The ultra-fine CeO2 precursor for optical glass polishing material was prepared by selective oxidation and precipitation, washing, drying and calcination from low-cerium complex rare earth chlorides solution with NH3.H2O as precipitator, air and H2O2 as oxidative agent.The effect of reaction conditions and feeding mode on the content of CeO2 in precursor,and the correlativity between calcination temperature and particle size,specific surface area and mineralogical composition of precursor powder were investigated.The results show that by forward dripping, pH value controlled within 4.5 and 5.5,Ce3+ can be oxidized into Ce4+ to form hydroxide precipitant,followed by separation with other RE ions the ultra-fine polishing powder and precipitation before calcinations at 600～700 ℃ to obtain ultra-fine CeO2 precursor with CeO2 content over 80%,median particle size D50 less than 1.5 μm.

A new type wearing-resistant alloy powder block was made from nano-structured WO3+C composite powder. Processing performance test is made for the analysis of surfacing layer structure,composition and hardness,etc.The results showed that the powder block has good welding processing performance,high deposition efficiency with tiny structure in the surfacing layer mainly containing W-enriched carbides of (Fe6W6C), acicular martensite and austenite.The hardness of the surfacing layer was over HRC60,max.HRC63.Compared to the micron powder,nano-powder block is characterized by higher W content in matrix,tiny structure,higher hardness,suitable for wearable surfacing.

Description is made of the theory and method of interfacial study between metal and ceramic,focusing on the interfacial structure?doping effect and active mechanism of various doping elements of Ti(C,N)-based cermet.Process for interfacial design and surface alloying is reported.

Failure analysis is made of cemented carbide die for drawing copper tube by scanning electron microscopy,etc.It was indicated that grain abrasion and adhesive abrasion were the main types of failure in the drawing die under boundary lubrication and dry friction.Based on the analysis of surface abrasion morphology and action of cyclic load and friction heat of the drawing die,theoretical analysis is made of its failure behavior.Based on the cause of the failures,exploratory suggestion is made for longer service life of the drawing die.

Study is made of the conditions for the determination of Ni in the reclaimed cemented carbide by atomic absorption.The results showed that the use of the operating conditions indicated in the paper can result in the 98%～105% measured recovery and relative inaccuracy ≤17%,the measured results basically conforming to the standard value.When Co content in the mixed material is ≤13%,Co will not interfere with the measurement,as can satisfy the production measurement.

In the paper is reviewed the applications of Cs in terms of photo-electric effect,energy conversion system, atomic clock, optical science, electronic parts and medicine and up-to-date extraction separation technology. Advantages and disadvantages of the said technology are investigated.

This is a brief review is made on preparation of bioceramic coatings on titanium and/or titanium alloys by cathodic electrodeposition.Some technical parameters are discussed,such as temperature,deposition time,pH of the electrolyte,current density as well as cathodic potential.Ideas are given on the future research.

s:The paper has reviewed present status of the surface metal coating technology of cermet particles.Discussions are made on the basic principles,effect and application of various methods.It is pointed out that chemical plating and fluidized- bed CVD are well established now.The future development of the technology is prospected.

This paper presents Zr-based amorphous alloys and their hydrogen absorption and desorption behavior.

The paper has reviewed the new developments and applications of tantalum and tantalum alloys in recent years, in respect of electronic industry,high-temperature alloys,weapon system,corrosion-resistant alloy and cladding material.It is pointed out that there will be large increase of Ta demand and sustained development of Ta application range.