A series of cerium-activated lutetium aluminum garnet (LuAG:Ce) phosphors were synthesized via a novel and fast microwave-induced solution combustion method. The influence of calcination temperature, metal ions/fuels ratio, content of active ions and LiF flux on microstructure, morphological feature and optical properties of prepared phosphors were investigated. The properties of phosphor samples were studied by means of X-ray diffraction technique, differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and photoluminescence spectroscopy. Single-phase cubic crystalline LuAG:Ce formed at around 900 °C. The emission spectra displayed a characteristic broad green-yellow band of Ce3+ ions in the range of 460–700 nm. The phosphors exhibited optimal luminescent properties when the fuels /metal ions molar ratio was 0.5. The quenching concentration of Ce3+ in prepared LuAG:Ce powders was 1.0 mol% and the emission spectra showed a red shift at higher Ce3+ concentrations. The results also revealed that an appropriate amount of LiF significantly intensified the luminescence of LuAG:Ce phosphors, and it reached the maximum at 3 wt%.

•High NIR reflective blue pigments were synthesized via sol–gel method.•The pigments have completely crystallized after calcined at 900 °C for 2 h.•The color of the Sr1−xEuxCuSi4O10+δ pigments changed from sky-blue to dark blue.•The developed pigments reached an optimal NIR solar reflectance of 72.31%.Environmentally benign near-infrared reflective blue pigments Sr1−xEuxCuSi4O10+δ (x ranges from 0 to 0.4) were synthesized via sol–gel method. The pigment samples were characterized by thermogravimetry and differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction technique, X-ray energy dispersive spectroscopy, scanning electron microscopy, UV–vis–NIR diffuse reflectance spectroscopy and the Commission Internationale de l’Eclairage 1976 L*a*b* colorimetric method. The prepared powders exhibited single-phase tetragonal crystalline structure. The color of the pigments changed from sky-blue to dark blue due to the substitution of Eu for Sr in SrCuSi4O10. With increasing Eu content, the near-infrared solar reflectance increased first and then declined. Adding specific amount of Eu can enhance the near-infrared reflectance and solar reflectance. The prepared pigments presented an optimum near-infrared solar reflectance of 72.31% when the doping content of Eu is 20 mol%.

Submicrometric TiB2 powders were synthesized by carbothermal reduction process using titanium dioxide, boron carbide and carbon black as the starting materials. The influence of different amount of boron carbide (22.0–26.8 wt%), calcination temperature (1400–1900 °C) and holding time (15–90 min) on the composition and microstructure of the product was investigated. The resultant powders were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Results showed that hexagonal impurity-free TiB2 crystalline powders with the grain size below 1.0 μm could be successfully prepared at 1600 °C for 30 min in Ar atmosphere when the amount of boron carbide was 25.3 wt%. The increase in temperature contributed to reaction completion and grain growth, but the abnormal grain growth and oversintering took place above 1800 °C.

To enhance the fracture toughness of pressureless-sintered SiC ceramic, graphene was introduced as an additive. The effects of graphene contents on the fracture toughness, bending strength, micro-hardness, phase compositions, and microstructure evolutions of the SiC ceramics were investigated in detail by scanning electron microscopy, energy dispersive X-ray spectroscopy, and metallographic microscopy. The fracture toughness, bending strength and micro-hardness increased initially, and then decreased with the graphene content increasing from 0 to 5.0 wt%. The highest fracture toughness of 5.65 MPa m1/2 was obtained for sample with 1.0 wt% graphene sintered at 2130 °C for 1 h in Ar, which was about 22.6% higher than that of SiC sample without graphene. In addition, the highest bending strength and micro-hardness of 434.14 MPa and 29.21 GPa corresponded to the SiC samples with graphene content of 0.5 wt% and 2.0 wt%, respectively.

In the present work, SiC ceramics was fabricated with AlN using B4C and C as sintering aids by a solid-state pressureless-sintered method. The effects of AlN contents on the densification, mechanical properties, phase compositions, and microstructure evolutions of as-obtained SiC ceramics were thoroughly investigated. AlN was found to promote further densification of the SiC ceramics due to its evaporation over 1800 °C, transportation, and solidification in the pores resulted from SiC grain coarsening. The highest relative density of 99.65% was achieved for SiC sample with 15.0 wt% AlN by the pressureless-sintered method at 2130 °C for 1 h in Ar atmosphere. Furthermore, the fracture mechanism for SiC ceramics containing AlN tended to transfer from single transgranular fracture mode to both transgranular fracture and intergranular fracture modes when the sample with 30.0 wt% AlN sintered at 1900 °C for 1 h in Ar. Also, SiC ceramics with 30.0 wt% AlN exhibited the highest fracture toughness of 5.23 MPa m1/2 when sintered at 1900 °C.

In the present work, nano-sized 10B-enriched boron carbide (B4C) powders were prepared by carbothermal process using 10B-enriched boric acid (H3BO3) and citric acid (C6H8O7·H2O) as raw materials, and the precursor was prepared by sol–gel method. In order to reduce the residual carbon in the final products, an effective decarbonization method was explored with a controlled final calcination technology. In the resultant B4C powders, the abundance of the 10B element was tested to be 57.50 % by ICP-MS. The microstructure and phase composition of the powders were characterized by SEM, TEM and XRD. X-ray pure B4C was obtained, and the particle size was estimated to be around 100 nm with a uniform distribution. The specific surface area of the powders tested by BET method was 38 m2/g.

•High NIR reflecting nano pigments Y6−xNdxMoO12 were synthesized by sol–gel.•The pigments crystallized completely at 900 °C with particle size less than 100 nm.•The doping of Nd3+ changed the pigments color from yellow to yellow-green.•The pigment Y5.2Nd0.8MoO12 exhibited the optimum NIR solar reflectance of 89.9%.High near-infrared reflecting nano pigments Y6−xNdxMoO12 (x ranges from 0 to 1.0) based on yttrium molybdate doped with Nd3+ were synthesized by sol–gel. The pigments samples were characterized by means of TG-DTA, FTIR, XRD, SEM, UV–vis–NIR spectrophotometer and CIE L∗a∗b∗ color measurement. The results showed that the pigments crystallized completely at 900 °C with particle size less than 100 nm. The substitution of Nd3+ for Y3+ in Y6MoO12 induced the absorption in the region of 585–605 nm and as a result the color changed from yellow to yellow-green. The near-infrared reflectance and solar reflectance increased first and then decreased with increasing Nd3+ content. When x = 0.8, the pigment exhibited an optimum NIR solar reflectance of 89.9%. The thermal and chemical stability of the pigments was also evaluated.

A dysprosium aluminum garnet (DAG) nanopowder was synthesized by aqueous sol–gel method using Al powder, HCl and Dy(CH3COO)3·4H2O as raw materials. The dried amorphous gel was heat treated in the range of 800–1,200 °C. The influence of heat treatment on crystallization and phase transformation of the dried gel was investigated using X-ray diffractometery, scanning electron microscopy, thermogravimetry and differential thermal analysis and Fourier transform infrared spectroscopy. It was shown that the gel calcined from 900 to 1,200 °C resulted in the formation of a crystalline DAG nanopowder with particle size distribution ranges from 26 to 98 nm.

Yttrium aluminum garnet (YAG) fiber was prepared by sol–gel method using water as the solvent. The spinnable YAG sol was synthesized using Al powder, Y(CH3COOH)3·4H2O and HCl as precursors, polyethylene oxide as viscosity adjusting agent. Gel fibers with diameter of 5–10 μm were prepared from the YAG sol by using centrifugal spinning technique. YAG crystalline fibers were obtained by drying gel fibers and heat-treating at selected temperature. TG/DTA analysis showed an exotherm at 906 °C attributed to formation of YAG phase and weight loss of 45% at 1000 °C. XRD and FT-IR analysis showed that phase-pure YAG can be formed at 900 °C, and no other intermediate was observed. The grain size of YAG fibers increased from 25 to 220 nm and tensile strength decreased rapidly from 970 to 380 MPa when the sintering temperature increased from 900 to 1550 °C.