National Science Council

National Science Council of R.o.c.

Nan-Chung Wu

Huei-Jung Wang

Sheng Shyan Yang

Ruey-Mo Lin

Shin-Gei Chen

Kuang-Hsing Liu

This patent application discloses a new process for preparing the sintered article of aluminum nitride at low temperature. It comprises coating aluminum metal film on aluminum nitride powder, then directly molding or homogeneously cold pressing, followed by sintering at 1650.about.175O.degree. C., and finally forming dense aluminum nitride article.

Sintering process for AIN powder coated with Al film

A process is provided for producing a bioceramic composite in which an alumina based ceramic substrate is coated with an intermediate calcium pyrophosphate layer to cement a porous calcium phosphate material to the alumina based ceramic substrate. In one aspect of the invention, the porous calcium phosphate material is a porous lattice made from natural bone. A bioceramic composite which includes an alumina-based ceramic substrate, an intermediate calcium pyrophosphate layer and a porous natural bone material bonded to the intermediate calcium pyrophosphate layer is also disclosed.

Process for producing a bioceramic composite material containing natural

Disclosed is a process for preparing Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2 ceramic sintered bodies. Lithium fluoride powder is added to a calcined Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2 powder prepared by sol-gel process as sintering agent. The resulting powder mixture is compressed into a molded article and sintered at a temperature of 950.degree.-1250.degree. C. to obtain the sintered bodies of the invention. The sintered bodies according to the present invention have a relative density of 97.9% and a thermal expansion coefficient of 10.sup.-7 /.degree.C. magnitude.

Process for the preparation of LAS ceramic sintered bodies

Disclosed is a process for producing an ultrafine powder of aluminum nitride. This process is characterized in adding 1-5 wt % of aluminum nitride powder to the mixture of alumina and carbon black and heating the resulting powder mixture at a temperature of 1550.degree.-1650.degree. C. in an atmosphere of nitrogen. Preferably, prior to heating, the powder mixture is shaped into a compact. The aluminum nitride powder prepared by the process of the present invention has an average particle diameter of about 0.45 micron and a purity of above 98.1%, and is therefore a very suitable material for making printed circuit boards and heat release boards for IC, LSI and VLSI.

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Tainan, Taiwan

Nan-Chung Wu