Systematic study is made of the key factors (precipitant moisture)affecting the preparation of ultrafine zirconia.The experiments have showed that pH value of the reaction system,seed crystal,disperser etc.are critical to the water content in precipitant and also to the various properties of zirconia.

ATO nanometer-sized Zr-doped powder has been prepared by a sol-gel method.Analysis and comparison is made of the powder with or without Zr in respect of the resistivity,particle size,specific surface area.Results show that Zr-doped powder is characterized by larger resistivity,remarkably smaller particle size and less agglomerationIn the permissible range of electrical property character,proper Zr doping can reduce the particle size.The calculation results have shown that some aggregate remains in the powder,as is to be further studied for the solution.

Study is made of the effect of rolling temperature and single-pass deformation rate on Kovar/Cu/Kovar laminates . The results show that Kovar/Cu/Kovar electronic packaging material has good interfacial combination strength with acceptable resistivity and high tensile strength at 800℃ and 50% single-pass deformation rate.

Based on differential thermal analysis(DTA),metallurgical structure observation.cold tensile test, optical microscope and scanning electron microscope(SEM) observation, analysis is made of the effect of different solid-solution processes on the microstructure and mechanical properties of high-Zn Al-10.4%Zn-2.2%Cu-2.4%Mg-0.1～0.15Zr-0.224%Ag alloy.The results show that the use of intensified solid solution process at almost low-melting-point eutectic fusion temperature and single-stage ageing can result in remarkably better mechanical property than that by single-stage solid solution and low-temperature intensified solid solution with tensile strength>770Mpa and about 8% to 10% elongation.Compared with other domestic 7000-series alloy,it has super-high strength and good plasticity, indicating that proper solid solution process can result in good coordination of the strength and plasticity in the highly-alloyed super-high-strength Al alloy.However,the SEM observation shows that certain number of coarse second phase particles remained in the solution structure,as will bring about negative impact on the overall properties of the alloy . Thus,further optimization is to be done on the solid solution.

The trend of research and development of Kennametal's new cemented carbide products is described,and some of Kennametal's latest products are presented.

This article describes the situation in the recent years of extraction and stripping technology and equipment in hydrometallurgy of Ta & Nb in China,focusing on description of the latest development and techno-economic data in HF-H2SO4-Octanol-2 extraction-stripping system as well as the existing technical problems,related measures and ideas for the improvement and solution.

Description is made of a new environmentally- acceptable process for regeneration of cemented carbide scraps developed by professor V.P.Bondarenko research group of Institute for Super-hard Materials of the National Academy of Sciences of Ukraine.The process is based on cemented carbide scraps as raw material in the steps as follows:oxidation,crushing-mixture gas-phase reduction-carbonization to obtain carbon-controlled regenerated cemented carbide, followed by pressing,CH4 and H2 mixed gas low-temperature sintering and high-temperature gas-phase sintering to produce regenerated cemented carbide, whose property conforms with Ukraine State Standard 3882-74.

The paper describes the new developments of producing high purity indium by vacuum distillation and thin layer fused salt electrolysis refining,as well as production of high purity metallic indium powder via disproportioning indium monoxide in aqueous medium.

In the paper is reviewed the study of strength and structure of WC-Co hard alloy. It indicated that WC-Co hard alloy is characteristic of particle compound reinforcing material,based on which investigation is made into the microstructure and preparation technology of the said alloy.