Guangdong University of Technology

Dongguan South China Design and Innovation Inst.

Shanghua Wu

Chengyong Wang

Qimin Wang

Bo Wang

Wei Liu

Shangxian Gu

Ying Long

Qiangguo Jiang

Maopeng Zhou

Weiming Guo

Lixia Cheng

The invention proposed a novel hot pressing flowing sintering method to fabricate textured ceramics. The perfectly 2-dimensional textured Si3N4 ceramics (Lotgering orientation factor fL 0.9975) were fabricated by this method. During the initial sintering stage, the specimen flowed along the plane which is perpendicular to the hot pressing direction under pressure, through the controlling of the graphite die movement. The rod-like &#x3b2;-Si3N4 nuclei was easily to texture during the flowing process, due to the small size of the &#x3b2;-Si3N4 nuclei and the high porosity of the flowing specimen. After aligned, the &#x3b2;-Si3N4 grains grew along the materials flowing direction with little constraint. textured Si3N4 ceramics fabricated by this invention also showed high aspect ratio. Compared to the conventional hot-forging technique which contained the sintering and forging processes, hot pressing flowing sintering proposed is simpler and lower cost to fabricate textured Si3N4.

Method of making textured ceramics

The present invention provides an AlOcoated SiNcutting tool comprising a SiNbased substrate body and a coating layer on the substrate body, wherein the coating layer has at least one AlOcoating layer consisting of amorphous AlOor nanocrystalline &#x3b1;-, &#x3b3;-, or &#x3ba;-AlO. The hard and wear resistant refractory coating is deposited onto the SiN-based substrate body by reactive sputtering using bipolar pulsed DMS technique or dual magnetron sputtering method at substrate temperatures of 300-700&#xb0; C. During the deposition, preferably, the substrate temperature is controlled to achieve the desired crystal structure of the coating. To form amorphous AlOcoating on the surface of the substrates, the deposition temperature can be controlled from 300 to 500&#xb0; C.; on the other hand, to form nanocrystalline &#x3b1;-, &#x3b3;-, or &#x3ba;-AlO, the deposition temperature can be controlled in the range of 500-700&#xb0; C. The coated cutting tools of the present invention are suitable for high-speed machining of metals by turning, milling, drilling or by other similar chip-forming machining methods.

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Growing community of inventors

Dongguan, China

Shanghua Wu