at 400 °C, the Al₂O₃ phase was crystallized in an α-phase at 1200 °C during the sintering for 2 h. Using the sol–gel Al₂O₃–ZrO₂(Y₂O₃) powder, a typical nano-composite having a nano-crystalline phase (less than 20 nm) can be successfully obtained by a pressureless-sintering process even at 1200 °C for 2 h.Using the sol–gel Al₂O₃–ZrO₂(Y₂O₃) powder, a typical nano-composite having a nano-crystalline phase (less than 20 nm) can be successfully obtained by a pressureless-sintering process even at 1200 °C for 2 h. The values of relative density and Vickers hardness were comparatively high value with about 96.2% and 1100 Hv, respectively, even though it was made at low temperature. In the composite sintered at 1400 °C, the hardness value was saturated with 1570 Hv and the values of fracture toughness were almost same with about 6 MPa m^1/2.     

Effect of calcination temperature on structure and thermoelectric properties of CuAlO<Subscript>2</Subscript> powders

Copper aluminum oxide (CuAlO₂) with delafossite phase was synthesized by the Pechini method using different calcination temperatures to evaluate its influence on the structure and thermoelectric material properties. X-ray diffraction and Raman spectroscopy confirm that delafossite phase was formed at 1100 °C with the presence of 2H-CuAlO₂ and Al₂O₃ impurities, while at lower calcination temperatures (900 and 1000 °C), a mixture of CuO + CuAl₂O₄ (spinel phase) was observed. Energy-dispersive X-ray elemental maps display an even distribution of copper, aluminum and oxygen in the sample calcined at 1100 °C. Direct optical band gap, E _g = 3.6 eV, was calculated from reflectance diffuse spectra by Kubelka–Munk and Tauc methods. An absorption band at 1.7 eV accounts for defect levels, masking the characteristic indirect transition. The thermoelectric properties, such as Seebeck coefficient, and thermal and electrical conductivities of the sample calcined at 1100 °C were measured at different temperatures. Hall voltage and positive values of the Seebeck coefficient (425.8–434.4 µV K^?1) confirm the material’s p-type character. The independence of the Seebeck coefficient on the operation temperature indicates a small polaron electrical conduction mechanism. Thermal conductivity decreases exponentially with the temperature from 43.45 to 23.9 W m^?1 K^?1, where the principal contribution is due to phonons. Figure of merit ZT of sample calcined at 1100 °C between 100 and 800 °C increases from 1.42 × 10^?8 to 4.94 × 10^?4 in the order of the literature reports. From the Arrhenius plot ln(σT) versus 1000/T, an activation energy E _a = 0.32 eV for the electrical conductivity was calculated.     

Low indium content In–Zn–O system towards transparent conductive films: structure,properties and comparison with AZO and GZO

In this work, low content indium doped zinc oxide (IZO) thin films were deposited on glass substrates by RF magnetron sputtering using IZO ceramic targets with the In₂O₃ doping content of 2, 6, and 10 wt%, respectively. The influences of In₂O₃ doping content and substrate temperature on the structure and morphology, electrical and optical properties, and environmental stability of IZO thin films were investigated. It was found that the 6 wt% doped IZO thin film deposited at 150?°C exhibited the best crystal quality and the lowest resistivity of 9.87?×?10^?4 Ω cm. The corresponding Hall mobility and carrier densities were 9.20 cm² V^?1 s^?1 and 6.90?×?10²⁰ cm^?3, respectively. Compared with 2 wt% Al₂O₃ doped ZnO and 5 wt% Ga₂O₃ doped ZnO thin films, IZO thin film with the In₂O₃ doping content of 6 wt% featured the lowest surface roughness of 1.3 nm. It also showed the smallest degradation with the sheet resistance increased only about 4.4% at a temperature of 121?°C, a relative humidity of 97% for 30 h. IZO thin film with 6 wt% In₂O₃ doping also showed the smallest deterioration with the sheet resistance increased only about 2.8 times after heating at 500?°C for 30 min in air. The results suggested that low indium content doped ZnO thin films might meet practical requirement in environmental stability needed optoelectronic devices.     

Tubular alumina as a key component of new thermally stable ceramic materials

Using scanning electron microscopy and X-ray diffraction, we have examined processes that occur in tubular alumina during heating in air to temperatures in the range 1100–1200°C. The results demonstrate that, starting at temperatures between 600 and 700°C, α-Al₂O₃ (corundum) is formed in the solid material. Heating the tubular material to 1000°C converts some of the starting alumina into χ-Al₂O₃ and some into α-Al₂O₃. The samples calcined for 2–10 h at 1100°C contain α-Al₂O₃ and æ-Al₂O₃. Heating to 1000–1300°C has no effect on the shape of the tubular particles. The ceramics obtained in this way are stable in contact with water. When tubular alumina with a SiCl₄ vapor hydrolysis product deposited on its surface is heat-treated at temperatures in the range 1100–1300°C, we observe the formation of mullite (Al₂O₃ · 2SiO₂) on the surface of the tubular particles.     

The effect of Ni additions on the oxidation behaviour of Co–Re–Cr high-temperature alloys

Abstract

The present study focused on the influence of Ni on the microstructure and oxidation behaviour of Co–Re–Cr-based alloys. Alloys with three different Ni contents were tested in laboratory air at 800–1100 °C. A refinement and a reduction of the σ phase volume fraction as well as a change in the matrix microstructure were observed. Thermogravimetric measurements showed that the alloys with higher Ni contents possess a better oxidation resistance when exposed to higher temperatures. All alloys suffered from continuous mass loss during oxidation at 800 °C due to the formation of porous oxides scales, consisting of Co₃O₄, Co(Ni)O and Ni-doped CoCr₂O₄, which allow the evaporation of Re-oxides. At 900–1100 °C, only the alloy with 25 at. % Ni showed parabolic oxidation kinetics after a short period of transient oxidation. This is a result of the fast formation of a protective Cr₂O₃ layer. It was also found that exposure to air at 1000 °C leads to a phase transformation of the bulk material; an oxidation-induced formation of fine hexagonal close-packed (hcp) grains was observed near the oxide scales. It is supposed that the improved oxidation resistance of Ni-containing Co–Re–Cr alloys is a result of enhanced Cr diffusion caused by the Ni addition. The extensive formation of the fcc phase in the alloy matrix had a detrimental effect on the oxidation behaviour of the Ni-containing Co–Re–Cr-based alloys.     

Synthesis and characterization of borosilicate glass/β-spodumene/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> composites with low CTE value for LTCC applications

Glass?+?ceramic composites based on low-softening-point borosilicate (BS) glass, β-spodumene and Al₂O₃ were produced in this work. The influence of ceramic filler composition on the microstructure, sintering quality, mechanical properties, thermal properties and dielectric properties of composites were studied. XRD and DSC indicated that both kinds of ceramic filler as well as the BS glass maintained their characteristics after sintering. The addition of β-spodumene would decrease the coefficient of thermal expansion (CTE) value of composites to match with silicon well. The better wetting behavior between β-spodumene and BS glass would lead to better sintering quality, microstructure and dielectric properties for composites containing more β-spodumene. With appropriate Al₂O₃ content, the flexural strength of composites could be enhanced. Composite with 45 wt% BS glass, 30 wt% β-spodumene and 25 wt% Al₂O₃ sintered at 875 °C showed good properties which meet the requirements of low temperature co-fired ceramic applications: dense microstructure with high relative density of 96.27%, proper CTE value of 3.57 ppm/°C, high flexural strength of 156 MPa, low dielectric constant of 6.20 and low dielectric loss of 1.9?×?10^?3.     

Low temperature sintering and dielectric properties of Li2ZnTi3O8–TiO2 composite ceramics doped with CaO–B2O3–SiO2 glass

The effects of CaO–B₂O₃–SiO₂ (CBS) glass addition on the sintering temperature and dielectric properties of Li₂ZnTi₃O₈–TiO₂ (LZT) composite ceramics have been investigated. Due to the compensating effect of rutile TiO₂ (τ_f ≈ +450 ppm/ °C), the temperature coefficient of resonant frequency (τ_f) for Li₂ZnTi₃O₈ + 4 wt% TiO₂ with biphasic structure was adjusted to a value near zero. The pure LZT ceramics were usually sintered at high temperature of about 1,160 °C. It was found in our experiment that a small amount of CBS glass additives could effectively lower the sintering temperature of LZT ceramics to 900 °C. With increasing the content of CBS glass, both of dielectric constant (ε_r) and quality factor (Q × f) value decreased. Typically, the 1 wt% CBS glass added Li₂ZnTi₃O₈ + 4 wt% TiO₂ ceramic sintered at 900 °C for 4 h exhibited good microwave dielectric properties of ε_r = 26.9, Q × f = 23,563 GHz and τ_f = ?1.5 ppm/ °C, which made it promising for low temperature co-fired ceramics technology application.     

Pressureless sintering of Si3N4 with Y2O2 and Al2O3

Pressureless sintering of Si₃N₄ with Y₂O₃ and Al₂O₃ as additives was carried out at 1750°C in N₂ atmosphere. Si₃N₄ materials which had more than 92% relative density were obtained with 20wt% addition of additives. The flexural strength of as-sintered materials containing 5 to 8.6wt% Al₂O₃ and 15 to 11.4wt% Y₂O₃ was in the range of 480 to 560 MPa at room temperature. The glassy grain-boundary phase of as-sintered materials crystallized to 3Y₂O₃ · 5Al₂O₃ (YAG), Y₂O₃ · SiO₂ (YS), Y₂O₃ · 2SiO₂ (Y2S) and 10Y₂O₃ · 9SiO₂ sd Si₃N₄ (NA) by heat-treatment at 1250° C for 3 days. A specimen containing 15wt% Y₂O₃ and 5wt% Al₂O₃ sintered at 1750° C for 4 h was heat-treated at 1250° C for 3 days to precipitate YAG and YS. The nitrogen concentration of the grain-boundary glassy phase of the specimen was found to be very high, and therefore the flexural strength of the crystallized specimen scarcely decreased at elevated temperatures (the flexural strength of this specimen is 390 MPa at room temperature and 360 MPa at 1300° C). Resistance to oxidation at 1200° C of the specimen was good as well as the flexural strength, compared with that of as-sintered materials.     

Low temperature sintering and dielectric properties of Ba<Subscript>3</Subscript>(VO<Subscript>4</Subscript>)<Subscript>2</Subscript> microwave ceramics using Co<Subscript>2</Subscript>O<Subscript>3</Subscript> additives

The Ba₃(VO₄)₂–x wt% Co₂O₃ (x?=?0.5–5) ceramics were prepared by the solid state reaction method in order to reduce the sintering temperature. The effects of the Co₂O₃ additions on the phase composition, microstructures, sintering characteristics and microwave dielectric properties of Ba₃(VO₄)₂ ceramics are investigated by an X-ray diffractometer, a scanning electron microscope and a network analyzer. As a result, the Q?×?f value of 54,000 GH, the ε _r of 14.6 and the τ_f value of +58.5 ppm/°C were obtained in the sample of the Ba₃(VO₄)₂–3 wt% Co₂O₃ ceramic sintered at the temperature of 925 °C, which is capable to co-fire with electrode metal of high conductivity such as Ag (961 °C). Moreover, the Q?×?f values of the sample with Co₂O₃ higher than that of 3 wt% additions decreased because of the formation of Ba₂V₂O₇ phase.     

Low-temperature firing and microwave properties of TiO2 modified Li2ZnTi3O8 ceramics doped with B2O3

The low-temperature firing and microwave properties TiO₂ modified Li₂ZnTi₃O₈ ceramics with B₂O₃ addition have been developed. B₂O₃ addition could reduce the sintering temperature of Li₂ZnTi₃O₈ ceramics from 1,150 to 900 °C, which is attributed to the formation of liquid phases during the sintering process observed by SEM. The 1.5 wt% B₂O₃ doped Li₂ZnTi₃O₈ ceramics sintered at 900 °C have ε _r = 23.3, Q × f = 48,817 GHz, and resonant frequency τ _f  = ?15.35 × 10^?6/°C. Further, due to the compensating effect of rutile TiO₂ (τ_f  = 450 ppm/°C), the temperature coefficient of τ_f for with TiO₂ was adjusted to near zero value. The 1.5 wt% B₂O₃ doped Li₂ZnTi₃O₈ ceramics with 3 wt% TiO₂ dielectrics sintered at 900 °C exhibited the optimal microwave properties: ε_r = 25.9, Q × f = 46,487 GHz, and τ_f = ?0.35 ppm/°C.     

Phase formation and magnetic property evolution processes of the hexaferrite with composition BaO⋅0.9Sc<Subscript>2</Subscript>O<Subscript>3</Subscript>⋅5.1Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>

The phase formation and magnetic property evolution processes of the hexaferrite with composition BaO?0.9Sc₂O₃?5.1Fe₂O₃ have been investigated. Results show that when the calcination temperature is lower than 1000 °C, the spinel phase BaFe₂O₄ and M-type hexaferrite phase BaFe₁₂O₁₉ dominate. The M-type hexaferrite BaFe_12?xSc_xO₁₉ (0?<?x?≤?1.8) appears above 1050 °C and becomes a single phase BaFe_10.2Sc_1.8O₁₉ above 1200 °C. A two-step decrease of both the coercivity and remanence ratio is observed above 1050 °C, which agrees well with the appearance of soft magnetic phase BaFe_12?xSc_xO₁₉ (0?<?x?≤?1.8). The saturation magnetization of the sample increases with calcination temperature until 1100 °C and then decreases. Raman spectra results show that the above magnetic property evolutions can be explained by a temperature dependent incorporation of Sc³⁺ into the lattice sites nearby the magnetic blocks’ interfaces. This weakens the local magnetic exchange interactions between Fe³⁺ and thus leads to a change in the magnetic structure.     

Effect of sintering temperatures on properties of BaO–B<Subscript>2</Subscript>O<Subscript>3</Subscript>–SiO<Subscript>2</Subscript>–Al<Subscript>2</Subscript>O<Subscript>3</Subscript> glass/silica composites for CBGA package

BaO–B₂O₃–SiO₂–Al₂O₃ (BBSA) glass/silica composites synthesized by solid-state reaction method were developed for CBGA packages, and the effects of sintering temperature (900–950 °C) on the phase transformation, microstructure, thermal, mechanical and electrical properties were investigated. XRD results show that the major phases quartz and cristobalite, and the minor phase BaSi₂O₅ are detected in BBSA composites. Furthermore, it was found that the quartz phase transforms to cristobalite phase at 930–940 °C. The formation of cristobalite phase with higher coefficient of thermal expansion (CTE) led to the increase of CTE value of BBSA composites. However, excessive cristobalite phase content would degrade the mechanical properties and the linearity of thermal expansion of the ceramics. BBSA composites sintered at 920 °C exhibited excellent properties: low dielectric constant and loss (ε_r = 6.2, tanδ = 10^?4 at 1 MHz), high bending strength (179 MPa), high CTE (12.19 ppm/°C) as well as superior linearity of the thermal expansion.     

Effects of MgO on properties of Li2O–Al2O3–SiO2 glass–ceramics for LTCC applications

Li₂O–Al₂O₃–SiO₂ (LAS) glass–ceramics for low temperature co-fired ceramics (LTCC) application were prepared by melting method, and the effects of MgO on the sinterability, microstructure, dielectric property, thermal expansion coefficient (CTE) and mechanical character of this glass–ceramics have been studied. The X-ray diffraction images represent that the main phase is β-spodumene solid solutions. And some ZrO₂ and CaMgSi₂O₆ phases in LAS glass–ceramics are detected. The LAS glass–ceramics without additive (MgO) sintered at 800° had the dielectric properties: dielectric constant (ε_r) of 5.3, dielectric loss (tanδ) of 2.97 × 10^?3 at 1 MHz, CTE value of 1.06 × 10^?6 K^?1, bulk density of 2.17 g/cm³, and flexural strength of 73 MPa. 5.5 wt% MgO-added LAS glass–ceramic achieves densification at 800° exhibited excellent properties: low dielectric constant and loss (ε_r = 7.1, tanδ = 2.02 × 10^?3 at 1 MHz), low CTE (2.89 × 10^?6 K^?1), bulk density = 2.65 g/cm³ as well as high flexural strength (145 MPa). The results indicate that the addition of MgO is helpful to improve the dielectric and mechanical properties. The formation of CaMgSi₂O₆ crystal phase with higher CTE leads to the increase of CTE value of LAS glass–ceramics due to the increasing MgO content, and the increase of CTE is favourable for matching with silicon (3.1 × 10^?6 K^?1). The prepared LAS glass–ceramics have the potential for LTCC application.