Two different chemical processing routes were successfully used for the fabrication of lithium aluminosilicate (LAS) specimens having dense and homogeneous microstructure with an essentially pore-free state. These are (i) sol-gel route using the hydrolysis-condensation reaction of metal alkoxides and (ii) mixed colloidal processing route. Lowering Li content in the sol-gel-derived LAS significantly enhanced densification and retarded the crystallization. The β-spodumene (∼0.8 μm) seeding in the sol-gel-derived LAS modified the sequence of phase transformations and lowered the crystallization temperature by 120 °C. Therefore, combining the epitaxial seeding with the sol-gel process, one can bring down the crystallization temperature to the sintering temperature range (∼800 °C). Similarly, the LAS gel prepared by the mixed colloidal processing route exhibited a noticeable shrinkage over a broad temperature range (600–950 °C) and produced a dense sintered body with an essentially pore-free microstructure.

Cordierite gel powder prepared by the hydrolysis of an alkoxide complex was seeded with crystalline α-cordierite particles. The effects of seeding on the phase transformation and mechanical properties were studied. The unseeded cordierite gel powder crystallized into α-cordierite via μ-cordierite at 1050 °C. The μ-α cordierite transformation caused microcracks which led to poor flexural strengths of about 30 MPa, although the strength of μ-cordierite was 160 MPa. The seeding appeared to promote a direct formation of the α-cordierite from the amorphous state. The development of microcracks due to μ-α cordierite transformation could be prevented by the modified crystallization behavior, resulting in the improved flexural strength of α-cordierite of 190 MPa. The seeding also lowered the crystallization temperature of α-cordierite to 900 °C, which could be attributed to the epitaxial crystallization of the complex-alkoxide-derived cordierite gel powder.

The first suspensions of rod-shaped dielectric particles in an infrared transmitting solvent are reported. Specifically, micron size β–FeOOH rods have been produced in chloroform, carbon tetrachloride, and carbon disulfide. A technique to transfer the particles from water into organic solvents is demonstrated and a novel optical method to determine the degree of stability of the organosols is used. Sedimentation times vary with preparation technique over the range of minutes to hours, often being long enough to allow the use of the material as an infrared Kerr medium with large electric field induced birefringence. Dispersions in hexane, which has good microwave transmission, have also been produced.

Ultrasonic energy was used to accelerate the formation of hydroxyapatite (HAp). The experiments were carried out in aqueous systems on two different sets of reactants: (1) a mixture of Ca4(PO4)2O(TetCP) and CaHPO4 · 2H2O (brushite) and (2) α–Ca3(PO4)2 (α–TCP). The reaction systems were exposed to ultrasound of 20 kHz for various times ranging from 5 to 80 min. The products were characterized by XRD and SEM. Parallel experiments without ultrasound were carried out for calibration. The results show that the ultrasound substantially accelerates both reactions. With ultrasound, the time required for the TetCP-brushite system to complete the reaction forming HAp was reduced from 9 h to 25 min at 25 °C, and from 3 h to 15 min at 38 °C. At 87 °C, α–TCP does not hydrolyze within 1 h in de-ionized water unless the pH is adjusted. Hydrolysis of α–TCP was induced by sonication in less than 20 min, and longer treatment results in the formation of a homogeneous sol of HAp.